If you are running this on the road then use vacuun advance.

Lots of carbs and a hot cam are not insurmountable - connect EACH carb to a common 'rail' from which you then take the distributor vacuum.

If there is too much interaction, put a short lenght of small bore tube in each line from the carb to the 'rail' (the restriction acts much like a one way valve).

No vacuum advance really will kill low down performance!

Thanks Art. I just wondered what the benefit was of running without it. I'd only seen this on cars that had been modded for sport. I had an ex series production XU-1, another multiple side draught carbed straight six. Like riding in a wheelbarrow, but it could corner with you hanging on for grim life at the tiller with ya legs out the window before it would let go:laugh: . The distributor had the vacuum point blocked and the points plate spot welded to the baseplate. Mine was not the only race car I had seen with this done. Remember this was early 1970's series production racing and technology....so I guess it was of some benefit higher up the rev range?

Anyway I have a Crane Fireball unit not doing anything at the moment . If I can get the bits needed to set it up on the Nissan 6 I'll try that. Hmm.. I was thinking controlled dwell and all, but I might have to investigate if the unit wants the vacuum adv. or not. I'm off to do a bit of research now!

If any of you good folk want to post in a bit of free advice about the subject of ignition systems please feel free to do so:classic:

Jim.

Interesting thread, did you find out what the problem was? I'd be very interesting in what parts your running in your engine. Is the head N42? Does it have L14 rods? I guess your still wondering yourself.

Regards,

G'day all:classic:

I checked under the bonnet Gav, it's an N42 head sitting on an N42 Block.

Today I had an over voltage problem addressed. The battery was being presented with 14-18V by the alternator!! The car was using the old "vibrator" type voltage regulator, and after ensuring the battery was still serviceable, I had the regulator replaced with an electronic unit. We had to wait a few hours for a new unit to be delivered, so I pulled the alternator and the auto sparky fella pulled it to bits to give it a thorough check. The diodes had been replaced, and thankfully everything else was fine. On the testbench the alternator was pumping out a healthy 50+ amps.

With the new regulator in place the charging cct was performing perfectly now, 12.8-14v.

I had some time to observe these guys Riversone Pde Auto Electrical at work and I recommend them highly, particularly anything to do with oddball vehicles being built. For example;Sorting the electrics for an old crewcab VW Kombi fitted with a 3.8 litre V6 Holden (GM), and a Toyota Van fitted with a 3litre twin cam Toyota straight 6!

I'm booked in at Stewart Wilkins next week...should be interesting

Jim.

I picked the car up this morning. Main problem was loose main jets,some were one turn from dropping out! timing was way out, advanced to where it should have been pinging its head off. No parts needed, and engine is in sound condition. Appears the head is a low compression unit says Mr Wilkins.

I thought it was OK before, but the difference on the road is amazing. Much smoother, and crisper revving, and more usable torque. Acceleration in 4th gear is great:laugh:

The attached graph says it all, better power and broader torque. Not a big numbers motor, not as much as I expected but still a fun package:classic:

1 hour on the dyno

2.5 hours labour

What nice results Jim! All ready for the Bathurst run now I see! Just in time too. I've got new spark plugs and points yesterday, but I'm thinking maybe I should replace the leads too? Is this easy to do? Not sure what else I can do within a week to up performance a bit. Gotta keep up with those Princes...

What a difference the tune did. The dyno chart really says it all.

If the age of the dizzy cap is unknown, it's advisable to replace it as well, include rotor button, condenser, leads, plugs. Doing it for the first time can be daunting,the right tools, specs and info are a must. Better to get an experienced friend to show the way, but once you've done it I'm sure you'll agree it's a piece of cake. The icing would be if you can get your hands on a vacuum gauge and incorporate that as tool into the job. They are a very good visual indicator of how your tune is going.

Glad to hear that you've got your motor sorted out. Mine is still in the shop. 5 weeks! Don't know when I'll be getting it back . . . . The head is being overhauled because it's burning oil.

Hi Miles,

I'd be interested to hear more about your engine. I gather it's still a 2 litre? Interesting choice for someone to add all the nice bits, like triple twin sidedraughts and a decent header/exhaust sytem. It seems to me that any of these GT's that are for sale all have had the 2.8L transplant, which makes yours all the more interesting!

Do you know what other work has been done? Any plans for it now it's in the hands of a rebuilder??

Cheers,

Jim.

Jim,

The car is mostly unmolested. The engine is stock, save for headers (extractors) and a Fujitsubo exhaust system.　The head work is going to include a mild cam re-grind from 62 to 64 degrees for better low end. I have the twin SUs that will be going in later. Other than that, no plans. You`re right that most of these cars have had the 2.8 transplant with triple webers. But the hot set up now is the 2.6 RB transplant. Will wait and see what comes after the head work.