Car is a 1995, 6-speed, LT1. I am a very novice mechanic, but enjoying the challenge of doing my own work. Yes, I have the FSM! Its invaluable. Yes, I use the search function alot.

Over the winter, I installed a Hot Cam kit, 4.10 gears (with mechanics help), Adj. fuel pressure regulator, EM long tube headers, high flow cats, true dual 2 1/2" exhaust, MSD opti, hurst shifter, new water pump. All went pretty smoothly, including startup and initial break-in of the cam.

However, I am now getting a large noise that sounds appears to be coming from somewhere near the passenger side valve cover or underneath the intake manifold. Sounds like TICK, TICK, TICK, TICK, etc. I can easily hear the noise from inside the car. The noise is not apparent at idle, nor at 2000 rpm, but starts at about 3000 RPM. The noise started about 1/2way through my 1st test drive of about 5 miles.

Oil pressure is good. Fuel pressure is good. I have adjusted the valves several times using the methods outlined on this forum while car is running. No success in getting rid of the noise. I re-used the lifters and push rods, being careful to re-install them in their original locations. The push rods were straight. The lifters did not show any wear. Spark plugs are tight, no exhaust leaks. I will double check the firing order again tonight. Driver's side does not make this noise.

I used dino 10W30 to break-in the cam and am about to change back to the recommened Mobile 1 oil & new filter. Could this change in oil cause this type of noise somehow?

Car starts and runs fine. No codes. I removed the drip tabs from the valve covers. Rockers are not hitting the valve covers. Running the car with the valve cover removed does not reveal any apparent improper operation of the valves & springs.

Any ideas about what may be causing this noise or how to diagnose it? I really do not look forward to removing the intake again. Thanks in advance for your help!

 

Sounds like you may have some dirt in one of the lifters. Try using some of that Engine flush, or some Marvel Mystery oil and then do an oil change and see if that doesn't free up that sticking lifter.

I just thought of something, did you check the specs on the cam against the capabilities of the stock LT1 springs, or did the kit come with new springs? If you used the stock springs and they can't handle the lift of the new cam, that could be causing your problem and that would explain why it sounds fine at idle and up to 2000 rpms but after that starts making noise.

 

The Hot Cam Kit did include new springs, which I used. I put a quart of Marvel Mystery Oil in the crank case last night and ran it for a few minutes without any change in the noise. I was worried about possible engine damage if I ran it too long. How long does it take for MMO to do it's job? Can the engine/car be run with a sticking lifter?

 

Have you attempted to isolate the noise to a single cylinder or valve? That may be a good first step.

 

I have tried and I think I narrowed it down to one of two cylinders, but that is close as I can determine.

 

You say you fitted headers? They can make a TICKING noise if one of the ports isn't sealing correctly?

 

Thanks for the suggestion Dan. I looked for an exhaust leak and did not find one. Even so, I have already removed the header on that side of the engine and re-installed it. No change. Is there a definitive test I can use to determine if there is an exhaust leak?

 

Does the noise occur when the car is at standstill but the engine is running 2 or 3K? Apparently it does if you can eliminate all but 2 cylinders. If so, why not use a mechanic's stethoscope with the valve covers off to further isolate the cause?

 

Yes, the noise can be heard with the car stationary. I tried the screw driver method, but could not determine the exact location of the noise. I will buy a stethescope on my way home tonight and give that a try.
Thanks for your suggestion!

 

The one way I found a exhaust leak I didn't know I had was to pour some Seafoam into the vacuam hose coming off the brake booster. This will let you know real quick by sending smoke out of the leak. WW

 

Try re torquing the headers first.

 

Have you check to see if the rockers are making contact with the valve cover?