95twinturbo

I'm doing a top end on my 1995 993 and one cylinder head shows the factory ceramic liner in the exhaust port chipped off in a couple of areas and also showing a hairline crack running from the valve seat to the exhaust flange. I'm thinking it's only a matter of time before all the ceramic is gone down the exhaust.

I know minor chipping is normal and factory once came out saying OK if < 1 sq cm and not down to bare aluminium, but that's what I have now.

Porsche mechanic says not worth replacing the head. I searched forums, but still unclear on any downside to letting the entire coating come off and go into the exhaust --unless I drive the car upside down . The alternative is a new head for $1,500 or a used one with minimal ceramic wear, which I haven't been able to find (if you know where to find a used 993 head without flame ring cut I would be eternally grateful).

Does anyone know of anybody recoating exhaust ports with the same ceramic material (Swaintech is only 0.002" vs factory 3mm so different) or can anyone comment on their experience living with this situation?

Also I am new to Rennlist and this post is a repeat of what I posted on pelicanparts forum, if there is a protocol for avoiding duplication please let me know. Thanks!

MarinS4

I would chase down a good used head. I would not trust that one. Can't be too expensive.

On another note why do you have the motor torn down?

95twinturbo

MarinS4 thanks I;m ooking for a used head. You have a good question about tear down, it's because I got concerned about blue smoke on startup + 1 qt oil every 400 miles + borescope showing oil puddling in cylinders.

NineMeister

Replace the head, the last thing you need is ceramic particles going through the turbine at high rpm.

95twinturbo

Good point, especially since my exhaust is basically a hollow tube with cat converter removed...