[Fot] Finding TDC

[Charly Mitchel]

		Mark, I have a tdc tool you screw into the spark plug hole.
Charly
----------------------------------------

				From: "Mark York"
<m-syork at comcast.net>
Sent: Saturday, June 07, 2008 10:16 PM
To:
fot at autox.team.net
Subject: [Fot] Finding TDC 

Amici,

I'm finally
getting some time to finish the final assembly of my motor for
the TR3 racer,
the machine shop did most of the work (pistons/sleeves,
crank, cam, and
head), and I'm doing the rest. I called the machine shop to
ask how to find
TDC since the flywheel has been replaced with a lightened
one and none of the
indicator arrows are there, I was given the following:

1) Rotate the engine
until the #1 intake has just closed and the
exhaust valve is just opening
(mark this position)

2) Rotate the engine 360 degrees, this is
approximately TDC.

Now here is where it gets a little weird:

3) Weld a
bolt to the bottom of a spark plug.

4) Rotate the engine a quarter turn
counter clockwise

5) Install the spark plug / bolt

6) Rotate the engine
clockwise until the piston makes contact with the
bolt on the end of the
spark plug, mark this point

7) Rotate the engine counter clockwise until
the piston again contacts
the bolt on the spark plug, mark this point.

The
2 points marked are approx 17 deg before TDC and after TDC. 

My questions
are: how long should the bolt be on the end of the spark plug
(won't the
length make a difference where the piston meets it)? Does
somebody have an
easier way?

The head is mounted and torqued, I really don't want to take it
off. Doesn't
this process seem a little Rube Goldberg-ish? 

Confused in
Seattle

Mark

PS: Thanks in advance
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