Lost pushrod??????

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glockr

glockr

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Just got my car back from the shop. Brand new 318, supposedly broken in correctly. Ran good, test drive was good, then called and told me #7 cylinder was out and that it was acting like either a stuck valve or a flat cam. Told me that if it was stuck valve, the pushrod was likely bent and maybe no longer in place.

Called engine builder, he told me to pull valve cover and see if valves are moving up and down when engine is turned over. Pulled valve cover, pushrod had popped out (lifter still seems to be in place) but it's straight, not bent at least to eye and not enough to pop out. Valve looks like it's in closed position.

Could a flat cam or stuck valve could have caused this? Which is more likely? Anything else that could have caused it to happen? Has anyone else had this happen to them?

Thanks,
Ken
 
I'm thinking one of two things happened.
1 yes the cam lobe is wiped out and the push rod poped out do to the extra clearance
2 The valve stuck open and left a gap causing the push rod to pop out
I would put it back in and turn the crank over by hand and see if the valve opens or if it sticks. You need to consider it might have bent a valve too.
 
I'm hoping for stuck valve. The machine shop told me if that's the problem they'll make it good. If flat cam lobe it's fault of shop that did the trans conversion and installed/broke in engine BUT since its an "engine problem" don't know if I'll get any joy from them. Also stuck valve only involves pulling intake and one head, cam change would be a major PITA with engine still in the car. Dang, thinking about this is starting to make me depressed. I was supposed to be driving the dam* thing today, not tearing into a brand new engine.
 
It sucks you cant drive it yet. Please let us know how this unravels. Which shop did you have build your engine?
 
If it was over-revved and the springs are nothing special you can pop out a pushrod easilly. If it came out while the shop was road testing it I'd ask them what they were doing with it at the time.
 
Both shops involved have very good reputations. I know sometimes s*** happens. Don't want to name names until I see how it works out. Then they will get a very GOOD mention if it works out good, or maybe a bad mention if not. The cam is a Comp Cam XE268 with Comp's recommended lifters and springs (rockers are also Comp Cams). The owner of the machine shop is coming over this afternoon to take a look at it. He's already told me if it's a machine shop problem he'll fix it. If it's a flat cam not sure id the other shop will make good or not. They're the ones that started it and broke it in but they can say "cam problem is an engine problem."

FWIW I don't think they were getting too crazy on the test drive 'cause the rear end (7-1/4") ain't broke:)

cheers,
Ken
 
kdeboy said:
Also stuck valve only involves pulling intake and one head, cam change would be a major PITA with engine still in the car.
Click to expand...

Cheer up! It could be way worse. Try a cam change in an early A with a slant without pulling the front clip and radiator support. Here's hoping you only have a valve with a little less guide clearance than desired.
 
Just finished looking it over with the machine shop owner. Cam looks fine but almost all the valves are sticking. He said it could be caused by bad gas (the car sat for several years and the shop that put the engine in said they had to drain the tank and blow out the gas line before it would run). He offered to tow the car to his shop at his expense, pull the heads and see what's causing the valves to stick. He told me if it's bad gas, I'll pay to have it fixed, if not it won't cost me anything. That sounds fair to me. He said it DOESN'T look like the cam is flat. The only thing different than his suggestion is that I'm pulling the heads myself and taking them down because I don't feel comfortable leaving the car in his lot while it gets fixed - not the best neighborhood. At least now I can say I worked on it some myself:)

If it does turn out to be bad gas I'll be kinda PO'd at the shop that did the install - I told them it had been sitting for a few years - didn't ask them to drain the tank but maybe they should have had an idea about it since they have a lot of experience working with old cars. Oh well.

Cheers,
Ken
 
kdeboy said:
Just finished looking it over with the machine shop owner. Cam looks fine but almost all the valves are sticking. He said it could be caused by bad gas (the car sat for several years and the shop that put the engine in said they had to drain the tank and blow out the gas line before it would run). He offered to tow the car to his shop at his expense, pull the heads and see what's causing the valves to stick. He told me if it's bad gas, I'll pay to have it fixed, if not it won't cost me anything. That sounds fair to me. He said it DOESN'T look like the cam is flat. The only thing different than his suggestion is that I'm pulling the heads myself and taking them down because I don't feel comfortable leaving the car in his lot while it gets fixed - not the best neighborhood. At least now I can say I worked on it some myself:)

If it does turn out to be bad gas I'll be kinda PO'd at the shop that did the install - I told them it had been sitting for a few years - didn't ask them to drain the tank but maybe they should have had an idea about it since they have a lot of experience working with old cars. Oh well.

Cheers,
Ken
Click to expand...

Well I hope this is a wake up call for you to pull the tank and clean it before you try and start it again. I had this same thing happen on a ford truck that had sat for a couple of years.
 
Bad gas wont stick valves. It make sthem run like garbage, but at no point is fuel going up the guides. But, if it sat there could be other issues. It does sound like he's treating you fair so aside from gettng ready to pay him, sounds like you're doing all you can.
 
This might help. I had a Bronco with new engine, 13000 miles, running fine. Let it sit for a year, fired it up, 1 cylinder missing (non-adjustable, bolted to the head). Pulled the rocker cover off; pushrod, not bent, just sticking in the air; rocker solid to the head. Pulled the rocker, re-installed; good to go. Never could figure it out, until now. Bled -down lifter, maybe? let the pushrod jump?
Makes sense.
 
Right when I started reading your post I thought "Comp Cam is the blame." Or the lifters..... comp has some crappy lifters.
 
What rockers are you using? There was an issue with comp rockers galling a while back. I would check to see if they are galled as this would act like valves sticking at higher toms when the motors warm.
 
I'm using Comp Cams ss rockers. I don't think that's the issue. When I pulled the shafts the rockers move freely, no binding. After pulling the shaft he had me bump the engine to make sure the pushrods are moving up and down like ther'ye supposed to. They are, that's why he said probably nothing wrong with the cam. Bolted rocker assembly back on and bumped engine. Valves moving like they should, but as engine turned pushrod would briefly pull away from the rocker arm before the valve would close. Sticky valves. Heads are coming off this weekend and going back to shop for troubleshooting. Hopefully won't cost too much (for me at least) to fix.
 
Two things to look at BEFORE it's all disassembled. First... Look down the intake ports. Are they clean, or very oily and sooty looking all the way to the valve from the opening. Second, check to see how much lifter preload you have with the shafts bolted down solid and each lifter on the base circle (no lift). If there's crap all up the port (oily residue) or around the guides/head of the valve, you have an issue with valve guides or seals, possibly intake sealing or too large a cam(reversion). If you have less than .040 preload on the lifters, you will need to replace them to get longer ones to get the proload you need. I'd also look really hard at the valve job and valves. If the pistons have nicks in them when the heads are removed, it's not "sticky" valves... But bent valves. My money's on not enough preload and/or incorrect spring pressure and it bent some valves.
 
moper said:
Two things to look at BEFORE it's all disassembled. First... Look down the intake ports. Are they clean, or very oily and sooty looking all the way to the valve from the opening. Second, check to see how much lifter preload you have with the shafts bolted down solid and each lifter on the base circle (no lift). If there's crap all up the port (oily residue) or around the guides/head of the valve, you have an issue with valve guides or seals, possibly intake sealing or too large a cam(reversion). If you have less than .040 preload on the lifters, you will need to replace them to get longer ones to get the proload you need. I'd also look really hard at the valve job and valves. If the pistons have nicks in them when the heads are removed, it's not "sticky" valves... But bent valves. My money's on not enough preload and/or incorrect spring pressure and it bent some valves.
Click to expand...

All the intakes look pretty clean except #7, the same one that had a popped pushrod on the exhaust side. I'm not sure how to check lifter preload but on all the cylinders where the lifter is sitting on the base part of the cam I can turn the pushrods easily by hand. Is that normal or are they loose?

I haven't removed the heads yet. I think I can get them pulled OK but no way I can see to get them installed correctly since the header flanges are right over the outer row of head bolts. I can get a flat wrench on them but I doubt a socket on a torque wrench. That sucks, I was really hoping to avoid pulling the engine.
 
kdeboy,

Yes, the pushrods should turn freely. Mine do w/ 90 lb spring seat force.

It is fairly easy to check a few valves with the head on. Remove the rocker arm, move the piston to TDC (feel w/ wire in spark hole to insure). With the piston up, the valve can't drop. Forget about air pressure or stuffing string in the cylinder. Remove the valve spring and seal.

Try moving the valve up and down, wiggling it and rotating it. You might have to drop the piston a bit, but don't be stupid (keep magnet on valve). It should move freely but no perceptible motion side to side. You should be able to feel if it is sticking. If sticky, removing the head won't help, unless you must change the valves. Gummy fuel would probably just affect intake valves. Worst case is removing the intake to access the stems, though you could probably spray solvent down the ports and guides to clean them.

You should be able to pull the valve up using a screwdriver in the slots to get the keepers back in. If not, use air pressure in the spark hole, but lock the crank first. They have spun on me many times (I'm lazy). I have never dropped a valve, but the flying wrench is scary.
 
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