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Discussion Starter #1
Digging deep over the last couple of months to set things right on a new-to-me 73 Spider finally brings me to verify the Spica pump timing.
I'm asking the collective intelligence of this great BB, an endless resource for me, thanks to all.
Here's the question, is there a good reason for the timing marks to be about 1/2 inch off? Is this an "old trick" to "adjust" the timing by purposely setting the pump pulley one notch off? Was it just put on years ago a little bit off? Or could the belt have "jumped" one cog?
The belt looks to be in good condition to me, not stretched or anything.

Here's the crank timing setup, on the I Mark. And #1 was TDC, just opening the intake valve.
I Mark.jpg


This is how I found it. Close, but no cigar. Is there a good reason for this? Verifying rotor to #4.
timing close but not on.jpg

Closeup of timing marks. I should note that even moving the pump pulley over one cog won't line up the marks perfectly. Has the belt stretched?
spica pump timing marks.jpg

Thanks,
Bill
 

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It's been a while - 25 years or so - but I think its suppose to line up. Then again, 1985 in Italy in the Navy wasn't that long ago to me.

Look for some information authored by Joe Benson "maybe". Something about retarding the injection for increased proformance with 1750 cams. Your on the right track. Research.

Whew.... This is a brain teaser from yesteryears.

Bud Feigel
 

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John Stewart wrote in post #7 in this thread that the timing mark should be within half a notch. It appears the pulley is in the wrong position.
 

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Remembered reading about SPICA timing variance but alas, where is the information when needed? Quick search produced this one reference anyway:SPICA belt 1 tooth off

Post #2 was interesting:
I'm not sure about smog effects, really, but if you have cams timed to open the intake valves earlier than stock, Wes actually says to advance the spica timing by a tooth.
 

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Discussion Starter #5
Great feedback, thanks. I knew there was something to being just one notch off. I figured if it was wrong it would either be 180 out, or completely messed up. One notch is just too curious. So, I think I'll play with it. I'll put it back to center, (almost center since it won't line up), and see how she runs. It may have been an old smog trick, or something related to the intake cam timing... I'll check on that. I may buy a new belt too, I'm questioning now if it might not be stretched just a little.
Thanks again for the great input.
Bill
 

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Just be extra certain that TDC "P" correlates to the beginning of the induction stroke; i.e., the distributor rotor should not be firing cylinder #1.
 

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Discussion Starter #7
I wanted to add some info on the timing marks.

Bud, you were right about Joe Benson's name. I had ordered the SPICA tech notes from AROC when this process was starting. It happend to arrive in the mail yesterday. There is an old article in there by Joe Benson from 1981.

He talked about tweeking the pump timing by a notch. I learned that turning the pump pulley clockwise past the timing mark is advancing the pump timing. And basically he suggested that if the timing mark falls 1/2 notch off (which it often does) at least err on the side to being advanced 1/2 notch. Well, as I previously posted, I was "1 and 1/2" off, but to the retarded side.

So, I am now replacing the belt two notches over from where I started, which will leave it 1/2 notch advanced. Pictures and road test results to follow in a couple of days.
 

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Discussion Starter #8
Okay, SPICA timing has been adjusted to 1/2 notch advanced. Car put back together and road tested Sunday. Happy to report that in my opinion it is running better. It started easier, I felt it "pulled" better in 2nd gear, and it idled a little better, too. But then again, Pat Braden say just washing your Alfa makes it run better. So, I would conclude that is was mistimed before, and that this timing, although 1/2 notch off, is better. Thanks for the inputs, it was a worthwhile thread.

Picture after adjusting to 1/2 notch advanced.
spica pump mark set one half advanced.jpg
 
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