Anyone know what the max recommended advance for a standard size bore and compression Mk1 1275 Cooper S is?

Also, for a standard bore and compression with a 276 Kent cam?

Does anyone have a proven advance curve I can use?

With my hearing, I can't always hear detonation, so I need a 'safe' curve

thanks
John

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johnl

With a standard 1275 chamber shape head, I would say max advance = 32°BTDC. Try 30-32°.
With a bathtubbed head like mine (no squish area), 38° is OK and needed.

It is usual to reduce the dizzy's internal advance to 9-10° (= 18-20 crank degrees) so this gives you around 10-12° static advance. You want the max advance all in by 3500rpm or so with that cam or similar ones. I would put the (worth $$$) Cooper S dizzy on the shelf and modify a 45D instead, also bung an electronic module in it instead of points.

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DrMini- 1970 wasaMatic 1360, Mk1S crank, 86.6HP (ATW) =~125 @ crank, 45 Dellorto (38 chokes), RE282 sprint cam, 1.5 rockers, 11.0:1 C/R.

I believe this is the same curve I have used in my Mk2 1275. Similar cam as well.

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SooperDooperMiniCooperExpertEngineering

All garage work involves equal measures of enthusiasm, ingenuity and a fair degree of irresponsibility.

Hi

are you trying to plot a curve on an adjustable dizzy (eg 123) or manipulate the springs on a regular dizzy.

Docs version is pretty much bullet proof - 10degrees idle, 22-23 degress at 2000rpm and 30-32 at 3500 and above. If you have a regular dizzy , i would set it for WOT and then check idle etc after. If you are after more plot points go to 123 ignition and they have curves for 16 versions- pick one close to Docs recommendation

Thanks for the responses.

I've actually ordered a CSI distributor from Minispares in the UK. Like the 123, it has 16 pre-programmed advance curves.

I went for this one over the 123, as you don't have to remove the distributor to change the curves, you access the adjustment through the base-plate with a screwdriver. Although there are 16 curves, it's hard to know which one to start with.

All the curves have the max advance at 4,800 rpm varying from 16-23 @ 2000 and 24-28 @ 3,500

I'm not looking for absolute power, I don't drive the car hard, just want a good, but safe, curve

cheers
John

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johnl

I forgot. With the new distributor (similar to the 123) should I open the plug gaps up a bit or leave them at .025 ?

John

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johnl

Open them up to .030".

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DrMini- 1970 wasaMatic 1360, Mk1S crank, 86.6HP (ATW) =~125 @ crank, 45 Dellorto (38 chokes), RE282 sprint cam, 1.5 rockers, 11.0:1 C/R.