68 engine question

**Joseph Sanfilippo** · November 23, 2003, 05:51 PM

Re: 68 engine question

Kurt, if I were you, I would contact the engine builder and let him figure it out before you damage something-Good luck.

**Roger Legge** · November 23, 2003, 06:18 PM

Re: 68 engine question

Sometimes an exhaust leak can make a heck of a noise that sounds like a 'mechanical' noise. Maybe check the three nuts connecting the head pipe to the exhaust manifold? This is an L79, correct? Assuming a hydraulic lifter, there could be a lifter acting up. Just a couple thoughts.

Roger
#36316

**Kurt B.** · November 23, 2003, 06:36 PM

Re: 68 engine question

Roger,
I checked the exhaust. It's OK
Are there any visible telltale signs of a bad lifter?
I removed the valve cover and expected to find a loose rocker arm or broken spring but everything seemed in order. What should I see or look for if it is a bad lifter?
If it is a lifter (they were all new hydraulic lifters) will it cure itself or does it require removal of intake manifold to remove and replace the lifter?
Thank you for any input.
Kurt

**Roger Legge** · November 23, 2003, 06:56 PM

Re: 68 engine question

Kurt, the lifter is just a guess. If the lifter is somehow bad, it won't (shouldn't?) get better. This can get messy, but you can run the engine at idle with the valve cover off - lower the RPM, the better because oil can fly everywhere. You can take a long screwdriver or some sort of metal rod, put one end on the top of the rocker stud, then grab the other end with your hand and hold it by your ear - you're 'listening' via the rod. Much more noise on one than the others, that's the loose/bad one. We should probably back up here. It could be a lifter is simply out of adjustment. How were they adjusted? How far past zero preload? It could be a number of things besides a lifter - I was just mentioning possibilities. Others will chime in, I'm sure. I'd check easy things first, etc. Gotta run.

Roger
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**Terry F.** · November 23, 2003, 11:49 PM

Re: 68 engine question

Also, compare the volume of oil coming out the oiler hole on the the loud rocker arms. If rocker arms are adjusted properly and you have minimal oil coming from them, that can be indications of deeper problems. I would rotate the engine up on TDC for that cylinder and grab the rocker arms. You should be able to tell if there is too much play in them. You can adjust them at that point or start the engine and adjust them that way. A bad lifter will usually require the intake to come off.

**Chuck R.** · November 24, 2003, 03:25 PM

Re: 68 engine question

It figures doesn't it?

I would look real hard at your push rods for bending or plugging and then move on to lifter land.

Sticky or plugged lifters are only readily accessable by pulling the intake I'm afraid.

The biggie of course is locating just what is making all the racket first before you start pulling a fresh power plant apart.

Many times I've located problems with the ole screw driver stehescope.

But....my pesonal favorite was an 1/8" piece of copper tubing that I soldered a larger washer on so I wouldn't end up with the tube comming out the other ear if I slipped.

As you stated that the problem first went away after the engine warmed up, I would put even money on upper end components ie. lifters, push rods, rockers, rocker studs etc.

If the engine was tanked etc. you may have been blessed with a small piece of debris that finally made it's way to a lifter or push rod.

Good luck with it Kurt,

Chuck

**Richard Hayes** · November 24, 2003, 10:22 PM

Re: 68 engine question

Kurt,

I would check the intake bolts-they might be a bit to long. Back them out a turn or two and see if it cures the noise. It happened to me- one time when I changed manifolds. And a simple washer was the fix.

Richard

68 engine question

68 engine question

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