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I need to use/borrow a good bore guage]

Subject: I need to use/borrow a good bore guage]
From: Larry Colen <>
Date: Wed, 23 Aug 2006 01:55:49 -0700
I'm totally stoked, because I think that I finally have all of the
parts I need to put Jasmine's motor back together.

When Armando did my crank, he machined the rod journals to tighter
than stock tolerance, and told me to use thinner oil. The premise
being that with the blower, the tighter tolerances will allow less
room for the rods to pound on the crank.

When I went to measure the clearances at my previous machine shop,
Gary's bore guage didn't have ball bearings at the ends and it seemed
to scratch the rod bearing and give inaccurate results (we're trying
to measure to less than a thou, so any scratch in the soft bearing
will screw things up).

Don (my current machinist) has a bore guage, but won't let anyone but
himself (not even employees) touch it, and he doesn't have time for a
while. So, is there anyone relatively near Santa Cruz with a decent
bore guage I can use to check my bearing clearances?

Between the aluminum head, aluminum flywheel, aluminum backing plate
and gear reduction starter it looks like I'll probably knock about
45lbs off the weight of the motor.

With my garage torn apart (literally:
) I don't have the original starter handy, but I weighed the parts I
do have handy:

Part       Orig  New  Savings
Head       41.0  18.6 12.4
Back Plate 17.4   5.2 12.2
Flywheel   21.0   9.0 12.0
Rods        8.2   5.6  2.6
Starter           8.8  9??

I've found that with MGs or Miatas, every 100 lbs is about a second
per lap at the local tracks, so the weight savings alone in the new
motor should be good for about half a second per lap.

I'm starting to get really excited. Jasmine's been off the road for
about three years. I'm sure that I'll run into a couple more issues
putting her back together, but as of today, I theoretically have
everything I need, in my possession, to turn her back into a running

While I'm at it, does anyone have a wide band O2 sensor, and a guage
for it in their spare parts bin?  I've got a guage for my old narrow
band O2 sensor, but I don't know if it'll work with the wide band.

I'll keep you all posted on my progress, at least until people start

My friend Bill just dynoed his supercharged MGB, in his words 

"... we did a base line dyno and only got 96 HP with 113 tourque,
runing way rich, and retarded @ 15 degrees.  Did not have time to
tweek, but going back later this week."

In my experience with dyno tuning the previous incarnation of my
motor, he's likely to be putting 105-115hp to the ground by the time
he's done, depending upon how far off he is with timing and mixture.

For reference, a stock rubber bumper MGB normally puts about 50 hp to
the ground. A stock chrome bumper about 65 hp to the ground. Naturally
aspirated, mine was a peppy 75 hp to the ground. With the blower, I
saw 95-105 depending upon street or race gas, but it turns out that I
had a cracked head, and then some other issues.

Software that holds your hand is one thing, software that holds your
hand and won't let go is really, really annoying.
Larry Colen     

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