Neil's '41 Super Model 51

[Konrad]

First I need to apologize to Neil. As pilot in command it was my responsibility to make sure this kind of rookie mistake didn't happen.  I failed to make sure all the push rods were seated in the rocker arm before torquing down the rocker towers.  As the cup is very thin and we didn't bend any push rods I think the damage may be limited to the push rod and adjuster screw. 

 

As to the torque I couldn't get a crowsfoot to work as I had less than 60° free movement.  (A 12 point crows foot might have worked but I don't have any of those in in the bay area). So we pulled the rocker shaft. 

 

The head needed to be re torqued! Generally the cold side bolts had a break a way torque of about 10 ft/lb less than what I had torqued the bolts to originally.  Re-torquing these bolts I wound up on average adding another 1/4 turn (some more some less). The hot side of the head had the break a way torque about 15 ft/lb less than what I had torqued the bolts to originally.  Retorquing these bolts I wound up on average adding about another 1/2 plus turn (some more some less).

 

 

Edited March 29, 2022 by Konrad (see edit history)

[Konrad]

WOW, that looks like doing it the hard way!

 

To those that advocate adjusting the valves with the engine running what is to be gained? How is the precision and the how accurate are you to the spec value? 

 

From here it looks like a good process to strip the locking nut and may even break the adjuster screw. I hope nobody is going to tell me that it helps with the exhaust stem expansion. (I'd think at idle the EGT is so low as to have little effect worth addressing this way. Many high powered engine have a clearance spec larger for the exhaust valve even with an engine at operating temps, as the valve stem does grow based on the power setting ). 

[EmTee]

On 3/25/2022 at 7:49 PM, EmTee said:

0.016" cold is too tight.  They are supposed to be set to 0.015" when fully hot.  I set mine cold (engine off) to 0.018" because I suspected mine were too tight when I received it.  It's much easier to get accurate settings with the engine off.  As I said, I used 0.018" as the 'GO' and 0.019" as 'NO GO'.  I'm still driving the car with that setting and it isn't as loud as I had anticipated.  Having driven about 200 miles since I set them, I'm going to re-check the cold setting since I had a valve cover leak and now have the valve cover off.  The plan is to reset them hot (to 0.015") in another couple hundred miles.

An update/correction to what I said above.  I reviewed my notes yesterday before re-checking the lash on my '38 before reinstalling the valve cover and discovered that I had actually set the lash to 0.019" cold, with 0.020" as the 'NO-GO'.  Good news is that most were still as I set them.  Only a handful required minor 'tweaking' (roughly ~0.002").

 

As I was doing this, I couldn't help to think about just how hard this would be with the engine running.  As Konrad said, there's no way I can imagine getting the same level of precision with the engine idling.  My plan forward is to run mine at the current settings for another 200 ~ 300 miles and then immediately following a drive, remove the valve cover and do a clearance check (engine idling) as quickly as possible.  I'll then compare the hot measurements to cold measurements (the next day) and tweak the valves cold to approach the 0.015" hot lash target.

Edited March 31, 2022 by EmTee (see edit history)

[Matt Harwood]

For adjusting the valves, I did it with the engine running the first time. I turned down the idle until it was almost stalling and it wasn't that bad, although it is obviously less accurate. I noted the position of the screw slot when the feeler was correct, then secured it at that angle. The second time, I got smart and simply warmed it up with a drive, then used a remote starter button to bump it over for each cylinder and did my adjustments while it was still hot. You have to work quickly so that it doesn't cool off too quickly, but if the adjustments are close it's not difficult to do. I don't like the idea of doing it cold and guessing what it will be hot.

[EmTee]

9 hours ago, Matt Harwood said:

I don't like the idea of doing it cold and guessing what it will be hot.

Yeah, but that's why I plan to measure the hot clearance and then compare that to the cold measurement.  The objective is to empirically determine the lash shrinkage due to temperature.  If, for example, the average hot measurement is 0.003" less than the cold value, then I'd set the cold lash to 0.018".  I anticipate that the lash change due to temperature will be different for the intake and exhaust valves, with the exhaust difference likely larger.  In any event, I plan to perform the experiment and I'll report back whatever I discover... 

[valk]

I think you’re on the right track. Measuring the gaps while the engine is hot and running is straight forward once you get the hang of it,  and can be done repeatedly if needed until they are all .015.  Adjusting them when running is a different story. So measure them all hot and running, shut it off, adjust each up or down, and try again….

[Gary W]

Probably the biggest up side to adjusting the valves on a hot, running engine is you can actually hear which valves are a bit noisy, focus in on them and adjust them accordingly.  When these engines are idled down, they turn over slow enough to make the initial measurements with a feeler gauge.  Then just adjust the ones that are not .015. 

I posted the video because I thought that was the proper technique for adjusting the valves.  My buddy John, who has been working on these cars for 75 years does it like that, and he showed me how to do it.  A little clumsy for sure, but I didn't know there was another way!  Always learning!

Neil, keep at it!  Thanks for posting your work.  I'm looking forward to a successful finish!

[neil morse]

Thanks, Gary, and thanks to everyone who has contributed to the valve adjustment discussion.  Very interesting.

 

And, yes, please, let's get to that successful finish!  It's the unforced errors that are getting to me.  Just waiting on the new pushrod and I will get back on it in a few weeks when I'm back in town.

[neil morse]

Back on Track (part 2)

 

I got back from my trip yesterday and was happy to find that Cars, Inc. had delivered the new pushrod and adjustment screw that I had ordered.  The pushrod was different at both ends from the other ones on my car.  Here are comparison photos ("new" one on top, original below).

 

 

Newbie that I am, I was concerned about whether these variations would make any practical difference.  After being assured by both Don and Konrad that they wouldn't, I went ahead and put everything back together.  Started her up, and was very happy and relieved that it's back to running just the way it was before we broke the pushrod!  So I'm very relieved and looking forward to doing the timing and "hot" valve adjustment that we were set to do when disaster struck.  Stay tuned for more updates.

[EmTee]

As long as the lengths are the same, I consider it "functionally equivalent". 

[neil morse]

Core Plug Project Complete!

 

I am very happy and relieved to report that this project is DONE!  We did the final "hot" valve adjustment today, put the new gasket on the valve cover, and declared the job finished.

 

Konrad was (and I believe remains) skeptical about the utility of doing the valve adjustment with the motor running, but I persuaded him to try it after finding this entry in the Owner's Manual:

 

 

Here's a little video of our efforts (that's Konrad on the feeler gauge and me on the screwdriver and wrench).

 

 

I was pleased with the result, although I'm not convinced that it made a huge difference to do it with the engine running.  But the bottom line is that my car is back up and running with the coolant leaks taken care of (and running 10 degrees cooler to boot).  A long project with a few wrong turns, but I'm a very happy camper in the end!

[valk]

Bravo! Still not sure If I’ll ever do it this way but nice to know it’s possible! 

[EmTee]

Definitely easier with 4 hands, but easy to see that this would be a real chore alone. 

 

Congrats on getting her back on the road!

[Konrad]

Yikes, this process was by the same engineers that had us torque the head using the periphery method.

 

It works, but I see no benefit and it actually is rather difficult.

 

I did learn that it is possible to adjust an engine with solid lifters while running. It's not a process I'm likely to repeat. But I did learn a new process.

[neil morse]

Fine Tuning

 

Konrad and I went down to Don's today so I could return the tools I had borrowed and we could do some more work getting the timing right and the idle smoothed out.  Or more accurately, I should say Don and Konrad did some more work while I watched and tried to learn some things.  A very productive morning -- she's running just as well now as before we took the head off, which is very well.  (In photo #3, that's Don's Roadmaster in front with my Super in the background.)

 

 

 

 

 

 

 

[EmTee]

1 hour ago, neil morse said:

...I went down to Don's today...

Ah, so that's Don's 38 -- I like it!  He's been a help to me via this forum but, I envy you being close enough to just 'drop by'. 

[JohnD1956]

2 hours ago, neil morse said:

Fine Tuning

 

Konrad and I went down to Don's today so I could return the tools I had borrowed and we could do some more work getting the timing right and the idle smoothed out.  Or more accurately, I should say Don and Konrad did some more work while I watched and tried to learn some things.  A very productive morning -- she's running just as well now as before we took the head off, which is very well.  (In photo #3, that's Don's Roadmaster in front with my Super in the background.)

 

 

 

 

 

 

 

how does that tool work?

[Grimy]

5 minutes ago, JohnD1956 said:

how does that tool work?

It is placed on top of each air horn to measure the suck from each carb, so you adjust throttles to be identical.  I use a vacuum gauge as well on idle mixture.

[JohnD1956]

57 minutes ago, Grimy said:

I use a vacuum gauge

Ah ha!  Thanks.  

[neil morse]

2 hours ago, EmTee said:

Ah, so that's Don's 38 -- I like it!  He's been a help to me via this forum but, I envy you being close enough to just 'drop by'. 

That's ONE of Don's 38's.  He also has a Special Coupe.  And yes, it's wonderful to be able to "drop by" Don's place and benefit from his knowledgeable assistance!  I won't praise him any more because he would be embarrassed.  He has been extremely helpful and generous to me.

[Grimy]

41 minutes ago, JohnD1956 said:

Ah ha!  Thanks.  

JohnD1956, I use the vacuum gauge first to get the idle screw adjustment.  The Uni-Syn is then used on multiple carbs to (literally) measure the suck, as I said, and then we tweak each carb's throttle adjustment so that all carbs have the same reading on the Uni-Syn.  I'm sure there's a much more scientific explanation, but that's how I learned it many, many years ago and it has worked for me on infrequent uses.  EDIT:  It's a back-and-forth process:  I do it a second time, and occasionally a 3rd time on twitchy engines, to get a finer balance between idle screws and throttle screws.

Edited April 26, 2022 by Grimy
added last sentence (see edit history)

[EmTee]

9 hours ago, Grimy said:

I use the vacuum gauge first to get the idle screw adjustment.

Do you adjust mixture screws to achieve maximum vacuum reading, or do you then back-off a certain amount (e.g., 1/2 turn) from the max vacuum?

[Konrad]

I'd like to add my thanks for Don's gracious assistance and access to his shop.

 

This project got a bit out of hand with the failed push rod, ignition timing and carb adjustments. We basically lost all the base lines. But with Don's knowledge and tooling we got Neil's car back to being the smooth machine she was prior to pulling the head.

 

I feared that with the pushrod issue the valve might have tapped the domed piston. I wanted to make sure that the engine was mechanically sound before doing any more "tuning work". As Don has a leak down tester we drove Neil's car down to his shop. I was pleasantly surprised at just how good a shape the engine is in, mechanically. The leak down showed 15% leakage and even after the rings dried was still above 20%. All the leakage was past the rings. (This is a good sign, it means the rings aren't so tight as to be adding too much drag).

 

This was the first time I was in the car after taking off the head. On the drive down. I noticed that the carbs would sneeze under trailing throttle, The car bucked at low speed in stop and go traffic. But I didn't notice any pinging when accelerating. All these symptoms could be signs of there being an open valve or too much ignition timing (other than the lack of a knock). On the drive down I was getting more and more depressed talking myself into thinking that the valve was bent. 

 

At Don's place we shut down Neil's car and played a bit of a shell game moving some other cars around. When Neil tried to restart the warmed up engine the starter protested. Both Don and myself knew what the issue was. I was feeling much better! But since we had made the trip down we went ahead with the leak down test. If for no other reason than to eliminate any lingering doubt.

 

So what was the issue? Well, too much ignition advance! This brought up an issue I was having earlier in that I couldn't find the timing marks on the flywheel.  Changing the distributor one tooth had it's own issues. We will need to look into these ignition issue a bit more in detail. But for now the engine is a smooth as we have ever seen her. But she is running a bit retarded. 

 

We synced carbs at idle and adjusted the carb idle mixture. Mainly because Don had a Uni-Syn.  

 

(Hint: If you guys have multi carbs make sure all are flowing at idle so as to keep the fuel circuits purged and ready to flow when you demand it [step on it]. Far too many folks think the stumble is from too much fuel when the second carb opens up. When in fact it is the lack of fuel from the second carb while it purges the vapor lock). 

 

So how did the push rod fail if the valve didn't hit the piston? With the effectively longer push rod from the rocker sitting on the edge of the bucket the valve spring became overly compressed and coil bound. With the coil bound solid, something had to fail. Luckily the push rod bucket failed with no secondary damage.

 

The car still needs some fine tuning but that's for another day.

 

 

Edited April 27, 2022 by Konrad
spelling (see edit history)

[Grimy]

1 hour ago, EmTee said:

Do you adjust mixture screws to achieve maximum vacuum reading, or do you then back-off a certain amount (e.g., 1/2 turn) from the max vacuum?

@EmTee my technique for mixture screws is usually to set them as lean as possible at highest vacuum.  That is, there is usually a "shoulder" of adjustment at max vacuum from lean to rich, and I stay on the lean side of the shoulder.  But with the 10% ethanol we're stuck with in California, I now go a bit richer on the shoulder.

 

Backing off is done when setting ignition timing with the vacuum gauge--the old "power tuning" I learned 60 years ago:  With a warm engine at slow idle (below first stage of centrifugal advance), advance distributor to max vacuum, then back off (i.e., retard) about 0.5 to 1.0 inches Hg.  Then road test, looking for (1) slow, suffering cranking speed such as Neil encountered and (2) pinging under sudden low-rpm load (floor it in 2nd gear on an upgrade), either of which indicates too much initial advance.  Back off (retard) another 0.5 in HG and re-test.

[Grimy]

@Konrad and @neil morse when you look at the timing, please determine whether the distributor is fully retarding at shutdown.  Flathead Cadillacs 1937-48 for sure, and some Buicks, have their distributor plates mounted on three small ball bearings in a channel in the inner circumference of the distributor body.  I owned a 1939 Cad 75 for 40 years and this was a problem:  the balls get flat spots, lack of lube, the channels get flat spots.  The distributor plate then does not fully rotate (retard) at return-to-idle or shutdown, resulting in starter groaning/suffering and thus appearing that the timing is too far advanced.

 

There were two aftermarket solutions back in the day:

* "Spark-O-Liner" snap in new channels that usually came with new ball bearings

* "Dyna-Flite" replacement plates mounted on multiple ball bearings (I may have a Buick one left).  But these ancient parts, new in box, still have to have the old hardened grease removed and relubricated.

[DonMicheletti]

NUTS !

Grimy is right about those 3 balls on the distributor point mount plate. I forgot to check motion of that.

I have yet to work on one of these distributors where the ball groove wasnt crudded up.

 

I think we did have fun yesterday.

Edited April 26, 2022 by DonMicheletti (see edit history)

[Grimy]

3 minutes ago, DonMicheletti said:

NUTS !

Grimy is right about those 3 balls on the distributor point mount plate. I forgot to check motion of that.

I have yet to work on one of these distributors where the ball groove wasnt crudded up.

 

I think we did have fun yesterday.

Don and Neil, I MAY have a Spark-o-Liner and Dyna-Flite for Buicks left in my stuffed garage.  I'll look later today.  Glad you guys had fun--wish I'd been there to learn and to kibbitz!

[DonMicheletti]

I didnt know about that neat replacement for the troublesome 3 ball breaker plate mount when I did my distributors. As a result I have a worlds supply of replacement balls.

 

My one "on the road" failure of the Roadmaster, in over 35 years, was the breaker plate coming loose from the loss of one of those balls. The good part was that I was 1/2 block away from home.

[Konrad]

9 hours ago, Grimy said:

@Konrad and @neil morse when you look at the timing, please determine whether the distributor is fully retarding at shutdown.  Flathead Cadillacs 1937-48 for sure, and some Buicks, have their distributor plates mounted on three small ball bearings in a channel in the inner circumference of the distributor body.  I owned a 1939 Cad 75 for 40 years and this was a problem:  the balls get flat spots, lack of lube, the channels get flat spots.  The distributor plate then does not fully rotate (retard) at return-to-idle or shutdown, resulting in starter groaning/suffering and thus appearing that the timing is too far advanced.

 

There were two aftermarket solutions back in the day:

* "Spark-O-Liner" snap in new channels that usually came with new ball bearings

* "Dyna-Flite" replacement plates mounted on multiple ball bearings (I may have a Buick one left).  But these ancient parts, new in box, still have to have the old hardened grease removed and relubricated.

@Grimythank you for your insight! I think you are on to something here. While I think I saw the advance moving when the throttle was goosed. Next time I see the car I'll pay more attention to the behavior of the advance curve.  I'm thinking the advance maybe frozen as Neil is reporting gross mileage numbers. 

 

I have a question about setting the mixture. My understanding of the mixture screws is to allow for production tolerances and wear when setting stoichiometric mixture strength at idle. If so, finding the lean mixture highest RPM has the same result regardless of the energy density of the fuel or oxygen content of the fuel. This means there is no need to run the engine richer than peak rpm regardless of the fuel.  True, fuels with a higher oxygen content or lower BTU content will have higher flow rates at peak rpm (idle mixture screw will be out more). I see no reason to add to this flow value by richen the engine even further. This is true for steady state conditions. Is the rich setting to deal with off idle surges, lean transition ports?

 

Now if tuning for dynamic conditions (acceleration) with carbs set up (manufactured) for higher energy density fuel, things can get complicated when using alcohol fuels with the undersized acceleration pumps, power valves, emulsion tubes and transition ports. These are tractability issue with flat spots in the throttle response. Richening the main metering jet and idle mixture may mask this issues. But I like to first try to lengthen the acceleration pump stroke (volume) and speed (jet size) when tuning a carb to run on fuels that carry oxygen. 

 

Full disclosure; I'm a big proponent of lean of peak tuning. I learned of this with the Allison and Packard aircraft engines, of WW2, thanks to Lindbergh's long distance work. Don't confuse this with overly lean engines and associated burned engine components!

Edited April 27, 2022 by Konrad (see edit history)

[Grimy]

3 hours ago, Konrad said:

@Grimythank you for your insight! I think you are on to something here. While I think I saw the advance moving when the throttle was goosed. Next time I see the car I'll pay more attention to the behavior of the advance curve.  I'm thinking the advance maybe frozen as Neil is reporting gross mileage numbers. 

 

I have a question about setting the mixture. My understanding of the mixture screws is to allow for production tolerances and wear when setting stoichiometric mixture strength at idle. If so, finding the lean mixture highest RPM has the same result regardless of the energy density of the fuel or oxygen content of the fuel. This means there is no need to run the engine richer than peak rpm regardless of the fuel.  True, fuels with a higher oxygen content or lower BTU content will have higher flow rates at peak rpm (idle mixture screw will be out more). I see no reason to add to this flow value by richen the engine even further. This is true for steady state conditions. Is the rich setting to deal with off idle surges, lean transition ports?

 

Now if tuning for dynamic conditions (acceleration) with carbs set up (manufactured) for higher energy density fuel, things can get complicated when using alcohol fuels with the undersized acceleration pumps, power valves, emulsion tubes and transition ports. These are tractability issue with flat spots in the throttle response. Richening the main metering jet and idle mixture may mask this issues. But I like to first try to lengthen the acceleration pump stroke (volume) and speed (jet size) when tuning a carb to run on fuels that carry oxygen. 

 

Full disclosure; I'm a big proponent of lean of peak tuning. I learned of this with the Allison and Packard aircraft engines, of WW2, thanks to Lindbergh's long distance work. Don't confuse this with overly lean engines and associated burned engine components!

Konrad, you have much more sophisticated knowledge and experience than I do!  My efforts on vintage iron the last 30+ years have been on flathead engines (Cadillac and Pierce), where it is an article of faith to keep them richer than stoichiometrically optimal to minimize the chances for burning valves and worse.  The "worse" pertains primarily to my dual valve T-head 1918 Pierce (Pierce had dual valves 1918-1928), where there is very little iron "meat" around the valve seats near the top of the cylinder bores--resulting in a sharp edge where the deck meets the top of the cylinder and creating a hot spot.  The Best Practice for rebuilding a dual valve Pierce is to sleeve back to standard or even 1/8" less, then chamfer the top edge about 45* to eliminate the hot spot.  Neil's OHV Buick probably does not need the additional fuel.

 

As to the advance/retard issue, my experience is that a worn 3-ball system fails to retard--i.e., the springs cannot overcome the friction during a return-to-idle or complete shutdown.  With the rotor in place, try to turn the rotor in the retard direction and you'll provide a small boost to the spring effort and overcome the friction.

Edited April 27, 2022 by Grimy
fix typo (see edit history)

[Konrad]

My experience is as an industrial mechanic in my youth. Later I had a hand in some Porsche based race teams. But most of my professional  experience is with turbine engines. So while I know my way around a combination wrench. I yield to the hands on knowledge of guys like you and Don when it come to these engines.

 

I have countless hours building/rebuilding the Chrysler Industrial (Ind) flat head six cylinder engines. 

 

I have never seen a gasoline engine damaged by too lean a tune. Yes, I've seen burned valves and holed piston when things fail like the jets get blocked (dirty fuel). Or the fuel metering orifice falls out off the fuel injector return line.  So yes it is possible to damage an engine by going over lean. But you have to go way over lean. I've never seen using fuel as a combustion chamber coolant actually work*. In fact I've seen this cause accelerated cylinder wear from the washing off of the cylinder oil film. These were on high duty cycle industrial engines.  

 

Is there any documentation from the SAE, OEM or other credible source to give credence to the idea of using fuel to cool the combustion chamber to add life (safety margins).

 

* With super charged direct injection engines I have seen the non fuel ladened inlet charge allowed to flow past the exhaust valve during valve over lap to cool the valve.  Later after the exhaust valve closes fuel in introduced into the inlet charge.

 

 

Edited April 27, 2022 by Konrad (see edit history)

[Konrad]

44 minutes ago, Grimy said:

...

 

As to the advance/retard issue, my experience is that a worn 3-ball system fails to retard--i.e., the springs cannot overcome the friction during a return-or-idle or complete shutdown.  With the rotor in place, try to turn the rotor in the retard direction and you'll provide a small boost to the spring effort and overcome the friction.

Understood. I just need access to the car.

[Grimy]

1 hour ago, Konrad said:

So yes it is possible to damage an engine by going over lean. But you have to go way over lean. I've never seen using fuel as a combustion chamber coolant actually work*. In fact I've seen this cause accelerated cylinder wear from the washing off of the cylinder oil film.

An entirely different factor at play here in the old stuff, but allied, is the propensity to overheat, especially unpressurized cooling systems.  Wish you'd seen the valves in my 1922 Paige (L-head 6, 3.75 x 5)--the worst valve and seat recession I've ever seen--but that car had the most buggered cooling system ever, as well.  I'll check to see if I still have the (magnetic) valves for your inspection.  There are now new exhaust valves with hardened seats.  Couldn't find any stainless valves of the proper size so had to go to a slightly larger stem diameter magnetic (steel) valve, and I reamed the existing guides to fit.  As to washing oil off cylinder walls (and resultant crankcase dilution), I haven't seen ill effects in engines I've had to open up more than once.  I'm aware of the vulnerability and try to balance.

1 hour ago, Konrad said:

Is there any documentation from the SAE, OEM or other credible source to give credence to the idea of using fuel to cool the combustion chamber to add life (safety margins)

I haven't worked on the Chrysler Industrial sixes, but have had a 1934 Chrysler 6, 1947 and 1948 DeSoto Suburbans, and a 1949 Chrysler 6.  All had strong, durable engines that would almost run forever if not frequently overrevved.  Sixty years ago, the crowd I ran with used to say, the sound of a slight knock in a MoPaR 6 means you have 50,000 miles left before you have to open it up.  If memory serves, Chrysler adopted hard seats in the mid-1930s.

 

I've seen no such documentation.  My 1918 and 1925 have adjustable main jets, adjusted on the run from steering column (1918) or dash slider (1925).  The owners manuals are vague.  Absent a 5-gas machine with dashboard readout, it's seat of the pants calibration behind the wheel, and I've become sensitive to the feel and the engine's response under varying conditions.  Climbing through 8,000 feet in Idaho four years ago, it was indeed nice to be leaning the carb out during the climb while fixed jet cars calibrated for sea level were belching black smoke.

[Konrad]

Balance is the key concept here. 

 

I've seen many an engine with burned valves. Exhaust valves cracked to the point I wondered how the engine even ran as it wasn't making any kind of seal. Pistons seized to the point the rods failed.  And the common issues is overheating! This is the prominent failure mode with industrial engines as they often are run at over 80% duty cycle. 

 

The VW was an engine notorious for burned valves as the heads often had the cooling fins blocked. And being undersized often were run at full power for a long periods up long grades.

 

The Chrysler IND flat six engine is the same engine you are familiar  with. Chrysler made a "Winnebago" engine  It was some long stroke big block 419 cid with sodium filled exhaust valves.

 

As difficult as it was for me to understand the exhaust valve is responsible for getting approximately 80% of the combustion chamber heat into the water jacket.

 

I saw  lot of engines with soft bronze valve seats ranging from Cosworth to Datsun.  Also saw a lot hard Stellite seats. It is fun to see what concerns the engineers had in what application.

 

But on a dyno I never saw where a rich mixture was used to cool. As I recall the fuel mixtures were kept between 15:1 to 13:1 by mass. 1 being the gasoline. 

 

Yikes, did these engines with the operator adjustable mixture have any EGT feedback? Tractability is a good way to stay safe as long as the operator is paying attention. But how many times have we seen engines run out of oil were the driver said "It was just making engine noises"!

 

I love these old engines. I like to see how the engineers and bean counters tried to solve the problem they confronted.

 

*I only go back 45 to 50 years as I worked my way through school as an "automotive machinist and engine builder". I saw a lot of distressed metal, especially at harvest time!

 

Edited April 27, 2022 by Konrad (see edit history)

[Grimy]

My 1934 Buick 50 series also had sodium-filled exhaust valves from new.  That engine was a real rock-crusher.  The stuff I play with is long-stroke (4.75 is shortest), low rpm (2,500 redline on the 1918, 3,000 on the 1925 Series 80) with torque peaks at 1000-1400 rpm.  With the unpressurized cooling systems (and vacuum tank on the 1925 only), you climb hills on warm days by paying close attention to the temperature gauge/Motometer:  Stay at sweet spot as much as possible, even if you have to drop down a gear, because the more fuel that goes in, the more heat generated that needs to be extracted by the cooling system--and vac tank cars aren't pulling fuel forward if you're beyond half throttle.

 

EGT gauges?  No such thing!  It's all done seat-of-the-pants, and we who drive these cars must develop a great deal of perception sensitivity if we want to avoid massive repair costs--as did their original owners.  That said, today we probably drive these cars more aggressively than when they were new. 

 

Oil levels and pressure are closely monitored.  Were you aware that oil control rings weren't adopted until the mid-1920s?  I had a 1928 Buick owners manual which stated (essentially) "an engine properly broken in and in good condition can be expected to consume ONE GALLON [emphasis mine] of oil per thousand miles"--and that was with oil control rings.

 

I'm tagging @edinmass since he is our resident expert on adjustments to compensate for modern fuels, and who carries a 5-gas analyzer in his backpack or perhaps even his back pocket.  Ed, can you please address some of Konrad's questions?

Edited April 27, 2022 by Grimy
fix typo (see edit history)

[NailheadBob]

There is a special inexpensive valve adjusting tool by Snap-On number V21-E ($14,00) and newer version V-22 ($22.00) on e-bay that would make valve adjusting so much easier, shallow 3/8" drive socket attaches on one end and the adjusting knob on opposite end has the straight blade screw driver end.

 

Bob

[edinmass]

51 minutes ago, Grimy said:

My 1934 Buick 50 series also had sodium-filled exhaust valves from new.  That engine was a real rock-crusher.  The stuff I play with is long-stroke (4.75 is shortest), low rpm (2,500 redline on the 1918, 3,000 on the 1925 Series 80) with torque peaks at 1000-1400 rpm.  With the unpressurized cooling systems (and vacuum tank on the 1925 only), you climb hills on warm days by paying close attention to the temperature gauge/Motometer:  Stay at sweet spot as much as possible, even if you have to drop down a gear, because the more fuel that goes in, the more heat generated that needs to be extracted by the cooling system--and vac tank cars aren't pulling fuel forward if you're beyond half throttle.

 

EGT gauges?  No such thing!  It's all done seat-of-the-pants, and we who drive these cars must develop a great deal of perception sensitivity if we want to avoid massive repair costs--as did their original owners.  That said, today we probably drive these cars more aggressively than when they were new. 

 

Oil levels and pressure are closely monitored.  Were you aware that oil control rings weren't adopted until the mid-1920s?  I had a 1928 Buick owners manual which stated (essentially) "an engine properly broken in and in good condition can be expected to consume ONE GALLON [emphasis mine] of oil per thousand miles"--and that was with oil control rings.

 

I'm tagging @edinmass since he is our resident expert on adjustments to compensate for modern tools, and who carries a 5-gas analyzer in his backpack or perhaps even his back pocket.  Ed, can you please address some of Konrad's questions?

 

We use EGT when available.........Pierce 12 manifolds have a plug in them to tune.....also we have drilled a few manifolds when we have tons of spares just to get readings. How do I fine tune a car.......simple. I take the entire fuel system apart stem to stern..........actually tank to carb, as well as the ignition, and check the mechanicals. To properly tune a pre war car that has been restored or rebuilt..........I figure 20 hours minimum. Could take 50. Checking gaskets for leaks, modified throttle linkages, incorrect parts from different series........it's amazing what you can find wrong.........and all the little things add up. Buick's with overhead valves are a much more efficient engine than a L or F head and make better power for their size. Different carbs restrict how much you can tune and improve or adjust for modern fuels. Running a hotter plug today is usually a help. I usually tune by the seat of my pants.......being sure to keep the mixture rich and drive the car for 500 miles that way. Learn if it's hard to start hot after sitting an hour, see if it overheats pulling hills, pushes water........is a large scope process. Year and platform considerations, ect. I recently was working on a car that came from "the expert's garage" .....they guy who knew these cars better than anyone else. Shit.....he couldn't even set up a dual point distributor and get the timing right. It's all about the basics........finding the best performance possible by trying different settings, and going down the road for miles. My stuff runs great.....because we spend a ridiculous amount of time getting them right........we don't give up, and we don't stop till we know there is nothing more to get. With this Buick engine, just the fact of a bent push rod makes me draw certain conclusions but without standing there, they are hard to quantify. We have pulled engines all the way down several times on a Pierce eight because we couldn't figure out why we were down on power. That doesn't go over well with paying customers........fortunately in this case it was my own car. These old cars are WORK, and nothing is easy on them. If someone says they are easy, they don't know what they are talking about. Today time is our most valuable commodity but almost no one wants to put it into making a car run, drive, stop, and shift correctly. 98 percent of the cars I drive have slight to moderate clutch chatter........and a well know restoration shop said to me they all do that. Nope.......I fixed it first try, because I have done similar clutches fifty times and worked through all the issues.........today there are very, very few mechanics that have 5000 hours in a shop spinning wrenches. There is no substitution for time in the garage, and that is causing 80 percent of the problems on early cars. The other 20 percent is "it's just an old car and that's how they are.  

 

When I had a chassis dyne, we tuned all the cars on it. While it is gone now, the skill set that was learned there carries over and we seem to do ok now without it. It was a valuable tool in learning how to get cars to run properly. 

 

Edited April 27, 2022 by edinmass (see edit history)

[Konrad]

Yep, these old machines weren't "turn key" devices. 

 

Even some "modern" engines have high oil consumption. I recall the 1979 Porsche 901 (911) engine with aluminum cylinders (Alusil) burned a quart/ 1K miles. 

[Konrad]

I too have to laugh at some of the tuning errors I see with modern equipment. I recall that the stop watch was one of the main diagnostic tools we had to find the "tune" (seat of our pants). Another tool that is lost to the pages of time is reading the spark plug. 

 

From my aviation background and time on the dyno I fail to understand this rich setting. Lean of peak is a well proven tuning state. This is for engines that run at much higher duty cycles than our cars. But yes, many of these older fuel system are rather limited in their capacity. As demands for performance, reliability and tractability increased so did the sophistication of the fuel metering system. 

 

Can you tell us what was the final finding on the engine that took multiple tear downs to find?  I too have had some engines that were a bear to get right. I'm think of some that just had stubborn vibration issues that were out of specification. In the end this was traced to a soft curvic coupling allowing the shaft to flex too much.

Edited April 28, 2022 by Konrad
Remove ref. to bent push rod. (see edit history)

[BobinVirginia]

I enjoy the tuning comments and information. Intake velocity and maximum carb signal with a properly tweaked timing curve through the rpm range are huge with drivability. I enjoy the challenge of wringing out all of the performance and economy from an old engine. Although, I’ve never worked on such an old setup but the principles still apply. Especially with altitude and air density. Thanks to all of you for sharing your knowledge!