Tom M'Guinn

Thanks for all the inputs gents. The new lifters are marked with a big "INA" but came from the dealer in a Porsche box. The old original lifters (that came with the car in 86) are also marked INA but it's a much smaller marking that is stamped into the metal, rather than being printed or etched like the new ones. The metal in the well part is also a different color in the old ones --the originals are gold/bronze colored, whereas the new ones are all silver colored. I may have to cut a few up to investigate.

The cam lobe was discolored a bit on the base circle, but felt smooth. I'll be changing the cam soon regardless, though now I'm not sure what lifters to use -- old originals or new ones like these?

Crazy Eddie

Somehow Tom, that sounds more like that's going to be a fun thing for you rather than a chore
Also, this post title is killing me....Every time I see another thread, I think about the movie in college with a very similar title

Tom M'Guinn

What, reefer madness?

Tom M'Guinn

Well, here's an update. I put in replacement lifter for the bad one and all seemed well (except for some ticking after start up). I recently took the top end apart for some other R&R. When I pulled the tower, I saw that the replacement lifter on that lobe was damaged just like the one I had replaced. The replacement was an old factory original, but was damaged just like the newer one. So I pulled the cam out to give it a closer look and now see that the No. 4 exhaust lobe has worn a virtual flat-spot. If you look closely at the photos below, you can see the flat spot on one of the exhaust lobes compared to a normal exhaust lobe on the same cam. I'm kicking myself for missing it before, but was fooled because it's still shiny and smooth. Lesson learned there.

I guess it's possible the new lifter damaged the cam, and then the cam damaged the factory lifter. However, in light of the ticking I was getting early on, I am inclined to believe it was the cam that started the fight. Bottom line is that I'm once again not sure I believe that the new lifters from Porsche are prone to fail.

Chris White

Stock cam?

tconn

Wow, thats an odd ware pattern. Almost looks like it was ground into the lobe.

Tom M'Guinn

It is, there's almost a little valley where the high spot used to be.

Crazy Eddie

For some reason I never saw this response
YES ...
Sorry, but I forgot what you said today, was this cam stock, just gotten from another source?
Regards
Ed

333pg333

Thanks for the pics and post Tom. So what came first, the chicken or the egg?

m42racer

That LOOKs like a welded Cam. If so, I would guess the issue is the incompatibility of the welded lobe and the tappet.
On start up these engines have to have RPM 2500 RPM or more. never let them idle on first start up.

DDP

I'm curious as to why you say that. Please explain.

333pg333

Running the cam in.

944Phil

Just an idea, if you send me a factory original and a aftermarket lifter i can do a hardness test on them. That'll tell us if there is a difference in the heat treatment or materials used.

Scott H

I've always heard that if you're going to replace the lifters, then you need to get the cam refreshed at the very least. Something about the cam wearing into the original lifter and then when you put a new lifter in the cam starts smacking it a lot harder than it should since they are slightly convex when new. Could be total BS, but it sounds possible.

DDP

Oh, on initial startup. Guess I missed that. I thought he meant everytime you start the car, lol.