[TR] weird distributor "out of phase" problem--It's alliiive!

[Tim Gaines]

Three years ago, when my Spit engine problem first developed, I had found a very small tear in the piston diaphragm and replaced it with a new one.  That didn't fix the problem, and I ended up letting the whole thing go at the time.  So, last week, when I took the carb apart piece by piece, I concentrated on everything but the diaphragm, especially the intricate autochoke with its bimetal spring, stepped cams, vacuum piston, etc.  I did look at the diaphragm, but since it looked good, I left it alone.  Yesterday I unscrewed the chamber cover again and lifted out the piston and diaphragm.  The diaphragm has two little raised tabs, one that fits into an indent in the ring around the piston and one for an indent in the outer ring of the chamber body.  The one for the body wasn't in place.  I was careless 3 years ago, and then again last week.  I put it right, tightened the cover down, and gave the key a turn.  It started immediately!  The engine was smooth, the rpms were just about right, and as it warmed the rpms dropped as they should if the autochoke is working.  I guess that misplaced tab made for a small vacuum leak, just like the original problem.  It probably needs a little adjustment with the timing light, and I plan to do that later, but it is very close to perfect now.  Finally.

Tim Gaines
Clinton, SC
1980 Spitfire
1974 TR6

----- Original Message -----
From: "Tim Gaines" <mtgaines at presby.edu>
To: triumphs at autox.team.net
Sent: Sunday, March 15, 2015 11:47:46 PM
Subject: Re: [TR] weird distributor "out of phase" problem

Thanks to all who have ruled out my timing chain theory.  I'm relieved I don't have to get into that!  Though I WAS sure at the time that I had cylinder #1 at tdc on the compression stroke, I am backtracking now.  I had been checking the clearances on all of the valves and after that I really thought I had cycled back to the compression stroke on #1 but . . .  I guess I'll find out tomorrow when I go out and take a look.

My big surprise was that the distributor would only fit in one orientation.  That would be a very good design I guess, but I had always heard that it was very easy to get it wrong.  Was it really designed that way, or is there something special (damage) about mine?

Thanks again,
Tim