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RE: TR3 Timing

To: <Triumphs@autox.team.net>
Subject: RE: TR3 Timing
From: "Randall" <tr3driver@comcast.net>
Date: Fri, 23 Dec 2005 15:38:41 -0800
> I know that the "official" way of setting the timing on a TR3 is to
> set the engine 3/8" from TDC and then adjust the distributor until a
> light, that is connected the  distributor  terminal and any
> convenient ground illuminates.

That's only a first approximation ... I always recommend doing a road test
afterwards.

> What I would like to know is where the flywheel should be using a
> timing light.

If it's anywhere but between the crankshaft and transmission, you've got a
definite problem !

Seriously, it's not marked.  The problem with using a timing light on a TR3 is
that the centrifugal advance may have already started to move, and even if the
advance mechanism is within specification, the specification allows a rather
large margin of error.  For example, the workshop manual gives the advance as
0-2 degrees @ 200 rpm (measured at the distributor) which translates to 0-4
degrees @ 400 rpm measured at the crankshaft.  Add to that the fact that many
original tachometers are inaccurate at low rpm, and trying to measure advance
with a timing light becomes almost meaningless.

So my advice is to get the engine running (by setting timing statically) then do
a road test.  My personal preference is, once I've found the setting where I can
just make it ping by lugging in top gear (which is where the book says to leave
it), I like to back off by 2 degrees just to be sure.

Randall


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