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J.A.P. vtwin engine timing

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de oude gek:
Hi
I'm looking for camshaft and ignition timing information for a J.A.P.60degree Vtwin engine of '33-'34 vintage.
Thanks
Frank

rogerwilko:
I only have the engine no. system. I would suggest contacting the Brough Superior club? Try googling.

cardan:
Inlet opens 16 degrees before TDC
Inlet closes 65 degrees after BDC
Ex opens 65 degrees before BDC
Ex closes 25 degrees after TDC
Ignition 38 degress before TDC

Leon

de oude gek:

Thanks for replys,
Leon, 38 degrees for ignition is with ignition fully advanced? seems a lot(am used to postwar engines :)).

Je leert hier elke dag wat
Frank

cardan:

Hi Frank,
Yes, 38 degrees is what it says, and that would be fully advanced. The info comes from a table "Valve and ignition timing for 1932-48 JAP engines" under the Type of Engine "1100 c.c. S.V. A/C 60 degree Twin" (S.V. = side valve, A/C = air cooled, presumably) which I guess describes your engine.
Interestingly, many of the OHV motors have ignition listed at 45 degrees before TDC - now that does seem a lot! Perhaps fuels were different (slower burning) then?
Cheers
Leon

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