FE Power Forums
FE Power Forums => FE Technical Forum => Topic started by: Jim Comet on May 25, 2026, 09:36:31 PM
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I have been running an MDS locked out distributor, Pertonix digital 510 control box, HVC coil and have new MSD plug wires. For the last few years with this setup, I set the timing at idle to 32 degrees. But when I rev the motor to 2000 to 4000rpms the timing retarded 4 to 6 degrees. I was told this was due to the magnetic pickup in the distributor. Over the winter I installed an Innovators West crank trigger as everything I've read said this should solve the timing moving issue. I installed this and it fired right up and ran great. I then checked the timing, only to see it moving less but still retarding 2-3 degrees. Do any of you have experience with a crank trigger setup. Any Ideas what might be causing this. I set the gap on the crank trigger to .060. Thanks, Jim
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A friend of mine just had this problem in a circuit race 351 cleveland I will find out exactly what he found to fix it I know part of it was the pickup it was doing the same retarding ignition around 4deg too would only rev to 5k he has not raced since he got it fixed but it dose not retard now once timing is set
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Any chance the pickup is wire backwards? That's the only time I have seen it unstable timing, but usually much worse behavior.
In some harnesses, the color matches don't make sense and actually look backwards when correct. In the end, a good way to look at it quickly, using MSD wires, is that purple should not go to purple out of the distributor. Bl;ack/orange goes to purple, and purple connects to green.
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I have been running an MDS locked out distributor, Pertonix digital 510 control box, HVC coil and have new MSD plug wires. For the last few years with this setup, I set the timing at idle to 32 degrees. But when I rev the motor to 2000 to 4000rpms the timing retarded 4 to 6 degrees. I was told this was due to the magnetic pickup in the distributor. Over the winter I installed an Innovators West crank trigger as everything I've read said this should solve the timing moving issue. I installed this and it fired right up and ran great. I then checked the timing, only to see it moving less but still retarding 2-3 degrees. Do any of you have experience with a crank trigger setup. Any Ideas what might be causing this. I set the gap on the crank trigger to .060. Thanks, Jim
You can run that pickup tighter than .060". I like to sneak them up pretty close.
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If the wires from your pickup are not twisted together, try twisting them up. Twisting the wires together along their full length allows the wires to reject EMI through the principle of common mode rejection where the EMI affects both wires equally and cancels out.
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......purple should not go to purple out of the distributor. Bl;ack/orange goes to purple, and purple connects to green.
Yeah, never understood this about MSD. It's like they purposely try to make it more difficult than it needs to be, just because they can. Match the freakin' colors!
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Thanks for all the replies, I am using shielded wire, but they are not twisted. I did make a jumper harness with reverse connections in it and per the Innovators West instructions I tried it both ways. The instructions state that whichever orientation gives the most advance with a digital system is the correct way. The engine seems to run very good in the shop. I have a data logger that should record my timing during my passes and graph it out. I am going to test on the 30th hopefully and will report how all is working then. I may order a new shielded, twisted and grounded pickup wire from MSD if the data logger shows timing movement during my runs.
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Jim, any other control box there you can easily swap in? The module in my locked out RTR distributor was losing degrees as the rpms went up. ( no box in system at the time)
Perhaps the brain in your Pertronix is the culprit?
The moving timing problem put me into crank trigger land also. Innovators West utilizing the 4 magnet wheel. Timing stays at 33* except for when I ask the Ultra Box to take out 20* at crank.
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Not easy unless I buy another Pertronix control box. I was very careful to route both my trigger wires (signal from pickup) and the output to coil wires separate and away from other (especially higher current) wires. Inevitably some wires do cross but do not run parallel. I will test as is this weekend and then if I still see it moving, I will get the new MSD grounded trigger wire. If that doesn't do it I will look into a new/different ignition box. Jim
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Jim, what happened at track?
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Sorry guys, between my work and my sons schedule, we haven't made it out yet. I'm ready to go and have purchased entry into the Show and Go @ BIR over the 4th weekend. I'll let you know how it goes. I'm excited to make some passes with the data logger and see what's happening during each run. Jim
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Check the end play on the distributor shaft. If you have a lot, the timing will move with oil pump load.
I would shim between the gear and housing there is more than about .005".
Camshaft end play would have the same effect, but the fix wouldn't be as easy as shimming the distributor shaft.
John
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MSD has a spec for that play. IIRC it’s .020-.030
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I disagree with MSD - it doesn't need .020" to .030" clearance. Could say .010" and be very safe.
FYI - .020" endplay results in 1.9 degrees of shaft rotation.
John
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I had Brent Lykins install a new steel gear for me a year ago when I got a cam from him. I am also running a crank trigger so the distributor has no effect on timing as long as the rotor is properly phased and not jumping spark between posts. I do have a large MSD cap with a hole drilled by #1 cylinder for testing, so I was able to confirm that the spark is only going to #1 and not jumping to #5 or #8 as I revved the motor. Jim
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Well I finally made it to the track this year for the first time. Over the winter I completely rewired the car, added a crank trigger and a data logging system. The car fired up better than ever and ran really well in the garage and loading onto the trailer. Little did I know. When we got to the track we drove the car around the pits and it ran great. When our 1st time trial came up my son did a burnout and staged. As you can see from the datalog #2 the timing was steady but the motor wouldn't rpm. This became very apparent when he launched the car and he let off and basically cruised down the track and back to the pits. With only a few time trial available before eliminations I decided to run the ignition off of the MSD's magnetic pickup and retime it which solved the rpm problem allowing the motor to rev past 5000. One thing to note is how much more the timing "sewing machines" in the datalog #13 which is a pass using the MSD's distributors magnetic pickup. The car and really consistent the rest of the weekend so I did not spend more time on the crank trigger. Today it dawned on me that for some odd reason I have had to run my ignition box on the "points rising trigger" setting to make the MSD distributor work in the past. I think if I change my ignition box setting to magnetic falling it will solve my issues with the crank trigger. I guess that will teach me to go to a competitive race weekend with zero test passes on a new combo. Jim
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Looks like you are using an RPM data logger. I like their stuff and their customer service has been really great.
How is the timing captured by the logger? Is there a sensor for that or is it a box connection that is reading what the trigger is doing?
You said car ran well later. Any improvements over last year?
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There is a separate sensor similar to the crank sensor that mounts on the opposite side of the trigger wheel. There is a calibration function that you can enter into the data logger to compensate/match the timing output of the crank trigger. The car ran really consistent but only had a best ET of 11.19. The da was about 3500 ft. with an air temp of 80+ all weekend. I am sure once I get the crank trigger sorted out I will be back in the high 10.s. We ran a best mph of 120 this weekend where the last time out with the old setup and better air we were consistently running 123-124mph through the traps. Jim
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Jim, wouldn’t mind seeing a pic of that timing sensor.
What is the engine supposed to be timed at for peak power? I see via the graph that it’s moving around a few degrees
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Here are a couple of pics of the sensor during setup. I had to make the timing sensor bracket. Jim