RustyRotors

So I found this 96 - 993 that I think I might like to purchase. The valve guides and SAI decarb were done at 52000 miles. It now has 70000 miles. The previous repair was done at a Porsche dealership under warranty. It used to burn about a litre of oil between oil changes and now - still - does not use any oil at all.

My question is - what is the possibility that this engine will need to do guides or decarb again? Is this a one shot deal? Is the repair a permanent fix or something I can look forward to dealing with again. If so, at what mileage? Should I worry about it or forget about it? The repair was done in 2002.

It may be a deal but not if I am going to have to deal with that again any time soon.

Thanks in advance.
- Ron

Brett - 1996 C4

Question is, what replacement valve guides did they use? Same ones Porsche put in the first place ( ) or the better phosphorus-bronze ones. If the latter, interesting if that was done under warranty by a dealership. Perhaps they should be talking to PCNA about supplying valve guide replacements to the rest of us.

Flying Finn

I'd think they used Porsche guides since it was done at Porsche dealership (and under warranty) but still I'd think this as a plus since you have only 18 000 miles on those guides instead of 70 000.
Worth still to ask though.

You might have to repair quides at 100 000 again or you might not have to worry about it until 300 000. Depends a lot how well they were seated etc.

In any case, those quides should be better than if the work was not done. I wouldn't stay away because of replaced quides, not at all.
Valve quide wear is quite common on these car so it doesn't mean car has been abused or otherwise maintained bad or something.

RustyRotors

It was done at the Porsche dealership. Porsche won't pay for someone elses valve guides. They would have used their own. Are they the bronze ones? Would Porsche have made an updated improved version since the car was built in 96 and the repair was done in 2002? I have talked to so many technical people now that I can not remember who said it, but someone said that the original guides get pushed back into the head from the carbon build up causing the valve guide wear problem in the first place. The heads were re-worked and the new OEM guides properly seated. If that is the case, what is the likelihood that the SAI carbon issue will resurface? Maybe routine inspection and cleaning can save a valve issue? What is involved in cleaning? Can it be done without dismantling the engine?

Thanks
Ron

Mike J

Do you have the repair bills?....that would show the part numbers for the guides.

I am pretty sure the "new" guides that Porsche use are the same crappy ones they put into the engines originally.

The cause of the SAI issue is not totally understood but high oil consumption due to bad guides is certainly a culprit. Then again, my car has 76,000 miles, no SAI issues (I checked all the vents are clear) but its needs valve guides bad.....so go figure.

Good maintainance (i.e. oil changes, etc) is the best you can do for the valve issue. Not much else can be done except to make sure your engine cover is off (keeps the engine cooler). Another oil cooler or the manual oil cooler switch to keep the oil temps down helps.

Cheers,

Mike

Darrell E

The 96 C4 that I just bought had the top end and SAI work done at a dealership (not under warranty however). I was told by both the owner and the independant shop that did the PPI that this dealer subs all this work out to a very reputable shop who does the work right, ie phosphorus/bronze valve guides and the old style seals. I'm sure each dealership does things differently however. The fact that it was done under warranty, would lead one to think that maybe the same old Porsche OEM stuff was used in this instance.

RustyRotors

The warranty repair was done at Rusnak Pasadena. My understanding is that they are a large reputable shop.

Any comments on which guides they would have used?

- Ron

trojanman

I'd ask them straight out... they should tell you although as stated several times they were likely OEM. I think it's a great find to have discovered a car that's only got 18k miles on guides and SAI ports. I think many would tell you it's their greatest fear as the miles start to stack up on their 993's.

Most of the rest of the car's maintenance is manageable (in general), so putting the SAI/valve-guide fear at bay is huge, IMHO. If the car is truly not burning more than normal oil, your guides are likely doing great.

As always, PPI, PPI, PPI. Where did you find the car, btw? Private party or dealer?

Good luck.

RustyRotors

Private sale. USA car in Canada. I am in Canada. One owner, purchased at Beverly Hills Porsche. All service history and well maintained. Does not use any oil at all. Before guides were done it was up to one litre between oil changes. As everyone has said, and I agree, I can handle anything else that comes my way but the guides issue would make me pretty sour if I bought a car that needed a top end rebuild. I am going to replace a daily driver 1990 944S2 with this 993.

I am starting to feel better about this car. It could be the one.

On a related note. I was looking at a 1990 964 with 177k kms. Again, full history available. I told the seller the mileage was too high. He says the engine was done at 158k. I got him to fax me the invoices. The repair invoice complaint was to repair oil leaks. After new pistons and cylinders, oil cooler, flywheel, clutch, O2 sensor, a couple of fog lights and a bunch of misc gaskets and seals etc. the invoice came to $12k. Interesting.

- Ron