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Re: where is the timing mark?!

To: "MG List" <mgs@autox.team.net>
Subject: Re: where is the timing mark?!
From: Max Heim <mvheim@studiolimage.com>
Date: Tue, 17 Oct 2000 15:47:14 -0700
Well, you can check one thing very simply. First note which position on 
the cap the wire from the #1 cylinder (furthest forward) leads to (it 
could be any of them, depending on the position of the distributor body). 
Then remove the distributor cap without removing any of the wires (you 
can detach the center wire to the coil if it makes it easier). Now note 
where the rotor is pointing. Turn the engine over (by rolling the car in 
gear, or turning the crankshaft pulley nut with a wrench) until the rotor 
is pointing at the position of the #1 spark plug lead (you can test fit 
the cap from time to time to get this correct). At this point the timing 
mark on the pulley should be in sight, somewhere in the general vicinity 
of the TDC mark (if the car was running at all). If it is not (as appears 
to be the case), then you have a problem!

One possibility is the fact that different years had the timing marks 
attached in different positions on the timing cover, and therefore 
required different pulleys. If some DPO installed either a timing cover 
or a pulley from the wrong year, it would result in the problem you are 
experiencing. I agree with the comment that the odds of pulley "slip" are 
very remote.

The distributor itself is keyed and cannot be installed 180 degrees out, 
but the distributor drive gear could be, although that seems very 
unlikely. The position of the vacuum advance pot unfortunately doesn't 
tell you anything, since one can rotate the entire distributor in 
increments of 90 degrees, and compensate by shifting the spark plug leads 
one position in the opposite direction, in order to end up with the pot 
aiming in whatever direction seems to be convenient.

I hope this helps.


Evangelos Makris had this to say:

>Thanks people for your helpful ideas.
>When the strobe pin is on cylinder #3 the mark appears to be 10-15
>degrees AFTER
>TDC, that is, further clockwise from the 0-degree notch.
>
>So, how do I start checking if something is indeed 180 degrees out and
>correcting it?
>
>Is there a picture somewhere on the web that shows *approximately* where
>the
>vacuum advance unit points when it's timed OK and to which of the four
>holes on
>the distributor cap the #1 sparkplug lead goes?
>
>What is a gulp valve and where should I look for it? I have two HIF4
>carbs and a
>small almost cube-shaped Facet electric petrol pump. When the engine is
>off but
>the ignition is on, that pump won't stop ticking after a while, like the
>
>standard SU electric pump does on my 66 Sprite after the carbs fill up.
>
>Evangelos, 73 BGT
>
>
>


--

Max Heim
'66 MGB GHN3L76149
If you're near Mountain View, CA,
it's the red one with the silver bootlid.


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