JJC Posted September 3, 2019 Report Share Posted September 3, 2019 What’s the internal difference between the 40403 and 40783 or 40795 distributors? JJC Quote Link to post Share on other sites
ctc77965o Posted September 3, 2019 Report Share Posted September 3, 2019 (edited) 403 is a DM2, the 783 and 795 are both 25D type. They all physically fit a TR 4 cyl, the difference between the 25Ds is the mechanical advance curve (means in detail the springs and the 'end stop' for the advance). I cant comment on the DM2 never seen this prehistoric type... Edited September 3, 2019 by ctc77965o Quote Link to post Share on other sites
JJC Posted September 4, 2019 Author Report Share Posted September 4, 2019 Thanks. So can you convert a 403 for use on an 86mm engine? JJC Quote Link to post Share on other sites
ctc77965o Posted September 4, 2019 Report Share Posted September 4, 2019 If you know what advance curve you want I am sure Martin Jay can make it work. Or you could just suck it n see, assuming it's in good order. Quote Link to post Share on other sites
iain Posted September 5, 2019 Report Share Posted September 5, 2019 (edited) Martin can definitely tailor a 25D to your engine spec. Edited September 5, 2019 by iain Quote Link to post Share on other sites
TR4Geoff Posted September 5, 2019 Report Share Posted September 5, 2019 Unless you can check the advance curve yourself, I would strongly suggest you ask Martin Jay (Distributor Doctor) to check it out. If it is giving you too much advance you could end up blowing the engine! I didn't blow my engine, but got close too it! Geoff Quote Link to post Share on other sites
JJC Posted September 5, 2019 Author Report Share Posted September 5, 2019 Yes agree Martin is the authority. Given the Snap On timing light I guess I can measure the advance. But at the moment the weights seem somewhat stiff so there’s a bit more investigation needed. JJC Quote Link to post Share on other sites
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