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RE: TR4a engine timing: some answers

To: "Triumphs List" <triumphs@autox.team.net>
Subject: RE: TR4a engine timing: some answers
Date: Wed, 2 Jun 2004 22:38:31 -0400
I consulted a local expert and picked his brain about the tuning issue and he
had a few good things for me.

1)  26-28 degrees total advance should be enough.  30 as I have it now at the
outside.

This means that at idle, the timing light should be showing 4 to 8 degrees of
advance.

2) In his experience he has seen the problem with the lifting pins not causing
the expected engine response and inability to get the colortunes to get lean
enough without stalling the engine.  He thinks it is quite possible that the
valve guides are worn enough to leak air during high vacuum states
sufficiently to mess up the ability to tune the carbs.  Yes, even at 28,000
original miles, even when not raced.

So, I hooked up a vacuum gauge to the PCV manifold port and got 17-18 inches
of vacuum.  He said it ought to be 22 or so.  So, it looks like I will need
new valve guides some time.  I think that also means I will be trailering the
car to VTR.  Otherwise I will probably foul the plugs significantly.

He said the engine will run pretty well, but will get bad mileage and foul
plugs after several hundred miles.  So no rush.  Maybe this fall.

-Tony





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