(I apologize if you received this message twice: the first time I sent it
from my Blackberry, and it appeared not to be delivered.)
Steve:
I am not comfortable contradicting my learned list friends, but here is my
experience:
In my garage sits my MK 1A Tiger with an early 289 block in the engine
room.
It is bored to .060", and has a SCAT rotating assembly which includes a
stroker crank. It now mesasures 331 cu.in. The block was professionally
hot-pressure cleaned, crack tested, and found to be sound. It was bored
using proper boring/torque plates by a NASCAR level machine shop. The bores
have been fitted with Keith Black forged pistons.
C/R is 9.5:1 With all the other components installed, it makes considerable
torque and hp, and I have it electronically rev-limited to 5500 rpm.
I did not build my engine - I wrote cheques. Lots of them. The guy who did
the deed was an ex-Rootes Group (U.K.) Technician. He is a competent
mechanic, with little experience with SB Ford engines. But he knew the right
questions to ask, and to whom to ask them, as well as where the shops that
could do the machine work were located..
Controversially, he was told by his U,S. "expert" friends that early 289
blocks had thicker cylinder walls than later ones (when did they change the
castings?) And as the story goes, the shade tree race mechanics of the day
discovered that you could bore these early blocks to .100" and they would
actually run cooler (!) Than the stock blocks.
The later blocks, also as this story goes, were cast with thinner walls to
access this extra cooling factor.
Now remember its not nice to shoot the messenger! This is not my story, and
for all I know its cock and bull, served up to convince me to go for the
.060" bore job.
I can tell you this engine overheated from start-up, but after applying all
the remedies proferred by the gurus on this list, it now runs comfortably
cool as a cucumber rolling down the highway making prodigious amounts of
power, sturm und drang. Fun!
I now have roughly 8K miles on the clock, and it is running like the
proverbial Swiss watch. ( Well, almost....)
I am looking forward to getting straightened out on this thick-walled block
story: truth or fiction?
And how come my .060" 331 engine runs so well?
I think there are more of these over-built engines out there.
.
Dave
----Original Message-----
From: Ron Fraser <rfraser@bluefrog.com>
Date: Mon, 15 Dec 2008 17:39:37
To: 'Tiger Man'<Tigerman67@hotmail.com>; 'tigers'<tigers@autox.team.net>
Subject: Re: [Tigers] Machine shop questions
Steve
You really need a bore gage to read the diameter. You also want to
make sure the bores are not trumpet shaped.
You can do this with a snap gage but you also need a 4" micrometer to get a
really good reading. If you want a rough guess at the top just under the
ridge; measure the width of one of the rings, put it square in the bore,
then measure with your calipers add in 2x ring width. You can always
measure what the top is and then guess what the ridge thickness is for a
rough estimate.
Got a machine shop in your area; you need to talk to them.
40 over is pushing it, you really need to sonic test all the bores to know
if it can be bored that much.
Not sure what the cost is for sleeving an engine.
They make stroker kits for just about every engine.
Hardened seats should be obvious if they are in the heads, I believe. I
have been told that you don't need hardened seats unless you plan for the
engine to live a 5,000 rpm or more mostly but I'm no expert here.
Ron Fraser
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