Date: Tue, 8 Sep 1998 19:39:14 -0400
Reply-To: Dan Johnston <johnstond@MAILSERVER.VOLVO.COM>
Sender: Vanagon Mailing List <Vanagon@vanagon.com>
From: Dan Johnston <johnstond@MAILSERVER.VOLVO.COM>
Organization: Volvo Cars of North America
Subject: Re: Head bolts on Air cooleds oil leaks
Content-Type: text/plain; charset=us-ascii
Actually I cut the tin on a '78, retorqued the heads and pushed it all back
together. I used 3M sealer (that yellow snot stuff) on the tin until the next time
when I pulled the engine. Then I brazed my cuts. Worked just fine.
dan
GMBulley@AOL.COM wrote:
> VCR50A@prodigy.com ( MICHAEL G BENTHIN), type2@bigkitty.azaccess.com
> Subject: Re: tightening head nuts, '78
> Content-Type: text/plain; charset="us-ascii"
>
> At 4:33 AM -0700 9/3/98, MICHAEL G BENTHIN wrote:
> >No one answered my query on oil leak from engine/cylinder connection in my
> >78 Westy. So I went ahead and retorqued the lower head nuts while doing
> >the seal work. Stopped it on one side, other side still leaqks a bit.
> >Anyone know if this is worse than leaving it alone or know if the upper
> >nuts can be reached? Would holes have to be cut in the tin?
>
> Don't know if cutting holes in the tin would work. I would be very wary of
> tightening only the lower head bolts. It is possible (though not easy) to
> remove the top tin with the engine in the bus and tighten the top bolts too
> - that's what I would do. Were the bottom ones really loose? If not, it
> suprises me that tightening them would stop the leak.
>
> When the engine was put together it should have had sealant applied to the
> base of the cylinders to prevent leaks. If this was not done, the only
> real solution is taking the motor back apart, cleaning the base of the
> cylinders and putting the sealant in. This is a lot of work (Probably 8
> hours for someone that knows what they're doing) so if the leak is bearable
> I'd just live with it until rebuild time.
>
> David--
>
> You've brought me temporarily out of "sniveling lurker" mode. I am G. Matthew
> Bulley, tollerated mostly on the vanagon list, and former VW motorbuilder. I'm
> not trying to flame the above writing, but there are a couple of errors in
> fact, and you are considering some no-no's.
>
> DO NOT cut your tin. never. That would be equal to drill holes in a radiator.
> even if you plan to weld over it, the tin is made a certain thickness, color,
> and dimension for very (German) calculated reason. Don't paint it, undercoat
> it, cut it, whatever.
>
> There is never any "sealant" applyed to the base of the cylinders. Never. the
> base of the cylinder is a heat transfer surface--it transfers some of the heat
> from the jug to the block. the only thing that should be there is a very thin
> metal gasket, which deforms slightly on torque, and seals and case to cylinder
> imperfections. Your builder may have neglected to put these in. The only
> remedy is to disasssemble, and insert them.
>
> DO NOT worry about your upper head bolts. They never get re-torqued, NEVER.
> They are about 1/3 shorter, and are on the "cool" side (the top) of the motor,
> thus they don't stretch like the lowers. You torque them on assembly, and
> that's it. The lower head bolts on the other hand, are on the "hot" side, are
> quite a bit longer, and thus stretch. They are to be retorqued every other
> valve adjustment, or at least every 20k. NEVER torque above the spec for your
> engine as you can hear a sound that will live in your mind forever, the sound
> of a case stud popping out of the case. POING! If your torque is correct and
> EVEN around the engine, and you still have this leak, disassembly is the only
> option.
>
> HOWEVER: I have (in a hundred or so motors) never seen a leak at the base of
> the cylinder that was even worth worrying about. It sounds more like you have
> a push-rod tube leak, which is much more common, spills a lot more oil, and
> much easier to fix.
>
> See you at BUGGOUT in Manassas. Stop by, have a free Diet Coke, and see our
> 1976 "silent" bus (for sale) Its's marigold Yellow, and has a blue side tent.
> Good Luck.
>
> G. Matthew Bulley
> cary, nc
> 1982 White Westy
> 1985 Jetta Turbo Diesel
> 1976 "silent" bus (soon to be former owner)
> .
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