123 ignition for Datsun L6 on my L28

atomman

Club Member
Nice thanks @atomman - do you mind sharing your MAP curve as well?

No worries , I did spend a bit of time making a little box with open cell foam inside ( to smooth out the pulses) with all the 6 signals plumbed into to it then feeding to the dizzy , but ended up taking it all off an just using the main curve , so don't use it anymore , My thinking was more things to go wrong,
 
  • Like
Reactions: rcv

240L31

Club Member
So what is the current opinion on this distributor? Initially I planned to install one of these, but I'm a bit unsettled due to @AliK s review regarding the distributor cap failures etc. I mean my 280ZX dizzy works flawlessly, but the tunability (especially for idle) would be nice. It seems like my engine needs lots of initial advance (~18-20°) in order to idle smoothly.
 

jonbills

Membership Secretary
Site Administrator
IMO, distributorless with Speeduino (for example) is cheaper and better. (but it is more work to install)
 

jonbills

Membership Secretary
Site Administrator
So what is the current opinion on this distributor? Initially I planned to install one of these, but I'm a bit unsettled due to @AliK s review regarding the distributor cap failures etc. I mean my 280ZX dizzy works flawlessly, but the tunability (especially for idle) would be nice. It seems like my engine needs lots of initial advance (~18-20°) in order to idle smoothly.
You can do 20 degrees at idle easily enough with a 280zx distributor. What can't you do with the 280zx dizzy? Do you need less advance after idle?
 

240L31

Club Member
@jonbills yes I'm afraid it would be too much advance at higher engine speeds. I think I'm at 38deg BTDC right now, with 17deg at idle.

Interesting, I'll look into the speeduino thing.
 

jonbills

Membership Secretary
Site Administrator
@jonbills yes I'm afraid it would be too much advance at higher engine speeds. I think I'm at 38deg BTDC right now, with 17deg at idle.

Interesting, I'll look into the speeduino thing.
you can take mechanical advance out of the 280zx dizzy - you just fill the last few mm of the slot the weight runs in. I reckon 5mm is worth about 10 degrees.
So you should be then able to set 20 degrees at idle and still be mid 30s at high revs.
 

AliK

Vehicle Dating Officer
Staff member
Club Member
Hello chaps.

sorry for the delayed response, I’ve been off forum for a while and just getting back in the saddle on all things Z!

So, would I recommend 123 ignition? DEFINITELY! It’s really grown on me - that is once I got past the poor quality caps and started using the Bosch ones.

speeduino is definitely a better proposition but if my understanding is correct, it’s not plug and play in the same way. Is that right @jonbills ? I recall you doing a fair bit of soldering etc but have things changed since?

As for sharing my curves (!) - I like Atomans curve a lot!! In fact I will steal it and experiment. Mine is a lot more conservative for now - for various reasons I won’t go into for brevity - and has some bumps where I have been experimenting with reducing the effects of reversion through my carbs (please don’t laugh at it, it’s rough). As he said, it’s very much still a work in progress! I have an additional bump at the beginning of the curve as an anti-stall.

C23226A1-76B2-4103-A626-CD920F6EECB5.png

Note that mine is now set at 10 degrees static timing to allow for easier cold start so you have to add 10 degrees to all my mech advance numbers.


My vac curve is very mild also but that’s because I’m paranoid about knock and wanted to start safe, especially as I can, in certain situations, run very rich (13 or less) at cruise around the reversion points of the rev range! That’s why it’s starting at 3500 rpm.

0EC3E32A-4C82-4CBA-BF53-A47C5754070A.png

This vac curve mimicks the stock dizzy curve but with about 10 degrees shaved off it! once I finish my carb tuning / needle experimenting antics, I’ll focus more on fine tuning the timing.

Incidentally, I found anything more than 16 degrees at idle (1k on mine) caused running on when switched off after a long period of idling. It was clearly causing too much heat. I NEVER get run-on now.

@atomman - what is the compression and cam on that L28?
 

jonbills

Membership Secretary
Site Administrator
well yes, I did solder my Speeduino board, but even if I'd bought it assembled or bought a different EMS, the installation with a crank trigger wheel is a lot more work. I suspect though it would be comparable to the 123 install if you trigger the EMS from from the distributor.
 

AliK

Vehicle Dating Officer
Staff member
Club Member
10.8:1 with a 280 degree and 0.490 lift cam IIRC|

Thank you. It seems our specs are pretty similar, so I'll definitely experiment with your curve.
 

jonbills

Membership Secretary
Site Administrator
Yeah, looks like it would do it, although rather a lack of credit to the Speeduino project on display.
I'd more recommend https://diy-efi.co.uk/ who I know to contribute to the project and cheaper than that ebay one.
 

AliK

Vehicle Dating Officer
Staff member
Club Member
Thanks Jon! If I did it again and I was going coil on plug, this would be a serious contender!!!
 

Graeme - CZ

Club Member
Hi all,

I'm curious what folks think are the various options for Distributor refurb / renewal? I see here 123 ignition and Speeduino.

What else?

I was just looking at this: https://www.rockauto.com/en/moreinfo.php?pk=28194&cc=1209204&jsn=816

I think what I really want to do is renew what I have, more than achieve some further performance gains. I've already made a pretty good leap with the Zstory exhaust system.

Also, my vacuum return is not functioning, so i need to renew something.

Welcome peoples experience / ideas?

Cheers, Graeme
 

uk66fastback

Club Member
So that Rock Auto dizzy is essentially a recon one (that you send them), which still has points ...

It’s a fairly cheap way of getting what should be a reliable set-up. Electronic is the way to go though, surely ...
 
Top