Thread: Bad Comp cams lifters?

Tweet

Not a lot to go on here Jeff, but here's a possible explanation (assuming it's a flat tappet cam we're talking about).

Your builder is correct in that there are, "... a lot of problems..." however, it's not the lifters as much as lack of proper break-in.

Nearly every late-model production engine now uses roller lifters and as such, the nice folks at American Petroleum Institute (API) have lowered the ZDDP (zinc dialkyl dithiophosphate, or more commonly referred to as just "zinc") levels in motor oils listed as meeting the current SM oil rating. Simply stated - modern oils are sans the zinc we used to have and they do not protect against the extreme friction at initial start up.

Many people will install a replacement flat tapped cam and fail to read the instructions and just fire up and go... Sad story there. If break in instructions are not adhered to, things will go bad - usually cam lobes - but lifter faces are subject to tremendous stress on start up as well.

So probably the situation is traceable to initial fire up and lack of zinc additive. It's critical for the first 20 minutes as the wear pattern is irreversibly established at that time.

My two cents,
Glenn

When I broke in the motor the zinc was being reduced and knew nothing about it,if its a bad lobe I would think it would have shown up sooner as the motor has made 3 trips to Florida and runs great except for what sounds like one lifter making noise which is getting slightly worse. The builder of the motor installed the wrong cam and would like to replace it but since he had a questionable reputation I am afraid I am going to open a can of worms since it does blow some oil out the breather.