Yet another 355 valve guide thread

Year?

Realistically you are never "in the clear." Even some late model cars have had a problem.

 

Nope.

 

Pretty much need to find a mechanic who really knows how to do a leakdown test properly. Just had the guides done on mine 13 years old and 26K miles.
You'll find threads on here about values, etc.. Use the search function on this site, it's your best friend!

 

+1

I've replaced the valve guides on all three of my Porsche's, one of them as early as 40,000 miles.

 

I honestly believe that 50K is about all you can expect to get out of guides in any sort of performance application

 

My car is 95 and have 78,000 km on the clock. The belt change is due end of this year and Im debating with my mechanic if the topend rebuild should be perform during the same period as well. I am afraid that I can give you the report only at the end of this year. (so far, it has been running well)

cheers
P.

 

As stated earlier, you need a leak down test, compression test and a pre-cat emission test. I've also driven cars that ran strong with no smoke and
had terrible leak down numbers (>5% is not good).
the pre-cat emission test will indicate if the guides are starting to fail. You don't want to see HC more than 200ppm in this test.