View single post by discogodfather
 Posted: 01-13-2021 03:44 am
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discogodfather



Joined: 09-17-2007
Location: San Francisco, California USA
Posts: 221
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 If you are not mechanically inclined or know the inside of a distributor the best way to go about this is to buy a used 23D/25D on ebay or elsewhere and then have it sent in to Greg or someone who does Lucas rebuilds. It doesn't matter if the dizzy has a vacuum unit or not. The ones that don't just have a metal plate in place of the vacuum unit, and ANY distributor with a vacuum unit can be easily removed in about 1 minute. Blocking the hole that is left is easy with some silicone.

Plenty of 23D and 25D modern "new" manufacture diszzys out there but they lack 2 important features:

1) They have NO INTERNAL OIL SEAL. Only Jensen Healey and Lotus have these special seals added and without them they dump oil all over the place as the dizzy shaft sits right inside the oil pump.

2) They have incorrect advance curves for the 907 engine. They work (I have tried them) but it isn't ideal. Unfortunately if you engine is tuned or modified a stock 907 advance isn't correct either.

I have rebuilt distributors and replaced oil seals, that is actually pretty easy. I also have made my own distributors by buying 23D housings from a British supplier and then swapping out the shaft and centrifugal advance into the new housing after machining an oil seal pocket into the new distributor housing. A bit of a Frankenstein but it works.

Number one problem will all distributors both new and old is the awful design around the clamping area where the thin sheet metal clamp exerts lots of pressure when you fix the distributor in place. Because these are die cast housings and can't have any areas that are thicker than a few mm, they chose to leave the area behind the clamping ring support-less (there is a 1mm gap). The metal fatigues and crushes over time and the distributor becomes loose and can pop out. The fix for this is to machine a small ring to fit behind it to fully support it, or to machine the entire housing down and fit a steel ring in place of the thin and easily broken aluminum lip ring.