<VV> Verdict on: Bad Idle (66 140)

corvairs lonwall@corvairunderground.com
Mon, 16 Aug 2004 10:20:21 -0700

With all due respect Larry!  We have seen NO evidence of anything of 
this (or other) type of failure due to Teflon stem seals. BUT, there 
exists considerable controversey in regards to guide liners - or at the 
very least, the inconsistant ability of some shops to do the work 
properly. Having said that I am in no position to tell Joe what caused 
his problem, but I feel it necessary to respond to what i think are 
incorrect statements!

You'd be surprised about the internet - anyone can post an opinion - 
someone posts that Ed Cole is coming out with a new book and I get 100 e 
mails asking me what it will cost and whether he will be available to 
sign copies.........yikes... Lon


Larry Forman wrote:

> At 01:25 PM 8/14/2004 -0400, N. Joseph Potts wrote:
>>      The VALVE GUIDE on that intake valve, which had been resleeved with
>> bronze, had broken, evidently near the end that's in the combustion 
>> chamber.
>> I am missing that inch, more or less, from that end of the guide (which
>> pulled out of the head by hand). This head had been professionally
>> refurbished in May 2003, and installed in February 2004. Less than 5,000
>> miles. Teflon valve-stem seals were installed then.
>> Joe Potts
> Hi Joe,
> The question is: WHY?  One idea is that the Teflon valve-stem seals 
> might have provided too good of a seal and starved the guide for 
> lubrication.  I would recommend pulling the other intake valves and 
> compare the look inside the stems with a good microscope looking for 
> evidence of excessive heat.  Do the valve stems have any evidence of 
> excessive temperatures?  Also measure the diameter at the ends of the 
> guides and see if it has increased wear there.  Another idea might be 
> to pull the exhaust valves and compare wear to those with the seals.
> -- Larry
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