Ceramic port liner

[fl993]

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?

[stanglife]

bump old thread - but had the same question - so...

[fl993]

stanglife: I talked to a few shops about recoating and they did not have the capability to apply the same type of coating and thickness as fatory does, so I followed advice from mechanic and reused the heads with cracked liner, no issuers since.

[nickd]

My port liners are similar and I abuse the engine quite a bit with no issues. The only concerns I can think of are accelerated valve guide wear, and possible pinging from the extra heat transferred to the head. The latter would be noticeable audibly and/or feeling the power get pulled back by the knock sensors. Although, aftermarket heads don’t use ceramic liners an they seem to do just fine under brutal conditions.

The only fix is a new factory head, gamble on a used head, or go aftermarket.