E: Engine Comet ignition advance

Peter Holmes

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VOC Member
What is regarded as optimum ignition advance for a post war Comet in standard factory tune, coil ignition, Lucas distributor.
 

Comet Rider

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VOC Member
Hi Peter,
On my 580cc Comet with a very similar setup I run 34 Deg fully advanced which gives about 10 deg fully retarded
For 12V I run a 5 Ohm single output coil made by Dynatec

Neil
 

Peter Holmes

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VOC Member
OK, Thanks for that info, with full advance set at 34 degrees what would be the optimum degree figure for for the fully retarded spark, ie the static kickstart retarded figure.
 

Martyn Goodwin

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Non-VOC Member
OK, Thanks for that info, with full advance set at 34 degrees what would be the optimum degree figure for for the fully retarded spark, ie the static kickstart retarded figure.
Optium full retarded for easy starting - all the time - is 4 BTDC and link that with full advance of 34 BTDC. You may need to modify the ATD to achieve this but take care DO NOT bend the ATD ears less they later stress fracture and break off! The prefered method is to have some more metal added to the face of the ears (ie weld metal) then file back till you get the range you want. See OVR #42 that has detailed instructions
 

Peter Holmes

Well Known and Active Forum User
VOC Member
Optium full retarded for easy starting - all the time - is 4 BTDC and link that with full advance of 34 BTDC. You may need to modify the ATD to achieve this but take care DO NOT bend the ATD ears less they later stress fracture and break off! The prefered method is to have some more metal added to the face of the ears (ie weld metal) then file back till you get the range you want. See OVR #42 that has detailed instructions
Thanks for the info Martyn, I will be using a distributor on my Comet, but the distributor I will be using is brand spanking new and for a BSA C11 correct in all departments I believe, except the advance and retard settings, but the DISTRIBUTOR DOCTOR can sort this for me, he has the most extensive library of catalogues, Lucas etc. But a 500cc Vincent with coil ignition was not in it. I told him there was only one or two made!
 

Bill Thomas

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VOC Member
Have you the address of the Doctor, Peter, I bought a Triumph Twin Distributor and ground one lobe off the cam, For use on a Comet.
But need a pair of clockwise bob weights. Cheers Bill.
 

Peter Holmes

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VOC Member
Have you the address of the Doctor, Peter, I bought a Triumph Twin Distributor and ground one lobe off the cam, For use on a Comet.
But need a pair of clockwise bob weights. Cheers Bill.
Bill, I can give his details, no problem, but it would be worth you searching him out on google, just search for THE DISTRIBUTOR DOCTOR and you find his great website, loads of interesting info, I was at his workshops yesterday, this guy knows his stuff, apparently he cleared the spares club out of all the old Roy Price stuff, I am desperate to find a 50 or 270 distributor cam for a Lucas distributor, he does not have them, he considered manufacturing them, but the minimum viable amount is 100 units and he is not sure that he would ever sell more than 1 or 2, let me know if you cannot find him and I will send you the info. Cheers Peter
 

Bill Thomas

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VOC Member
Just spoke to the Doctor !, Very helpful and nice to talk to.
He is sending me some stuff in the post.
Cheers Bill.
 

Bill Thomas

Well Known and Active Forum User
VOC Member
Just thinking about a Vincent Twin points cam, If you can find a Triumph Twin cam, 180 degrees, Maybe grind it by eye, I have just shaved one cam off for a Comet, The cam is not made very hard.
Cheers Bill.
 

Bill Thomas

Well Known and Active Forum User
VOC Member
Just spoke to the Doctor !, Very helpful and nice to talk to.
He is sending me some stuff in the post.
Cheers Bill.
Ordered my bits Fri noon, They are here already !!, Wish I could work as fast as The Doctor ( Martin ).
I don't like dealing with new people on the phone, Just shows how silly I am.
 
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