Motor noise ?

[69Bee]

I'm still not real clear on this subject. If there are two different lifters with different pushrod seat heights - then there must be two different length pushrods also (or different rocker arms). Yet, in reading up on the subject there seems to only be one length pushrod available (stock anyway). Checking pushrod length is relatively simple compared to checking lifters. If there is a shorter pushrod and that turns out to be what is in my car now - I would probably install longer ones just to see if it solved my problem.

From my Melling catalog:

66-78 440 Chry
66-67 Hyd JB-812 Lifter and MPR-151 Push Rod
68-78 Hyd JB-976 Lifter and MPR-323 Push Rod

Push Rod Specs:
MPR-151: 9.375" long, 5/16" dia, rounded top and tit(cone) bottom
MPR-323: 9.315" long, 5/16" dia, ball top and ball bottom

 

[AR67GTX]

From my Melling catalog:

66-78 440 Chry
66-67 Hyd JB-812 Lifter and MPR-151 Push Rod
68-78 Hyd JB-976 Lifter and MPR-323 Push Rod

Push Rod Specs:
MPR-151: 9.375" long, 5/16" dia, rounded top and tit(cone) bottom
MPR-323: 9.315" long, 5/16" dia, ball top and ball bottom

Thanks - that's .06 inch difference. That's a sixteenth of an inch so that is getting to be substantial. Looks like I need to pull the valve cover and see what I have. Prior owner said he installed a new cam and lifters but I would guess he used the original pushrods. This is a 68 motor but he might have purchased a 67 cam and lifters.

New heater coil a few years ago. The noise pre-dates that work. As above, I've dropped the belts off the engine a few times in the past and it doesn't make any less noise. AC compressor was re-sealed and inspected 5 years ago and no issues.

Also, I stripped the engine down 5 years ago and detailed it, sandblasted the exhaust manifolds and reinstalled them with high temperature sealent on the manifold surface. New TTI exhaust all the way back. I'm like 99.9% it's not exhaust related. I know it's hard to tell much by a video tape but I'm thinking this pushrod/lifter issue is looking like the likely culprit.

Thanks

 

[AR67GTX]

I'm gathering that putting new pushrods on the old lifters might be kind of risky due to different push rod ends and lifter seats. I'm starting to suspect that I might be running 67-style lifters with 68 pushrods.

 

[RustyRatRod]

Tell you what I would do first I believe. It would be super easy to remove one valve cover, one rocker shaft, one pushrod and one lifter. You don't even have to remove the intake. Measure the pushrod and lifter and see what you got. At least that way, you'd be verifying instead of simply throwing parts at it. Wish you were closer. You could come over spend the day drink some cold iced tea and we could figure the thing out. Would be fun to, meet a new friend.

 

[AR67GTX]

Tell you what I would do first I believe. It would be super easy to remove one valve cover, one rocker shaft, one pushrod and one lifter. You don't even have to remove the intake. Measure the pushrod and lifter and see what you got. At least that way, you'd be verifying instead of simply throwing parts at it. Wish you were closer. You could come over spend the day drink some cold iced tea and we could figure the thing out. Would be fun to, meet a new friend.

I'm kind of embarrassed to say I've been working with my old Corvette and it's engine so long I didn't recall I could get a lifter out with a magnet w/o pulling the intake on my GTX. If that's the case then you're right, that's what I need to do.

That would be fun. But, I do think this may be solving the puzzle of why this thing sound like a Detroit Diesel at idle but otherwise seems to in such good running shape. :hello2:

Thanks

 

[62 Dart Convertible]

My only experience ever with a strange noise in an engine I built was loose bolts holding the flex plate to the torque converter. I started pulling it down 100% sure I had a bottom end knock... cheapest and easiest fix ever. I hope yours is an easy one too...