cyl pressure to high?cam to small?

805 Views 5 Replies 4 Participants Last post by jeff swisher, May 13, 2008

yenkomike

Discussion Starter · May 12, 2008

i have a 468 . im running manly 50 cc dome pistons with 990 heads. my cam is a solid flat 258/268 at .050 lift 595 621 intake installed on a 105 i have noticed that my starter was working very hard so i reworked the distributor so it had less initial advance and it starts good . i did a cold compression test and its between 215 and 220 . thats cranking until it stops rising. with the throttle open. is this to much? that has to be 240 hot. im just thinking i should have added more cam. i can say one thing it is responsive .thanks

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jeff swisher

· #2 · May 12, 2008

that is fine ..you might try a kill type switch that allows you to crank it over without fire to the plugs (or should i say coil) .. then flip the switch and light it off...

I have ran 245lbs with 22 inital and 41 total..with the above setup. that was 245 with the throttle closed

some eletronic boxes have a start retard function, that may be of some help

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jeff swisher

· #6 · May 13, 2008

I never had to use anything but a well built stock starter..and instead of locked out timing my curve was real quick...
for the 229 gears it was all in by 1700 rpm and with other gears it was in by 2200rpm...
No vacuum and the advance plate was secured. so that high rpm flutter was taken care of...

I had probably spent 2 weeks of driving and tweaking that distributor..to get the best of everything out of it....
Lots of grinding and welding.

You can weld extra weight to the advance weights .to help tailor the curve..

with quick curves the idle gets weird ,due to the curve coming in soon.

Mine would start advancing at 1100 rpm , that was my idle rpm , throw it in neutral at stops ...

Cam and lifters last longer that way

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