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Timing mark on crank pulley

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RandallRK

RandallRK

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Could someone help me out by showing me what the timing 'notch' should like like on the crank pulley?

I've been avidly following the posts about setting up a Pertronix unit as I just put one on my BN1. It's all set up and engine is running OK but I want to fine tune the timing. However I cannot, for the life of me, find the timing notch which should be there on the crank pulley. The arrow is no problem to see but I'm lost as to where the notch is.

Also- which cylinder is #1- meaning front/rear of engine. I've tried to look it up but can't seem to find out.

Thanks so much!

RK
 
The timing/TDC mark is a tiny dimple on the inside (belt side) of the rear pulley flange. Hard to see & not very useful, but it IS there. I have marked it in red on the attached pic. I would suggest putting a notch or something more visible on the outer circumference of the pulley. Additional 10 degree BTDC marks would be about 1/2" apart & in a clockwise direction viewed from the front of the car.

Front cylinder is #1.
D
 

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  • 4991-BNTDCmark.jpg
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#1 is closest to the front. Try cleaning the damper. It should be visible on the outer perimeter of the damper. You can always try feeling for it, also.
 
Nice shade of red Dave, your's? /bcforum/images/%%GRAEMLIN_URL%%/blush.gif

Ha, just joking around.
 
johnny, yes dave is very innovative, he uses the matching "lip stick" for marking wires! /bcforum/images/%%GRAEMLIN_URL%%/devilgrin.gif
 
I just painted mine white yesterday with some basic white paint. I used a long stick and dipped the end of the stick in the paint. I carefully and slowly touched the stick on the notch a few times. It makes a world of a difference when using the timing light now...very easy!
 
Yep Brandon,but what are you going to do when the small notch gets dirty? I paint mine Black then paint white stripes about 1/2" wide on each side of the notch. Then the dirtier the notch gets the better I can see it.---Keoke- /bcforum/images/%%GRAEMLIN_URL%%/cowboy.gif
 
No Brandon, they are 1/2" wide on each side of the notch and the damper only need to be wiped off.---Keoke
 
Use a bit of modeling white paint on both the notch on the pully and the pointer on the front cover (BT7).

It is really easy to see with a timing light that way.

Cheers
 
I just installed the same ignition in my BJ8 and I found that my vacuum advance is not working properly. The difficulty you can run into if you only time from the 10deg mark suggested above is that your mechanical advance can take you beyond the max timing of 35deg for my car. I do not know what your max advance is. Here is what I suggest: Barrow or buy timing light that allows you to dial in the # of deg. and adjust same to the max for your car at high RPM. Say 35deg @ 4500 RPM. With this type of timing light you only need to line up the TDC mark on the pulley with the arrow. Now what you will have is a properly timed motor @ higher RPM'S which is most critical. Next dial in the desired timing for low speed (suggested to be 10deg as stated above). You should be pretty close to the 10 deg. If you are not then you may have the same problem I have which is a leaking vacuum advance. Good with what ever method you choose. The previous owner of my car set only the low speed and when I got the car it had way too much timing @ high speed.
 
BobHorvath said:
I just installed the same ignition in my BJ8 and I found that my vacuum advance is not working properly. The difficulty you can run into if you only time from the 10deg mark suggested above is that your mechanical advance can take you beyond the max timing of 35deg for my car. I do not know what your max advance is. Here is what I suggest: Barrow or buy timing light that allows you to dial in the # of deg. and adjust same to the max for your car at high RPM. Say 35deg @ 4500 RPM. With this type of timing light you only need to line up the TDC mark on the pulley with the arrow. Now what you will have is a properly timed motor @ higher RPM'S which is most critical. Next dial in the desired timing for low speed (suggested to be 10deg as stated above). You should be pretty close to the 10 deg. If you are not then you may have the same problem I have which is a leaking vacuum advance. Good with what ever method you choose. The previous owner of my car set only the low speed and when I got the car it had way too much timing @ high speed.
Click to expand...
Hi Bob,
I agree except the vacuum part. As you say, the initial advance plus the centrifugal advance with vacuum disconnected, should be no more that around 35 degrees at what ever rpm it reaches max.

The vacuum advance should NOT be part of the picture when setting timing. It is a "ported" vacuum advance which means that no vacuum should be applied at idle. As the throttle blade is opened vacuum is now applied to the distributor unit. If engine load increases, vacuum decreases & retards the timing. If the vacuum was connected during the 4,500 rpm timing check it might show 55 degrees of total advance since the vacuum would be very high under the no load test conditions. It might also show 55 degrees under normal light load cruising conditions which would be expected.

If you tried to set the max timing at 4,500 to 35 degrees with vacuum connected, the engine would be severely retarded under all other conditions.

You can check the idle timing, after setting the 35 degrees, but will have to live with whatever it comes out at since the vacuum is not in operation at idle. Or at least it should not be.

Maybe this is what you are saying & I just didn't understand. If so, forgive me, or just tell me to go away.
D
 
Yeah I been setting here thinking about that too Dave. As a matter of fact some mechanics will shut the Vac Advance off if they find the unit is defective. I am going to check mine shortly and see where it is on the car. I set the Dizzy up on the sun machine and have never checked it on the car using this method. Don't have any complaints from the car though---Keoke
 
Learn something new every day as they say. I had no idea the vacuum unit was before the throttle as you stated. Although it becomes obvious upon inspection of the attach point. I hope what I am doing is correct as the car high end is running great except for a retarded idle. Let me go back to a basic. When I found the hi-low discrepancy I sucked on the vacuum line going to the vacuum unit. I could not detect any movement in the advance and the diaphragm seemed not to hold vacuum. I looked into replacing the vacuum unit and found it expensive relative to my uncertainty as to its condition. I set the high advance as stated above with the questionable unit still hooked up. What I should do now, based on your enlightenment, is to check the timing at high and then low speed first with and then with out the vacuum unit in the circuit. I will do that later today and report back. In the mean time Randall listen to these two experts, not to me, until I find my way through this one.
 
BobHorvath said:
the same problem I have which is a leaking vacuum advance. .
Click to expand...

Bob,

Jeff at Advanced Distributors has these rebuilt. he charged me abot 75 USD and was fast, fast.

No financial interest just a satisfied customer.
 
I got way into my distributor yesterday. I cleaned and lubed all moving parts and confirmed their correct operation. The heavy spring seemed a bit loose but I put it back as is. I found that the vacuum advance is functioning however the tube connecting it to the carb had inadequate sealing to the vacuum unit. Upon further inspection I found that someone had apparently tried to seal the vacuum unit with a black substance now plugging the connection point. Once I corrected all of these deficiencies the vacuum unit would respond to my sucking on the tube. I put it all back together and confirmed the effects of the vacuum unit at high rpms. I could not whiteness any effects at low rpm. Today I will obtain and install the proper ferrule for the connection tube and have more results tomorrow. Does anybody have data on no-load timing with and with out the vacuum unit, going to Dave’s earlier point about same?
 
Thanks to BIGHLY & Dave
I talked to Jeff today and he shed considerable light on what is going on with my distributor. I fixed the leak but I still have a hardening diaphragm plus issues with the advance springs. I will be sending my distributor to him for a complete re-build. I will then develop and publish a complete set of advance #s for others to ponder.
 
From a BMC technical service bulletin dated September 1, 1964
-----------------
Re: Ignition Timing for Austin Healey 3000 Mark I, II and III.
We have received many requests asking for the actual crankshaft pulley measurements necessary for adjusting and checking the ignition timing. We would like to advise you that the corresponding distance from the T.D.C marking on the crankshaft pulley is as follows:
5 degrees - 17/64" (.265625 or 6.747 mm)
10 degrees - 17/32" (.53125 or 13.494 mm)
12 degrees - 21/32" (.65625 or 16.669 mm)
15 degrees - 51/64" (.796875 or 20.241 mm)
 
I have used Michael Nesmith's Mother's wonderful invention to mark the timing mark, 10, and 15 degrees (approx) I note that I have a "ported" vacuum to a 123 Bluetooth, with the 123 set to mimic the standard setting on a Mk iii (BJ8), and a 15 degree static advance. Works beautifully.
 
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