[Es2] Oversize Pistons?

Mark Wetzel Mark.Wetzel at verizon.net
Tue Aug 10 15:54:41 EDT 2004

Don't know about the guides, other than one of the guys who rebuilt my
notor put the wrong ones in. It had to be redone a second time(not by
the same guy). It was burning a ton of oil.

The ridge is normal, it's  the gap between the top of the top ring and
the deck of the head. It's never going to see a ring. So honing it
should be fine. Indeed have it measured, I suspect it'll be fine. After
honing you can either look at stock rings, or even a slightly oversized
ring. A compression test before disassembly would have told you a lot.

I don't know off the top of my head what the tolerance is for the bore,
but check the Bentley and go from there.


-----Original Message-----
From: es2-bounces at audifans.com [mailto:es2-bounces at audifans.com] On
Behalf Of n-engelbert at terrans.net
Sent: Tuesday, August 10, 2004 1:29 PM
To: 200q20v at audifans.com; es2 at audifans.com
Subject: [Es2] Oversize Pistons?

I've got my donor motor out (229k miles) at a local machine shop and the
guy I'm working with wants to bore it since he can "tell just by looking
at it" that it needs to be bored.  There is a definite ridge at the top
of the cylinder, but there are remaining hone marks from the bottom of
the stroke to about 1/4" below the ridge.  I've asked him to measure the
bore for me, but he has yet to do that.  I'm in Chicago, but the working
is going on in Dayton.  The only oversize pistons I've been able to find
are through the worldpac distributors for at least $880 for the set.
Boring and sleeving the bores is going to run me about $700.  Are there
any other options out there, like using the 7a pistons and boring out to
82.5mm (walls between cylinders too thin?), or is there a cheaper source
for .50mm over pistons, or should I take the block somewhere else for a
second opinion?  I'd like to just hone the block and put new rings in,
but I don't know yet whether I'm over the wear limit for the engine.  It
burned no oil prior to disassembly.

Also, what is the proper style of valve guide for the 3b head?  I
ordered 027 103 419 from Rod at The Parts Connection, and the machinist
says that with the shoulder that is on them, that they aren't the
correct parts, but he can lathe them down to work.  Something about the
ones that are currently in the head are ~.330" and he needs ones that
are ~.450" which is 8.5 and 11mm respectively.  I see that the worldpac
sites show a 8.5 and an 11mm guide, with the 11mm one without a
step/shoulder.  Are these the ones I need?


Nathan Engelbert
83 UrQ DA900453
89 90q
91 200q20v donor

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