Joe:
While the engine will run with pistons proud of the block, no
one seems to do it.
Kas Kastner says to pre-assemble and measure, then disassemble and deck
the block accordingly.
As I recall (always risky) he claims that approximately 0.015" will get
you a zero
deck block. If you have one piston that is high, you will need to have
it milled to
match the others. Since you might need to trim a piston, it only makes
sense to pre-assemble
with the same components you intend to run in the motor when it is
complete. BTW, I simply decked
mine 0.010" and called it good (I'm a lazy biscuit).
If the pistons stand proud of the block too much, you will have
piston to
head contact. I suppose this is obvious, but what is not so obvious is
how much is too much?
Since I have not read of anyone who has done this, I have no way of
advising you on what you might
get away with. Therefore, the "0 deck" option is the safe one.
By the way, decking the block removes the serial number. Not a
big deal unless you are
concerned about a "matching numbers" engine. It also increases squish,
which will get you a
bit more power and better knock resistance.
Copper gaskets are robust, reusable, and will raise the
compression ratio. I am sure that
a good fiber gasket would deal with light scratches/gouges just fine,
though. Do make sure
that you get the correct gasket for your block (later blocks are cut for
fire ringed gaskets) and
that you machinist restores the grooves in the block after he decks it.
A word to the wise here;
DO NOT put the head gasket on upside down. In my gasket set the head
gasket was not marked. The
DPO had installed the gasket upside down, and it was blown as a result.
All the holes line up
just fine if the gasket is on upside down, but the fire rings will end
up facing the head rather
than the block. The gasket will not last long if you make this mistake.
Cheers,
Vance
-----Original Message-----
From: owner-6pack@autox.team.net [mailto:owner-] On Behalf Of
Lizirbydavis@cs.com
Sent: Sunday, October 10, 2004 1:37 PM
To: 6pack@autox.team.net
Subject: damaged block
I'm sorting through a couple of engines I have in search of a good
candidate for a donor block. I have one that has a few very shallow
"gouges" on the deck. None of the marks are near the combustion
chambers, but one crosses over one of the water passages at the front of
the engine. I have to assume the damage happened when the head was
taken off. All of the marks are very shallow. I plan on shaving the
deck to obtain a zero deck clearance. I'm almost certain that this
would eliminate any marks on the deck. My question is 1) Do I
determine how much to take off the block by measuring with the current
crank/rod/piston configuration, or do I assemble the engine with the new
components and THEN measure the clearance? 2) Can the pistons run a
little "proud" of the block? I'm sure the gasket would prevent any
interference with the cylinder head. 3) would the use of a copper
gasket vs the fiber gasket eliminate any problems with small
scratches/nicks on the deck surface!
? ThanksJoe Davis
Check out the new British Cars Forum:
http://www.team.net/the-local/tiki-view_forum.php?forumId=8
|