b.benz at charter.net
Mon Oct 9 14:08:51 EDT 2006
Replacing valve guides requires head removal. A head overhaul, automotive
machine shop facility. Yes, the exhaust guides tend to wear more than the
intake guides because they run hotter. When guides are replaced the stem
seals are always replaced, so unless guide wear is measured and actually
excessive, it was the seal replacement that likely solved the problem, not
new guides. Exhaust valve stem sealing is not critical because there is not
a large pressure diff across the seal as there is across the intake seal,
which can suck in oil thru a bad seal.
So, inasmuch as you have to tear down externals to remove the head, before
doing so one can measure valve guide wear and decide if seal replacement is
all that is necessary.
> From: "Derek Pulvino" <dbpulvino at hotmail.com>
> Date: Mon, 09 Oct 2006 09:37:28 -0700
> To: patrick.anderson1 at comcast.net, eric.huppert at us.army.mil,
> Jeff.Bernstein at pneumaticscale.com
> Cc: 200q20v at audifans.com
> Subject: Re: Burning Oil?
> How long did that job take you? And I've heard the same about valve
> guides...exhaust going a little quicker than intake.
> Derek P
>> As for idling in traffic causing a little smoke. I had that symptom and by
>> replacing the exhaust valve guides I fixed the problem. From what I hear,
>> the intake guides don't go bad as quickly as the exhaust ones.
>> ----- Original Message ----- From: "Derek Pulvino" <dbpulvino at hotmail.com>
>> To: <eric.huppert at us.army.mil>; <Jeff.Bernstein at pneumaticscale.com>
>> Cc: <200q20v at audifans.com>
>> Sent: Friday, October 06, 2006 9:36 AM
>> Subject: RE: Burning Oil?
>>> From what you described (smoke on startup and when running cold) it looks
>>> like we're having a different thing going on. While I do get some smoke
>>> sometimes right at "startup," or when the cars is cold, the problem I
>>> encountered the other day happened after the car sat and idled in traffic
>>> for upwards of a half-an-hour. The "cold" smoke is what I'd say is
>>> for a relatively rich running cold-start car. The other "startup" smoke
>>> usually occurs when restarting a warm car after it's sat for half an hour
>>> an hour. I've never had the oil burning/smoking condition that I
>>> the other day happen outside of the "idleing a warmed up car for more than
>>> 10-15 minutes in traffic" situation. Again that's only happened three
>>> times, and again every time it was after idleing in shitty Seattle traffic
>>> for longer than normal periods of time.
>>> And your oil conusmption is substantially more favorable than mine...I'm
>>> a quart/500-miles or so.
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