Gimme a Lift
I performed a basic rebuild on the 350 small-block V-8 in my '85 Chevy pickup. I installed new rings, bearings, camshaft, lifters, timing chain, and gaskets. I didn't touch the oiling system or have any machine work done. The engine ran fine for a while, but then it developed a bad lifter. The same intake lifter failed a couple times. This doesn't seem normal. Could there be some other problem that I'm missing? Thank you.
It would be unusual for a lifter to fail repeatedly in the same lifter bore, so the problem is most likely a damaged camshaft. Once the hardened surface of a cam lobe gets damaged, it will continue to deteriorate. The only cure is a new camshaft.
Even though the camshaft was new, you might not have followed the correct break-in procedure. A flat-tappet camshaft and the lifters need to be thoroughly coated with a moly-type break-in lube. This lube is usually included with the cam and lifter kit, but it's also readily available separately at any auto parts store.
Great care needs to be exercised when inserting the camshaft into the block. You don't want to nick any of the lobes.
A typical break-in procedure should last about 20-30 minutes with the engine held steady at 2,000 rpm. It's important to do this all at one time. Don't stop the engine before the specified time. The break-in procedure helps establish a uniform wear pattern between the camshaft lobes and the lifters.
If you carefully followed the break-in procedure, it's possible that you could have a tight lifter bore. When you removed the lifters, they should have come out pretty easily using your fingers. If they were more than finger tight, there could be a tight bore.
The best way to determine bore diameter is with an inside bore micrometer. If you feel confident that the troublesome bore is a little tight, you can relieve it with a lifter bore hone. You just want to lightly hone the bore. Immediately wipe the bore clean, and soon after you start the engine you should change the oil and filter. It's easy to do more harm than good, so you might really want to consult a professional engine shop.