i'm almost afraid to ask:

while re-installing the rocker arms on my 68 390, (two turns at a time, #4-#1, #5-#8), all of a sudden the push rod on #4 snapped in with a loud pop.

took off the rocker arm and pushrod. it was intact and not bent. however, that arm then seemed to sit about 1/8 to 1/4 lower than the others, (just by eyeing it)

i put the arm back in and was able to torque it to spec.

i just had the heads replaced with stock rebuilt from machine shop with hardened valve seats about 1500 miles ago.

any ideas? can i start her up? go easy: i'm not familiar with rocker arms, cams, valves and lifters beyond their names and a general idea of where they are.

also, if i start the engine with the valve covers off, what kind of oil spray am i expecting - never done that- does it just splatter a little or shoot out all over?

mike

 

If your lucky, the push rod might have been sitting on the edge of the lifter and when under pressure 'popped' back into the hole. If your not lucky, the rocker arm might have been damaged. when you say that one rocker is lower than the others that could be because it's on a different part of the cam lobe than the others.

I'd carefully inspect the rocker arm for damage and turn the engine over by hand with a wrench on the pully bolt. then see if the rocker seems to be ok.

I ran my engine with a HV/HP oil pump and the usual FE oiling mods and no restrictions to the oil passage in the head. The amount of oil that cam out was very small. I placed a few bags over the exhaust just above the plugs and it caught most of the oil. I usually suggest starting the engine without the valve covers so that you can check the operation of the rockers and the flow of oil. I look carefully at the sides of each rocker as there should be very very little oil there (almost none) and you should see oil comming out the tips of the rockers and none around the shaft.

this is also a good time to look at the amount of oil that puddles up in the head, if it starts to overflow, I'd consider restrictors under the valve shaft stands.

 

Have any spare valve covers? I do and am tempted to take them and have the tops sawed off w/ like a bandsaw. I could use those when I want to run my engine and inspect or adjust my valvetrain. I invested in Cranes adjustable rockers for FE motors awhile back and have run mine w/o any oil mods. I would spatter some oil allittle bit. Mostly the back corner of the head would pool up w/ oil and overflow the edge of the head after awhile which is messy. Having Valvecover sides would solve this.

BBT

 

you two are always there for me...

looks like i got lucky. started her up with the valve covers off and everything seemed to be pumping and rocking smoothly

of course, we're talking a pretty untrained eye here!

nonetheless, no squeaking, poping, rattling, sticking or other breakage i was sure I was going to see,

all the arms oil except one on the #2 cylinder - the one closest to the fan belt side of the engine: what does that mean, is it serious, anything i can do? (i made sure the oil holes were not blocked).

oh, and no huge oil mess like i imagined. i started it cold and ran about 5 min, and it didn't even puddle in the head that much.

 

If you have 1 rocker that's not flowing oil, I'd take a close look at the sides and see if it's bleading off the sides.

If that's not it, take the shaft off and inspect it because you might have something stuck in it or it could be damaged on the bushing.

You could also check to see if it rocks back and forth by turning the engine until it's off the lobe and move it over a bit then trying to rock it sideways. I think they should have enough clearance to be able to feel a slight rock.

Maybe a shot of carb cleaner down the hole at the end of the rocker might help too. Not too much, just a few shots should clear it up.

Don't run it if the oil isn't flowing properly.