Jeff Ward

Hi Folks, I was discouraged to see in a recent post that none other than the much-revered Bruce Anderson claims our 964s are prone to premature valve guide wear. In searching our archives, I noted that the spectre of early wear was raised, but no one seemed to actually be experiencing that symptom. I accidentally did a search on the 911 Forum, and ended up with a screen full of reports, however, all for earlier cars, of course.
I'm not in a position to challenge Bruce's opinion, but I am curious as to whether a careful 964 owner can take preventative steps to avoid or minimize such wear.
Would different oil, more frequent oil changes, more frequent valve adjustments, oil additives for better lubrication, different cool-down techniques, or warm-up techniques tend to help?
I know we are all well aware of the different opinions about removing the engine underpan, so I am really asking about other things that could possibly be done.
I'd appreciate your thoughts, as I don't relish the idea of someday pulling an otherwise wonderfully performing engine to deal with valve guides.
Thanks, Jeff
1994 Cabriolet C2

Bill Verburg

The enemys of valve guides in no particular order are

• heat
• high rpm
• contaminated oil
• misadjustment

Porsche hasn't done us a favor by their choice of oem guide material either, it is somewhat soft compared to other available alloys. Do what you can to address the listed issues to extend the life of all of the engine components.

JonSeigel

Wayne Dempsey reported that Bruce A. said that *all* 3.6s he'd seen disassembled exhibited valve guide wear. Therefore, both 964s and 993s have these problems (if, indeed, there is a widespread problem, something that I view with skepticism). 3.2s also suffer from this problems and there was a recent article on this in 911 and Porsche. So we are looking at this problem from '84-'98, fifteen years and three generations of the 911.

If nothing else, take off that undertray!

Bill Gregory

There is a thought that the 3.6L engines were pushing the envelope for an air cooled production engine, resulting in shortened valve guide life. While it may be an erroneous conclusion to say that ALL 3.6L engines will have to have a top end rebuild to address worn valve guides earlier rather than later, I think it is fair to say that the 3.6L engines seem to be more prone to excessive valve guide wear than earlier Porsche engines (although there were some 3.2L problems early in their run). As Bill V. mentioned, there are several factors that can lead to valve guide wear, some of which you can influence.