Technical All exhaust pushrods bent?!

Did they check the heads to check they are not warped?
General if an engine has pushed freeze plugs out it has been very hot at some point. This happens very often in oval track racing after an engine has been hot.

 

Curiosity just sucks you in, doesn't it?

 

Perhaps I didn't use the correct language, the freeze plug didn't blow out in the sense of a pressurized cooling system from a blown head gasket, extreme overheating or even freezing. The freeze plug just simply rotted and started weeping coolant and the system wouldn't hold pressure. So there shouldn't be a head warpage issue since there was no extreme overheating scenario or the like that lead to the underlying issue. Make no mistake about it, the decision to pull the heads and have them rebuilt with a new cam and lifters was all elective surgery, and they could have simply dropped the trans, pulled the faulty plug and hammered in a new one and been done. This would have been my course of treatment because from a cost/benefit standpoint the subject vehicle quite simply isn't worth the effort or expense. But what's done is done now, and I've been enlisted to help fix it.

 

Hate to say it, but early in our learning curve with a new engine combination, every time we hit a piston with a valve on our race engines we soon spun a rod bearing. Always within a couple nights.We hit pistons/valves one night and I completely tore the engine down and mic'ed the thickness of the bearings and those that hit were slightly thinner than stock bearings or those that didn't hit. Something has to give and I guess our bearings were taking part of it, too. Got to when we tagged valves we always automatically swapped bearings and never had that problem again.

SPark

 

I don't doubt that for a second. There's obviously a significant compression force on the piston/rod assembly and the force has to go somewhere from the interference. In this application though, this engine will never see the RPM or abuse that a race engine would see. This is a beater driver in every sense of the word, a low-performance emissions huffer. If this vehicle last another 2 years in it's current condition it would be astounding.

 

Cam timing 180° out???? That was a joke... right???

 

Ummm,,,, I don’t think it was?
When I read it ,,,I decided to remain silent !

Tommy

 

You didn't

say witch 318 [pre 1965] you are working on . I do know if you have an early 318 and installed a late late cam a lot of things get bent .

 

Stale gas can cause valves to stick in the guides and bend pushrods. And in hot weather gas don't have to be very old to stick valves.

 

True for sure, but I'd expect the intake valves to stick in that case,

 

Fair question. This is a decidedly post-65, non-polysphere, small block LA 318 of 1980s vintage.


Sent from my iPhone using H.A.M.B.

 

That’s true, but this was a runner until it wasn’t, so the gas shouldn’t be that old. And everything was just rebuilt on the top end, so nothing was sticking to that degree. It’d also be the craziest coincidence in the world that only the 8 exhaust pushrods bent.


Sent from my iPhone using H.A.M.B.

 

Pull the timing cover and be done with all the guessing for god sakes. How long do you want to debate all the possible scenario's.

 

Had a convo with the vehicle’s owner today. Interesting tidbit of info came to light. When they first put it all back together, they noticed the crank was turning, but not the distributor and the valves weren’t moving. They then discovered they forgot to put the key in the cam. They stuck the key in and apparently rotated the engine to when the dots lined up. Allegedly. I’d highly doubt this was done with a resetting of the engine back to TDC at #1, assuming the first few cranks didn’t cause any damage. So improper cam installation and timing is likely the culprit.


Sent from my iPhone using H.A.M.B.

 

Oh that’s neat

 

Duh oh.........well, at least they had the right idea. Unfortunately, they failed to execute one more little detail.

 

I would pull one head first to gain some insight. You can't really do any testing unless it gets put back together and the problem will still exist. Pull the one head, pop the keepers out of any valve that may have touched a piston. Blue up the seat and hand-lap the valve to see how it contacts the seat.

 

Why can’t he do any testing first? Pull the rocker shaft so both valves are closed, piston at top dead center, leak down will show if there is a valve issue.


Sent from my iPhone using H.A.M.B.

 

No compression,,,,why leak down?

 

Exactly, with zero compression it will be difficult to do a leak down test!

 

I was wondering the same thing!

 

MIGHT be able to determine if piston or valves. I think we know, though.

Ben

 

Just Incase one questions actually holding bent pushrods and zero compression,,,,
You could put air into the cylinders and listen for the escape,,, probably out the exhaust

 

Was beer involved in this rodeo?

 

Didn't we just hash out that 6-12 12-12 thing in another post. If you turn the crank one turn the 12-12 setting will turn into a 6-12 . If the cam is not turning how did he bend every exhaust push rod and no intakes.

 

It’s not apart yet -,,,is it ?

 

Sadly no, though I'm certainly going to have one when I finish fixing it

 

No not yet, I'm going to pull it apart first thing next week. I changed the oil in my BMW tonight and Thursday afternoon I'm taking off in my 61 Olds for Canada and the Jalopy Jam Up, a much needed break. When I get back I'll be sure to post pictures, I'm really curious too haha

 

Exactly. I think a leak-down test would actually be helpful for the sake of completeness. Obviously the cam is out of time, and the cranking compression compression of 0 could be attributable to the intake and exhaust valve being open at the wrong time. Now that the pushrods and rockers are off, and the valves being held shut, a leak-down test will tell me if the exhaust valve is still sealing or not, potentially saving a rebuild of the head. That being said, I fully expect at least a few valves to be bent and a leak-down test to show that the exhaust valve is not sealing.