1938 Studebaker President -

[Guest jimrie]

Hi All,

I have a 1938 President Straight 8 engine. I have noticed a puffing sound while listening to the exhaust. It becomes very rhythmic when the RPM’s are increased. I held a piece of paper up to the exhaust pipe and the paper was sucked to the pipe when making the puffing sound.

Anyway, I am looking at my options for repair.

I would assume this indicates a bad exhaust valve. I was going to check compression and see what cylinder is the culprit. Then I was planning on making sure the tappets are adjusted to .016. The only other thing I was going to try is some carbon blasting. I have read that pouring a small stream of water into the carburetor can clean out years of carbon from the cylinders and more importantly the valves.

Before I do anything I thought I should see if any of my Studebaker buddies had any other ideas.

The car is running very good other than a little shaking at idle. Reeves up nice and starts good.

Please share your thoughts.....

Jim Rieschl

[Guest jimrie]

I performed a compression test all cylinders last night. They were all equal @ 90 psi.

I am going to investigate the points and timing next.

[Guest stude8]

I was thinking you had the right plan when I read your first post. The equal compression sort of confuses the plan?

I just thought that you still might want to open the lifter gallery plates and watch and listen for a broken exhaust valve spring with the engine running.

Theoretically with the engine not running a valve with a bad spring could still close and give good compression reading but when running the time between the cam lobe lifting it is so frequent that a weak or broken spring could possibly allow the valve to stay open between lobe lifts. Or even a sticking lifter for that matter. Has this engine been sitting unused for an extended period?

Sitting unused for long periods could allow rust to build up on the lifter OD.

I have had an old 1929 President engine that the lifters prevented it from cranking (20 years in a pasture) and it took weeks of soaking them with trans fluid and Liquid Wrench to free up. It did eventually run but had other serious ring problems so it was off to rebuilder. Stude8

[Guest jimrie]

Thanks for your reply stud8,

I forgot to mention - That the first thing I did was remove the lifter covers and watch while the engine was running. I could not see or hear anything out of the ordinary.

This engine has been run every year and for the most part it runs very good. I have noticed a slight puffing sound ever since day one and never really thought much about it. I am 46 years old and never really heard a straight 8 engine run before, so I did not really know what to expect.

The reason I am leaning toward a timing issue is I have not touched or changed the points or distributor cap since I started using the car. I have a NOS cap, rotor and points in the box so I was thinking about giving that a shot next. Unfortunately I do not have any equipment to sync the dual points. I was planning on making something with a protractor to get the second set of points to break at 45 degrees. I was planning on setting the first set off the timing mark according to my shop book instructions.

If a spring was broke - Would I see it very easily? I did not really inspect them that close while the covers were off.

The puffing noise seems more rhythmic when the engine is revved up a bit. This would lend itself to a possible weak spring.

Jim

[Guest stude8]

Jim

Too bad you don't live in Southern IL, I have a Sun 504 distributor machine, sync'ing points is easy with it, check any local older established shops whether they have a Sun machine or equivalent to setup the distibutor on. In the photo is a 1929 President 8 dual point 668C distributor being tested.

Stude8

[Guest jimrie]

Thanks Stud8,

I could not open your photo. But I have seen pictures of the Sun 504 before. I wish I was closer to you also....

I replaced the points on Friday. Only took about 1/2 hour. Started the car and it appears to be running much smoother. When I first started the engine the puffing slowly started going away. I was so excited...Then after the choke opened up and the idle slowed down the puffing returned.

I have not replaced the cap and rotor yet. The contacts are burnt on the cap.

I was going to clean some of the carbon out of the engine using the water in the carb method. I plan on slowly injecting the water using a squirt bottle. I have never done this but have heard it work well.

If none of these things stop the puffing, I will probably remove the side valve covers and re-inspect the valves and valve springs again.

I am currently trying to locate a head gasket in case I want to pull the head and really inspect the valves.

Jim

[Guest jimrie]

I replaced the cap and rotor last night. No change. He is still puffing from the exhaust.

I am planning on the carbon blasting tonight.

If the exhaust valve does not seat after the carbon cleaning I will be forced into pulling the head.

But before that I will try to re-examine those valve springs.

The saga continues..............

[Guest jimrie]

Well –

Carbon blasting did not help at all. I am gearing up to pull the head and see what is really going on. I purchased a valve spring compressor on Ebay. In the meantime I will examine the valve springs again.

The only thing I am still wondering about is the timing on the points. When I replaced them the only thing I could adjust was the gap with a feeler gauge. I have not figured out a way to get the second set of points correctly set to break at exactly 45 degrees. It is my understanding that each point provides the spark for 4 of the cylinders. So, if the second set is not timed correctly could it be causing a misfire in 4 of the cylinders? Could half the engine be getting the spark before the exhaust valves have closed all the way?

I may have to buy a cheap protractor and make my own gauge……………..

Jim

[rbk]

I can get you a head gasket.

Robert Kapteyn

studebaker@mac.com