So, I need to adjust the amount of advance that my capsule provides. Mine is an 86 on a Lucas system and it has an adjustment screw with a lockdown nut.

Does anyone have any information on just how many degrees total advancement the vac cap should produce at 15inches of vac?

 

No idea on the USA market, or those adjustable capsules.

Mine ran 18 @ 15".

My distibutor base was a PreHE unit, with 15deg??? (and that is memory, which sort of sucks), but it was 3deg more than the HE unit.

1985 Australian market, not standard, as in NO emissions, large throttles, no AAV or balance pipe, so probably ilegal over there.

 

That's interesting. Probably old news to some on this site but I am now curious what the differences are in the various versions of the V12 for the different markets including which ones there are. So far I've seen UK, Europe, South Africa, Australia, Canada and the US.
Recently I saw a picture of V12 sitting on moving pallet. I noticed that it had a two pronged sensor coming out of the front of housing connected to the lower radiator hose. When I looked for that sensor on a junkyard car here its not present. I tried to upload a photo but no luck. Or maybe it worked.

 

Thats the small electric radiator fan sensor.

It is screw in on the HE, and push in, to a rubber grommet, on later PreHE engines, and missing on real early EFI/carby PreHE, as that sensor is in the top of the RH radiator tank, and impossible to get at.

Many things change with our market, coz we got the real HE V12, as in 12.5:1 comp ratio, and very little emissions junk as such.

Air pumps came and went up to about 1987 when the went for good. EGR never existed. Ignition system Vac regulator never made it either, Cats appeared early 1988ish, and so on.

 

Grant,

Could it be 12º on the HE and 15º on the Pre-HE?

Dave, over on Jag-Lovers says his '88 HE without adjustment is 12º.

I don't think that it's crucial I know the exact spec. I'm just trying to dial my Vac adv back to sane level. Currently I am running none.

I'm assuming ( have not measured it yet ) that I'm getting way too much advance. Given that mine is adjustable, and looks like it's been changed, I'm thinking that the POs mech cranked on it.

I shut off my Vac adv ( got a brass vac valve ) and advanced my static timing a bit. This yields loads more power than I was getting and no detonation under any load conditions. I just can't keep mine from detonating with the Vac adv hooked up. I have to dial the static way back and putt around and I still get Detonation under heavy loading.

I want to set my static back to 10º and then run her at 3000 without vac adv to check the centrifugal adv contribution then dial my Vac up to spec and see if it resolves this. If I have a spec or not it's still down to gunning her up a hill and seeing if she's happy.

 

Maybe, lots of beauty sleep since those days, but I do remember it was 3deg better mechanical advance.

The old HE base is somewher in the shed, but that would be a search and a half at the moment.

You are correct, the amount is iffy, as long as it can handle what you give it without detonation, and the vac is set up to dump on acceleration, and come online at cruise, you can run a lot of advance on these engines.