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timing on austin healey bj7
- Thread starter Roberte
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For your car the specs are 10 degrees BTDC static; 15 at 600 rpm and 35 max.
In the Bentley reprint, this is on page 21 in the General Data section.
According to Norm Nock's book, p. 88, 12 degrees BTDC is 3/4" to the right of the TDC mark when viewed from the front of the car; 5 degrees is 5/16" - therefore 10 degrees is 10/16" or 5/8" -- that's where your static timing is set.
Note - don't do static timing with a Pertroix or it'll fry.
In the Bentley reprint, this is on page 21 in the General Data section.
According to Norm Nock's book, p. 88, 12 degrees BTDC is 3/4" to the right of the TDC mark when viewed from the front of the car; 5 degrees is 5/16" - therefore 10 degrees is 10/16" or 5/8" -- that's where your static timing is set.
Note - don't do static timing with a Pertroix or it'll fry.
Keith_M
Jedi Knight
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With a timing light just set it at 15 BTDC. Be sure to check your dwell angle or your point gap before setting the timing though.
I'm thinking that your hard starting problems could be caused by a problem with your choke. Check to be sure that choke cable is fully engaging the choke. You can do this by manually moving the choke on each carb to see how far it can go, then pull the choke cable to see how far it actually moves it.
I'm thinking that your hard starting problems could be caused by a problem with your choke. Check to be sure that choke cable is fully engaging the choke. You can do this by manually moving the choke on each carb to see how far it can go, then pull the choke cable to see how far it actually moves it.
Lotuswins
Jedi Trainee
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Roberte,
To answer your question as to why 15 degrees is recommended, I did a test on warm up at idle on my BJ8. Here are the results:
View attachment ign timing overheating.pdf
I hope this is viewable.... Anyways, it appears from the test the engine is very sensitive, cooling wise, to ignition advance at idle.
In my experience, the car actually started easier when advanced to the 15 degrees at 850 rpm than at the 10 degrees at 850 rpm. It also idled more smoothly. If you are having cold starting issues, I would look at the coil, wires, plugs, rotor/cap, and choke, in that order....pull the plugs and see if you get a blue or white spark that snaps. If yellow and not snapping, then the coil is weak or the wires are poor conductors. You can measure the wire resistance to see if you have conductivity with an ohm meter, and inspect the cap and rotor to ensure no tracking is occuring or moisture is present. Points must be clean and not pitted also. All has to be pristene if it is to start reliably.
To answer your question as to why 15 degrees is recommended, I did a test on warm up at idle on my BJ8. Here are the results:
View attachment ign timing overheating.pdf
I hope this is viewable.... Anyways, it appears from the test the engine is very sensitive, cooling wise, to ignition advance at idle.
In my experience, the car actually started easier when advanced to the 15 degrees at 850 rpm than at the 10 degrees at 850 rpm. It also idled more smoothly. If you are having cold starting issues, I would look at the coil, wires, plugs, rotor/cap, and choke, in that order....pull the plugs and see if you get a blue or white spark that snaps. If yellow and not snapping, then the coil is weak or the wires are poor conductors. You can measure the wire resistance to see if you have conductivity with an ohm meter, and inspect the cap and rotor to ensure no tracking is occuring or moisture is present. Points must be clean and not pitted also. All has to be pristene if it is to start reliably.