Re: Stupid timing light questions

[C2slayman@domain.elided]

Biba,

> Date: Sat, 26 Oct 2002 19:37:36 -0700
> From: alfacybersite <acs@domain.elided>
> Subject: Stupid timing light questions
> 
> 
> >May we interrupt the whining to make a salient point: Since the car is a
> '>75 and once upon a time had a Spica, the static timing mark (F) is 4 -
> >6 degrees BTDC on the pulley. Since I've gone Euro, it should now be 6 -
> >8 degrees ATDC - but it's not.
> 
After top dead center????  The Euro version must have vacuum advance and the 
6-8deg ATDC is with vacuum advance detached.  Or do you really mean 6-8deg 
BTDC?

> >Once home (shop) upon first firing up the timing light, idle was around
> >P (TDC) and max advance at (approximately) 5k rpm was about 12 to 15
> >degrees short of M (maximum advance mark). I shut off and advanced
> >distributor. Static timing (eyeball wise since there is no mark) looked

I'm a little confused by this statement.  What mark is missing?  The one on 
the pulley or the pointer on the waterpump?  If either one is missing, how do 
you know where you are? 

>about right. Car idled much better. Now max advance is 'only' about 10
>degrees short of the M mark (eyeball wise).

You should be able to use the dial on the timing light to figure out exactly 
how many degree short of M you are.  Just dial it in until you hit M.

>Methinks there might be a problem with the centrifugal advance
>mechanism. Didn't someone recently say in essence that the advance
>mechanism on the MarelliPlex distributor sucked? I also gathered it did
>so from birth.

My experience with Marelli is that it is good quality stuff .  If the advance 
mechansim  "sucks," it's probably because the curve was taylored for a 
different application. Double check what it's advance curve should be based 
on the MarelliPlex part number.  You can always have it "recurved" to your 
application.

> Must I go back to good old fashioned points and simply throw the timing
> light in the trash, or is there a better solution?
> 

Nope!  Don't do that!  The old point-style distributors are nice for original 
concours d'elegance cars where originality counts.  But they are the one's 
that "suck" from an engineering viewpoint.  Why use a mechanical system to 
make and break a circuit?  That's what transistors were invented for!

> Biba
> Frustrated, again, in Irwindale, CA USA
> 
> [So what else did you have to do on a (daylight savings) Saturday night?
> Have a life???].

Stick to it.  Once you've got an electronic ignition wrung out, it should 
last forever.

Cheers,
Charlie
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