Date: Sun, 9 May 1999 21:49:56 EDT
Reply-To: John Reynolds <kayakjr@JUNO.COM>
Sender: Vanagon Mailing List <vanagon@gerry.vanagon.com>
From: John Reynolds <kayakjr@JUNO.COM>
Subject: Re: Maybe I've got this "deck height" issue solved
Not posted, sinceI dropped the vanagon list - on type 2 though
My deck height did not match Wilson's either, so I called my mechanic (30
years of VW's only) and he told me I right on - sorry I can't remember
what it was though.
Definitely much less though. Think it was between .025 and .037". I know
that's a big range - just can't remember. When I asked this question, I
got all these replies on compression ratios - a little overwhelming. One
reply was the deck height is just a number and the C.R. is what's
important.
Well, here's my view. Deck height is important to make sure the valves
do not hit the pistons. On some engines - this may be a non issue due to
more than adequate clearance. they type 4 with dished pistons MAY (I
don't know) fall into this category. Then there is getting the C.R. that
you want - what ever that may be. I built mine stock and due to unworked
heads should get what the factory spec'd it at. Plenty will say that is
too much. I will use hi-test only as it is what meets the min octane
spec'd when the van was new.
Following is an old reply I received on this subject (P.S. just started
my engine Friday night - tomorrow is the first drive if all goes well.
Then it;s off to the garage for brakes - I'm a little burned out now - ?I
deserve a rest)
John Reynolds
kayakjr@juno.com
John, indeed from the 4 2.0's I've torn down, it looks about 0.040 or so,
but...
VW released a TSB in the 80's telling dealers to put 1.5mm thats 0.060"
shims under the barrels for an extra 10cc or so chamber volume and a
pretty
healthy decrease in CR of course. Now in fact the AMC heads come with a
.050-.060 ledge cut to do the same and AVP rebuilds their heads with a
similar .050 or so cut. However, from personal experience, the power
sucks
with this arrangement, badly. But on Steves engine there are other
issues,
like having to use 1 used mismatched piston (don't ask) which had a .010
or
so different pin height giving it about .025 deck, even with the .005
spacers that come with the Elring gasket set. So as the thick spacers
were
available and as Steve sure as shit is going to run trash gas in it, and
as
it is a Bus not a pig of a Vanagon I figured to err on the side of
caution,
even when I had to pull all the barrels again. Actually the heads we put
on
the thing were AVP rebuilds as well so he essentially has ended up with
better than 2 mm of extra space but I simply worried about the .025 as I
had
this vague recollection of Stephens saying to me even on their "zero
deck"
engines, the minumum was about .025. I'd guess you are great, but
probably
smart using the little seals. Funny you mention the baffles, actually
I've
been looking for a set, but I think his pictures are a 914 rebuild and
I'm
guesing that was the only place they were commonly found.
John
John Reynolds
On Sun, 9 May 1999 00:25:14 -0700 Tom Young
<young@SHERLOCK.SIMS.BERKELEY.EDU> writes:
>If you haven't been keeping up, I posted a question regarding deck
>heights in the 2.0L Vanagon engines I'm rebuilding. I measured
>something
>around .02" (with the barrel shims that came with the P&C's in place)
>whereas Tom WILSON (I said Watson in previous post) specifies a
>minimum of
>.04".
>
>HOWEVER, Steve Blackham said something to me that got me thinking (and
>it
>hurts!) about the head shim that came with my gasket kit. It measures
>right about .03", and .03" + .02" = .05", right in line with Wilson's
>figures. Since the Type4 engine is the only air-cooled VW engine that
>uses the head shim (I think) maybe Wilson was just sloppy in his
>writing? Maybe the real statement is "the distance between the top of
>the piston at TDC and the cylinder wall contact point of the head
>should
>be at least .04 inches; for Type4 engines, include the thickness of
>the
>head shim in this calculation."?????????????
>
>Whadaya think?
>
>---------------------------------------------------------------------
>Tom Young young@sherlock.SIMS.Berkeley.EDU
>Lafayette, CA 94549 '81 Vanagon
>---------------------------------------------------------------------
>
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