Neat idea

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Jadewombat
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Neat idea

Post by Jadewombat » Sun May 25, 2014 9:20 am


miniman82
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Re: Neat idea

Post by miniman82 » Sun May 25, 2014 11:24 am

Probably works well in a chain/belt driven cam engine, but it defeats the purpose of having crank angle accuracy which is the whole point of moving to a crank trigger in the first place. Not saying VW's have huge amounts of timing scatter, but it can be a problem. Why spend money on something like this, when crank trigger is better?
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Redline Weber

Neat idea/needs help

Post by Redline Weber » Sun May 25, 2014 11:33 am

I too have made this "style" of TW for thirty (30) years.

NOT sure if his design will work well.

The ratio of tooth width/window width COULD be better.

Example :
Good = window is greater than sensor pole piece diameter.
Bad = tooth width could be longer for a better magnetic appearance.

The ONLY way is to test using the correct sensor AND a scope on a test bench for correct output measurement.

Lance

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Jadewombat
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Re: Neat idea

Post by Jadewombat » Sun May 25, 2014 7:31 pm

miniman82 wrote:Probably works well in a chain/belt driven cam engine, but it defeats the purpose of having crank angle accuracy which is the whole point of moving to a crank trigger in the first place. Not saying VW's have huge amounts of timing scatter, but it can be a problem. Why spend money on something like this, when crank trigger is better?
Yeah, when you're talking about the much older 6 cylinder MB engines were similar to a type 1 in that the distributor was on the side of the block and driven off a gear, of course the gear is going to have some play linking 3 different moving pieces.

But not all MB engines were like this. Some were driven directly off the cam to take this slop out of the equation. 500e engine:

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Piledriver
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Re: Neat idea

Post by Piledriver » Sun May 25, 2014 8:54 pm

Apparently folks are not happy with the crank sensor options for that Mercedes engine, could be a packaging issue.
..based on the 500E above I can see why using one of the OH cam driven distributor locations in an otherwise stuffed like sardines engine compartment would be a huge win.

If he eliminated one of his missing teeth it would allow sequential on ms3 and Redline etc.
(MS2E if it was just a 4 banger)

72-1 cam speed, direct fire, only needs one sensor for full sequential.
(On MS2E the "saved" I/O line is a ~big deal, as it is kinda short on extra lines given all the possible uses.)

No edis, but no loss IMHO.

Would be trivial to give folks the option.

I have made a hall sensor setup that would likely work with that wheel, but as Redline Weber noted, the wheel and sensors have to work well, together.
I, for one, regularly embrace our new robot overlords, as I am the guy fixing the robots...

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juki48
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Re: Neat idea

Post by juki48 » Mon May 26, 2014 8:45 pm

miniman82 wrote:Probably works well in a chain/belt driven cam engine, but it defeats the purpose of having crank angle accuracy which is the whole point of moving to a crank trigger in the first place. Not saying VW's have huge amounts of timing scatter, but it can be a problem. Why spend money on something like this, when crank trigger is better?
I'm not sold on the timing scatter issue with using the distributor drive. I've been running for a while now using only a 12-1 wheel in a gutted distributor. I've messed with a timing light all over the rpm range and the timing is solid. my old dizzy would bounce like girls on trampolines. I think 99% of the scatter is from the dizzy. sure the gear drive has some play in it, so does the dizzy coupling but that all gets loaded to one side once spinning.
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Piledriver
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Re: Neat idea

Post by Piledriver » Mon May 26, 2014 9:54 pm

juki48 wrote:
miniman82 wrote:Probably works well in a chain/belt driven cam engine, but it defeats the purpose of having crank angle accuracy which is the whole point of moving to a crank trigger in the first place. Not saying VW's have huge amounts of timing scatter, but it can be a problem. Why spend money on something like this, when crank trigger is better?
I'm not sold on the timing scatter issue with using the distributor drive. I've been running for a while now using only a 12-1 wheel in a gutted distributor. I've messed with a timing light all over the rpm range and the timing is solid. my old dizzy would bounce like girls on trampolines. I think 99% of the scatter is from the dizzy. sure the gear drive has some play in it, so does the dizzy coupling but that all gets loaded to one side once spinning.
I can't see any variation with my 36-2 setup either.
I, for one, regularly embrace our new robot overlords, as I am the guy fixing the robots...

Redline Weber

CAS Finally Approved and Understood

Post by Redline Weber » Tue May 27, 2014 11:13 am

The two above reports are missunderstood though completely TRUE and CORRECT proven again by observation measurement.

The missing tooth wheel decode requires "tooth timers" that when used correctly ONLY report
acceleration AND are then averaged together BEFORE the Interrupt is generated to create a "Spark Instant", "Injection Instant", or other degree based event.

Thus the "shake" in the missing tooth TW will NOT be seen in a DEGREE BASED EMS.
When in a NON-DEGREE based EMS it "sees" the shake producing Spark Scatter.

When a DEGREE BASED EMS "sees" a shake GREATER than the missing tooth width it will start Knock Retard to save the engine.

Lance

miniman82
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Re: Neat idea

Post by miniman82 » Tue May 27, 2014 8:14 pm

It's easiest to see with a normal distributor, and sure it gets 'better' when you put a wheel in there but why not be sure you got rid of the whole problem? Crank is the only place I will ever mount a trigger wheel, call me OCD.
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