38 Special - insert bearings

[jeff]

I have a nice set of 1950 248 cu in connecting rods and pistons that I purchased some years ago. Now, I am thinking of taking on the upgrade project. Hollanders confirms that both the connecting rods and pistons are interchangeable with the '38. My motivation is to not only upgrade to insert bearings, but also improve on my piston set. Years back (like 15+) I replaced one piston, leading (I think) to some vibration (out of balance)issues.

A hand-written note on some paperwork in the box says "could be an issue with crank journal radius". Hollanders seems to say I'm OK to proceed.

Any experience with this?

Jeff

[Guest 40series]

No but this has been a recent discussion on this board and a conversation with Jim at vintage auto left me feeling that you may need to turn the journals down but otherwise it is a go.

Keep us posted as I plan to do the same with my 35

[jeff]

Here's an update...

I dropped the pan and removed one old bearing cap. I then fitted the "new" 1950 cap (with insert) to the journal, it fits perfectly. No issues as far as I can see. This is essentially what Hollander was indicating as well. So, I guess I will proceed to remove the cylinder head.

From previous postings, I am one of those who has been wondering about cruising speed - some Special owners report extended highway trips - not necessarily faster than 55 or 60, but comfortable cruisers. (its agreed that the Special is no high-speed cruiser!) On mine, I find myself backing off around 45 - 50, with noise and vibration seeming to limit my willingness to push any faster. I just finished reading a tech article in Hemmings Classic Car on engine balance. They point out that any energy going into vibration is a corresponding loss to the output of the engine. Not to mention the wear and tear. Makes sense.

I am anxious to see what kind of improvement I may get.

Jeff

[Steve_bigD]

A funny thing is that my 38 special feels like it is really stressing the engine at 55-60MPH. But if I take it up to 65-70 it smooths out and although it is revving it doesn't feel like it is unhappy. I once took a 120 mile highway trip at mostly 65MPH and it did fine. Only got 13MPG though.

Steve D

[Guest 40series]

Jeff,

Did you notice if the crank was drilled for oil? There was some question as to the oil pressure at the bearing?

[jeff]

Yep - the crank is drilled to supply oil to the rod bearings. When I had the engine out 15+ years ago, I spent a lot of time on those cross-drills. Actually found some plugged, and had to use a nail and stiff wire to clear all of the drill paths. When I was done, I used water at high pressure to prove that all paths were clear and no debris was left inside.

I had forgotten that the rods themselves are not drilled all the way up to the wrist pins. Just a short drill path to give a shot of oil (to the cylinder wall?) with each rotation. The rings must channel oil back to the wrist pins.

Interesting.

Jeff

[jeff]

Another update, and a question...

All the rod caps are off, and the crank looks good. With a quick measurement (using calipers), I get 1.998 or 1.999 - which checks out fine. Tonight I will measure them all, more accurately with a micrometer.

Now, Motors says to fit the new bearing, using Plastigage to determine the clearance (0.0008 to 0.0018 desired, if I recall). If you have too much clearance, use an undersize bearing (I picture the Buick mechanic just going up to the parts counter for this). So, there must have been 0.001 under, 0.002 under or some other small increment of undersized bearings to choose from.

Now, the catalog guys (Bobs and CARS) seem to only know STD, .010 and .020 under. These under-size choices imply that you have had the crank turned.

Are the smaller increments still available??

[Guest 40series]

You could get -.001 back in the day but no longer. This is because the variance is more than .001 now. Check a set of new standards and you may be suprised.

[jeff]

Looks like Egge carries -0.001. Re-reading the paragraph in Motor's, it still reads like there used to be more choices. I re-measured my jounals with micrometers, it looks like -0.001's are the size for me.

Now for the problem... When I pushed out my pistons yesterday, I found three with broken rings. One cylinder is also damaged. So, my project has just escalated. I will need to pull the block and have it machined. The next decision will be to sleeve one cylinder back to standard and still use my 1950 piston set, or, go 020 over on all of them and invest in new pistons and rings.

I now know why my engine was not performing up to par. I am surprised it was still running as well as it was.

I was really hoping to do this upgrade with the block still in the car. Now it will be more time, effort and $$.

Oh well, at least the engine repaint can now be done really well, with the block on a stand.

Jeff

[Guest Art Williams]

Jeff,

I noticed in your first post that you had replaced one piston and then had a vibration. I have my engine (320)apart just now and when looking at the specifications sheet in the Buick manual the difference between piston should not exceed 1/8 of an ounce. The rod shims that I've measured are all about .0015".

[jeff]

Thanks Art.

1/8 ounce isn't very much. I bet I exceeded that by changing only one piston, and not checking the weights.

You can peel off .0005 (I think) increments from your shim packs. Tighten your caps with Plastigage in place, then determine how much shim to remove. Use your pocket knife to separate the layers of shim.

Jeff

[jeff]

Time for an update...

The block and crank are at a local machine shop. Looks like we will go .030 over on the cylinders, and probably take off .010 on the crank (both main and rod journals).

So I will be ordering oversized pistons. Hollander Interchange manual says the pistons are interchangeable, but there is a criptic note that says "uses special head". Does that mean the pistons are interchangeable IF you use a special head? The 1950 pistons measure .042 longer than the '38s, about .015 of this is in the location of the wrist pin. (so this piston will reach .027 higher into the combustion chamber). Bottom line: THEY AREN'T THE SAME.

If anyone has done this connecting rod upgrade - did you use newer pistons with your newer connecting rods, or '38 pistons? Just to further muddy the waters, the wrist pins differ by .001, just enough to keep the '38 pins from sliding into the '50 pistons.

Sure don't want to choose the wrong parts at this stage.

Option 1: '50 rod and new '50 oversize pistons - trust Hollander.

Option 2: '50 rod and new '38 pistons - need to verify the wrist pin fit.

Option 3: have the '38 rods machined to accept the insert bearings.

Any thoughts?

Jeff

[GSW38]

JEFF, I REBUILT MY 38 MODEL 41 AND USED 1949 BUICK CONNECTING RODS WITH NEW .O2O OVER PISTONS. I BOUGHT THE PISTONS FROM TERRILL MACHINE SHOP IN TEXAS.I HAD THE BLOCK AND CRANK SHAFT MACHINED BY GOOD MACHINE SHOP.I HAVE ABOUT 3000 MILES ON THE ENGINE SINCE THE REBUILD RUNS GREAT WITH THE INSERT BEARINGS.DONT THINK YOUR MAKING A MISTAKE WTTH THE INSERT BEARINGS.

[jeff]

Ok, new update.

Going with: 1950 rods, new 1950-style insert rod bearings (.010 under); new 1938 main bearings (.010 under); new 1950-style pistons and rings (.030 over). (ok'd by Egge experts)

The machine shop will also rework the head, as my intent to simply lap valves and reassemble won't address the worn guides. So, new bronze guides, machined seats, and ground valves. They will also install rubber guide seals, unless anyone knows of a reason not to. The shop advises that the valve stems will still get adequate lubrication, and that excess oil consumption will be about zero.

Flywheel, pressure plate and harmonic balancer will also be balanced with the crank. I suppose when the pistons come in, I will let them balance them as well. Why not, there's nothing else that can be done, as far as I can tell.

If you want to know how much paint to buy, you'll need about 1/4 pint more than the one quart can. So, just get two quarts at once, and save on shipping.

At least I am still allowed to sleep in the garage - just until the project is done and the wife's van moves back in. Then I will sleep in the backyard, I guess!

Jeff

[Guest Brian Kearney]

Hi Jeff, just went through the same thing rebuilding my '38,248. Used all of the old parts except pistons and installed 20 over pistons from Bob's (Egge).The lower end showed little wear and everything was reusable. My old pistons had broken lands and rings, but I had no damage to the cylinder walls. My machinst bored the cylinders, miked everything, cleaned and polished and weighed everthing and I reinstalled the engine. Haven't been able to start it because of a weak starter that I had rebuilt at Cars in NJ. Just doesn't seem to be enough push from the thing to get the engine spinning fast enough. I'm thinking to drag the car in third to get the engine spinning and see if it will start so I can get some hours on the engine. Maybe then the starter will be able to turn it over for starting.

Brian '38 special

[jeff]

Thanks Brian. Sounds like you stayed with the babbitted bearings??

For your starter, here are a few things you may have already checked: good ground connection from the battery to the block (because that's where your starter finds ground); load tested battery (don't just check voltage, but take it to Interstate Battery or someplace with a load tester); timing (not too far advanced).

In my case, I had a battery that looked good on the charger, measured 6.3V, but had no remaining "capacity" when asked to produce serious amp-hours (like when you engage the starter). A new battery from Interstate (they carry a very similar case, but rated at about 650 CCA instead of the 350 CCA I had) did the trick.

Jeff

[Guest Brian Kearney]

thanks Jeff, yes stayed with the babbited bearings and had to remove only one shim from the rod cap. Have a new 6v battery fom Napa thats 950 cca but I'm thinking my cables are too small to carry the amperage of a 6v system. I set the timing up at 4 degs. btdc just like the book wants or better still tdc in #1 cyl. with the flywheel mark at the 4 degs. btdc mark showing and then with a test light across the points just flickering. Just can't seem to get it spinning fast enough. That straight 8 crank is heavy and with a basically new engine it might just be too tight also.

thanks Brian

[West Peterson]

When I bought a new cable that fed to the starter, 00 gauge was recommended, much heavier than the factory gauge.

[critterpainter]

Just a thought and a reminder...When installing the flywheel make sure it is indexed correctly so that the timing marks are accurate. The flywheel is not "keyed" to the crankshaft and can be installed wrong so the timing marks will be off!!

Bill

[Guest Brian Kearney]

update on starting my rebuilt '38. Pulled the car at around 15 mph in third and was able to get the motor spinning and subsequently now able to spin the engine with the starter and a pair of 2/0 cables and the new battery which is a 965 cca battery. Engine will now start with one pump of the throttle, no choke but will not stay running longer than two or three seconds and will not acelerate at all, only stall when I try to apply more throttle which is where I have been all along. Carb has a kit in it and been cleaned throughly. Plugged anything that was pulling a vacuum. I'm fresh out of ideas on this and any and all thoughts would be appreciated. Just feels like it's not getting any gas on the high speed circuit although it's not really idling either. Like I said it will start now but won't idle or throttle up. Would hate to spend the time and frankly the money either locating a carb (carter) with a 3 bolt pattern or losing the carb for a month to a rebuilder only to find it's not that.

thanks Brian

[West Peterson]

You might want to try hooking up a low-pressure electrical fuel pump.

Has your mechanical pump been rebuilt recently?

[Guest Brian Kearney]

West, I have a new pump, but I'm running it off a 1 gal. tank on gravity feed to the carb. I know the bowl is filling

and there should be enough fuel to run it. I have run cars in the past this way to eliminate everything in the fuel system but the carb and thus give me an idea of where trouble lies. My tank is presently out of the car and therefore out of the system. The old pump is acting as a plate to prevent oil loss at the block. should run on gravity feed if the carb is right and I think it is, although not 100% sure. Gets a good shot of gas from the accelerator pump when you open the throttle, just won't accelerate or even idle for that matter. Strange thing is when I first reinstalled the engine it started and ran for about 5 minutes and then developed an exhaust leak on the manifold gasket. I shut it down fixed the gasket, finding one of the sleeves on the intake port had shifted in installation and had then caused the exhaust leak. I left those sleeves out and just used a new gasket to reinstall the manifold and also found out that I had blown a head gasket because the rebuilder had inadvertantly not torqued the head past 20 lbs. I replaced the head gasket and have not been able to get it to run since.

thanks Brian

[jeff]

How about valve adjustment? Could you have left your valves too tight, so as it warms up they are no longer seating?

I think the approach is to leave the valve setting a bit too large (like .020 to .025 cold), then when the engine starts, warm it up and set to .015 warm, with the engine running. (By the way, has anyone out there mastered this pain-in-the-butt process?)

The other thought is that the timing chain is off by one tooth. And/or the distributor is off by one tooth. Try this: pull the number one plug and see if you can find top dead center by having someone hold a 1/4 inch wooden dowel in contact with the top of the piston while you manually rotate the engine. Then, look at the valve status and the position of the rotor with respect to the cap. While you are at it, double-check the spark plug wire routing to make sure you have them in the right order. Check the integrity of the spark by holding the wire 1/8 inch away from ground while you crank the engine. Maybe your points have slipped out of adjustment or gotten damaged in the handling of the parts.

Just a few quick thoughts - chances are you have already considered them.

Jeff

[critterpainter]

What condition is the ignition system in?? Old coil that is on its last legs?? Bad plug wires or coil to dist wire?? or wrong gap on ign points???

Another test, with engine running spray some carb cleaner or penetrating oil into the carb (anything that will burn). If the engine smooths out you have a carb/intake or fuel quality issue.

Bill

[Guest Brian Kearney]

Bill, thanks for the info, but all that is replaced, all new ignition parts, wires,coil, etc. etc.. It won't run long enough to spray anything into the carb. As I said I'm running off a gravity feed tank with new fuel.

thanks again, Brian

[JoelsBuicks]

Brian, I thought that the fuel pressure needed for proper carb operation was around 3-4 psi inlet pressure. If that is true. then you'll need to elevate your gravity feed tank 8 to 10 feet above the carb in order to mimick that pressure.

Joel

[Dave_B]

Brian, maybe run your small grvity tank to the fuel pump to insure proper pressure to the carb. My 2 cents.

Dave

[Guest Brian Kearney]

I'm leaning to not enough fuel in all of this and that might be the best solution. Install the new fuel pump, replace the piping to the carb and hook up the external tank to the inlet of the pump and see what happens. I'm just not getting enough fuel. If it starts with one pump of the accelerator and one tap of the starter button but won't run for more than a few seconds it sounds like fuel not timing or valves or anything else. Any more info will be appreciated.

thanks Brian

[West Peterson]

Brian

Keep us informed on the progress.

However, so as not to continue highjacking Jeff's post here, may I suggest you start your own post?

Thanks.

[Guest Brian Kearney]

Sorry didn't realize I was stepping on any toes.

Brian

[Guest Brian Kearney]

Hi to all that have helped me so far. This is concerning the 248 cu. in. engine that I had rebuilt, reinstalled and now trying ot start. I hooked up the fuel pump drawing out of an external tank, checked to see if I had fuel at the carb under pressure and tried to start with no avail. Have tried advancing and retadring the spark and the engine will catch, run for a few seconds and die. No idle, no acceleration, just an initial start and then a sound like a big sigh and vapor back through the carb. Not a backfire persay, almost like a compression release. Any help would be appreciated, I'm out of ideas.

[Steve_bigD]

The engine should be able to run for a minute or so on the fuel in the fuel bowl of the carb. There is a brass screw on the side of the carb that when removed shows the fuel bowl level. It should be even with the bottom threads.

Since the engine was rebuilt we can assume the compression is good and the valve timing is OK. You said that you checked the ignition timing and it is at 4 deg. Was the flywheel removed in the engine rebuild? Did you check that the distributor rotor lines up with #1 wire when the flywheel is at 4 deg?

Remove the center distributor wire from the cap and hold it 1/4-3/8" from ground (use an insulated pliers)and have someone crank the engine. Assuming that the battery is reasonably charged you should get a nice strong spark.

If you have spark, compression, fuel, and the timings are set the engine should run unless there is a large vacuum leak somewhere. Connect a vacuum gauge to the wiper manifold connection and watch the gauge while cranking. While it will not read the running 18-22" because of the slow cranking speed, it should read at least 10-12" and be fairly steady.

If these are all good the only thing left is the carb. Perhaps it was rebuilt incorectly and it runs on the idle system but the intermediate and high speed systems are not working properly.

Hope these ideas help.

Steve D

[jeff]

OK, time for the final update.

I finished the rebuild, and lined up the front clip. Ran the engine up to temperature a few times in the driveway, and adjusted the valves closer to their final .015. (still left them a bit loose) Engine starts easily, hot or cold. Oil pressure and temperature perfect. Everything ready to go at the end of the day Saturday.

Took it out for the first time Sunday. Eased up to speed (25 mph) for a trip around the neighborhood. Next, off to my friend's house about a mile away. Great, now I've done 30 mph! A brief visit, restart, time for a 35 mph run. All systems go. In fact, perfect. Nice, quiet boulevard, 35 mph speed limit.

Signal left to begin my return run, slow to make my turn - WHAM! The only other car in sight slammed me from behind.

3.5 miles into my break-in period.

Rear bumper, bumper supports, frame, trunk lid, rear lower body, left rear fender, and body creases on both sides below rear passenger windows (2 dr sedan).

Nobody hurt.

[Ben Bruce aka First Born]

AHH, Jeff, that is too bad! You should not have left that magnet in the trunk!

Seriously, glad the engine came out fine. Sure is exciting and satisfying the first time it starts, is it not?

Ben

[Thriller]

Incredible. It is good to hear that things went together well and it is running better. It's a shame that some bozo wasn't paying attention though. Most of the time I find that folks give a bit of respect (read distance) when I'm driving the old iron, but there are enough folks out there who don't have a clue to make things interesting (read dangerous).

[jeff]

Yeah, she readily admitted to the officer that she wasn't paying attention and just hit me. I picked the perfect road for this type of drive - absolutely no other traffic to speak of. Just her!

Does anyone recall someone offering newly fabricated trunk sheetmetal?? I seem to recall that tray section being offered for sale recently. I'll need that, plus a bunch of stuff that I listed on the Buick buy/sell site.

Also, any recommendations on the insurance thing? Seems like I may need an appraisal or estimate of my own, in case I don't like the solution her company offers. Anybody been down this path?

Thanks,

Jeff

[trp3141592]

Hi Jeff,

I have not had the collision experience, but I have had near-misses. For some reason gawkers don't register in their brains that the "wow-lookit-that" car is first and foremost a CAR that has to be dealt with on the road like any other. Gawkers will admire your car for a moment, then turn right in front of you, pull out right in front of you, and/or ram you from behind.

It struck me that those tiny 6-volt tail lights just don't grab any attention. My solution on my 37 Roadmonster and my 40 LaSalle was to add inexpensive plastic-based removable extra trailer lights spring-mounted to the bumper. They're connected with plugs and sockets and are easily removed for showing off the cars. I'll do the same with my Cord when it's more roadworthy. On the Roadmonster I wired them with an EBay-obtained aftermarket turn signal and brake light switch. I don't know if they actually keep me (and the cars) safer or not, but at least I FEEL safer.

As for insurance, do you have collector car coverage, including collision, from Taylor or Haggarty, or similar? If not, consider it before your next distracted-motorist incident. They understand us old car guys and our special cars. And it's much cheaper than your standard-issue insurance.

--Tom

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[jeff]

Certainly agree with your visability comments. Among my local old car friends, this has been a frequent topic of discussion. All have agreed that my '38 Buick has about the best tail and brake lights of any car of that era. Nice and bright, good side visability, etc. Having said that, I still plan to upgrade them when the car is back on the road. Thinking about an LED type high mounted option, either inside the rear window or on top of the license plate. Also thinking about a rear mounted machine gun, with one of my kids acting as tail gunner (only kidding)!

My insurance is part of the package - home, daily drivers, plus the '38. Wasn't very expensive, has agreed coverage, etc - now I get to test the customer service part! Hope its not a bad experience.

Live and learn, I guess.

Jeff

[Thriller]

It struck me that those tiny 6-volt tail lights just don't grab any attention. My solution on my 37 Roadmonster and my 40 LaSalle was to add inexpensive plastic-based removable extra trailer lights spring-mounted to the bumper. They're connected with plugs and sockets and are easily removed for showing off the cars. I'll do the same with my Cord when it's more roadworthy. On the Roadmonster I wired them with an EBay-obtained aftermarket turn signal and brake light switch. I don't know if they actually keep me (and the cars) safer or not, but at least I FEEL safer.

Tom,

Would you mind sharing what type of light you did this with? My '29 was retrofitted with a turn signal and using tractor lights (which are also 6 V). However, I would prefer to go to an LED strip setting up both signal and brake / tail lights. I haven't looked that hard though.

Jeff - I like the idea of a tail gunner. I've long held that unless we do a better job licensing and enforcement with respect to driving that I should be able to mount armament to get those fools out of the way.

[trp3141592]

Hi,

The turn signal I used on the Roadmonster was obtained on Ebay--"Universal TURN signal switch 3pc KIT NEW Chevy Ford 6V" was the item description. The driver-take-notice bulb in the handle is 12 volt, but the flasher is 6 volt. I had to lathe-modify the plastic tip of the handle to get a radio Shack 6 volt bulb to fit into it. It wires up pretty easily, taking its power from your brake light switch. Other than tapping power from the brake light switch, I wired it independent of the existing brake lights. For light units I used some really nice teardrop units that I got inexpensively at the local Harley-Davidson shop.

The Lasalle already had factory-installed turn signals, so all I had to do was add additional lights front and rear and wire them to the existing connectors. For the exterior lights I used gray plastic-base add-on lights that I think got at the TSC tractor place. They were not expensive. They came with 12 volt #1157 bulbs, but I just switched in 6-volt 1154's in their place. I fabricated mounts to go on the bumpers. I used red on the rear and double amber on the front. The lenses are 3" or 3-1/2" or so. They burn bright and are easily visible.

When I wire the Cord I'll do as I did with the Roadmonster.

I am unaware of any neon strip lighting in 6 volt. On a websearch I did find 6-volt LED bulbs, but at $30.00 a pop I decided to go the other route.

Hope this helps!

--Tom

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