Date: Tue, 13 Feb 2007 14:30:21 -0800
Reply-To: gary hradek <hradek@YAHOO.COM>
Sender: Vanagon Mailing List <vanagon@gerry.vanagon.com>
From: gary hradek <hradek@YAHOO.COM>
Subject: Re: My 2 cents on head leaks and rubber studs
In-Reply-To: <45D236CA.605@verizon.net>
Content-Type: text/plain; charset=iso-8859-1
Mike,
I think that the rubber seal is the real problem.
It is just the worst gasket system ever designed.
Now it could be that some stretching occurs when your
torque but 160 psi is not what I consider high
pressure on such head bolts. I could see that they
might stretch and the head warp if you are
overheating. But it really is a matter of the
chicken or the egg as to which came first.
--- Mike Collum <collum@verizon.net> wrote:
> It never threw a rod. A valve seized in it's bore
> (didn't hit a piston)
> and a pushrod bent. It had an overheating problem
> before that that I
> attribute to a head that wasn't sealing.
>
> Mike
>
>
> gary hradek wrote:
> > Mike,
> > So maybe it stretched when the engine blew???
> > The simple explanation is that when the rod let
> loose
> > and the piston hit the top of the head, that is
> when
> > the bolt stretched. Why do you need to explain
> it
> > any other way???
> > --- Mike Collum <collum@verizon.net> wrote:
> >
> >> When my '84 was given to me back in '91, it came
> >> with a blown engine.
> >> One of the head studs on that one had stretched
> to
> >> the point that I
> >> could wiggle the capnut and it was screwed all
> the
> >> way down.
> >>
> >> Mike
> >>
> >>
> >>
> >> gary hradek wrote:
> >>> I am not so sure about just how much of a
> problem
> >> this
> >>> stretching stud idea is. First of all when
> does
> >> all
> >>> this stretching occur. I think it is a bit of
> a
> >>> stretch to say that the stud acts like a spring.
> >>> I think the stretch occurs when you torque the
> >> head
> >>> down or perhaps when you over torque. I agree
> it
> >> is
> >>> a good idea to replace studs and nuts when the
> >> threads
> >>> look suspect or perhaps with a major rebuild but
> >> for a
> >>> simple head leak, keep it simple. If it leaks
> >> again
> >>> it is more likely to be caused by poor
> >> installation
> >>> than stretching studs. Gary
> >>>
> >>>
> >>> Date: Tue, 13 Feb 2007 13:10:35 +0000
> >>> From: Dennis Haynes <dhaynes@OPTONLINE.NET>
> >>> Subject: Re: My 2 cents on head leaks. Old hash
> >> I'm
> >>> sure...
> >>>
> >>> I have mentioned the studs on many occasions.
> >> Anytime
> >>> you have internal
> >>> head gaskets leaks, the initial cause was the
> stud
> >>> failing to hold the
> >>> heads down under load. To simply replace gaskets
> >> or
> >>> heads without
> >>> addressing the stud failure is just asking for a
> >>> repeat. The nuts should
> >>> always be replaced and new studs should be
> >> considered.
> >>> Not only can they
> >>> corrode and break from stresses they are
> designed
> >> to
> >>> act as springs. And
> >>> like a pen spring, once it is over extended they
> >> will
> >>> not return to
> >>> their original state. Proper lubrication of the
> >>> threads and a suitable
> >>> sealant on the nut flange is important to
> >> obtaining
> >>> the proper pre-load.
> >>>
> >>> Dennis
> >>>
> >>> ----- Original Message -----
> >>> From: Jeff Hogue
> >>> Date: Tuesday, February 13, 2007 7:49 am
> >>> Subject: My 2 cents on head leaks. Old hash I'm
> >>> sure...
> >>> To: vanagon@GERRY.VANAGON.COM
> >>>
> >>>> I too have rebuilt/resealed many (maybe
> hundreds)
> >> of
> >>> boxer
> >>>> engines over the past 23 years. I don't hear
> any
> >>> talk about the
> >>>> head studs being stretched. The heads are held
> to
> >>> the block with
> >>>> very little torque, and the hardware integrity
> is
> >>> very
> >>>> important. Just compare a new stud with a
> >> previously
> >>> used one,
> >>>> maybe on that has been torqued 2, 3, 4 or more
> >> times
> >>> and it's
> >>>> obvious that they do stretch. Also, sealer on
> >> these
> >>> head gaskets
> >>>> is very important, I use perm-a-tex ultra grey
> >> and
> >>> have never
> >>>> had a problem. Ever. But be very careful not to
> >> use
> >>> too much.
> >>>> This is not a case of lot is good, more is
> better
> >>> and too much
> >>>> is just right, like my fathers view on
> >> horsepower.
> >>> On the top of
> >>>> the block I use the same ultra grey. Be
> >> absolutely
> >>> certain to
> >>>> clean, clean, clean the sealing surfaces, use
> >>> alcohol base
> >>>> cleaner or something that won't leave a
> residue.
> >>>>
> >>>> I'm sure this has been bounced around plenty,
> so
> >>> forgive me for
> >>>> the broken record... That's my 2 cents on the
> >> leking
> >>> head gasket
> >>>> talk that seams to haunt the list.
> >>>> Jeff Hogue
> >>>> 84 Westy
> >>>> 87 Syncro Doka
> >>>> 8? Iltis Diesel
> >>>> 03 Jetta TDi Wagon
> >>>> 90 son
> >>>> 94 daughter
> >>>> 62 wife.....
> >>>>
> >>>
> >>>
> >>>
> >>>
> >
>
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> >
> >
> >
> >
>
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