Late AAZ timing adjustment

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Blaizefed
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Late AAZ timing adjustment

Post by Blaizefed »

Gents, I am building up an engine for my Westy, its a late AAZ. just now getting round to the cam belt and adjusting the timing. My plan was to set it at 1mm as per damn near everyone online, however I have the new 2 piece injection pump pulley with the locking pin slot (and no elongated mounting holes). It is currently at about .92mm at TDC. I wonder is it worth adjusting it up to 1.05mm? And if it is, how do I do that? The engine is on the stand now so I have time to fiddle with it and its clean, I would much rather get it set now and not have to do it in the bus in a few months.

I will be planning to charge cool it, change the boost pin, and whack the boost up to 15PSI. (yes, an EGT gauge and boost gage are on the way) I am looking for a reliable 100-110 hp out of it. In anticipation of all this, I was going to set the timing now to 1.05 but its not adjustable on this pump. SO how to I adjust it? anyone know of a guide? I presume I'll need to reset the position of the inner pulley half on the shaft? is that easy, or am I playing with fire taking it apart?

anyone been down this road before?

Blaizefed
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Re: Late AAZ timing adjustment

Post by Blaizefed »

Just sitting here thinking about it and I think i've got it.

If I set it up at TDC (cam lock in and shimmed, crank mark lined up, pump pin in place), and get my dial indicator in and setup, I should be able to pull the locking pin out of the pump, and rotate the center nut till the dial indicator is at 1.05, then lock down the three pinch bolts on the pulley. And that would be it done. Don't know why it didn't occur to me earlier, seems obvious the more I think about it.

colinthefox
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Re: Late AAZ timing adjustment

Post by colinthefox »

I think you've got it right.

Then turn the engine 2 full revolutions forward to TDC and check that the pump lift is still correct as it will be different to your last reading due to belt tension etc. It would be factory set so that the pin goes in the hole exactly at TDC, but you're going for a different lift setting, so the hole won't line up exactly. Don't loosen the centre nut.

Could I just suggest tying a coloured ribbon to the pump timing pin (like aircraft technicians do on stuff which is supposed to be removed). It's ever so easy to forget it and turn the engine with it still in place. Yes I did that!
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Oldiebut goodie
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Re: Late AAZ timing adjustment

Post by Oldiebut goodie »

Bit like tying a length of string to your spanner when working on a boat engine - if you have ever lost one in the shyte that collects in the bilges under an engine you will know what I mean!
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