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Completely rebuilt big block installed in my 68 with roller rockers, lifters etc. When listening to the valves with a stethoscope the exhaust valves are very quiet, but the intake valves are just hammering. Valves have been adjusted professionally, new lifters installed, same problem. Any ideas?
Modify an old tin valve cover by cutting the entire top of the cover open...install the modified cover.......you can see/hear/adjust rockers without getting engine oil everywhere....
Do you have different springs on the intake valves than on the exhaust?
Same brand & ratio rockers on the intake and exhaust?
As Stingr alluded to, if the intake lift is greater than your coil-bind or retainer-to-guide clearance, then you could cause the lifter plunger (hydraulic cam, right?) to fully collapse, creating slop > hammering when closing. That can also wipe out the lobes & lifters.
I have not worked on a BBC in decades, but do recall on those "porcupine heads" the pushrods are of different lengths. 8 EXH and 8 INT.
Somebody didn't get the pushrod install order backwards did they?
The pushrod question seems legit...of course check it all
Pull the valve covers then let it idle youll know real quick whats going on. Noise can move around with them on and drive you nuts.
Those XE cams hammer the valve seats pretty good they are going to be a little noisier in general.
As ERIC from South Main Auto says....."Well that's your problem lady"
That series of cams are well known for making lots of noise, very aggressive ramps.
I had one in my engine and got sick of the noise, so I pulled it. Then put in a slightly larger cam from Crower and now no noise at all.....the only thing that was changed was the cam.
Do a search, there's lots of info out on the web.
The pushrod question seems legit...of course check it all
Pull the valve covers then let it idle youll know real quick whats going on. Noise can move around with them on and drive you nuts.
Those XE cams hammer the valve seats pretty good they are going to be a little noisier in general.
The pushrod question is not legit because the intakes are almost one inch shorter than the exhaust....impossible to mix them up....
Using stock covers with drippers? Had a clearence issue using roller tips. Busted two drippers before I figured it out and just bent the last one that was making noise. Problem solved.
Thanks everyone for the input. Ended up taking the motor back to the builder and the pistons were hitting the intake valves. He fixed the issue and i finally have it in and running.
ok, check with the builder and ask him what he did to fix the problem. get it in writing. are these iron chevy heads or aluminum aftermarket? ask him what diameter the intake valve heads are. ask him the part numbers of the pistons. ask him the cam timing. ask him what all he replaced. and when he says what he replaced, if all 8 intake valves were not on that list, ask him why not. and tell him if an intake valve loses a head he is buying you a new motor.
Intake valve hammering
That's something that should have been caught during the initial build....I guess some guys just don't check those things.
