FT,
There are also differences in vacuum advances. The 83mm engine distributor
(40850) is all centrifugal advance without a vacuum advance. I was comparing
Randall's numbers for the 40795 distributor to those in the chart from my
repair manual. The difference in Randall's advance numbers were 2 times the
chart crankshaft advance numbers. I realize that there are some considerable
differences between distributors. I do not know if the early distributors for
TR4's were measured in camshaft degrees or crankshaft degrees in the
distributor specifications. But my repair manual chart is in crankshaft
degrees.
Greg Perry
-----Original Message-----
>From: fred thomas <frede.thomas2@verizon.net>
>Sent: Sep 11, 2006 8:02 PM
>To: Greg Perry <rgperry@earthlink.net>, Randall <tr3driver@comcast.net>,
>triumphs@autox.team.net
>Subject: Re: [TR] Vac Advance Update
>
>
>
>> Randall,
>>
>> After looking at the other vacuum advance numbers in the chart, the
>> advance is lower for the distributors for Lucas number 40735 and 40795.
>> If one doubles the degree advance numbers for these distributors, one gets
>> advance numbers in line with the rest of the distributors in the chart for
>> the same vacuum. I bet that the original specs for these distributors
>> were originally in camshaft degrees from what your earlier post stated.
>>
>> Greg Perry
>============================================================================================================
>When you start refering to other dist and vac. advance, lets not forget the
>weights and springs are quite a bit different for each model, also piston
>size makes a g difference, that has been the problem with replacement dist.
>over the years, installing the original factory dist with 83 mm piston and
>now you have 92 mm piston, just will not work for the best performance for
>your engine, many variations to even a T/R 3 & 4, piston size is the most
>vital to know. "FT"
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