How do I check the timing of my engine with a timing light if I have an MSD ignition installed? I'm running pertronix in the distributor along with an MSD ignition box on my 1972. Thanks.
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Denis,
You'll need to remove the engine cover behind the seats to access the front of the engine i.e. pulley and timing marker. Connect the timing light between the No. 1 plug wire and spark plug (facing the rear of the car its the front right cylinder), aim the light at the marker with the engine warm and idling and normally itiming is set with any vacuum advance disconnected and the pipe plugged. You can loosen the distributor clamp and rotate the distributor until you have the timing set where you want it. Mines set at 10 BTDC this way and I have another 21 degrees of combined vacuum/mechanical advance, for a total 31 degrees, which by others comments seems about right.
Others have indicated that the factory timing marks and pointer can be a ways off 'true'. If you want to go the whole hog and check a dial gauge would be required inserted into No.1 cylinder and hand turning the crank until the No.1 psiton hits its highest point and ensuring the pulley TDC marker aligns with the pointer.
George, has a simple recommendation to turn the distributor and set the timing where the engine idles at its highest. Personally, I found there were large degrees of turn in the distributor that didn't really make any distinguishable change to idle.
Good luck,
Julian
You'll need to remove the engine cover behind the seats to access the front of the engine i.e. pulley and timing marker. Connect the timing light between the No. 1 plug wire and spark plug (facing the rear of the car its the front right cylinder), aim the light at the marker with the engine warm and idling and normally itiming is set with any vacuum advance disconnected and the pipe plugged. You can loosen the distributor clamp and rotate the distributor until you have the timing set where you want it. Mines set at 10 BTDC this way and I have another 21 degrees of combined vacuum/mechanical advance, for a total 31 degrees, which by others comments seems about right.
Others have indicated that the factory timing marks and pointer can be a ways off 'true'. If you want to go the whole hog and check a dial gauge would be required inserted into No.1 cylinder and hand turning the crank until the No.1 psiton hits its highest point and ensuring the pulley TDC marker aligns with the pointer.
George, has a simple recommendation to turn the distributor and set the timing where the engine idles at its highest. Personally, I found there were large degrees of turn in the distributor that didn't really make any distinguishable change to idle.
Good luck,
Julian
Thanks Julian, but what I'm concerned about is since the MSD iginition has "multiple spark" at each firing won't the timing light flicker so that an accurate strobe cannot be obtained?
Denis,
Hmmm, I hadn't thought about that, all I can say is I'm running an MSD distributor and 6A box and I set my timing with a timing light and hadn't noticed multiple flashes. Maybe its time for a question to the MSD Tech support forum.
Julian
Hmmm, I hadn't thought about that, all I can say is I'm running an MSD distributor and 6A box and I set my timing with a timing light and hadn't noticed multiple flashes. Maybe its time for a question to the MSD Tech support forum.
Julian
Dennis,
Have you tried using the timing light yet? It should be a non-issue.
My advice is that you do not need a timing light. Start by connecting the vacuum advance to ported vacuum. Leave the vacuum retard disconnected. Loosen the distributor locking bolt enough to allow adjustment. Start the motor, let it idle, once up to operating temp, slowly rotate the distributor in the advance direction. (clockwise). As you rotate the distributor, the idle speed will increase, continue to slowly rotate the distributor until you just reach the point where the idle speed stops increasing. This is the ideal advance setting for idle, and it will be significantly different than the specified setting from Ford. Ford’s setting was derived to meet emissions, it never was an ideal setting. If you’ve modified the motor in any way, the oem setting no longer applies anyway.
This new setting is more efficient, your motor creates less waste heat, and therefore overheating at a stoplight is less likely. Fuel consumption will improve. Drivability, low rpm power & throttle response will all improve.
The full advance setting is likely to be off now, but how often do you drive at 4000 rpm or higher? The centrifugal advance will eventually require re-curving to something like 10 to 16 degrees in by 3000 to 4000 rpm. It all depends upon your motor’s state of tune, the fuel you use, etc. Full advance is best determined on a chassis dyno.
When twisting the distributor, as Julian wrote, there is a spot where further twisting results in no change in idle speed, if you continue to twist the distributor the motor would eventually begin to buck. You want to set the distributor at the point where the motor just reaches its highest idle speed.
Afterwards you will need to re-adjust your idle stop to set the motor for an idle of about 1000 rpm, and re-adjust the needle jets for highest idle speed too.
Rather than adjusting these settings using the tachometer, you can just as easily set them with a vacuum gage attached to the intake manifold. The ideal ignition setting and the ideal idle jet setting will result in the highest intake manifold vacuum as well.
There are circumstances where the setting derived in this manner may have to be backed off a bit, but this is a good starting point. The problems you may encounter are engine knock under heavy load or difficulty cranking the motor. The first fix for these problems is to connect the vacuum advance to manifold vacuum rather than ported vacuum, then readjust the distributor & carburetor settings in the same manner as the first time. You’ll never know if this is necessary until you give the first method a try.
Your friend on the DTBB
Have you tried using the timing light yet? It should be a non-issue.
My advice is that you do not need a timing light. Start by connecting the vacuum advance to ported vacuum. Leave the vacuum retard disconnected. Loosen the distributor locking bolt enough to allow adjustment. Start the motor, let it idle, once up to operating temp, slowly rotate the distributor in the advance direction. (clockwise). As you rotate the distributor, the idle speed will increase, continue to slowly rotate the distributor until you just reach the point where the idle speed stops increasing. This is the ideal advance setting for idle, and it will be significantly different than the specified setting from Ford. Ford’s setting was derived to meet emissions, it never was an ideal setting. If you’ve modified the motor in any way, the oem setting no longer applies anyway.
This new setting is more efficient, your motor creates less waste heat, and therefore overheating at a stoplight is less likely. Fuel consumption will improve. Drivability, low rpm power & throttle response will all improve.
The full advance setting is likely to be off now, but how often do you drive at 4000 rpm or higher? The centrifugal advance will eventually require re-curving to something like 10 to 16 degrees in by 3000 to 4000 rpm. It all depends upon your motor’s state of tune, the fuel you use, etc. Full advance is best determined on a chassis dyno.
When twisting the distributor, as Julian wrote, there is a spot where further twisting results in no change in idle speed, if you continue to twist the distributor the motor would eventually begin to buck. You want to set the distributor at the point where the motor just reaches its highest idle speed.
Afterwards you will need to re-adjust your idle stop to set the motor for an idle of about 1000 rpm, and re-adjust the needle jets for highest idle speed too.
Rather than adjusting these settings using the tachometer, you can just as easily set them with a vacuum gage attached to the intake manifold. The ideal ignition setting and the ideal idle jet setting will result in the highest intake manifold vacuum as well.
There are circumstances where the setting derived in this manner may have to be backed off a bit, but this is a good starting point. The problems you may encounter are engine knock under heavy load or difficulty cranking the motor. The first fix for these problems is to connect the vacuum advance to manifold vacuum rather than ported vacuum, then readjust the distributor & carburetor settings in the same manner as the first time. You’ll never know if this is necessary until you give the first method a try.
Your friend on the DTBB
quote:and the ideal idle jet setting will result in the highest intake manifold vacuum as well.
George, may I add..
My experience with marine engines is that setting the air screws to highest vacuum (in neutral) produces a pronounced dull spot right off idle, its a very lean state of tune that provides low torque and finiky behavior off-idle, often many overcompensate by wildly adjusting the accel pump system.
A manual trans car is the hardest to set these screws best...with an autotrans, highest vacuum in neutral shows a dramatic drop in idle speed when finally put in gear, demonstrating the low-torque tune. Opening the throttle takes the fuel droplets out of suspension faster than the accel pump can recover...then a dull spot off-idle results. Settting the screws for strongest idle (and even best vacuum) in gear provides enough load on the engine to now set the idle mix such that the difference in rpm in and out of gear is quite minimal, often less than 100 rpm and off-idle throttle response is dramatically better.
In boats I set these air screws idling in gear vs neutral. The result is no-throttle starting when warmed up, and the boat leaps out of the hole instead of stumbling or having to feather the the throttle to overcome an off-idle bog. The end user is usually quite happy with the results.
Naturally, its hard to load a your manual trans car similarly. The typical end difference in the air screw is 1/4-1/2 turn in from the highest vacuum position (no load), a slightly richer condition than the typical highest-vacuum condition.
So, my point is try a slightly richer idle condition than you may have now, you may be happy with the results.
A standard timing light works fine with an MSD box. Sometime the light might miss a trigger but it is stable enough to find the timing mark.
Thanks so much for the detailed explanation. I really appreciate it. I plan to use your advice next time I tune the car.
Dennis
Dennis