Setting Timing Mark For BJ8

[pkmh]

Hi All!

Simple technical question and if anyone dares to answer, I would appreciate it or any input on the topic of timing!

From various sources, the "Strobscapic" setting for the ignition timing of a BJ8 is listed as 15 degrees BTDC at an idle speed of 600 RPM's. This info is listed from the BMC Handbook.

Another source is close by saying it's 16 degrees.

Now before I go any further, I am using the above data to establish the engine timing by advancing the distributor as needed while using a timing gun. So if the data or language I am using above is misleading then please advise so as to not confuse the issue here.

But assuming I am making sense so far, then the one degree difference is not so much of a concern to me (or should it be?), but rather what I am curious to know is, when using a strobe or timing gun on the one and only "notch" or mark on the pulley, if that notch is about a half inch away from the fixed point (zero degree mark), what do you suppose that measures in degrees, given a 1/2" away?

Or would one want to take a guess what the distance the pulley mark should be, measured in inches or fractions thereof?

BTW, even if I wanted to further advance the timing closer to the "zero" mark, I cannot for the vacuum advance unit attached to the distributor bumps into the oil filter support bracket adjacent, leading me to believe I'm possibly over adjusting.

Please let me know what you all think about this or ideas on the subject.

Much appreciated!

Paul

 

[Patrick67BJ8]

Hi All!

Simple technical question and if anyone dares to answer, I would appreciate it or any input on the topic of timing!

From various sources, the "Strobscapic" setting for the ignition timing of a BJ8 is listed as 15 degrees BTDC at an idle speed of 600 RPM's. This info is listed from the BMC Handbook.

Another source is close by saying it's 16 degrees.

Now before I go any further, I am using the above data to establish the engine timing by advancing the distributor as needed while using a timing gun. So if the data or language I am using above is misleading then please advise so as to not confuse the issue here.

But assuming I am making sense so far, then the one degree difference is not so much of a concern to me (or should it be?), but rather what I am curious to know is, when using a strobe or timing gun on the one and only "notch" or mark on the pulley, if that notch is about a half inch away from the fixed point (zero degree mark), what do you suppose that measures in degrees, given a 1/2" away?

Or would one want to take a guess what the distance the pulley mark should be, measured in inches or fractions thereof?

BTW, even if I wanted to further advance the timing closer to the "zero" mark, I cannot for the vacuum advance unit attached to the distributor bumps into the oil filter support bracket adjacent, leading me to believe I'm possibly over adjusting.

Please let me know what you all think about this or ideas on the subject.

Much appreciated!

Paul

I use a timing light that I can dial in the 15 degrees and that way I just line up the two marks. If you're using one without this feature then about 3/4" is good. BTW: Sounds like you may have to take your distributor out and turn it one gear notch so it won't hit the oil filter.

 

[tahoe healey]

Yeah, something isn't right if you are hitting the oil filter if your filter is in the right place. Where on the distributor cap(as you look on a clock)is the #1 spark plug wire?
Invest in an advancing timing light. Best money you will ever spend. I actually run at 18 degrees at 800-900 rpm, vacuum advance disconnected.

 

[TimK]

15 degrees is about 4% of 360 degrees. So measure the circumference of the pulley and calculate the distance in inches.

 

[Keoke]

15 degrees is about 4% of 360 degrees. So measure the circumference of the pulley and calculate the distance in inches.-------ITS 3/4"--Keoke-- :laugh:

 

[pkmh]

Hey, thanks Patrick, TimK, Tahoe and Keoke all for the great info and advice (and thanks Keoke about posting pictures from my last post a while back).

To answer Tahoe's question re: "position of the #1 Spark plug wire", I have an old progress photo I took a couple of months ago but which is still accurate at present and you can see enough of the present setup of the distributor cap, the vacuum advance unit and the oil cannister.

Now that I see the position of the #1 wire and subsequently, the positioning of the distributor cap, did I accidentally do a "flip" of the distribtuor cap, or is it still okay to leave the way it is?

Please let me know.

Thanks again all!

Paul

 

[tahoe healey]

It looks correct. I'm not sure how you can hit the oil filter. You man be rotating too far for the 15 degrees.

 

[TimK]

This is my correctly timed distributor from a different angle. The timing light should flash so that the v in the pulley is 3/4" to the left of TDC.

 

[tahoe healey]

Paul, you did not mention the model you have. Notice Tim's dizzy sits higher than yours. If you look closely at the wires coming from the dizzy to the plugs, they are in a different order than Tim's. You may be off simply by 1/6 of a firing sequence which would make you have to rotate more than should be to compensate. If I am correct, you just need to switch the wires at the dizzy.

 

[TimK]

Tahoe, amazing powers of observation! But that's what you'd expect from an optometrist!