1956 - 365 c.i.d. - pushrods destroyed

[56Fleetwood]

When warming up my '56 Fleetwood after winter storage I heard a ticking sound that sounded like a lifter - thought it would pump up and go away so I drove it but it got worse and I ended up with one broken and one badly bent pushrod on the SAME cylinder.

Was not able to remove the valve springs to examine valves for sticking (spring compressor tool I had would not compress springs enough to remove however I was able to spin the valves around so they do not appear to be stuck).

Lifters appear to be ok on visual inspection. I'm leery about just putting in new pushrods without knowing more about the cause. I replaced all the pushrods and lifters 3 years and few miles ago when I replaced the heads, and engine has been running perfectly up to this situation. I double checked the lifters and pushrods to ensure I had the correct 1956 parts (as there were of course changes to the lifter and pushrod dimensions for 1957) and they are correct - so no mixing of parts.

Any suggestions or ideas would be greatly appreciated!

Thanks

[Caddy Wizard]

Lifters push the pushrods up and the valve springs push them back down.  If the pushrods are bent, that is usually because the lifters were pushing the pushrods up and the valves did not move to open, so the pushrods had no choice but to bend.  So bent pushrods are normally because the valves didn't open.   

But the valves not opening could have been because the valves were binding in the valve guides OR because the rocker arms were binding on the rocker shafts (this latter perhaps representing a lubrication issue). If you have the rockers off, try rotating them by hand on the shafts.  Check for any binding.  They should rotate back and forth fairly smoothly.

Another possibility is that the lifters were not pumped up with oil pressure, leaving undue slack in the valve train.  That is the usual ticking sound you hear as a sticky lifter when you first start an engine after sitting for a long time.  If the lifter sticks badly enough, the pushrod might become unseated in the lifter and then catch on the rim of the end of the lifter and subsequently try to push the valve farther than it can possibly go and then the pushrod will bend.  Look for any kind of damage on the ball end of the pushrod to see if this latter possibility was the culprit.

[Caddy Wizard]

Also, I might be not remembering correctly, but I thought there was a change in pushrod length halfway through the 56 model year...

[56Fleetwood]

Thanks for chiming in Art - excellent points to consider and will head into the garage tonight to check and will report back. As for the push rod length change you are correct, however my understanding is that happened early 1957.

My pushrods are 9.75" nominal length (9.7656 actual) and the lifters are marked VL 4 which is what I see in the Egge catalog as correct for 1956.

[James Landi]

Mike,  I've experienced this issue, and the cause of my challenge may be similar to yours.  These engines did not have positive crankcase ventilation, so if you start your engine during the winter months, let it idle for a time, the inside of your valve covers literally accumulate so much internal condensation, that it "rains" on your valve stems,where the metal to metal tolerances are very tight. So with the valve stems stuck with rust, as stated above, the push rod collapses.  Using a hammer, tap on the stems to ensure that the valves are NOT HUNG UP and rusted into place.  On one occasion, I could not free a valve stem, and needed to remove the head and have a machine shop perform the work. Lesson learned, if you're not going to drive the car for at least ten miles to dry out the inside of the engine and your dual exhaust components, don't start the engine!.  Hope this helps, James

[V63]

Another probable scenario for sticking valves is stale gasoline, specifically alcohol blended fuels. It is designed to degrade as the alcohol is a catalyst. This can happen in as little as 3 months. I do not believe stable additives are effective with blends. Tried them.

The varnish gas causes the valves to stick and ultimately seize them in their guides.

This is a very common problem people do not realize or accept but I have seen it many many times played out. Had a 57 365 you couldn't hammer the valve at all completely welded into the guides.

The head shop told me of one job he advised the customer it was caused by stale blended fuel and he thought it was nonsense and ran the new engine on the SAME gasoline only to return the heads days later.

[Lexi]

Thanks for chiming in Art - excellent points to consider and will head into the garage tonight to check and will report back. As for the push rod length change you are correct, however my understanding is that happened early 1957.

My pushrods are 9.75" nominal length (9.7656 actual) and the lifters are marked VL 4 which is what I see in the Egge catalog as correct for 1956.

Part #146 8453 is listed both in the tech sheet as well as the 1957 MPL for the new 1957 Push Rod. Like Art I thought it was '56, but there were 2 cam shafts that year ('56) as well as other unspecified engine changes. Clay/Lexi

[56Fleetwood]

As per Art's suggestion I checked the rocker arms and shaft for binding and good thing I did; although the arms don't bind at all I noticed that the oil hole on the rocker arm was hammered closed, so I drilled it out. I further noted that the cup in the arm (where the pushrod makes contact) was now out of spec as the broken pushrod must have hammered the cup so hard that it is now too deep and I must replace the rocker arm.

Clay's suggestion makes sense although I did plumb a PCV into the system, I'm sure there could still have been significant condensation. Although I did not remove the springs completely I was able to compress the springs enough to be able to rotate the valves so I'm assuming the valves are not stuck.

At this point I'm going to replace the pushrods, rocker arms and lifters on the offending cylinder. Once installed I'll turn the engine by hand and check pushrod and valve movement.

Any further suggestions greatly appreciated!

[56Fleetwood]

While waiting for some new parts from Terrill (spoke with Feltz - what a super nice guy - we need more people like this in the hobby) I decided to replace my exhaust manifold gaskets with the Remflex brand.

Did the left side (engine in car) so far - a job I never want to do again. Hope these gaskets work as advertised!

[Coupe]

22 years ago I had a similar problem with push rods and rockers in my 57 Cadillac. Twice push rods wore thru a rocker and the push rods got bent.  The rockers were after market. I took a failed rocker and was able to cut it in half with a hack saw.  I tried to cut an original rocker and barely scratched it.  I had the origin rockers bored and sleeved. 22 years later I have had no issues

[56Fleetwood]

Interesting - think I'll try cutting the damaged rocker arm when I get the new one (the damaged one was after market).

Finished installing the Remflex exhaust gaskets on the right side today - a bit easier than left side.

[Chopper1942]

If there is carbon/crud built up on the back side of the valves or as a precautionary measure, get some GM Top Engine Cleaner.  Put it in a squirt bottle. Start the engine and get to normal operating temperature. Put the engine of fast idle and spray the Top Engine Cleaner into the carb primarys. When you are just about out of cleaner, pour the rest down the carb to kill the engine.  Let it set for about 1/2 hour.  Now, put the air cleaner on and start the engine.  Take it out for a drive to blow out all the loosened deposits.

You may want to pull out the plugs when you get back and it cools down.  You may have to clean deposits off the plugs.

[35-709]

Don't do it in a nice neighborhood, and alert any nearby fire department, the amount of thick, smelly, smoke when you fire it will be copious! 

[Chopper1942]

Yah, I forgot to mention that it is going to kill all the mosquitoes in the county!

[56Fleetwood]

Hah! No mosquitoes up here this summer - either someone used some Top Engine Cleaner recently or the forest fire smoke got 'em.(I'm in Winnipeg, MB - my province has been spared the fires we're having elsewhere in the country but we get the smoke periodically).

Update on the busted pushrod situation: installed two new new push rods, lifters and rocker arms on the cylinder where the damage occurred (used assembly lube generously).Have installed rocker shaft assembly.

Any advice on checking for possible binding of the valves? I was thinking of rotating the motor by hand and having a second set of eyes watch valve movement.

[Chopper1942]

If you have not disassembled the rocker arm shaft assembly yet, when you do, keep the rockers in the same position when you reassemble it.  If you have the rocker shaft assembly off and disassembed, bolt the shaft back on the head and take a pry bar and hook it under the shaft, press down, and see if the valve moves.  You can also tap the valve with a plastic dead blow hammer and see if it moves.

The best way to check the valves is to get a valve spring compressor that hooks into the spring and pushes the retainer down. If you do this, tap the valve spring retainer with a hammer to free it from the keepers. Remove the spark plugs, insert a compression gauge hose in the spark plug hole and connect an air compressor to the hose.  This will hold the valve closed.  Compress one valve spring at a time and remove it.  Now reinstall the valve spring retainer and keepers on the valve.  Hold up on the retainer to keep the keys in place and remove the air from the hose.  You should now be able to move the valve up and down very easily.  If it does not move easily, there is probably carbon in the guide or the valve stem is galled or scored. If the valve mooves freely, connect the shop air, close the valve, remove the valve keys and retainer. Install a new valve seal, set the compressed valve spring in place, and reinstall the retainer and valve keys.  Remove the spring compressor and tap the valve hard enough to cause it to open. Repeat this on all the suspect valves.  If the valve seal is hard, I would replace all of them.

[56Fleetwood]

Update - after installing 2 new lifters, pushrods and rocker arms at the cylinder with the destroyed pushrods yesterday, I turned the engine over a few revolutions by hand and saw that lifter, pushrod and valve movement looked good so thought I was good to close it up and finish the project. Looked at it closely today and noticed more bent pushrods!!

 Took rocker shaft assembly apart and noticed that the rocker shaft was bent! (Absolutely positive that I installed the pushrods into the lifters and rocker arms properly).

Could this have been the underlying cause of the bent pushrods in the first place?  (I'm kicking myself for not checking the shaft in the first place. And yes the shafts are correctly oriented).

Now I'm looking for a replacement shaft for left side and more pushrods.

Thoughts please?

[56Fleetwood]

Update:

- had the bent rocker shaft straightened
- replaced damaged pushrods and rocker arms
- checked valve operation as per Larry L's great suggestion
- removed, disassembled and cleaned all lifters and partially refilled them with oil
- pre lubricated the engine by turning the oil pump with a drill
- closed everything up with new gaskets

And - success! Started without any ticking or other noise and runs so smoothly. Have done a few test drives and no bad engine noises.

Still wondering why the pushrods failed in the first place though.

Thanks to everyone who chimed in.

[dplotkin]

Still wondering why the pushrods failed in the first place though.

Likely bad gas. Seen it before.

Dan

[56Fleetwood]

Likely bad gas. Seen it before.

Dan

How so?