Timing?

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Leedy
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Timing?

Post by Leedy »

Hi. Can any one please give me the strobe timing for a 998 with an R20 cam. Running twin 40’s?
I.e 12 degrees at 4000 rpm etc. Thanks.
bks974c
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Re: Timing?

Post by bks974c »

You need a comp spec dizzy, time it to 36 degrees max advance at 4000 rpm and above

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Lotus-e-Clan
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Re: Timing?

Post by Lotus-e-Clan »

Leedy wrote:Hi. Can any one please give me the strobe timing for a 998 with an R20 cam. Running twin 40’s?
I.e 12 degrees at 4000 rpm etc. Thanks.
Assuming you mean ignition timing ....

If you have a proper competition curved dizzy - vacuum advance deleted - the dizzy should be set @ 36 degrees BTDC @ 4000- 4500 rpm.

Static timing should end-up @ 10 - 12 degs BTDC.

Same for all R- series cams. Tweak a degree or so either way to taste!

Clan004
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Leedy
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Re: Timing?

Post by Leedy »

I have the Aldon automotive electronic dizy. Supplied by Ben Bolt. So according to Ben it has the correct weights etc for the R20 or 360 cams. I’ve just ordered an adjustable strobe light. So needed to know what to set it to. Going off your comments. I set the strobe light to 36degrees BTDC and revs at 4200 RPM? Been a long time since I did this. Lol. Thanks again.
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Re: Timing?

Post by Lotus-e-Clan »

Leedy wrote:I have the Aldon automotive electronic dizy. Supplied by Ben Bolt. So according to Ben it has the correct weights etc for the R20 or 360 cams. I’ve just ordered an adjustable strobe light. So needed to know what to set it to. Going off your comments. I set the strobe light to 36degrees BTDC and revs at 4200 RPM? Been a long time since I did this. Lol. Thanks again.
Yes exactly. I have the same Ben Boult /Aldon dizzy - but I'm using mapped ignition atm.

I marked my crank pulley at both 10 degs AND 36 deg BTDC with white dashes - to save messing - but you might use a different method.
    • 1) Loosen dizzy clamp
      2) Use a bulb or multimeter to set the static timing to 10 degs BTDC - I could do this with mine even with a electronic trigger. In fact I could hear a click from my trigger - no need for anything else.
      3) Rev engine to (say) 4250 rpm and shine strobe on pulley mark
      4) twist dizzy until engine TDC pointer and 36 deg mark on pulley align.
      5) clamp up dizzy
      6) double check to see exactly at what revs the 36 deg mark arrives at the TDC marker. I used to aim for 4000 rpm which means the curve will be more advanced than if set @ 4500 rpm. You find your own sweet spot after road testing.
      5) recheck static timing for future reference.
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Leedy
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Re: Timing?

Post by Leedy »

Thanks for the replies folks. Much appreciated
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