993 value guide concerns - legitimate?

[porschesix]

The November issue of Porsche Panorama posted a gloomy article about the impending need for all 993's to have their valve guides (I think it was exhaust guides) replaced - stating it is not a matter of if, but when. Another article in GT (a European publication) that has a 993 buyers guide mentioned this too, but saying it is something that happens at about 60,000 or beyond. Does anyone have first hand knowledge of this being a problem with the 993s. I've always understood the motors to be bullet-proof. I've had a number of 993, but all with very low mileage and none with issues. Is this the real deal or an urban legend??? Thanks!

[AFJuvat]

So far for me this is an "urban legend".

I maintain several 993s, several with 80 - 100K miles on them with no sign of valve guide wear.

AFJuvat

[john walker's workshop]

i just did one with low miles that was smoking due to the guide wear and the exhaust seats were pounded out because of it. probably the last grind these heads will see without replacing seats.

[porschesix]

John - thanks for the post - since you have shop and specialize in 911s, was this a unique experience to you, or have you seen other 993s with this problem. Also, just how 'low' was the mileage on the one you just did. Thanks!

[ludovicbreger]

About a year ago, Jerry Woods enterprise rebuilt the engine of my 3.2l Carrera. We talked about 993s, and I was told that every single 993 3.6l engine they had taken apart to modify for racing needed new valve guides.

[Carrera3.5L]

According to the guys at Ollie's (respected Porsche Machine Shop that probably sees as many heads as anyone), the valve guide issue is about as prevalent in the 993's as it was in the earlier models.

When I was there picking up my parts, I saw quite a few sets of 993 heads getting the "treatment". If there is some consolation, at least the head stud problem seems to have been resolved with the 993 models, as Ollie's doesn't get nearly as many 993 cases then the older SC, Carrera and 964's.

Perhaps the 993's still have lower mileage and thus this problem hasn't cropped up in abundance yet or the issue is finally solved for most cases?

Ralph

[Bill Verburg]

The oem copper based guides have been an increasingly common issue from the first 3 liter engines(even on some 2.7s), age and larger, heavier valves have only increased the likelyhood of problems.

Plan on a rebuild w/ US phosphorus-bronze guides which are very durable.

[ljonespwc]

I just sold my 993 after spending $5000 on a top end rebuild. My exhaust valves and guides needed replacing--on a car with 55,000 miles. The Porsche head specialist who completed the job says he is getting plenty of work these days from 993 owners. I think people who deny that this is a problem are in a state of denial.

[maxnine11]

Some cars need valve guides at 40k miles, some guys are at ,or over, the 100k mark with no problems. Cross your fingers and start a war che$t just in case your car is was 'blessed' with poor valve guides.

[porschesix]

I've just 13K miles on my 96 and don't imagine putting more than 5K miles a year on it (I'm fortunate to have other toys and daily drivers) so I feel confident based on the responses here that this is not something I'll likely have to contend with for a while. Thanks to all the folks who have responded - very helpful and much appreciated.

[JWPATE]

This interesting topic, I understand will also apply to the 964 engine. And, again, my understanding is that the USA valve guides will make an improvment. Let's not forget though, that valve guide life has been an issue from the earliest engines onward.

[Wayne 962]

Jerry Woods has told me personally that he has never torn apart a 3.6 engine that didn't have worn valve guides. Big problem, according to him. If I remember, I'll ask him again next week...

-Wayne

[Rot 911]

Porsche has know about this problem since the 3.2 engines. So why haven't they "fixed" the problem?

[Bill Verburg]

They knew about it form the 2.7s

[kang]

Originally posted by Wayne at Pelican Parts
Jerry Woods has told me personally that he has never torn apart a 3.6 engine that didn't have worn valve guides. Big problem, according to him. If I remember, I'll ask him again next week...

-Wayne

As far as I know, Jerry Woods typically tears 993 engines down to turn them into race engines. My question would be: how many 993 engines have needed rebuilding BECAUSE of the worn guides.

I know some people have had top end rebuilds for the SAI smog CEL issue, but apparently it can be addressed by cleaning the passages. How many people have reached the point where the worn guides required a rebuild, just due to oil consumption and other symptoms of worn guides?

[stlrj]

Just curious, I wonder if the watercooled 996's have the same valve guide problems? I assume that because the heads must run so much cooler that the guides must last forever.

True?

-Joe