280ZX Distributor Advance Curve Reference

[Chickenman]

BTW. do physically check the actual stamping numbers on the Centrifugal advance plate . Reman distributors are often a mix and match of parts. You can't trust that they have the proper advance curves ( both mechanical and Vacuum ) for the stamped number on the dizzy. Use a Dizzy testing machine or a dial back timing light on the engine to check the actual figures. 

 

Edit: Link to Jason Grays dizzy advance curve page. Has full specs of most Datsun 4 and 6 cylinder Dizzy's from 1968 to 1984:

http://web.archive.org/web/20031006100309/http://home.att.net/~jason510/dizzy_specs.htm

Edited March 14, 2017 by Chickenman

[Walter Moore]

Three things:

1. There is no problem with the mechanical advance curve on any of the ZX (S130) distributors. The problem is the vacuum advance for the "Later" cars was crazy high because the second generation electronic module has an electronic retard feature. (Engaged by the knock sensor in the head on an S130)

2. If you don't hook up the vacuum advance, then there is no problem.

3. On my car I mechanically limited the movement of the vacuum advance to limit it to 17 degrees of additional advance. This prevented pinging so long as I used 92 octane or higher fuel.

See the attached pictures of my notes.

[Jeff G 78]

I run an '82 dizzy as-is vac advance and all on my race car with no issues.  I use a F54 block with a P79 head shaved 0.050" and a mild cam.  On 93 octane, it pulls strong to 7000 RPM.

[german240]

Thank you so much for all your help guys! I didn't know that I can recurve the vacuum mechanism  I'll set it up without VA first, though. Later I'll look deeper into this topic. 

This forum is of great help! Especially for someone like me who is building his first engine. 

Edited March 15, 2017 by german240

[Chickenman]

David Vizard's " Performance with Economy " has an excellent section on Vacuum advance tuning. It is especially important for fuel mileage on a street driven car. Triples make things harder to run Vacuum advance,  because of the induction pulsing associated with Independent runners. However, the factory SU's will benefit ( mileage wise ) on the street with a functioning and properly tuned Vacuum advance. 

[Chickenman]

The following link from " The510Realm " where we were discussing Weber set-ups, but got into Ignition advance set-ups for cammed engines. Covers some of the things I've learnt from Vizard's books and others on Ignition curve tuning. Might be worth a read:

http://the510realm.com/viewtopic.php?f=30&t=28635

 

Edited March 15, 2017 by Chickenman

[madkaw]

Jeff,
I would think you are more the exception than the rule as far as being able to run vacuum advance.
I wouldn't recommend anyone with a performance built L ( assuming higher CR) to just bolt a ZX dizzy and roll. Maybe your application of mostly hard throttle and WOT the vacuum is not a factor


Sent from my iPhone using Classic Zcar Club mobile

[Jeff G 78]

Agreed Steve.  My car spends very little time at part throttle.  It is either idling or running at high RPM.  I think I tied it without the vacuum advance and didn't have great results.  I'd have to try it again to see what it does.