1941 Buick Limited Limousine

[Matt Harwood]

First off, @JohnD1956 nailed it--the whirring sound is the belt! I would never have expected that, but to test his theory I installed the old one and it sounded exactly the way it did last year when I thought the water pump bearing was going bad. So I installed a new water pump I didn't need, but it's all new so I never have to worry again. I reinstalled the new belt, which, while noisy, at least has a more pleasing sound--more of a supercharger whine than a bad bearing grind. I did some searching online to see if I could cross-reference the Gates belt from Bob's, but it appears that this toothed belt is the only one with the proper specs. My friend at the auto parts store actually found an old book that lists 1941 Buick Limited fan belt part numbers and found one in his system, so he ordered it. It will be a few days since it's coming from Arkansas, but we'll see what it looks like when it arrives. Oh, yeah, it's $50. Maybe I'll live with the sound. Either way, big thanks to John, who nailed the diagnosis from 500 miles away--nice!

 

Second thing I did was disassemble the choke on the rear carb and do some reading in the manual. it's a complex little mechanism that's more than just the thermostatic spring--there's a little piston in there that is supposed to be pulled into position by engine vacuum, and that's what provides the resistance for the spring to push against. As the spring relaxes, vacuum pulls the piston deeper into the port, exposing it to atmosphere and releasing pressure on the choke blade. You may recall I went in there once before, but after reading about a special tool that's used to set the piston position (which, of course, I don't have) I looked carefully at the diagrams and realized that I had it set in the wrong position--that's why it flooded and why it had a vacuum leak once it was up to temperature. I reset the piston's location relative to the choke blade shaft and not only did the choke relax faster but the vacuum leak disappeared. Hopefully I'll get one more cold day where I can leave it outside for a few hours and see if it's still difficult to start cold, but I am optimistic that I got it right this time. The front choke will be doing most of the heavy lifting now.

 

  
Position of the piston inside the choke housing is important (these photos are from the first
time I rebuilt it). Getting it right seemed to improve operation.

 

Once I had the choke set back where I believe it should be, I printed out the suggestions earlier in this thread from John and CarbKing and did some additional tinkering. I disconnected the linkage and tuned the two carbs separately by ear until I got a nice, smooth idle and a clean exhaust note. I ended up fattening the fuel curve quite a bit and then took a longish drive. The Big Guy drives like it always has and I now do not believe anything was seriously amiss with the tune--it just runs too well and pulls too hard to have any serious issues going on. The stumble remains, which I believe is an ignition issue (more on that in a moment).

 

Oh, and with the hood off, it's easy to see how much the engine moves around--I have some new engine mounts around here, so I guess I'll install those. And there's quite a bit of what appears to be steam coming out of the oil breather on top of the valve cover, mostly under load. It could be blow-by, but it's clean with no residue on the valve cover or splashed on the windshield. I'm thinking it's just moisture evaporating from the oil and I just never see it because the hood is there. My car does not have the recirculating tube from the valve cover to the air cleaner, so perhaps I'll drill a hole and add an EGR pipe when I pull the valve cover to adjust the valves.

 

Anyway, after the test drive, it was as hot as I could get it (it's about 50 degrees ambient and with the new cooling system--and no hood--it was running at 165 or so). I attached a vacuum gauge to the port on the intake manifold and did some additional tuning. I should have done this a year ago, but I was lazy. The engine has very good vacuum at idle and was able to get it to stabilize at about 24 inches of mercury with all four screws tweaked. The video below shows the process, which is simple: just turn the screws until you get maximum vacuum that's STABLE. I started with the rear carb and turned in one screw until it started to flutter, then backed it out again (making it richer) until vacuum reached its highest value and the needle was not wiggling. Repeat for the other screw, and then for the front carb. I didn't do any voice-over, but if you watch the gauge, you can see each of the four screws being adjusted in this brief video:

 

 

I still plan to use my friend's 5-gas analyzer as @edinmass suggested. I might even be able to find a dynamometer to use--I used to work for a dyno manufacturer and know a lot of the tuners who bought our equipment. That should give us an even clearer window into the tune, but I still have a few more details I want to address before we get to the final stage: new plugs, new ignition components, and resetting the timing to base. I set it to about 4 degrees advanced beyond factory spec a few years ago when I first started driving it and I've moved it around since then, so who knows where it is now. I believe the timing is the source of my low-speed stutter.

 

Today I used a vacuum pump to verify that the vacuum advance in the distributor was working correctly, which it is. I lubricated the various parts in there and the rotor, points, condenser, and cap all look fairly recent, but I have all new parts so I'll install those, set the point gap properly, reset the timing, and set the dwell before I do any more carb tuning. I'll also pull the plugs and give them a read, a job I'm loathe to do simply because getting the plug wires back behind that side cover is a real PITA. 

 

I was exhausted and I still feel pretty sick, but I was enjoying some success so I didn't want to stop tinkering. Last job was fixing the horns, whose wall-eyed orientation has always bugged me. I pulled them off and realized that whomever installed them didn't merely reverse them, he also changed the location of the mounting studs to get the horns to clear the fuel lines. I had to remove the domes and switch one of the mounting studs with one of the little studs that sandwiches the assembly together around the perimeter. Once I did that, the horn dropped into place and faced the right direction. I did the same for the other side. While I had the domes off, I sprayed the little electromagnet with some contact cleaner and blew it off with light compressed air. The wires were apparently custom-made to fit the horns in their walleyed orientation, so one was very long and one was almost too short once I reversed the horns, but with a little tweaking I was able to make them fit and not look too hokey. 

 

  
I had to swap the mounting stud and one of the little perimeter studs to get the horns
to face forward.

 

The horns were a little dirty inside, so I cleaned them up.

 

Reinstalled and facing forward, which also gives me a bit
more clearance for the fuel lines. No idea why
they didn't get it right the first time--its like swapping
them side-to-side didn't even occur to whomever was
installing the horns in the past...

 

Going to do some more driving, tackle the ignition system, and adjust the valves, maybe as soon as next week. I have a hunch it's going to be quiet around the shop for a while. I hope we can weather this storm--our overhead is substantial (I don't want to let my employees go) and it makes me very nervous. I don't think we can survive for more than a few weeks if people stop buying cars. Yeah, I'm worried.

 

I'm also exhausted. I think I'm going to get some dinner and go to bed. Maybe I'll be less worried when I'm not so tired.

 

 

Edited March 16, 2020 by Matt Harwood (see edit history)

[edinmass]

Matt, the hesitation you are talking about.......we call it “a tip in” hesitation, when applying the throttle. Check you accelerator pumps, that they are operating as intended. Also check float bowl levels. Sounds like you 95 percent of the way there already. I really enjoy the super fine dial in of any pre war car..........making them start and run like a modern fuel injected engine with 70 year old technology. Our most recent car we dialed in to the “100 percent” potential is a Model J. It actually starts better than my new Ford. It’s actually amazing how well it fires off...........Such a great feeling of accomplishment when the car is dialed in. 👍👍👍

[Matt Harwood]

28 minutes ago, edinmass said:

Matt, the hesitation you are talking about.......we call it “a tip in” hesitation, when applying the throttle. Check you accelerator pumps, that they are operating as intended. Also check float bowl levels. Sounds like you 95 percent of the way there already. I really enjoy the super fine dial in of any pre war car..........making them start and run like a modern fuel injected engine with 70 year old technology. Our most recent car we dialed in to the “100 percent” potential is a Model J. It actually starts better than my new Ford. It’s actually amazing how well it fires off...........Such a great feeling of accomplishment when the car is dialed in. 👍👍👍

 

It's not quite a tip-in hesitation--I know what you mean. It revs cleanly from idle or tipping into the throttle at speed. What I get is a stutter when, say, I go around a corner and leave it in 3rd or even if I drop down to 2nd. I can drive through it by giving it a lot of gas, but it's not a smooth transition. I don't know how else to describe it, but accelerating on a roll from closed throttle to half open causes it to buck somewhat. 

Great throttle response, but a bit of bucking under modest acceleration at low speeds. I'm still leaning towards too much ignition advance, which is why I needed to test the vacuum advance (which actually retards it at low engine speeds/high vacuum) and why I need to reset the timing. 

 

To be honest, this is the one drivability issue that bugs me the most. Of course, I still have a few rattles to solve, but that's an ongoing thing...

[Matt Harwood]

Went in to the shop to work today, feeling better but really tired. Both kids also sick now. School canceled for three weeks. Melanie stayed home with the boys today. Quiet, but we did get a few calls which makes me feel better. I need to sell some cars so we don't starve.

 

Anyway, on my way out the door this evening I walked past the Limited. I reached in and moved the throttle linkage to unload the chokes. The front one closed all the way while the rear one only closed about halfway. Reached in the window, turned the key, and pressed the button. Vroom! Started instantly and idled smoothly without any assistance from me. Temperature was about 55 degrees in the shop, so not very cold but cool enough. I'm hopeful that my choke adjustments have been successful in alleviating the hard start when [very] cold. One more really cold day and I'll park it outside for a few hours to really chill it and see what happens. 

 

Of note, the front choke did not reset to the highest part of the high idle cam, just the middle setting. I think that's probably acceptable. Easy enough to fatten it up if necessary.

 

I also realized that despite my attempts to build heat stoves into the headers, they don't really direct all that much heat to the chokes so they are very slow to respond. I had it idling for about 10 minutes and the front choke never opened fully and the rear choke didn't move at all. On the road and a hood in place, I still think it will be sufficient. 

Going to order a new valve cover gasket for adjusting the valves this weekend--there's a pretty persistent tap from cylinder #2 so an adjustment is a good idea. A few more upgrades and it'll be ready to tour as soon as tour season starts (whenever that might be) and then I can jump back on the Lincoln--still aiming for Hickory Corners in August for Lincoln's 100th birthday party.

[TexRiv_63]

Matt, I just discovered this thread and have read through page six since not much else is going on these days. Very impressed with your work and your unflinching coverage, I am subscribed.

[Matt Harwood]

Valve adjustment. I've never done it on this particular car and there was one valve that was notably louder than the others (turned out to be the intake on cylinder #1), so I figured I'd adjust them properly. The manual has good details, with the goal being .015" lash at operating temperature. Since it was 30 degrees outside today, I wasn't able to run it up to temperature on the road, so I left it idling for about 20 minutes at high idle and blocked off a portion of the radiator to get it really hot. Unfortunately, I blocked a little too much and had boiling Evapo-Rust spilling out the overflow and about 210 degrees showing on the gauge. Grrrr... I unblocked the radiator and it cooled off rapidly so at least I know the cooling system is healthy. On the upside, that probably got it hot enough for adjustment. 

 

I pulled the valve cover off and was happy to see that it was clean in there--plenty of evidence that it has been rebuilt in the not-too-distant past (seller advertised it as 5000 miles on a rebuild when I bought it). I hooked up a remote starter button so I could crank it over and get each cylinder's lifters on the cam's base circle to check clearance cylinder-by-cylinder. Leave the ignition off and disconnect the coil wire just to be safe. Connect the remote starter button to the battery + terminal and the rearmost wire terminal on the starter solenoid and it'll spin when you hit the button. 

 

Pulled the valve cover and side cover for access. Glad to see

the valvetrain was in good shape and everything was clean.

 

Using feeler gauges, check the clearance between the valve stem and the rocker arm. I used both .015" and .016" gauges as a go/no-go. The .015 should slide in but the .016 shouldn't or should be very tight. Reading the manual, however, it says that if it was started and warmed up in the shop without driving .018" go/.019 no-go is appropriate. I'm not sure I agree so I went .015/.016. I discovered that almost every valve was too tight, more like .011, so setting them to .015 should be an improvement and I didn't fret too much about getting it exact given what the manual said. I may check again in the summer when I have the opportunity to get it hot by driving.

 

Check clearance with a feeler gauge. Spec calls for .015 at

operating temperature.

 

Adjust rockers by loosening the 9/16 lock nut and set clearance
by screwing or unscrewing the set screw. Pay attention when
you tighten the lock nut as it will tend to move the screw. 

 

I fired it up once I had adjusted all the valves and #1 intake was still a little ticky. I slid the .015" feeler in there and there was proper clearance but as I did, it became silent. Hmmm, could it be too loose even at .015? I thought about tightening it up a bit, but we'll see how it sounds once I can warm it up on the road. I don't want to go tighter than factory spec at the moment. I also noticed while it was running that the pushrods rotate properly, but cylinder 6's exhaust pushrod was pumping more oil than the rest. I'm not quite sure how they're pressurized, but is this normal? I'm not terribly concerned (too much is better than too little) but it's quite a bit more than the others. Check it out:

 

 

With the side cover off I checked the port in the back of the head where the factory temperature gauge sender should live and discovered there's a plug, which is good news. Obviously someone knew it was broken and closed it off properly. That makes me think maybe I can remove the plug and install the aftermarket gauge sender there so I can connect my heater properly. It may require some modifications on the side cover to give some clearance for the capillary tube. Maybe not worth it, especially if I plan to install a correct factory temperature gauge eventually. I need to decide pretty soon because I think I'll refinish the side cover while I'm refinishing the valve cover (more on that in a moment). 

 

Temperature gauge port blocked off with what appears to
be an oil pan plug. Need to decide whether I want to use it for
a gauge or leave it alone for now...

 

And as many of you know, when you start a project, you don't sometimes know where it's going to lead. As long I had the valve cover off, I thought I would add the PCV tube to the air cleaner, which has been missing probably for decades. Driving around without a hood showed me that quite a bit of steam or smoke or something was venting from the breather cap, so the tube would be a good idea. Unfortunately, my valve cover is from a later car so it doesn't have provisions for the tube that goes to the air cleaner. I assumed it would be easy enough to drill a hole using a multi-bit to gradually enlarge the opening without tearing it up or distorting the metal.

 

Most dual-carb Buicks have this breather tube between the
valve cover and the air cleaner, which acts as a primitive
PCV valve. There was a TSB that involved removing it and
filling the holes with rubber plugs, plus adding the breather cap

(this car, with a breather cap and PCV is incorrect, the cap

should be flat).

 

Unfortunately, even though this valve cover has no vent, it does have the baffle inside. Does that seem odd? Or was that just how they were built and when they no longer needed the vent hole, they just didn't stamp it? Why install the baffle? Whatever the case, my idea to drill a hole became a little more complicated, since there's not enough clearance to run a multi-bit through there. And as I was looking at the valve cover, I realized it was pretty beat up with lots of old touch-ups. Should I repaint it as long as it's off? That would mean ordering some Dante Red spray paint and a fresh set of decals... But yeah, now is the time to do it right.

 

Here's what the inside of your valve cover looks like. The baffle
(arrow) vents to the breather tube. Why would this be on a
valve cover that doesn't have a hole for the tube?

 

Since my existing cover wasn't going to accommodate the vent tube, I pulled the NOS valve cover I had on the shelf and cleaned it up instead--it's a correct 1941 piece with the hole already in place. There's copper mesh in the baffle that helps act as a filter, and I presume that the fine oil mist in the valve cover keeps it saturated well enough to trap any dust that might be moving around. I put the valve cover in the blast cabinet to remove the ancient Dante Red paint that was clinging to it, but I taped off the vent on top and the baffle underneath so it didn't fill up with sand and dust.

 

  

Copper mesh inside the baffle helps trap debris that might

migrate into the air cleaner. 

 

  

Then I blasted it clean and primed it.

 

I have a new valve cover gasket (although I'm not happy with how it looked after I pulled it out of the package) and I'll order up some Dante Red spray paint and new decals for the valve cover. Another delay and a few bucks I don't want to spend right now, but as long as I've got it apart I may as well refinish it. Welcome to the world of old cars.

 

Valve cover gasket was a little spindled and mutilated after
being rolled up to fit in a box, but I think I can make it work
with some gasket shellac. 

 

Next up is prepping the side cover for paint and finding something to use as the PCV tube. Hopefully later this week...

[JohnD1956]

I thought the mesh was in there to trap the engine oil and drain it back into the engine.  Otherwise you'd be sucking engine oil up the tube and dropping it into the oil bath eventually over filling it.  But wasn't there a TSB that said to disconnect that tube?  I thought I read here that the tube didn't really work well and it was discontinued?  Maybe I have that wrong. 

[Matt Harwood]

45 minutes ago, JohnD1956 said:

I thought the mesh was in there to trap the engine oil and drain it back into the engine.  Otherwise you'd be sucking engine oil up the tube and dropping it into the oil bath eventually over filling it.  But wasn't there a TSB that said to disconnect that tube?  I thought I read here that the tube didn't really work well and it was discontinued?  Maybe I have that wrong. 

 

You're 100% right on the second count and on the first, your explanation makes sense so I'm inclined to agree that it probably does help keep oil from being sucked into the air cleaner. There was a TSB that was designed to address plug fouling, which they believed was due to this tube and oil was coking on the plugs. The TSB included rubber plugs for both the air cleaner and the valve cover plus a replacement vented breather cap so the crankcase pressure had someplace to go (most cars use this vented cap regardless of whether they have the tube, mine included). The correct cap to use with the vent tube (I'm trying to find one) is a flat one as shown below:

 

 

The TSB also included instructions for drilling out the 10mm spark plug holes for larger plugs. Yikes! Buick did discontinue the tube in late 1941 or early 1942--I actually have a dual carb air cleaner without any provisions for the tube (no hole). Personally, i think it's unlikely that a bit of oil mist being sucked into the carburetor could foul plugs so badly that the car wouldn't run properly, but i guess it's possible. It's been my experience that the dual carb setup gets blamed for all kinds of things that probably weren't its fault. 

 

As part of this round of tuning, I'm going to replace the spark plugs with a set that are one or two ranges hotter, as Ed Minnie suggests. I'll get a read on the old ones to further diagnose the exhaust temperature and mixture question, but plugs that are a little hotter can help prevent the fouling that the TSB tried to address. I may just throw the old valve cover on there so I can keep tuning while I restore the other one; I'd like to throw a timing light on it and set the dwell in the next few days...

[JohnD1956]

19 minutes ago, Matt Harwood said:

 

You're 100% right on the second count and on the first, your explanation makes sense so I'm inclined to agree that it probably does help keep oil from being sucked into the air cleaner. There was a TSB that was designed to address plug fouling, which they believed was due to this tube and oil was coking on the plugs. The TSB included rubber plugs for both the air cleaner and the valve cover plus a replacement vented breather cap so the crankcase pressure had someplace to go (most cars use this vented cap regardless of whether they have the tube, mine included). The correct cap to use with the vent tube (I'm trying to find one) is a flat one as shown below:

 

 

The TSB also included instructions for drilling out the 10mm spark plug holes for larger plugs. Yikes! Buick did discontinue the tube in late 1941 or early 1942--I actually have a dual carb air cleaner without any provisions for the tube (no hole). Personally, i think it's unlikely that a bit of oil mist being sucked into the carburetor could foul plugs so badly that the car wouldn't run properly, but i guess it's possible. It's been my experience that the dual carb setup gets blamed for all kinds of things that probably weren't its fault. 

 

As part of this round of tuning, I'm going to replace the spark plugs with a set that are one or two ranges hotter, as Ed Minnie suggests. I'll get a read on the old ones to further diagnose the exhaust temperature and mixture question, but plugs that are a little hotter can help prevent the fouling that the TSB tried to address. I may just throw the old valve cover on there so I can keep tuning while I restore the other one; I'd like to throw a timing light on it and set the dwell in the next few days...

 

Does you engine have the road draft tube?

 

[Matt Harwood]

13 minutes ago, JohnD1956 said:

 

Does you engine have the road draft tube?

 

 

No, none of my cars have ever had one. 1941s did not have the road draft tube. I don't recall whether dealers were supposed to install one when they removed the PCV tube and plugged the holes, but I doubt it given that the road draft tube was part of the pushrod cover. I don't believe road draft tubes were ever installed at the factory, although I have seen cars with them in place which I regard as incorrect. On the other hand, there are factory drawings of dual carb engines with road draft tubes and the breather cap, as well as drawings of engines without the road draft tube and the PCV tube to the air cleaner.

 

 

(*Note the oddball routing of the fuel line on this one, which is an illustration from the 1942 service manual)

 

I don't do judging but my opinion after living and breathing these cars for 20 years is that a majority of dual carb 1941 Buicks were delivered with the PCV tube and a flat oil cap, so that would be correct. The TSB with the retrofit of a vented cap and removal of the tube is probably also acceptable, but I don't know what the plugs are supposed to look like. The factory did eventually discontinue the PCV tube and eliminated the holes in the valve cover and air cleaner entirely, but I don't believe they added a road draft tube in production. The PCV tube AND a vented cap--like on my car currently--is wrong in any circumstance. I would probably dock a '41 with dual carbs for having a road draft tube, regardless of how the PCV was configured, but it is possible that single carb Specials might have had them. 

You could go crazy trying to figure out what the factory did and when. I didn't mind not having the tube but after I saw how much vapor was coming out of the breather at speed I decided rather than having it spraying on the valve cover it would be better to suck it back into the engine and burn it. I also kind of like the functional look. 

 

[neil morse]

Just to further muddy the waters, here's an excerpt from an article by Bill Anderson on the Buick Heritage Alliance webpage:

 

10 mm Spark Plugs

The 10 mm spark plugs introduced in 1941 frequently fouled leading to many complaints.  This was not the fault of the smaller plug as many believed, but was principally caused by poor quality fuel than available.  The problem was of sufficient concern that the factory authorized revisions to the head to use 14 mm plugs (a simple machining operation because the heads were originally cast for use with 14 mm plugs). However, for those with engines still equipped today with 10 mm plugs, the quality of today's fuel obviates the need to change to 14 mm plugs.

PVC System Modifications

The simple PVC system introduced in 1941 was blamed for coking of the carburetor jets.  As a result, Buick offered a kit to eliminate the valve cover to air cleaner connection and install a valve cover breather and crankcase breather tube discharging to the atmosphere.  The 1946 and later models used a valve cover and crankcase breather as Buick abandoned the PVC system until it was required by the federal government in the 1960s.

 

https://www.buickheritagealliance.org/index.php/restoration/engines/straight_8

 

However, my car has both the PCV tube AND a breather cap, like the first pic you posted.  My engine also has no road draft tube.  And my car also has the 14 mm spark plugs.  So I think it's safe to say that there are a lot of variations out there, given the changes made both at the factory and by dealers doing the "factory authorized revisions."

 

[JohnD1956]

May I ask;  if the pcv hose is used with w flat non venting filler cap AND there is no road draft tube,  where does air enter the engine to provide scavaging of the vapors? 

[38Buick 80C]

9 hours ago, Matt Harwood said:

 

The correct cap to use with the vent tube (I'm trying to find one) is a flat one as shown below:

 

 

 

 

Here NOS on eBay

https://www.ebay.com/itm/New-NOS-OEM-GM-Crankcase-Oil-Fill-Filler-Cap-1304628-1938-1941-1942-Buick/183926716202?epid=654890138&hash=item2ad2e2f72a:g:BRcAAOSwqK9dXpER

 

[billorn]

1 hour ago, JohnD1956 said:

May I ask;  if the pcv hose is used with w flat non venting filler cap AND there is no road draft tube,  where does air enter the engine to provide scavaging of the vapors? 

 

Doesnt the action of the engine spinning create positive pressure in the crankcase? That plus the blow by plus negative pressure in the air filter should have no problem pulling fumes out. Matt mentioned the couls see steam coming out the cap vent when he was driving with the hood off. I dont think these old engines seal up good enough to need the vent tube. I would personally prefer less places for dirt to get in.

[Matt Harwood]

Home Depot is still open, so I went over and acquired a few pieces of 1/2-inch conduit to use as the PCV tube, as well as grommets to secure it. The thin-wall conduit was a little too loose and would probably rattle, so the thick wall threaded conduit was the better choice. I cut the threaded ends off, plus a little extra, then added an angle cut on the end that will be in the valve cover. My thought is that since it will be more or less sitting on the inside surface of the baffle, an angle cut ensures that it will still pull vapors. I cut the angle such that the opening faces away from the baffle vent inside the valve cover so that any oil mist will not have a direct shot up the tube. I'm considering stuffing some additional mesh inside the tube, but I'm not sure that's necessary. The slightly larger pipe is pretty snug in the grommets so it won't move around and with the angled cut, it slips in easily--once it's painted, I'll use a drop of Armor-All or liquid soap to help it slide in so it doesn't hurt the paint.

 

  
Starting with ordinary 1/2-inch conduit, I cut the ends off, added an

angle cut, filed the rough edges, then sandblasted it in preparation for paint.

 

  

Test fit with grommets and the primed valve cover. It might be just a bit thicker

than original and the curve might not be quite right, but few people will notice.

 

Once I was satisfied with the fit, I sandblasted the tube to remove the galvanizing and give it a good surface for paint adhesion, then hit it with a few coats of satin black. I also blasted the spark plug cover and primed it in preparation for fresh Dante Red paint. I ordered new decals and spray paint from CARS, simply because their shipping is a bit faster (NJ vs. Bob's in CA), so hopefully it'll all be here in two or three days and I can put it back together. 

 

Side cover primed and ready for Dante Red topcoat.

 

To continue the discussion about what combination of vent tubes, filler caps, and valve covers might be correct, here's a dual carb air cleaner I have that does not have any provision for the PCV tube. It came off a small series car, but all the air cleaners are identical, and since it came that way from the factory, I can only assume it's a late production piece. This car most likely had a breather cap and a road draft tube on the side cover as seen in the color factory illustration, above.

 

This dual carb air cleaner never had a PCV vent tube.

 

After that, Melanie, Riley, and I spent a few hours making a ride-and-drive video for this killer 1948 Dodge Power Wagon crew cab diesel--I gotta sell some of this high-dollar stuff if we want to stay alive...

 

[Buicknutty]

Interesting stuff, Matt. Thanks for all of the great detail.

 On my '41 McLaughlin Roadmaster there is no PCV tube nor a fitting for one, and it has the road draft tube. The few '41 McLaughlins I've seen are like mine, though there is no documentation on this, that I've found anyway. In this era there are only very slight differences between US and Canadian Buicks, but this has seemed to me, to be one of them. Mine also had a flat filler cap on it when I bought it, but am currently running a vented one, like of yours, Matt.

 Engine colour is another difference, there was no evidence to support mine ever being Dante red, and some to suggest it was always grey, which is why I painted it 1940 Buick grey. Two points on that, mine, like Matt's is a driver, though I like to keep it proper and correct, but, and second, it is after all simply paint. If there is some reason that it needs to be Dante red, then it can be done with some work.

Keith

[neil morse]

On 3/22/2020 at 4:08 AM, JohnD1956 said:

May I ask;  if the pcv hose is used with w flat non venting filler cap AND there is no road draft tube,  where does air enter the engine to provide scavaging of the vapors? 

 

There is an "inlet" crankcase vent on the left side of the engine, under the exhaust manifold.  It's visible in this pic of my bad core plug.

 

[JohnD1956]

@neil morse  Thank you!  That helps make sense of this. 

[Matt Harwood]

At least the mail is still working, and I got my Dante Red paint and engine decals from CARS today. Sanded the tinwork with some 800 grit to knock off any goobers then shot it with the CARS engine enamel. I'm not pleased with the way it sprayed--the can arrived with the nozzle missing so I had to use one from another can. Output was pretty tepid and the paint spattered quite a bit. I still managed to lay down a first coat and I'll let it dry to see how it looks. Another quick pass with the 800 grit should clean up any nonsense, but I'm not sure I can trust it for a final coat. I'll try it on the spark plug cover before doing the valve cover--we'll see how long it takes to dry. I really hope I don't have to strip it and try again and wait for paint to be delivered. Weather is getting nice and I don't have a car to drive at the moment...

 

Sanded the parts with 800 grit and wiped them down with a

prep solution.

 

   

Even though the spray can splattered quite a bit, I managed to get a reasonable first coat in place.
We'll see if it is able to get a satisfactory second coat on there. I really hate doing jobs twice.

[old-tank]

If that CARS paint is the same kind as the 55 Buick green, don't spray again after it is dry...it will crinkle and lift!  OK to spray multiple coats while drying slightly or months later.

[Matt Harwood]

1 hour ago, old-tank said:

If that CARS paint is the same kind as the 55 Buick green, don't spray again after it is dry...it will crinkle and lift!  OK to spray multiple coats while drying slightly or months later.

 

Roger that. Based on your suggestion, I went out and applied a second coat before I went home for the night. I was able to get a pretty good spray pattern if I held it closer than I preferred. We'll see how it looks in the morning, but I think it'll turn out OK. I'll give it plenty of time to cure before I install the decals and I probably won't install the tinwork until this weekend. 

[Matt Harwood]

The paint on the tinwork turned out just fine. Not perfect, but no wrinkles or other issues and it's much nicer than it was. I'll let the paint cure for a while before I install the decals. I also did some touch-up on the head between the spark plug cover and the valve cover where it hadn't been painted before and the bare cast iron was very noticeable. So it'll look good when it's all reassembled. The PCV tube is also ready to install and the grommets fit well. I laid out the crumpled valve cover gasket and it came back into shape pretty well. Then I cleaned up the mounting flange of the valve cover and used some gasket shellac to glue the gasket in place and left it to set up overnight. I'll use a layer of grease between the gasket and the head to seal it up but it should come off easily should I ever need to go in there again. 

 

Gasket is good to go.

 

  

Cleaned up the mounting surfaces. Ready to install.

 

Then I pulled the spark plugs from cylinders 7 and 8 and if anything, they show a slightly rich mixture. If it was running dangerously lean and burning up the headers, they'd be white and powdery. Instead they're a little dark but the insulators are still pretty white, so it's not ridiculously rich, just a little. It may also be due to running while doing my testing and valve adjustments--they might look better after a long drive. Anyway, this is conclusive proof that there's nothing amiss inside and the fuel mixture wasn't out of whack. No danger, no damage, no issues. 

 

Cylinder 7

 

Cylinder 8

 

Nevertheless, I'm going to go one, maybe two heat ranges hotter on the plugs just to cut down on these deposits. It can't hurt and may allow me to retard the timing to smooth out throttle response a bit. This weekend I'm going to reset the timing to stock specs, change the plugs, and set the dwell and points to get the ignition system in top shape. Then we'll see how this sucker really runs.

[Matt Harwood]

I'm going to call this day "What the heck happened?" I made two steps forward and three steps back and I'm not sure how it happened.

 

I started the day pulling all the spark plugs and giving them a blast in the little sandblaster spark plug thing. I set the gaps to .028" which is the high end of the range in the manual. That's about where they were anyway and the plugs themselves are fairly recent. So they're clean and gapped and reinstalled.

 

Clean spark plugs were gapped to .028". I'm still looking for some

R46s, which are one heat range hotter.

 

Next up I tweaked that pushrod for cylinder #6 that was just dumping oil all over the place (see the video in a previous post). I read a post this morning from another forum member that said the lifters are fed by gravity by the oil from the rockers, so I thought that maybe the pushrod itself was clogged. I loosened the rocker enough to maneuver the pushrod to the side and sprayed the hole with some brake cleaner. Then I chased it with a little piece of wire which didn't really go in very far (.044") but it seems to have done the trick because that one isn't flooding anymore. I fired it up and it started easily, idled well, and the valves sounded, well, about the same. If anything, they're noisier but it's hard to say without the hood in place. It is most certainly running as well as it ever has with no stuttering from the exhaust and a very smooth exhaust note. The thing runs great!

 

 

Then I reinstalled the tinwork, both the spark plug cover and the valve cover (which did, indeed, wrinkle after all--dang). I used gasket shellac on the valve cover side and a light coat of grease on the head side so it should be easy enough to remove without damage if I have to go back in there sometime soon. I skipped the decal installation for now because of the wrinkled paint and I haven't decided whether to strip and repaint or just let it go. I used a drop of liquid soap on the rubber grommets and the PCV tube and it slipped right into place. That part fits well and looks right.

 

Fresh paint looks pretty good...

 

...but the paint started to wrinkle on top of the valve cover.

 

My plan was to reset the timing so I fired it up and let it idle but within about three minutes, there was coolant spewing out from under the radiator cap and from the overflow. Temperature gauge was showing more than 200°. What the...? Revving the engine gave it a quick cool down, but it spiked back up instantly and it was very inconsistent. I don't know what that means. I thought maybe it was low on coolant, since this is the second time it has overheated, so I topped it off a bit but it took less than half a gallon--it wasn't very low. Surely half a gallon of coolant isn't the difference between normal and cooked on a cooling system this size, right?

 

Anyway, with it topped off, I took it for a brief drive to see if getting some air through the radiator would help and maybe there was an air bubble in there that would work its way loose. Nope, just more foam pushing out of the radiator cap but a rock solid 160° on the gauge. I can't explain this.

 

  

Foam from radiator even though gauge shows a rock-solid 160-ish. What the...?

 

Back at the shop, I put a hose in the filler neck and opened the petcock on the bottom of the radiator to try to exchange the Evapo-Rust for pure water. I let it idle for about 20 minutes while this was going on and it continued to give me odd readings. Gauge stabilized at 160°, but that's with the hose feeding hot water through the radiator (a trickle to match the drain rate of the petcock). But the stuff coming out of the bottom of the radiator was steaming--it was really hot. Again, I don't understand--how could the bottom of the radiator be the hottest point?!?

 

So there's VERY hot water coming out the BOTTOM of the radiator.
That seems wrong, doesn't it?

 

The thermostat housing should be the hottest point in the system.
That's where coolant is coming out of the engine and heading for
the radiator. This is also where I have my gauge sending bulb installed.

 

And then there's this weird reading in the middle of the radiator: 170° 

about halfway down. If it's 160° going in, where's that extra heat coming

from!?!? It can't possibly get hotter IN the radiator, can it? What the deuce?

 

Other side of the radiator in the same spot shows 143°. Very odd.

 

I was also sorry to see about 145° on the outlet side of the radiator. A mere 15-degree drop through that giant radiator, even at idle, seems pretty feeble. So I don't quite know what is going on. I left the petcock open to drain the radiator and I'll fill it with water in the morning and see what happens. The foaming at the radiator cap I suspect might be due to the cap not fitting properly, so I'll get a new one. Could the thermostat be defective? It seems to hold 160° pretty well. Could the Evapo-Rust have been causing it to stick? Is the Evapo-Rust more prone to foaming? Could I be sucking air somewhere? I think I'll remove the pantyhose filter on the thermostat outlet, maybe it's sucking air there? 

 

Maybe it's nothing and a new radiator cap will eliminate the foaming. Maybe the Evapo-Rust is more prone to foaming than regular coolant. Maybe there are still hot spots in there somewhere, or maybe air bubbles. I don't know. Maybe I just fixed it until it was broken, which is my specialty.

 

Sometimes I just don't get it.

 

 

Edited March 30, 2020 by Matt Harwood (see edit history)

[JohnD1956]

From 160 down to 145 sounds about right to me.  Keep in mind the exhaust manifold is running over 200* the 160 * at the return line with a 160 thermostat tells you the system is healthy.   The steaming water at the drain outlet could be 145*  That would be hot enough to throw steam while draining.  And 145* is hot,  your home water heater probably is set for about 120* and that throws steam when run.  

 

I can't answer for the 170* on the one side of the radiator.  That is odd. But the 145 at the return port is a good reading.  And if it got much lower than that your thermostat would be running closed most of the time, which you really would not want anyway. 

 

Can't answer for the foam either.  But chances are it is the evaporust product composition.  Just draining the radiator would not remove all the evaporust that was laying in the engine block.  Either that or cavitation from the water pump.  But don't quote me on that.  I would think at an idle that cavitation would be difficult.  

 

Does the evaporust have a need to be neutralized?  Like with baking soda possibly?

 

 

Edited March 30, 2020 by JohnD1956 (see edit history)

[Bloo]

2 minutes ago, JohnD1956 said:

 

Does the evaporust have a need to be neutralized?  Like with baking soda possibly?

 

I think how to get rid of it afterward is a question for edinmass, as he has done a bunch of cars. Baking soda is most likely not the answer because as far as I know Evaporust is not acid. It is sticky like sugar, and although nobody seems to know what is in it, it is likely a closer relative of molasses than acid-based rust removers.

[Matt Harwood]

Water is adequate to flush it, it doesn't need to be neutralized. I ran the engine with the hose in the radiator with the petcock open for 20-30 minutes until the stuff coming out was clear rather than goldish. Most of the Evapo-Rust should be out of there by now, but I'll refill it tomorrow and let it run and drain and fill again. Eventually I will put in a 70/30 water/anti-freeze mix.

 

 

I'm leaning towards the radiator cap being the problem and the Evapo-Rust being prone to foaming (which it did in the bucket when my electric pump was running too aggressively). I still don't know why it spiked up to 200 so quickly unless the thermostat was sticking a bit. Evapo-Rust is sticky. 

Edited March 30, 2020 by Matt Harwood (see edit history)

[Bloo]

If it is going to just climb and boil, and the lower end really IS boiling hot, I think you have a stuck thermostat. Also, if there is no tiny hole or check valve in the thermostat, drill a tiny hole. It helps immensely getting rid of air bubbles. FWIW I have seen an original bellows thermostat from a late 30s Buick. It had the hole.

 

I would leave the pantyhose filter in, or redo it. I don't believe you would get air there without seeing seepage. Is this a pressurized system? If so, you should see leakage for sure.

 

33 minutes ago, Matt Harwood said:

Surely half a gallon of coolant isn't the difference between normal and cooked on a cooling system this size, right?

 

Good question, but it could be, and it wouldn't surprise me. The hottest spots are the back side of the combustion chamber, and especially the exhaust valve seat. That is all up high. For what it's worth, a fairly small air bubble in a more modern car will cause the cooling system to seem to not work at all.

 

 

[edinmass]

Matt........foaming can be caused by a water pump causing a vacuum and pulling in air past the seal. Be sure your system is flushed with plain water to clear out the Evapo Rust. I would run cutting oil and water in it until your happy with the cooling system. Cutting oil will NOT foam. Check your thermostat, bypass if it has one, and your filter. The car should not overheat or push water after all this.....

[edinmass]

I have had similar results on the temperature gun, with the radiator having different temperatures on one side VS the other. I never tried to figure it out. Remember that under hood radiating heat from the exhaust can cause issues also. I bet clean coolant with cutting oil to lube the pump and prevent rust and a new cap, all will be fine.

[John_Mereness]

You have done a lot of work on it - my guess is that it needs to find its own "new" level in radiator and will puke out some guts.

 

I am wondering if bottom of radiator is more hot just for fact of water from block being able to backflow through water pump into radiator upon stopping verses on the top end of the radiator the water needs partially pumped into radiator at top hose connection. 

 

Also, make sure you have wires in the lower radiator hose so it does not collapse under any load - I think you mentioned though you had a wire in lower hose. 

Edited March 30, 2020 by John_Mereness (see edit history)

[Matt Harwood]

Filled it up with plain water today and it held steady at 160. Melanie was watching the gauge and it was rather remarkable that it crawled up to 200 and then the thermostat opened and it almost instantly dropped back to 160 and held steady there for about 20 minutes while I cleaned it up a bit. We're hosting a virtual field trip for kids tomorrow and the Buick will be one of the stars of the show so I wanted it to look good. I found a replacement radiator cap with two seals--one on the spring-loaded plunger and another around the perimeter so it should seal much better to the radiator neck. It's at NAPA but I have to go get it and decide whether I want to spend the $25 at the moment--things are pretty tight right now and we're getting nervous. Buying the decals for the engine felt frivolous.

 

No driving since it's raining today, but with plain water in the radiator now the foaming seems reduced (in the shop anyway--it didn't really foam until it was on the road). Temperatures have also stabilized. A drive will confirm whether the foaming is resolved and tell me that it's OK to fill it with a proper anti-freeze mix and then move on to the next project, which is likely getting back to work on the Lincoln. So much in limbo right now, particularly money. If we don't sell some cars, we'll be out of business by June and then I'm all done with cars anyway. Hard to see past that dark cloud right now...

[kgreen]

" If we don't sell some cars, we'll be out of business by June and then I'm all done with cars anyway. Hard to see past that dark cloud right now..." OUCH!  Sure hate to hear this, best of luck getting something to move.

[Matt Harwood]

Well, I had some free time today (a lot of it, sadly) so I figured I'd go out and do some extra tweaking. Several years ago when I first bought the Limited, a friend told me to add some timing which would really wake it up. So I did and it did. No idea how much I added, I just tuned it until it "felt" right; it ran great and I never thought much about it. However, it always had part throttle bucking, as when going around a corner and accelerating from a low speed without downshifting. It's definitely not a carburetor issue, so it has to be ignition. My friend Lawrence suggested too much timing was the problem. Now that I'm systematically going through all the main systems, it was time to check the timing. So that's what I did today.

 

First, here's a cold start and run with all the recent service work finished but without adjusting the timing. Even as-is, I'm pleased with the results:

 

 

Once it was warmed up a bit, I set the timing. I'm amazed that my digital timing light works on six volts. Hooked it up to the battery and connected the lead to #1 spark plug wire and sure enough, it's firing bright enough to see the marks on the flywheel. I figured I'd have to drag a 12V battery over and use that to power it, but no need. Nice!

 

I aimed the timing light at the inspection hole to find the mark on the flywheel and it just wasn't there. After spraying some brake cleaner in there, it was still missing so I assumed it was too faint to see or too dirty. Nevertheless, I loosened the hold-down bolt on the distributor and gave it a bit of a turn anyway. Voila! There's the mark, and someone has helpfully added a dab of white paint to make it visible. The problem? When I advanced the timing a few years ago, I added A LOT more than 4 degrees--more like 12 or 15. The mark was completely out of view. With today's high octane gas, the car never pinged and it ran well, so I didn't think about it. Last summer on that tour up in Canada, I got sick of the bucking and pulled out some timing in a parking lot, but it was just a little and just a guess. Ultimately, there was so much advance that even pulling it back a few degrees did nothing. With a little tweaking, I was able to see the mark and get to work. One problem is that the unshielded ignition system is so noisy that the timing light picked up a lot of stray pulses if I didn't hold it just right. I'm sorry about the quality in this video--it was difficult to get the timing light, my cell phone, and my hand down there to get a clear shot, and the camera's frame rate and the strobe effect on the timing light seem to fight each other. Have a look and hopefully you can still spot the white mark on the flywheel as I adjusted the distributor.

 

 

Once I could see the mark, I adjusted the distributor until the mark on the flywheel was centered on the pointer on the housing, indicating the factory base setting. I'm going to leave it there and see how it drives and perhaps add 3-4 degrees (using the light this time) once I have some hotter spark plugs. Interestingly, the manual does not mention disconnecting the vacuum advance on the distributor while setting the timing, so I left it in place during the procedure. As a side benefit, the idle dropped down from about 575 to 460, according to my timing light. I'll take that, too.

 

Here's the final idle:

 

 

 

Test drive tomorrow and we'll see if we've fixed the bucking problem.

[Bloo]

What brand/model is that timing light? Does it have dialback?

[Matt Harwood]

16 minutes ago, Bloo said:

What brand/model is that timing light? Does it have dialback?

 

It's a brand called Innova, which I wasn't familiar with but it was what was on the shelf at the local auto parts store. I bought it a few weeks ago in preparation for this part of the job since my old timing light seems to have vanished. It works well and as I said, I was shocked to see it fired on 6 volts. It also has an adjustable head so it can be aimed more easily, which I like.

 

 

https://www.summitracing.com/parts/ino-3568?rrec=true

 

 

Edited April 1, 2020 by Matt Harwood (see edit history)

[Bloo]

Thanks!
 

[maok]

Matt, I may have missed it in your posts and you probably know this, you should set the idle speed screw to the lowest you can before adjusting the timing, otherwise the advance weights in the distributor are going to giving you higher advance degree value on your timing light. I'm surprise that the manual does not suggest to remove the vacuum line and  plug it off.

[Matt Harwood]

Thanks Moe. I just double-checked the manual and there's no mention of disconnecting the vacuum. It does say to get the idle as low as possible, not to exceed 350 RPM, so I may have had it a bit too high when I was setting things up. I don't know if I can get it that low, to be honest. I backed it off until it started to drag and set timing at that point, but the tach on the timing light said that was about 500 RPM. It wasn't a clean idle and I wouldn't want it that way on the street. It's easy enough to adjust so maybe I'll try again tomorrow after a test drive when it's good and warm and more willing to idle well at low RPM. 

 

I wonder if disconnecting the vacuum advance would make a difference in the final setting? Would it advance or retard the overall timing if I set the base with the vacuum disconnected?

[Ben Bruce aka First Born]

The 1950 shop manual says idle speed of 350 RPM.   The vacuum "inlet" is ABOVE the throttle plate therefore has NO vacuum at idle.  I think you did "good" Matt.

 

  Ben

[RivNut]

My dad had a couple of these. The needed sized socket went on the long handle, the screwdriver was built into the knurled knob.  Made valve lash adjustment easy.  

It was still a two handed operation but there was no need to lay down any tools to use the feeler gauge.