distributor change

Sharpy · Post by **Sharpy** » Thu Jan 13, 2011 5:36 pm

Hi

Could you tell me if I will be able to change my dizzy? I have a RR engine circa 1970-1983 v8, at the mo it has a Lucas 35d8 and we have come across the later Lucas 35dm8, is it just a straight swop and will it work?

how do you know its in the right position when refitting it as we didnt put it in the engine ourselves so not sure if it was in the correct position to start with as we have never had the engine running so far.

Cheers

Paul

Pocket rocket · Post by **Pocket rocket** » Thu Jan 13, 2011 6:54 pm

The 35 DE8, DM8 and DLM8 Lucas distributors will all physically fit but the end of the dizzy shaft (usually held on wih a roll pin) may need to be changed depending on whether the end of the oiol pump shaft is male or female.

The DM8 and DLM8 as standard don't use a ballast resistor in the low tension circuit so they require a 12V coil. They also require an ignition amp (black box on the side of the dizzy or silver box with the coil). The DE8 (Opus) has its own ballast resistor/amplifier (BR9 (?)) with it.

That's probably created more confusion than anything - best to have a look at either Des Hammill's book or David Hardcastle's for the variants.

Sharpy · Post by **Sharpy** » Thu Jan 13, 2011 10:33 pm

I have the original dizzy and I can see that there is a roll pin holding the gear at the bottom of the shaft, if I change this over and get the electrickery right it should be a go-er?

Pocket rocket · Post by **Pocket rocket** » Fri Jan 14, 2011 4:44 pm

basically - yes.

Sidecar (Pete) has got some links to places on the web where he details alterations to the springs in the dizzy and other things which help to change the timing curve. I seem to remember that he says the roll pin only comes out one way so be careful!

DaveEFI · Post by **DaveEFI** » Fri Jan 14, 2011 4:52 pm

Pocket rocket wrote:basically - yes.

Sidecar (Pete) has got some links to places on the web where he details alterations to the springs in the dizzy and other things which help to change the timing curve. I seem to remember that he says the roll pin only comes out one way so be careful!

It could be the holes to gear and shaft are drilled all in one go - so I dunno if swapping a gear will always work.

Pocket rocket · Post by **Pocket rocket** » Fri Jan 14, 2011 10:35 pm

I'm pretty sure you can buy the gears separately to swop from P6 to SD1 type so i assume they are interchangable

sidecar · Post by **sidecar** » Fri Jan 14, 2011 11:20 pm

I've knocked out the roll pin on a few dizzies now, the last one I did looked like the gear would go on either way but in the end the roll pin definitely went in better with the gear one way rather than the other. It is important that you are careful because the roll pin requires a fair amount of force but the gear is weak and brittle where the hole is drilled.

RS sell the newer wobble drive gear undrilled, you could mark and drill one side of the gear then drill through this hole and through the shaft and out of the other side of the gear. Dunno if they sell the older gear.

The solid pin below the roll pin is not really designed to be knocked out. The dizzy that I'm messing with now had a loose lower, solid pin so I made a new one that was a thou or two larger. I made the new pin a fraction longer then peened over the ends. If this pin should ever drop out the engine would still run for a short while until it seized due to the fact that the oil pump had stopped!

Below is the link to the waffle that I wrote ages ago on dizzies....

http://how-to-build-a-pilgrim-sumo.wiki ... by-members

DaveEFI · Post by **DaveEFI** » Sat Jan 15, 2011 12:34 am

Pocket rocket wrote:I'm pretty sure you can buy the gears separately to swop from P6 to SD1 type so i assume they are interchangable

But do they come with pre-drilled holes?

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