Date: Sun, 10 Nov 2013 15:58:21 -0500
Reply-To: Larry Alofs <lalofs@GMAIL.COM>
Sender: Vanagon Mailing List <vanagon@gerry.vanagon.com>
From: Larry Alofs <lalofs@GMAIL.COM>
Subject: Re: My recent engine tear-down: All is good again
In-Reply-To: <CAHTkEuLAJB3z5fUKxjX0z78w7DPrNAFBgL1a1d9rDYJJYR-jkw@mail.gmail.com>
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Please describe "very flat table".
Larry A.
On Sun, Nov 10, 2013 at 10:38 AM, Don Hanson <dhanson928@gmail.com> wrote:
> 84 tin-top/westie interior with a 93 Jetta 2.0 liter ABA/1.8 liter
> 8-vave head (92 rabbit/jetta/etc) inline gas engine with a a 5sp and
> Vanagon diesel-parts 50 deg mounting. digifant EFI.
>
> Recently I 'lost' two cylinders in this motor after about 50k
> miles. After getting good advice from people here and doing a
> preliminary compression test, I pulled the head, leaving the motor in
> the van. About 4 hrs of work there...a real mechanic probably coulda
> done it in 2..
> I found a blown cylinder head gasket, a small breach between
> cylinders 3 & 4, across the castings between the pistons. When I
> built this motor a couple of years ago I was less than conscientious
> with my at-home head milling job, quitting too soon, with some
> discolored surface still showing right there where it blew. "Good
> enough" I told myself at that time..."The headgasket will compensate
> for that little "low" spot " Wrong, I found out. It did go for
> about 50k miles before biting me.
>
> Everything else in the motor seems fine. Valves look very good ,
> no wear apparent on the cam, the cylinder walls showed nothing bad.
> So I got the needed parts to put it back together ($120 worth,
> including a special 3-layer $50 head gasket) and this time, I was
> meticulous about surfacing my head. I guess I spent about 2 hrs of
> careful (and somewhat strenuous, shoving the head back and forth)
> lapping on ever-finer emery cloth on a very flat table, finishing up
> with 320 grit. This time, "good enough" was put aside and my
> completion-standard was "perfect is OK" I also replaced the timing
> belt and the injector O-rings as well as found that the green plug to
> the injector log, that had both wires bare and shorting
> together...perhaps the cause of my intermittent 'smoking sometimes
> during stop and go'...
>
> FYI, the head torque specs from Techtonics Tuning are different from
> Bently Books..(44ft/lbs+90+90 was what they suggested I use)
>
> So I finished and tested yesterday...after a lot of initial smoke
> out the pipe and some alarming bubbles coming into the expansion
> tank..("Oh Brother!" I thought..."I get to do this all over again, the
> head gasket is leaking again") . Everything settled down in a minute
> or two, the air all came out of the cooling system and she runs
> like a new motor.
>
> I'll finish up with an oil filter and new-untainted engine oil, a
> re-check of the timing belt tension and some new fuel line...
> Don Hanson
>
> PS..Why did I choose to surface my own head? Couple of reasons.
> First, I don't have a trusted machinist that I am familiar with.
> Removing all the valve gear and restoring it after sending out is
> pretty involved. It's been my experience that while machines are
> time-savers and allow unskilled workers to accomplish difficult tasks,
> they aren't always the only or best way to do something. The boys at
> T.T. mentioned they see their fair share of botched machine jobs on VW
> heads and are particular with where they send their machine work...
> So, yes, my arms got tired and my brain got numb pushing and pulling
> that lump around, but I know it is smooth and straight.
>
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