Choosing a crank trigger/wheel

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Fred
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Re: Choosing a crank trigger/wheel

Post by Fred »

WTDeuce wrote:VR sensors are noise prone... Dont have to use shielded wire with Hall sensors.
I think you need to qualify that statement. Everything I know tells me otherwise :-|
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Re: Choosing a crank trigger/wheel

Post by obi-lan »

VW uses hall and VR sensors with same 60-2 triggerwheel in different engines. I chose Hall for easiness but don't know what are the VW's reasons when to pick Hall and when VR...
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Re: Choosing a crank trigger/wheel

Post by pishta »

Some of the oem wheels i saw look like bike sprockets! Get yourself a 36 tooth and grind one down...i liked the square tooth with the tooth as wide as the sensor face. On a US Ford it was. 250 inch so that is what my cnc teeth will be cut at along with a much shallower missing tooth region per Fred's recommendation for magnetic flux retention.
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Re: Choosing a crank trigger/wheel

Post by pishta »

Another hurdle passed, I got my trigger wheel made. I was unhappy with my first hack job on a pulley that turned out to be not so round and not so true so I went back to OEM engineering and just milled some .250" teeth into the back of my balancer. Its true, round and thick enough to trigger the sensor, and it was free! (well, if you count a buddy that has access to a $xM aerospace 5 axis CNC mill). Might be easy on any mill but setup time and know how is beyond me. Will work fine. Yeah, its on the rubber isolated ring, but this timing hasnt changed in 53 years.....just need to tack weld mount into position and clean/paint. Belt goes right around it. Will grind missing tooth once I know exactly which one will go.
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Fred
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Re: Choosing a crank trigger/wheel

Post by Fred »

Looks nice! Is it missing tooth? If so, can we see that bit?

As for the rubber, let me show you a picture:

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This was one of my OEM pulleys. It hadn't moved in 15+ years... but it was moving while I was trying to set my timing and it cost me time. I wanted to make sure it wouldn't fuck me again ;-)

Now, setting timing is one thing, you're there, it's off, and you're measuring, etc. But for your signal, you're driving, and a significant timing change could be a big issue for your wallet.

Finally, the rubber in between is there to allow it to vibrate and move. That's not what you want for a timing reference on your crank shaft. It likely won't move much, but it will move a little.

My 2c. Use it and see how you get on :-)

Fred.
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Re: Choosing a crank trigger/wheel

Post by pishta »

Yeah, its not the best option, but its what Im going to attempt. The missing tooth is TBD. I have to mount it and find where the tooth will sit , then Ill grind it down {against all you told me ;-(} so as to not trip the VR sensor. If it gets crazy unstable, ill burn out the rubber, and mount the ring rigidly to the hub behind another balancer. I got a few. What if I just make it rigid as it sits, ie. tack weld the ring over the rubber to the hub? Slant six is butter smooth anyway, I doubt Im going to break a crank with harmonics at 3500 RPM and 200 hp......Im not going to spin it faster than 5500. We'll see. I just didnt like the way the off the shelf wheels stuck out as I have limited space up there.
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Re: Choosing a crank trigger/wheel

Post by Fred »

All fair, just wanted to make you more aware, that's all.
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