Neat idea
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- Posts: 3944
- Joined: Sun Apr 27, 2008 3:36 pm
Re: Neat idea
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?
Neat idea/needs help
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
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
- Jadewombat
- Posts: 1447
- Joined: Sat Jun 22, 2002 12:01 am
Re: Neat idea
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.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?
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:
- Piledriver
- Moderator
- Posts: 22520
- Joined: Sat Feb 16, 2002 12:01 am
Re: Neat idea
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.
..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.
Addendum to Newtons first law:
zero vehicles on jackstands, square gets a fresh 090 and 1911, cabby gets a blower.
EZ3.6 Vanagon after that.(mounted, needs everything finished) then Creamsicle.
zero vehicles on jackstands, square gets a fresh 090 and 1911, cabby gets a blower.
EZ3.6 Vanagon after that.(mounted, needs everything finished) then Creamsicle.
- juki48
- Posts: 473
- Joined: Wed Apr 04, 2007 9:04 am
Re: Neat idea
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.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?
Riley
74 Ghia 2276 Turbo MSII Extra
67 Beetle in restoration
Manx Style buggy 1600 stock
74 Ghia 2276 Turbo MSII Extra
67 Beetle in restoration
Manx Style buggy 1600 stock
- Piledriver
- Moderator
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- Joined: Sat Feb 16, 2002 12:01 am
Re: Neat idea
I can't see any variation with my 36-2 setup either.juki48 wrote: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.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?
Addendum to Newtons first law:
zero vehicles on jackstands, square gets a fresh 090 and 1911, cabby gets a blower.
EZ3.6 Vanagon after that.(mounted, needs everything finished) then Creamsicle.
zero vehicles on jackstands, square gets a fresh 090 and 1911, cabby gets a blower.
EZ3.6 Vanagon after that.(mounted, needs everything finished) then Creamsicle.
CAS Finally Approved and Understood
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
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
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- Posts: 3944
- Joined: Sun Apr 27, 2008 3:36 pm
Re: Neat idea
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.