Don Terrill’s Speed-Talk

Not surprised if it is MSDs usual crappy magnetic p/up. Too much air gap, & reluctor tips are too thick. IIRC, MSD claims up to 0.050" air gap is 'ok'. HEI & Bosch p/ups run about 0.005-6" air gap with fine pointed reluctor tips for timing accuracy.
Also, the BB Mopar has the front mounted dist, subject to timing chain slack/whip; timing always seems to dance around more than a rear mount dist that has the valve springs acting on the cam to stabilise cam movement.

bigjoe1 wrote:BB Mopar- Brand new MSD Pro billet distributor== My dyno has a MSD programmable -7 box and coil that I always run== When I get the timing close and just hold the RPM at 3500, the timing marks slowly moves up and down about 30 degrees with out moving the distributor at all. Anyone ever see anything like that ? JOE SHERMAN RACING

Joe, the stud that MSD uses to lock the advance mechanism is often not threaded enough...the nut bottoms out on the shank of the stud. This will cause the timing to hunt around.....though admittedly I've never seen one wander that much.

Worth a check, though.

bigjoe1 wrote:BB Mopar- Brand new MSD Pro billet distributor== My dyno has a MSD programmable -7 box and coil that I always run== When I get the timing close and just hold the RPM at 3500, the timing marks slowly moves up and down about 30 degrees with out moving the distributor at all. Anyone ever see anything like that ?




JOE SHERMAN RACING

Joe what part # is your distubitor? I just went round and round with msd on a similar issue and they admitted their module's are at fault.

The one I have is # 85463-- It is all black




JOE SHERMAN RACING

I have seen electrical water pumps false trigger msd stuff.

Firedome8 wrote:

bigjoe1 wrote:BB Mopar- Brand new MSD Pro billet distributor== My dyno has a MSD programmable -7 box and coil that I always run== When I get the timing close and just hold the RPM at 3500, the timing marks slowly moves up and down about 30 degrees with out moving the distributor at all. Anyone ever see anything like that ?




JOE SHERMAN RACING

Joe what part # is your distubitor? I just went round and round with msd on a similar issue and they admitted their module's are at fault.

Can you elaborate on this, what particular module and what exactly did it do?

I have seen a malfunctioning battery charger in a dyno cell cause crazy things to happen with ignition and ECU programming.

Tuner wrote:

Firedome8 wrote:

bigjoe1 wrote:BB Mopar- Brand new MSD Pro billet distributor== My dyno has a MSD programmable -7 box and coil that I always run== When I get the timing close and just hold the RPM at 3500, the timing marks slowly moves up and down about 30 degrees with out moving the distributor at all. Anyone ever see anything like that ?




JOE SHERMAN RACING

Joe what part # is your distubitor? I just went round and round with msd on a similar issue and they admitted their module's are at fault.

Can you elaborate on this, what particular module and what exactly did it do?

MSD 8365,,, module has wire that sets rpm limit when grounded at an rpm half of what you want rev limiter to work. at first the timming would jump 12* crank @ 2300 RPM on distubitor machine,,,when in car the engine ran like the timming was retarded even when I way over advanced it. Since it was new we returned it to MSD . MSD reported that the output of module was bad (low current in coil primary ). they replaced cap,coil,rotor,module and pickup coil. I retested as you suggested with a timming lite and it looked good, no extra advance. Customer will be here this week to install in car. I will report back.

bigjoe1 wrote: ↑Sun Sep 24, 2017 4:18 pm BB Mopar- Brand new MSD Pro billet distributor== My dyno has a MSD programmable -7 box and coil that I always run== When I get the timing close and just hold the RPM at 3500, the timing marks slowly moves up and down about 30 degrees with out moving the distributor at all. Anyone ever see anything like that ?




JOE SHERMAN RACING

Joe, did you figure out what caused this?

I am sooooo embarrassed to say---It was the balancer--- It was an SFI---BHJ unit-- The outer ring was not fastened to the hub--- BUT-- It had NO RUN OUT ATT ALL-- I have never seen a balancer where the outer ring came loose that did not wobble like a bent wheel-- OH WELL



JOE SHERMAN RACING

High fives Amilcar, we (well mostly you...) win the Tootsie Roll for the right answer!

bigjoe1 wrote: ↑Fri Oct 13, 2017 3:26 pm I am sooooo embarrassed to say---It was the balancer--- It was an SFI---BHJ unit-- The outer ring was not fastened to the hub--- BUT-- It had NO RUN OUT ATT ALL-- I have never seen a balancer where the outer ring came loose that did not wobble like a bent wheel-- OH WELL



JOE SHERMAN RACING

LOL It must be going around. Had exactly that yesterday with an original balancer on a '71 400 SBC. Somebody said, "Wobbles like a politician."

MadBill wrote: ↑Fri Oct 13, 2017 4:26 pm High fives Amilcar, we (well mostly you...) win the Tootsie Roll for the right answer!

Thanks Mad Bill, I do share the prize with you..

Dibs on the first bite..

Joe this last cleveland we dynoed did exact same. Brand new dist out of box. I have seen a bit of thos with high volume pumps on fords but nothing this bad. Even at higher rpm we seen the timing bounce a bit after the dist advance is obviously pegged.I talked with a few other guys and they are moving away from msd. .I see you found it we may have to look into ours closer.