VCCA Home Forums TECHNICAL - 1945 AND EARLIER 1933-1936 Another bent push rod

I have straightened solid pushrods several times in the past. A few straightened multiple times. Never had any rebending problems as long as the valves were not stuck. If the valve sticks it is preferable to have the pushrod bend instead of one of the alternatives. I also learned that a glass plate was not the best to determine if a bend rod was indeed straightened. I use a piece of 2x4 and watch both ends of the straightened rod. The pushrod ends are not always round nor centered. The wobble can be misinterpreted as the rod still bent.

After conversations with 3 friends....one a mechanical engineer, another a 41 year mechanic who now teaches automotive electronics and welding, and the 3rd is a retired mill wright.

All 3 gave basically the same answer, new ones NOS NORS are dirt cheap, why would the person want to ATTEMPT to straighten them and put them back into the motor.

The millwright also suggested to " put them in a lathe and check them for absolute straightness. Considering parts cost its a no brainer".


my last words on this thread.
mike lynch

Just to set the record straight. 1933-36 pushrods are not dirt cheap or easy to find either. Now if you are talking about a small block V-8 then yes they are available.

Being there are no usable "centers" on the push-rods, you pretty much have to check and/or straighten them on a lathe ( see my resent posts in the '46-'48 Forum on the straightening method I used )

I think it's really all about time spent vs. How deep your pockets...How available the part is vs. Equipment to repair the part on hand...

I have used a small arbor press to straighten pushrods and then roll them on a window glass mark the high spots and have another go at it on the press wirh a couple of 1/2" washers on the low places, or if you have some large hex nuts stick them thru the nuts, and press away. if they roll without lopeing they will work. If you ever worked on a farm you will learn to improvise!

Well, this has been a fun discussion. More fun for me, since every day I go outside and work on the car for 5 or 6 hours!!! And that's when I "verify" or "deny" your suggestions!!!


Here's my decisions.

1) I removed all rubber boots off the intake valves. I'm going to see how much oil it burns and whether there's a cloud of blue smoke when I drive it. (None of the exhaust valves had them installed.)

2) I am not going to manually straighten any of the pushrods unless I absolutely have to. Yes, two of them were VERY bent and "common sense" says -- "If it's broke, fix it."

Ha ha... Or... replace it!!!!

I straightened push rods in my '31 in 1985 and they are still running true today. So, on some engines, it can be done with effective results. (...and if I lived on a Farm, then I'd ALWAYS try to straighten them.)

NOW THE FUN ITEMS----

3) Looking at the photos below, I concluded that by removing the keepers that I can still use the small springs at the bottom of the push rods. The gap can be compensated by the valve adjustment. The spring pressure will be slightly less, but it still has a small effect on the tappets - hopefully keeping them in tension against the camshaft.

NOW THE REAL ISSUE -----

4) Holy cow. Look at the last photo below. That's the fuel tank - which Dick and I removed today. When we looked at the gas sending unit, it was obvious what was causing the stuck valves. The gas inside the tank was fully saturated with crude caused by OLD gas and possibly by some sort of paint-on tank lining. It looks like it going to be a LOT OF FUN cleaning that hummer.

Here's what the standard push rod assembly looks like.


Here's the uncompressed distance with the keeper in place.


Here's the uncompressed distance withOUT the keeper. (About 4/16" less)


And, lastly, the view of the crud that is inside the gas tank. (No wonder the valves froze up.)

I thought my tank was bad...

Is it possible to just buy a new one and get on with it...?

Without the retainer bar the springs will just be jumping around and could do futher damage.....don't do it. What color are your present regular valve springs? They may already be the later, stronger type.
Looking at the mess in the gas tank, now you know why valves were sticking. This could have gone on forever.

Yes.. I'll admit it... I ordered a new tank this afternoon. Sorry.. that was going to be MY secret. :-)
Sometimes life is just too short.

Gene -- "jumping around?".... ouch... Now you've got me really curious. It's 31 degrees outside, pitch black, cold, 8 pm, but dang, I'm going to go out and take a picture of the valve springs. All I can say is that they were VERY STRONG when working on them. Stronger than my '31 springs.

Let me put my shoes back on, and find a coat.. I'll be back in a little bit. Unless of course, I slip and die from exposure.


Gene: I installed the springs COMPRESSED by the retainer bar. The third photo above shows the spring before it was pushed down by the retainer bar. Only the keeper was left off when I installed it. My assessment is that the spring "should" remain under tension with the tappet even though it now takes up a slightly longer space due to the missing keeper.

Can somebody supply me with the length measurement of a 35-36 chev 207 push rod.
That way i can get a quote on the price of a new one.

mike lynch

1936 Push Rod


It looks like 13 11/64" to me.

Gene - they look like "steel" color to me.

The casting date on the head looks like an 8 to me . 1938 ??casting or is your car fitted with a 1938 engine??.

Mike,The length quoted in the 1950 parts book for a 207 1934-1936 is 13 11/64 inch. These were the longest stovebolt pushrods. the 1937-39 came in next at 12 47/64"

Looks like Bill has the right pushrods but can't measure within a 1/64". Doubt I would interpret the 64th either.

Ah... you guys. You forget who you're messing with!!

Go read my measurement again!! ha ha....

Now that is cheating. Changing the post after the hour was up. Yes we understand who we are messing with.

Ha ha ha... Sure wish that I had that power at HOME!!!! (you-all know what I mean!)

Now... there was a question about what year my engine was. Here is the casting info. (I just braved ice, cold and darkness to go take these pictures.)


Weird. My book say 37-40 should be 602977.


And what does "CONV-3" mean up above the casting info?

You freaked me out enough that I drained my tank, filtered it, and ran it in my other car. It was the previous owners gas so who knows!

Thats one gunky sending unit!

Your other car...? You mean your wife's car...? lol I leave the old stuff in old gas cans to be used for cleaning parts, chain saws, and a-like...Be careful reusing that old stuff...Now that it's mixed you may not smell it, but the yellow color is a give-a-way...!

Jack,
Here's the rest of that number on my head.



And the rest of the numbers are as follows.

837981 is the correct casting number for a 1935-36 head. The F 14 8 indicates it was cast in 1938 ( or 1948 for that matter).
And 836010 is correct for your engine casting number aswell.

I had the same problem with my 41 Chevy once. Valves were sticking and bending push rods. I also found it to be bad gas. You may not want to hear this....

Replacing the gas tank is only the start of fixing your problem. I had to remove my intake manifold and the head and take them to an engine shop so they could soak them in their engine cleaner. The varnish was so bad in the intake and head, I had no choice. By the time I was done, I had replaced the fuel tank, fuel lines, carburator, fuel pump, and all. Bad gas can absolutely ruin your engine.

Once it was all clean, I never had another stuck valve.

Brandon,
You're RIGHT! I didn't want to hear THAT!!!!

Well, I've replaced the fuel pump. And I'm thinking about the fuel line from gaspump-to-carb. So, maybe I'll just add a different carb to the mix too.... wow.... I think it's time for a different hobby... maybe faster horses, younger women and older whiskey!!!



-----Bill B

It's not to late to sell me that thing...! haha