VCCA Home Forums TECHNICAL - GENERAL Mechanical - Engine, Trans, etc Valve Adjustment 1928

When attempting to set the timing on 1928 chevy engine in 1927 Capital AA discovered the rocker arms were all out of tolerance by as much as 3/16 of an inch. The engine does run but creates quite a racket. When trying to set .006 gap on the intake ran out of thread for the lock nut. I tried lifting the push rod up and out but would not come. Wanted to check length of rod. Would like to know the procedure for removal of the push rods; and if adjustment screws are manufactured that are 3/8” to ½” longer to accommodate the lock nut? This is my first elder auto and is quite enjoyable and frustrating at the same time.

Hi Jim,

Welcome to the wacky and wonderful world of Chevy 4 bangers. ;-)

The push rods on my 1928 Chevy engines just lift out when the rocker arms are removed. You might have push rods that are too short. The '27 push rods are shorter than the ones for a '28 engine.

Here's a discussion about push rods that might be helpful: Push rods for a '26 engine with a '28 head.

If you want an overview of rebuilding these engines, there are two step-by-step stories on this site on the subject:

1. In the Members Only section of the main VCCA web site (vcca.org), go to the Technical Articles and look for "School is in Session", which documents the rebuild of a '28 engine by master mechanic Ray Holland.

2. Four years ago, I rebuilt the '28 engine in Lurch, my '27 one ton truck (see the links in my signature). During the rebuild, I replaced the bushings in the rocker arms and cleaned up the tip of the rocker arms where they press on the valve tops. The part of the story where I worked on the rocker arms is here: Refurbishing '28 rocker arms.

The beginning of this rebuild is documented here: Resurrecting a 1928 Chevy 4 banger.

Enjoy the journey! Every step forward is worth celebrating!

Cheers, Dean

Way to go Dean, that"s good advice.

Thank you so very much. Will attempt removing push rod while holding lifter down hopefully with a small piece of wood. Then match it with another push rod and compare the two for length. What a wonderful source for information Thanks Jim C

Thanks for the kind words, guys.

The 'stuck push rod' got me to thinking that there might not be good lubrication where the push rod goes into the lifter.

Before every drive, I usually pop the rocker cover off and squirt some oil onto each rocker and the top of each valve adjustment bolt. I know that I can squirt oil into the holes on the rocker cover, but I like the ease of mind of seeing the oil get to where I want it to go. If I'm going on a long drive, I give everything another squirt every 50 miles. I also give the big felt pad a decent squirting.

BTW, there should be little felt donuts around the ball of the rocker that gets pushed up by the push rods. The oil that I squirt onto the valve adjustment bolt drips into the donut and I believe also eventually finds its way down the push rods and onto the top of the lifters. See the pic below that points out the donuts.

I might be guilty of over-oiling things, but I'd rather have too much oil than too little. Besides, as an old Chevy owner, it is my obligation to help fulfill the road-oiling contract that we took over from the Harley folks.

;-) Dean

It isnt the road oiling job but the automatic rust prevention that is happening. Several British vehicles have copied Chev in that regards.
Tony

Thank you for all of the feed back and suggestions!!
Removed the #2 cylinder exhaust push rod; it measured 12 1/2" the bottom end had a very slight to the feel burr and was flattened. Forgot to mention there were no felt washer on the rods. Do not know if the flattening was normal wear and tear or the indication of another problem. Lubrication looks fairly well. When removing the valve cover for the first time there was standing oil in trough for #3 & #4 but none in the front trough but evidence of a wet oil surface all around. Cannot find the specified length of the push rods.

What is the condition of the rocker bushing? If it is totally worn (and the rocker is flopping around the shaft), that could account for approximately 1/8" extra travel at the valve adjusting bolt end. The worn bushing would also contribute to the 'racket' that the engine makes when running.

Dean

Tony’s comment reminds me of an old joke.

Why do the British not build computers?

They can not figure out how to make them leak oil!

Thanks for the feedback. I just removed the #2 cylinder intake push rod to make a comparison of the push rods and there is less than an 1/8" difference with the exhaust being shorter. I also removed the lifters for the two and was surprised to see a hole in the bottom of the exhaust lifter and none in the intake lifter. Wondering if the hole should be there and if not, could have that caused the flatness on the bottom end of the exhaust push rod. Thanks would appreciate your input as this is my first engine experience

The only feedback that I can offer is that the three '28 engines that I took apart in 2017 all had solid lifters with no holes in the bottom.

Hopefully other folks will chime in with their experiences.

I do not have any push rods laying around to measure. All the extra parts that I had from Lurch's rebuild went to a friend.

Dean

I read a while ago on another site about using pushrods that were too short, I think on a 235. They ended up putting the adjustment nut underneath the rocker.

. I tried to take a photo of a 28 push rod. It was in a box of parts that were supposed to be a 28 engine. I didn't take it apart. I was balancing on a 6 cyl engine on a rolling stand so hard to keep camera steady. I did line up the end but parallax view looks otherwise. Sorry it's not much halp. . Lou

Thanks for all the response; .you fellows are GREAT! I removed the push rods for the #3 cylinder and they appear just fine but I was not able to remove the lifters . They are definitely hitting some thing solid that is preventing the removal. Have not been able to find any replacement lifters. The two that came out of cylinder #2 are different... . I have attached to pics as files as I could not insert them. I am leaning towards placing the jam nut on the under side of the adjustment screw but that will not solve the problem of the hole in the exhaust lifter on #2 cylinder.

If you haven't had the oil pan off, now might be a good time to take it off and do an investigation of the bottom end. You do not have to pull the engine to take off the oil pan. If you lift the car and put the jack stands under the chassis (not the axles), the front axle will hang down further and give you more room to work in that area.

In the interest of complete disclosure, however, it is kind of a booger to work with the curved gaskets when putting the oil pan back on. In my engine rebuild saga, I cover a trick to dealing with the curved surfaces that need oil pan gaskets.

With the pan off, you can check out a couple of things:

1. Look at the cam lobes under cylinder 2 for any damage from the lifter with the hole.

2. With a little inspection mirror, make sure that all the oil reservoirs that lubricate the crank and cam shaft bearings.are clear of sludge. If these reservoirs get plugged, not good.

It is also a good chance to clean out any sludge in general that is down there, like on the oil pump pickup screen and in the bottom of the pan.

More data about what's going on is always helpful.

This is a great thread and thank you for taking us along for the ride!

;-) Dean

When you were talking about holes in the bottom of the lifter there should not be a hole in the absolute bottom. There may be one in the side of the lifter near the bottom to relieve oil build up in the lifter. Earlier 4 cylinder lifters were the mushroom style that had to be installed before the cam shaft was installed.

Thank you that explains why I could not remove #3 cylinder lifters.

There might be crud at the bottom of the lifters that prevent them from being pulled out the top.

Here's a photo of two lifters pulled out of Lurch's engine: one as found and one cleaned up.



Dean