I have confirmed three pireps on 1990's vintage TCM engines with pitting lifters. My right engine is a 1999 Factory Reman and my mechanic and I discovered several pitted lifters in the engine when we did the top overhaul to Superior Millennium Cylinders in 2006. My right engine had about 800 hrs on it. I selected Superior's PMA'd lifters available through Superior Distributors, call around and check their prices.

The recent pirep I got about Airpower was excellent, they priced the Superior PMA'd lifters at about half the price of Aircraft Spruce and the PMA'd exhaust valve was half of what the cylinder shop quoted him!

See the TCM SID 05-1 regarding lifters HERE

See Superior's TCM Replacement Parts listings HERE

PS: No, it did not NEED cylinders. When I worked for Superior, I was the recipient of a promotional program  to display their new Standard Cast cylinders. By the way, after about 300 hours the Superior cylinders and my LOP operations are going great with compressions all in the mid 70's!

The second lifter pirep is from an N35 owner, Paul S., with an IO470N engine from a 1992 overhaul with about 1100 hours on his engine.

If you have an engine from this time span, it might be good preventative medicine to examine your lifters for pitting. Pitted lifters can destroy a cam and start making metal and then you know what happens? We take your CSOB Membership Card away because you could have spent about $1,000 for the lifters to avoid a very expensive engine overhaul.

If you have a pitted lifter pirep please Email Me the details.

Pics of the Paul's pitted IO470N lifters circa 1992 are below.

15 October 2008 Update:

The N35 owner's TCM cylinders were all cracked at the exhaust port. Another classic TCM failure mode for this vintage of the 1990's from what I've heard. Tough news for Paul, he's decided on a new set of 6 new cylinders to completely freshen up his engine and get him beyond TBO.

Here is a pirep from Jim P., who reports having pitting lifters in his 1997 vintage TCM factory reman IO470L:

We had pitted lifters and light cam wear on a 900 SFRM IO470L installed 1997. How we found this out was we were doing the Savannah Conversion and we were going to sell this eng to a firm in Sweden and they are required a 10 year corrosion inspection. Fortunately we found this before the sale and shipment, we then sold the eng as a core. Nothing ever showed on oil samples or in the filter. The other eng had 1700 SMOH by a local engine builder and the cam/lifters were in great condition.

Click HERE for an article by Mike Busch  that discusses lifter degradation

Above is a picture of the stages of lifter degradation from the Mike Busch article. #2 has reached the un-airworthy stage.