mallory
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The figures vary a bit depending what dissy you have fitted.
I work on the following for my checks though.
Idle at 600 rpm with vac off 6 BTDC
900 rpm 6 to 9 BTDC
1200 rpm 9 to 12
1800 rpm 16 to 20
2400 rpm 20 to 24
3800 rpm 26 to 30
4800 rpm 30 to 34
These figure are the ones I would expect with my original lucas dissy on. The Mallory dissy give these readings within a degree or two.
Hope this helps. These are the figures for the P6 V8 I have been using up to recently. I also use the same figures for the 4.6 and it seems ok to me.
Perry
I work on the following for my checks though.
Idle at 600 rpm with vac off 6 BTDC
900 rpm 6 to 9 BTDC
1200 rpm 9 to 12
1800 rpm 16 to 20
2400 rpm 20 to 24
3800 rpm 26 to 30
4800 rpm 30 to 34
These figure are the ones I would expect with my original lucas dissy on. The Mallory dissy give these readings within a degree or two.
Hope this helps. These are the figures for the P6 V8 I have been using up to recently. I also use the same figures for the 4.6 and it seems ok to me.
Perry
Perry Stephenson
MGB GT + Rover V8
9.62 @ 137.37mph
Now looking for 8 seconds with a SBC engine
http://www.youtube.com/watch?v=nVscbPHgue0&list=UUqIlXfSAoiZ--GyG4tfRrjw
https://www.youtube.com/watch?v=eg3avnsNKrc&index=2&list=FLqIlXfSAoiZ--GyG4tfRrjw
MGB GT + Rover V8
9.62 @ 137.37mph
Now looking for 8 seconds with a SBC engine
http://www.youtube.com/watch?v=nVscbPHgue0&list=UUqIlXfSAoiZ--GyG4tfRrjw
https://www.youtube.com/watch?v=eg3avnsNKrc&index=2&list=FLqIlXfSAoiZ--GyG4tfRrjw
thanks Perry, ive got a unilite dizzy, well i started it , tried it at 8 btdc ,and it turns over easier and runs smoother, have been told 12 would be ok, plus does the earth from the dizzy need to be connected as ive changed the module in it as the other earth cable melted,
rich

Nightbreed racing, http://www.youtube.com/watch?v=NJoUTZ8UUps
On mine the red and green go to the trigger, and the Brown goes to a good earth. I did hear someone a long time back having a fault where the brown wire got really hot. I assumed this was due to a bad engine earth. So I put a heavy cable from the alternator bracket to a good body earth. Just to make sure.
Perry Stephenson
MGB GT + Rover V8
9.62 @ 137.37mph
Now looking for 8 seconds with a SBC engine
http://www.youtube.com/watch?v=nVscbPHgue0&list=UUqIlXfSAoiZ--GyG4tfRrjw
https://www.youtube.com/watch?v=eg3avnsNKrc&index=2&list=FLqIlXfSAoiZ--GyG4tfRrjw
MGB GT + Rover V8
9.62 @ 137.37mph
Now looking for 8 seconds with a SBC engine
http://www.youtube.com/watch?v=nVscbPHgue0&list=UUqIlXfSAoiZ--GyG4tfRrjw
https://www.youtube.com/watch?v=eg3avnsNKrc&index=2&list=FLqIlXfSAoiZ--GyG4tfRrjw
as it happens i got some new earth cables today, from bracket to chassi and battery earth, got the multi strand ones, had a battery leak and it got the old chassi earth, when i tried to start the car some time later the earth cable to the dizzy melted, i will connect the earth upto tomorrow, and what about the timing as ive set it 8 btdc ,or should they still be within the posted figures, at the moment when on tickover at 800 rpm its showing 10 degrees btdc, and it seems to be running alittle stuttery or is that the typhoon cam, thanks again for the replies,
rich

Nightbreed racing, http://www.youtube.com/watch?v=NJoUTZ8UUps