Sensing cam position on Buick/Rover V8

[DiDueColpi]

Looks fantastic David.
And it's doing the job as intended, can't do much better than that.
Cheers
Fred

[parrisw]

I need to do the same thing here. Any of these for sale yet?  Or do I need to make one.  I was just planning on using the crane optical pickup in the distributor as a cam sensor, just fill in all but one slit on the chopper wheel.

[parrisw]

Another question.  How are you setting the Sync on the cam sensor?  Like how to index it. Ford uses a tool that goes in place of the sensor when you install it, it indexes it in the correct position.

[parrisw]

Anyone? Anyone?  So I got a synchronizer out of a Ford 4.2L V6, it's the 3 wire sensor.  Now just need an old distributor to cut apart.

[Moderator]

Well... with a half moon set-up (180 degrees "on" and 180 degrees "off",) you don't have to be very precise. I just eyeballed it. I'm probably within 45 degrees or so!

[parrisw]

Wow!!  LOL. That's not very close!!  Ever think of using a Lab Scope?  Dual channel, then line up the waveforms?  So at #1 TDC, you'd want the half moon vane just at the edge of the sensor?

[Moderator]

As I understand/recall, MegaSquirt polls my Hall effect (3-wire) cam sensor just once while I'm cranking the engine and immediately after sensing the missing-tooth gap in my 36-1 crank position trigger wheel. It only needs to know whether I'm on the compression stroke or the exhaust stroke. Just after top-dead-center it's got to be one or the other, right? The half moon wheel gives me a whole lot of leeway.


(The sensor on the left is a Hall effect sensor. The sensor on the right is a two-wire VR sensor... and that's the kind you don't want to use in combination with a half moon wheel.)

[parrisw]

I've got the Hall effect one with three wires.

I've got my sensor all done. Was pretty easy actually.

Pics to come.

[parrisw]

Post on my site about building a sensor.

http://www.tr-8.ca/?page_id=132

[donkelly23]

Thank you for all the info.I am going to try the GN cam sensor I was able to buy on a close out sale for about $75

[Moderator]

Sweet!

[donkelly23]

Curtis, I am in awe of what you, Mr Nichols and Mr Blackwood do.
I am getting help with this from Will Parris and others on the TWOA site for my Wedge.
Most NW people I noticed. Should have done this before I left Seattle for the Beaches of Charleston

[BlownMGB-V8]

Don, that's a nice find on the GN cam sensor. Mind telling where you got it?

Jim

[donkelly23]

Jim, I bought it a least 2 years ago from Rockauto on a closeout.
Just looked at the pic. Took it 12/15/2014
Somebody mentioned it somewhere and I knew in the back of my mind I would MS the car eventually.
It's been sitting in my office closet since then

[BlownMGB-V8]

Got a part number for it anywhere by chance?

Jim

[donkelly23]

Yep, pretty sure it is NLS.
Just use the top number I think

[BlownMGB-V8]

Looks like that was an extremely good price. Makes sense of the mods Curtis and I have done. Cheapest I saw was about $175 on ebay (maybe) and prices between $230 and $375 otherwise.

Wonder if they sell just the sensor off the top? Maybe that could be useful. Don, would you be willing to remove the cap and take some pictures of what is inside?

Jim

[MG four six eight]

Interesting, I didn't realize that such a part existed. Although it's fairly expensive, it would have been easier then making one.
Looking back, I did enjoy using the lathe to fabricate one up though!

Bill

[donkelly23]

Jim
"Don, would you be willing to remove the cap and take some pictures of what is inside?"
Sure, I'll try to get to it today.

Right now I'm hassling with the lifter preload on my 4.0 motor

[donkelly23]

Looks like a standard Hall effects sensor

[BlownMGB-V8]

Hmm... Could be a photo-diode pair.

Jim

[DiDueColpi]

I`m going with Hall Effect for two hundred Jim!

Hold something ferrous, like a screw driver up to the sensor. If it`s magnetic then it`s a Hall effect.
Either way you will need to trim the trigger wheel so that it`s a 180 degree cut out for most systems to recognize it
Still a very useful part at an excellent price.

Live like you mean it.
Fred

[donkelly23]

Fred
"Either way you will need to trim the trigger wheel so that it`s a 180 degree cut out for most systems to recognize it "

English please.
Still new to all these modern dealies.

[TR8Driver]

I know this is an old thread, but I'm going to use this same sensor for my Rover V8.  I will have to change the drive gear, and have found that the Buick shaft is slightly thicker than the Rover shaft, so I'm waiting for a 1/2" reamer to open up the drive gear slightly.  I will also have to cut off the end of the Buick shaft, as the TR8 uses a different drive end.

But I wanted to comment on the comment from Fred:

"Either way you will need to trim the trigger wheel so that it`s a 180 degree cut out for most systems to recognize it "

If I want to use this as a single-tooth wheel, I believe it will work as-is, and I can define either rising or falling edge.  If I wanted to use a polled setup, then yes, I think you could widen the window to be 180 degrees.  But from what I'm reading the MegaSquirt manual, the only downside of setting it up as a single-tooth is it might take an extra rotation for the ECU to set sync.

[TR8Driver]

Just a note for anyone looking to use this Buick Grand National cam sensor (if you can find one).  It will require a pull-up resistor when using with a MegaSquirt.