I was just wondering how people have gone about drilling the hole through the E15 distributor shaft to install the a12 drive gear. Fairly important to drill directly through centre of shaft i'm assuming. Best done by a machine shop? Perhaps you just use a decent drill press and holding jig/clamp?

Also, do you have to provide a new roll pin or can you use the old one?

Cheers.

Old roll-pin can usually be re-used as long as it goes back in tightly. Make sure the new drilled hole is exactly same size as A-series hole.

It seems to me Datsun didn't drill them exactly on center. But it is important to get them the right spot along the shaft so there is not excessive space between the gear and housing. They are two sizes washer for spacing.

what is meant by the term recurve the dizzy?

Will be one of the best way to get rid of the old points system in my a12..

Recurve the distributor means to change:
* when the advance starts
* how much advance it can provide
* and when the advance reaches the limit

For more power, advance should build quickly, say fully advanced by 2400 RPM (but it may ping/detonate at that setting). Stock distributor are 4200 to 4800.

recurving a dizzy gives some noticable gains i used a GM hei recurve kit in my points dizzy and it worked well... sort of

i tested the dizzy before the recurve it would get all timing in by very late around over 4000rpm think it was 4400rpm

i then took out the springs and put in the lightest (Gold) springs in both primary and secondary.

this gave quite a differnt feel of the line like more power but the springs are not light enough they fully advance at similar rates around 3900rpm.

the primary side advances significantly faster which gives better bottom end but it needs springs to be lighter for the secondary side so you can get it down to around 2000 or 2400rpm.

anyone got ideas were to get lighter springs or i heard you can weld on the weights to add some weight to it which speeds up the advance but i figured the blob of weld would interfere with the dizzy cam?

Thanks for the threads. Informative as usual!

Thinking of just using a pertronix ignitor kit now for ease of purchase and installation. Preliminary investigation seems to suggest they're considerably cheaper to buy from the U.S but I'll look around.

Re: dizzy weights, I filed a little bit off my weights (where they hit the stop) to allow a few more degrees total advance after I read that a few more degrees total may be beneficial. It was years and years ago though (when I knew even less than I know now...so not much!) and I didn't give much thought to how it affected the progression of advance. Anyway, would be interested to see what curves people are using for different stages of engine tune.

You understand that the stock A12 distributor does not have a performance curve. Even the emissions distributor has a better curve. Which mean pertronix will not increase HP, but it will be more reliable than points.

Total advance is most important, and is manually adjusted by rotating the distributor. Changing the weights for additional advance will make it take even longer to get to full advance. Heavier weights or lighter springs is the way to go to improve the curve.

Yeah mate, all good :) I guess I'm interested in knowing what static timing and total advance people are using. And what revs they are getting total advance at. Having said that, I should go and read the wiki entry for this first. I'm sure there's something there...

Static initial timing is least important to HP. The Total timing is most important.

First set total timing, then note where initial timing falls. That's your new initial timing.

Is there any rough limit to how far static advance can be though (just out of interest) before it may have a detrimental effect to engine at low speed? Probably no reason to set it too far advanced unless you're compensating for a malfunctioning mechanical advance mechanism or something, but would you anticipate any problems setting it a long way from spec? Perhaps all is good as long as it's not knocking anywhere in the rev range??