VCCA Home Forums TECHNICAL - 1945 AND EARLIER 1929-1932 1931 Valve Train Issues

I was able to start and run my rebuilt engine on Saturday night. Prior to starting I had adjusted the valves cold to .006 (intake) and .008 (exhaust). My method of setting them was to turn the engine over by hand to to point at which the valves were closed for each individual cylinder. I began to hear a mechanical noise while the engine was getting hot. I had not an opportunity to set the idle speed, dwell, and fuel mixture. I shut the engine down and let it sit over night. Sunday, I went back out to revisit this again. Began by checking the valve lash and found adjusting screw for #1 cylinder (intake), with the threads pulled out. I replaced the screw and could not get any adjustment whatsoever. The rocker arm is set against the valve and the push rod. I noticed this similar issue with one of the valves on #5 cylinder. I pulled the lifter cover off, cranked the engine over and the vale train moved freely. I re-checking the valves with various adjustment methods. No luck. Seemed like no compression. Engine cranked fast. I checked compression, and have none in cylinder #1. I have 80-85 psi at each of the remaining cylinders.

I am beginning wonder if there is an issue with push rods or lifters? I am using new lifters, original camshaft, and original push rods. Does anyone have measurements of what the push rods and lifters should be? I tried to install new push rods, the cups would not fit on the rods and seemed too long.

I am going to get a cylinder leak down tool this week to verify nothing else is going on with rings.

All input appreciated. Thank you.

The parts books says the push rods are 12 " long. The push rod sits in the bottom of the lifter so the length of the lifter would not be important. Just the thicknes of the bottom of the lifter which is slight. This lifter was used from 1929-1939 and nothing like the lifters used after tha where the push rod sat on top of the lifter.

Hello GreenBayPacker14,
You might be interested in the post offered by Oldengineer on 09/08/12 labeled 'valve adjustment before 1st start up'. It's not your engine but should be helpful. After logging in, go to Users. Select O in the alphabet for Oldengineer. Select - show user's posts. Go to the posts on page 6. Select the post given on 09/08/12. Good luck.

Based on that either you have a Valve STUCK OPEN, or bad rings since the cylinder is NOT holding compression. Based on your post:
do you mean that when you turned the screw it did NOT move up and down or that it moved up and down but had no effect ?? And if the Rocker arm is against BOTH the rod & Valve and when you adjust the SCREW OUT you can NOT get a .006" gap that may mean that either the ROD is too long or the VALVE STEM is too long. Which would explain WHY there is NO compression on that cylinder. (Valve Stuck Open)

Double check your rods, they ALL should be the same length & type. Double check your Valves, Exhaust should be the same length, and intake should be the same length.

let us know what you find out ...

Lubricate the valve guides/stems on that cylinder....infact lube all of them by squirting a thin oil onto of the guide by going through the valve spriing. Your rebuilder may have made the valve stem to guide clearance too tight. A common problem and can get worse when the engine gets hot.

If you can't figure out the problem then you may want to consult with the place that rebuilt your engine and have them look at the issue. Your engine should be guaranteed.

Ok, here is what I found. (before we proceed, I had the rocker arm assemblies rebuilt as well as the cylinder head, which is not from this car). I performed a cylinder leak down test on cylinder #1, no leaks. I took the valve train off to confirm, I had compression at 50 PSI and no cylinder leakage. I have a second valve train assembly which I began to compare to. I tried moving rocker arms, found some inconsistencies. I then began to shim the rocker arm stands with machine washers to raise the height of the rocker arms(I had problems and cylinders 1 & 5 intake). I kept doing this until I found the right placement where I could adjust the valves(cold). I am beginning to think there is an issue with the cylinder head and valve train. I got this car without a cylinder head and a lot of extra parts. I bought a cylinder head from ebay and wondering if it is not for this application? Does anyone have the ability to identify the correct head and valve train?

The casting number on a 1931 head is 836273. They are the raised numbers on top of the head.
The rocker arms should have the 835549 casting number.
The push rods should be 12" long.
I would suspect you may have a 1932 836718 head or a 1933 836961 head.

Post the casting numbers that are on the cylinder head and we will tell you what you have.

The casting number on the head is 835503. Best I can tell from the rocker arm stands the casting number is 835572. I bought the head from ebay and the seller said it was for a 29-31 Chevy. I didn't notice until I began assembling this engine, there was no port for the water temp sender at the back of the head. It was located at the front under the thermostat housing. I ended up drilling and tapping a port at the back of the head to accommodate the water temp sending unit.

Your cylinder head is for a 1929 only. It is not for a 1931.

You have a 1929 head. It has equal size intake and exhaust valves.

The rocker arm stands ae the same for 1929-1931.
The 1929 head used the same sized valves for intake and exhaust. Would be intresting to see how the shop handled this.

Well, with this being a 1929 head. Do I need to stop where I am at or give this a try?

I would suggest installing the correct 1930-31 cylinder head.

Here are some photos of before and after the machine shop reconditioned the head.

It looks as if they used larger intake valves....no problem in its self.