Stick This In Your Ear

    DA: I have a 1971 Chevelle with a '69 307ci engine. It was supposedly rebuilt but I plan on removing it to replace several leaking seals. There is a distinct ticking noise, usually heard inside the car when driving and sometimes when under the hood when giving it some throttle. A couple backyard mechanics have told me its probably a lifter. How to I determine exactly what the noise is? If it is a lifter, is it best to replace all of them? I know the cam was replaced but I'm not sure if the lifters were changed.

    SC: Use a length of thin-walled garden hose as a "stethoscope" to zero in on ticking noise. It may be that a locknut loosened up and now needs adjusting. After you locate the ticking lifter, check the pushrod and rocker arm for wear. These two items are usually not replaced during a rebuild and may need to be, as should the locknuts that hold the lifter adjustment.

    F_: The garden hose is a good way to locate the problem. If you are taking the engine out to reseal it, take the time to eyeball the lifters. If they weren't replaced on a rebuild with a new cam, I would question the rest of the rebuild. It has been mentioned the studs could be pulling out; I would suspect cam wear. Check the bottom of the lifters carefully.

    DP: My '65 283ci had a pronounced ticking after a cheepo rebuild. Part of the noise turned out to be the "new" fuel pump. After replacing the fuel pump I still have a small lifter noise. My race engine builder friend told me the lifter might not be holding pressure properly. You might do well to replace the lifters.

    GM: Most noisy lifters that I have heard are noisy at idle, too. Some alternative sources may be: 1) A small exhaust leak (likely); 2) Distributor cap/rotor not tight or mis-aligned; 3) Electric fuel pump (if equipped).

    S_: Have heard similar noise from the mechanical fuel pump rod; it can be detected by the same rod-to-ear method.

    RW: If you are looking for a quick and inexpensive fix, try this. Take a metal or wood rod (1/4" is fine and about 24" long) and move it from exhaust port to exhaust port. The rod will transfer sound. Listen for a hard-hitting sound among all the other noise. Once you find what side it is on (and do this only if you suspect that it is a lifter) remove the valve cover and let the car idle. There will be a lot of oil. If you have an old valve cover you can modify it to collect the oil and still be able to get at the nuts holding down the lifters. Give the lifter a good looking-over with the engine running. Make sure all the push rods are rotating slightly. Take the rod again, and place it one the bolt one at a time. Listen again for the one that sounds different, with a ticking sound. If your engine has hydraulic lifters then first try to adjust them. If that has no effect, remove the lifter and push rod and check for excessive wear. Do not play mix and match with the parts. If one part is bad, then it won't be any better anywhere else on the motor.

    F_: Another thing to check is the end of the valve. It could be off-square causing the rocker to rock sideways. To check for this you're going to need to run the engine with the cover off and use a long handled screwdriver to listen; don't drop the screwdriver into the fan.

    Archivist: Tom Wilson

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