When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
L79 ticking:
I am trying to help a friend with diagnosis of an intermittent ticking sound consistent with a loose rocker arm on the passenger’s side. His 66 L79 was completely rebuilt by his engine builder, but then wiped the new camshaft. The builder completely disassembled the engine and boiled it out after the camshaft failure. He then reassembled it with a new L79 camshaft and lifters. Unfortunately the builder has passed away.
It occurs only after the engine comes to normal operating temperature and comes and goes (intermittent). It seems to be #6 exhaust valve where the noise is predominate. Engine runs well and no missing detected. Approximately 300 miles since rebuild.
Here is what has been done:
Checked for exhaust leak around manifold and heat riser valve at normal operating temperature. No leaks found. Wired heat riser valve open.
Ran a stethoscope under the pan from rear to front, and noise seems to be consistent along the total length of the pan. Does not have the sound of a rod or main bearing or wrist pin.
The fuel pump seemed to have some noise greater than what I have heard, so it was replaced with a new pump. No apparent damage to the push rod. No change in the ticking noise
Adjusted the valves with engine hot and running, repeated several times. Never found any loose rockers.
Removed spark plug from #6 and #5 and found the #6 appears to have some oil on the threads as well as a darker deposit on the insulator of the plug. I can't load the picture of the plugs. New AC R43S.
Cold Compression check of #6 and #5 for comparison - both 150 psig.
Removed the #6 exhaust valve spring and found the damper spring was ~ 1/2" shorter than the valve spring. The damper spring did not appear to be broken, but factory ends. Found no pieces of the damper spring which would indicate it had failed. Replaced the damper spring with believed to be correct damper spring. No visible damage to the spring.
The spacer under the spring was worn at the contact point of the damper spring.
No change after installing the new damper spring on #6, still have intermittent ticking at normal operating temperature only.
Pictures of the spring, spacer, and dampers: Spacer under spring appears to have damage from the damper. Valve spring, new damper, old damper, & spacer.
I am not convinced the new damper is long enough to be compressed with the valve spring, but I don't have experience with aftermarket springs.
I am thinking if it is a weak or partially plugged lifter, it would tick all of the time.
Any thoughts are appreciated.
Ron
My first thought is a hydraulic lifter that intermittently doesn't fully pump up. If you have run the engine with the valve covers off, are you getting a good continuous flow of oil through the push rods to the rocker arms ?
Thanks Ted,
We ran the engine with a cut-out valve cover which blocks the hole in the rocker, but the rocker ball seemed to have plenty of oil and there was oil squirting on the socket as we adjusted the rockers.
I thought about a weak lifter, but thought it would rattle continuously hot or cold. I also thought of putting a wooden hammer handle on the push rod side of the rocker to see if it would cause the rattle and on the valve end to see if it eliminated the rattle, but I thought of that after I came home. Do you think that would work?
I also thought about excess clearance on the thrust bearing of the crankshaft, but it the noise is not deep enough. I had the problem in a 302 and the noise went away when I pushed in on the clutch to force the crank forward.
I usually think of the hard to fix problems to find it to be a simple problem later.
What was the cause of the failed camshaft? All it takes is one shim too thick to make a spring too stiff especially during break-in. It would be wise to measure spring height of all springs. Since it only does this at operating temperature that eliminates things like a loose timing chain or piston slap. This sounds to me like a leaking lifter and I have seen those noises come and go especially as the oil gets thinner. I would be tempted to replace all of them. You didn't mention oil pressure. Have you checked it with an external gauge?
Last edited by acstephenson; May 4, 2026 at 12:27 AM.
Thanks acstephenson,
I have not asked him about the oil pressure. When I was there, we only worked on the car at idle. I sent him a text and asked him to raise the hot idle and monitor the oil pressure also. I'll ask if he has another gauge to check the pressure and spring height. And pass along your recommendations and see if he knows the cause of the 1st cam failure. It it worth looking in to.
He is on business for the next day or two, so I can't get an answer today. He is a little over an hour away.
Ron
I thought about a weak lifter, but thought it would rattle continuously hot or cold. I also thought of putting a wooden hammer handle on the push rod side of the rocker to see if it would cause the rattle and on the valve end to see if it eliminated the rattle, but I thought of that after I came home. Do you think that would work?
Ron,
Your idea of using the wooden hammer handle and putting some pressure on the push rod end would probably give you an indication of the lifter not being fully pumped up by a change in sound. The fact that this is intermittent would indicate to me that the plunger in the lifter is sticking (not sliding freely) or the plunger spring is weak. Do you have any good lifters left from the old cam ? You could temporarily replace that #6 lifter to see if the problem goes away. If it does, you may want to consider a new set of quality lifters.
I am thinking when the old cam failed, the pump may have put some particles thru the engine, and the disassembly and boil out didn't get it all. Maybe a bit it that lifter putting resistance on the internal piston and thus incomplete stroke of the lifter. I'll make a list of your comments and have him try them. I wouldn't want to put a used lifter on the new camshaft, but if the lifter is the problem, I would also recommend replacing them all or at least taking them apart and cleaning the internals. This would give us the opportunity check the cam lift on all of the lobes as well. I don't think it is lobe wear as it is not constant and the rockers are not loosening.
Thanks,
Ron
If you suspect debris in the engine, you'd better hope it's in the lifters because that's about the least evil place for it to be. I would put that theory to bed by cutting open the oil filter. The good news is that I have seen new out of the box (but not genuine GM) lifters do this.
i am told the builder had an excellent reputation for doing things right, so my worry about debris is a bit beyond what we expect to find. I can't recall the cam manufacturer for this last cam, but it was not a GM cam. I don't know about the lifters either.
My son put a used solid cam in a 350 and wiped the cam, lifters, rod and main bearings, and crankshaft before he figured it out. I hope he learned something.
We are going to pull the intake and look at the lifters. Also check the lift on the camshaft just for assurance he doesn't have a bad lobe.
We are looking for recommendations for replacement lifters. He had a recommendation for the Crower Cam Saver lifters. They are suppose to have a hole in the base or some way to provide additional oil to the lobe on the camshaft. Does anyone have experience with these Crower lifters?
What good quality lifter is recommended that you have used?
Thanks for the input.
Ron
He had a recommendation for the Crower Cam Saver lifters. They are suppose to have a hole in the base or some way to provide additional oil to the lobe on the camshaft. Does anyone have experience with these Crower lifters?
Ron,
Yes, I used those Crower lifters in a Ford 427 side oiler with a Crower SFT cam. I put about 14K - 15K miles on that motor with no issues at all.
Ted
Ron,
Yes, I used those Crower lifters in a Ford 427 side oiler with a Crower SFT cam. I put about 14K - 15K miles on that motor with no issues at all.
Ted
You gotta put up a pic of what car that side oiler was in........
Ron,
Yes, I used those Crower lifters in a Ford 427 side oiler with a Crower SFT cam. I put about 14K - 15K miles on that motor with no issues at all.
Ted
Thanks Ted, I will pass it along.
I was weaned on Chevrolets from the day I started driving, only because a $200 55 Shoebox was all I could afford. I have had Dodge products and my wife has a Stupidroo, but we have never had anything as beautiful as your FORD. Two of my Grandsons were influenced to the BLUE OVAL by their father, and the other two to Chevys mostly by their father. I can't say I love FORDs now, but I like anything old and I guess my wife does too as she hasn't thrown me out yet.
Ron
L79 Intermittent ticking
