Valve seal question

Bernie Benz b.benz at
Thu Dec 1 10:39:39 EST 2005

> From: "Feelstranger" <feelstranger at>
> Thanks Bernie.
> I just would like some feedback about the longevity of the exhaust guides.
> How many have opened heads and found guides that need to be replaced and at
> what mileage?
I've never had a reason to remove a cam cover, but at 200K+ and 160K+
respectively, the 3B goes 10K per Qt. and the 7A about 2 Qts. in 10K.  But
they've never had to put up with M1 either.

> How long will a new seal last if the guide itself is out of spec?
The seals are very compliant relative to the valve stem's latteral motion,
even in a slightly worn guide.

> Also, the smoke puffs at shifts are indicative of valve seals, not turbo,
> correct?
Intake valve seals only, caused by intake manifold vacuum at closed

> Thanks
> ----- Original Message -----
> From: "Bernie Benz" <b.benz at>
> To: "Feelstranger" <feelstranger at>
> Cc: "200q20V mailing list" <200q20v at>
> Sent: Tuesday, November 29, 2005 2:29 PM
> Subject: Re: Valve seal question
>> Yes, valve stem seals can be replaced without removing the head, and valve
>> stem clearance in the guide can be measured at the same time.
>> Bernie
>>> From: "Feelstranger" <feelstranger at>
>>> Hello all,
>>> I have not been subscribed to this list for a while (year?), so I hope
>>> this
>>> is not an anoying question.  I looked at the archives and tried to search
>>> them to no avail.  I am getting significant oil consumption.   I have
>>> seen
>>> the small puffs of smoke at shifts while tailing my SO.  I gather this is
>>> typical of valve seals, correct?
>>> I was going to have a shop do them, but they said it was a waste and that
>>> the exhaust guides should be done too.  Car is at 163K.  So, is this
>>> likley
>>> true?  Can valve guide wear be tested without head removal?
>>> How hard is a valve seal job only on a 20V?  I assume it can be done with
>>> head in car?
>>> Thanks!
>>> Nat

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