Mallory Vacuum Advance on Rover V8

[Marty V6]

Hi all,
I currently run a mechanical advance only, Mallory Dizzy on my RV8 - cos thats what it came with when I bought it. Have now got my mitts on (or will have when it arrives) a Mallory Dizzy with vacuum advance - 27 series dizzy.
I also have twin SU's which seem to make it go okay, so I'm not planning on swapping them anytime soon.

When I nail the new dizzy into the engine and connect the vacuum advance to the SU's, do I need to connect it to just one carb only, or to both via a 'y' piece connector?

Additionally, I understand that you can set the total mech advance by altering the advance stops within the dizzy, and the easy way to do this is by the 'Mallory key' which is graduated to show advance in degrees. Anyone know where I can get hold of one of these in this country?

Cheers

Marty

[David Large]

Hi

RPI sell all of the mallory stuff, have a look on their web site.

I have a vacuum advance mallory , but I don't recognise the key you refer to.

Regards

David

[craggle]

The vacuum advance usually connects to one carburettor only.

Haven't seen an advance tool either. I just ran a Mallory straight out the box on my old 3.5 and it was fine.

Craig.

[wilf]

If your engine is timed to run without vacuum, then I suspect that at light throttle openings with vac advance it will not run well. You don't need vac advance.

RV8s like lots of mechanical advance - more than any book says - but it is too long since I had one and I can't recall what I ended up with. But I recall that to get max grunt out of it I ended up at something like 11 - 12 degrees btdc at idle, and any vac advance made it run like a bag of spanners. Was great at WOT though.

[Marty V6]

Thanks for the info chaps.

I needed another dizzy, or parts for one anyway, cos the advance guide slots in my existing one are worn. It just happened that I managed to get hold of a vacuum version. I've heard that vac advance is good for economy on light throttle settings. Whilst I didnt buy a V8 Cobra to save the planet, if it helps a bit, then its a good thing. I suppose I could slow down a bit, but where's the fun in that.

I'll try it with and without the vacuum advance plumbed in and see what happens.

Cheers

Marty

[Purple AK]

Not sure if it applies to the Vac Advance Mallory's? But my non vac one has adjustment on the baseplate which alters/restricts the amount of total advance allowing you to tune the curve

[cliffords]

Originally Posted by Purple AK

Not sure if it applies to the Vac Advance Mallory's? But my non vac one has adjustment on the baseplate which alters/restricts the amount of total advance allowing you to tune the curve

Chris

Do you know where that adjustment is, I might want to restrict mine a bit and can't easily see a screw or something to adjust. Nothing in the instructions either.
Mallory Unilite no vac advance.

[Purple AK]

Originally Posted by cliffords

Chris

Do you know where that adjustment is, I might want to restrict mine a bit and can't easily see a screw or something to adjust. Nothing in the instructions either.
Mallory Unilite no vac advance.

Mines a converted Dual Point David. Two torks screws/slots in the baseplate that alter the relation to the mech advance plate. They might not exist on a Unilite

[cliffords]

Originally Posted by Purple AK

Mines a converted Dual Point David. Two torks screws/slots in the baseplate that alter the relation to the mech advance plate. They might not exist on a Unilite

Ah,
I think I have seen one of those and other is hidden , I will look tomorrow
Thanks