The V8 Owners Forum -

What is the actual difference between pre SD1 and SD1 gears ? They have a different part number.

Pre SD1 is a female drive on oil pump, with a male drive on dizzi, while SD1 is a male drive on oil pump, with a female drive on Dizzi.
I'm going to be fitting an SD1 end to my P6 dizzi (attaches by roll pin), but have to remove (by cutting I presume) the male end first as it is actually part of the dizzi shaft, whereas the SD1 gear is an extension (and male end would hit this if you tried to fit it onto shaft) - if this makes sense.

Pete

Assuming you're referring to the gear that's fitted on the end of the camshaft, the difference is in the ammount of offset clearance provided for oil flow to pass out via the camshaft keyway to lube the gears. P6 is flat machined, SD1 onwards has a slight offset against the fuel pump spacer to provide an oilway. If you fit a P6 gear with an SD1 pump cam spacer then virtually no oil will flow.

Didn't read subject fully.

Pete

plastic orange wrote:.
I'm going to be fitting an SD1 end to my P6 dizzi (attaches by roll pin), but have to remove (by cutting I presume) the male end first as it is actually part of the dizzi shaft, whereas the SD1 gear is an extension (and male end would hit this if you tried to fit it onto shaft) - if this makes sense.

Pete

You'r correct. I have fitted the MSD Pro Billet dizzy which is also P6 style.
I had to cut the male drive of the dizzy's shaft and I replaced the pre SD1 gear without the pump drive with an SD1 gear with pump drive. In my case the gear drives where interchangeble so it was a straight fit.
Before the Pro Billet came up I did the same to an old P6 points dizzy and drove this for about 5 years in our SD1 engine.

I found out thats also posible to fit the oilpump drive in an old style gear as gears are the same. But be carefull with drilling a hole for the pump drive dowelpin, gears will easely break so you'll better of with a new SD1 gear before you'll trie this.