TR6 CP series ignition timing

[Malcolm Clarke]

Why does the manual recommend static rather than dynamic ignition timing on early Uk cars, when dynamic is listed for US cars.?

 

Surely dynamic is more accurate, and the only basic difference between the distributors on either or both is the fact that late UK and US cars have got vacuum advance. According to my manual static timing for my distributor pn 41219 should be 11 BTDC. For USA market cars 12 BTDC or 4 ATDC. So is it not safe to assume that dynamic timing for 41219 should be similar ie around 4 ATDC.......... Iam not so much talking about exact degrees of advance or retard, as the principle of timing static or dynamic.

 

Am I missing something here?

[Mike C]

Hi Malcolm,

 

Maybe I am also missing something.I have a 1969 PI engine with a Lucas 22D6 distributor(P/N 41219 D 1969 ).I dynamically time it to section 86.35.15 0f the Brown Bible.My understanding is that the heading"** USA market vehicles only." in the BB applies only to activity item 22.Not that I really care as I have been dynamically setting timing whenever possible for years with no problems.My view is that dynamic timing sets the spark plug to fire with the backlash in the distributor drive train in the operating condition.

 

For the TR6 I just set the timing to 11 degrees BTDC with the engine speed at idle for starters,then adjust the micrometer control to advance the timing to just below the pinging limit.I cannot see why you would set a PI engine, with no vacuum advance ,to fire ATDC.

 

But maybe I am also missing something.

 

Regards,

[Malcolm Clarke]

Hi Malcolm,

 

Maybe I am also missing something.I have a 1969 PI engine with a Lucas 22D6 distributor(P/N 41219 D 1969 ).I dynamically time it to section 86.35.15 0f the Brown Bible.My understanding is that the heading"** USA market vehicles only." in the BB applies only to activity item 22.Not that I really care as I have been dynamically setting timing whenever possible for years with no problems.My view is that dynamic timing sets the spark plug to fire with the backlash in the distributor drive train in the operating condition.

 

For the TR6 I just set the timing to 11 degrees BTDC with the engine speed at idle for starters,then adjust the micrometer control to advance the timing to just below the pinging limit.I cannot see why you would set a PI engine, with no vacuum advance ,to fire ATDC.

 

But maybe I am also missing something.

 

Regards,

 

What started this all off was the fitting electronic ignition. Being a bit wary of allowing the "module" to be on for a relatively long period of time. (at the back of my mind I seem to remember that leaving the ignition on accidently was a good way of burning it out).

 

Anyway decided to time ignition by strobe rather than as before by "light bulb".

 

I then started to reread 86.35.15. Like you I had always taken the relevent page to mean that item 22 was the only difference. But if you reread again and again, why would you repeat operation 15 onwards. Or should I say what difference would repeating it make. I therefore came to the conclusion that the "** USA market only" refered to the whole page.

 

I think I shall re check the timing again set it to 11 BTDC (like you I cannot fathom setting it to ATDC at all) and adjust by hand to cure any pinking.

[Dave Worne]

Gentlemen.

 

Distributor Doctor recommends 12 degrees BTDC at idle

28 degrees BTDC at 2600 RPM.

for PI cars.

Beyond this the balance weights have no further effect.

 

Cheers

Dave Worne