36-1 wheel at cam speed supported?

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piledriver
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36-1 wheel at cam speed supported?

Post by piledriver »

Curious if the MS1-extra code can deal with a 24-1 or 36-1 wheel at cam speed and run sequential ignition?
(I suspect the answer is "no", but just checking, I do suffer from being an optimist)
Always doing things the hard way, MS2 sequential w/ v1.01 mainboard, LS2 coils. 80 mile/day commuter status.
jsmcortina
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Re: 36-1 wheel at cam speed supported?

Post by jsmcortina »

I think it did, but MS1 is obsolete so why?

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piledriver
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Re: 36-1 wheel at cam speed supported?

Post by piledriver »

jsmcortina wrote:I think it did, but MS1 is obsolete so why?

James
I was asked by an apparent ms1 fan who is selling a nice, cheap modified distributor missing tooth wheel/hall sensor setup for acvws.
I could not find the answer in the docs.

BTW, I am actually considering a project using ms1 to mostly run an eberspacher BN4 or BN2 gas heater.(or perhaps newer models)
keeping the basic factory safeties+ much better fuel/ignition system with positive fuel shutoff/status and temp/altitude, e85 compatible etc.

The BN2 lacks a proper fuel cutoff, and they use tiny gimpy fuel pumps that likely don't like E85.

The BN4 seems to LOVE E85, the wider flammability range allows it to start and run/relight perfectly reliably, I never got it to work as well with E10... It curently provides the heat in my favorite DD, as the factory exhaust heat exchangers restrict flow too much vs a decent header.

The later model heaters units have hideously expensive proprietary/undocumented electronic controls that tend to die on a frequent basis.
I suspect MS1 would not be too much overkill, and more than capable, esp. used with the factory interlocks.
Always doing things the hard way, MS2 sequential w/ v1.01 mainboard, LS2 coils. 80 mile/day commuter status.
Matt Cramer
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Re: 36-1 wheel at cam speed supported?

Post by Matt Cramer »

It will run this trigger wheel; you just need to set up the wheel decoder accordingly.
Matt Cramer -1966 Dodge Dart slant six running on MS3X
dontz125
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Re: 36-1 wheel at cam speed supported?

Post by dontz125 »

I just opened up TS with a MS1/x project, and there is no option (that I can see) to run at cam speed. What you can do, is remove one tooth 180 deg from the original missing tooth; this makes a 24-1 cam give the same signal as a 12-1 crank wheel.

Note that you need to be careful with your wheel selection vs the number of cyls; a 36-1 crank wheel works great with 4 or 6 cyls, but a 36-1-1 cam wheel operating as an 18-1 crank wheel can't drive a 4-cyl. 24-1-1 => 12-1, which works with either 4 or 6.
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racingmini_mtl
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Re: 36-1 wheel at cam speed supported?

Post by racingmini_mtl »

dontz125 wrote:... but a 36-1-1 cam wheel operating as an 18-1 crank wheel can't drive a 4-cyl...
That's not correct. There are 4 ignition triggers per cycle with a 4-cylinder engine so a cam speed 36-1-1 wheel will work since 36 is a multiple of 4. There are only 2 trigger events per crank revolution so 18-1 crank wheel works.

Jean
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dontz125
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Re: 36-1 wheel at cam speed supported?

Post by dontz125 »

So why then is a 4-1 crank wheel the minimum needed for a 4-cyl?

No, hang on ... you need teeth 1 & 3 as triggers; 2 & (missing) 4 are there to differentiate between A and B - right?

I'll get this yet ... :roll:
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racingmini_mtl
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Re: 36-1 wheel at cam speed supported?

Post by racingmini_mtl »

dontz125 wrote:So why then is a 4-1 crank wheel the minimum needed for a 4-cyl?
Because a 2-1 is only one tooth and you need at least one real tooth per trigger. The missing tooth gives you where tooth #1 is and then the other teeth can be used as trigger.

Jean
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piledriver
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Re: 36-1 wheel at cam speed supported?

Post by piledriver »

Will it allow sequential w/o the second sensor on MS1?

I guess I'll have to dig out one of the MS1 cpus I have and try it.

Looks like I can fit a 48 or 60 tooth 32 pitch wheel in the distributor body with room for the sensor
these work great and fit in a 8mm ID hole, or can be left in "popsicle form"
It has a few tiny SMD components soldered to the legs,
(I embed it all in epoxy after insertion into some 3/8" SS or brass/copper/aluminum tube)
Tested to ~12K RPM on a *36-2 32 pitch wheel.(about 30mm-ish diameter)


*I initially ground a tooth off, didn't work at that pitch.
...By filling in with a touch of weld, it works perfect, was probably messing with the base circle it was sensing.
Last edited by piledriver on Thu Nov 06, 2014 1:08 am, edited 2 times in total.
Always doing things the hard way, MS2 sequential w/ v1.01 mainboard, LS2 coils. 80 mile/day commuter status.
dontz125
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Re: 36-1 wheel at cam speed supported?

Post by dontz125 »

piledriver wrote:Will it allow sequential w/o the second sensor on MS1?
No; because you're getting the MS to think it's a crank wheel, you still need the second trigger.
QuadraMAP Sensor Module -- PWM-to-Stepper Controller -- Dual Coil Driver
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Matt Cramer
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Re: 36-1 wheel at cam speed supported?

Post by Matt Cramer »

4-1 is the minimum for a crank wheel; a cam wheel would need to be at least an 8-1 so you can set four trigger points.

That's the key here - you need to set four separate trigger points on the wheel when running at cam speed. A wheel turning at crank speed would have only two trigger points set.
Matt Cramer -1966 Dodge Dart slant six running on MS3X
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