Engine and Transmission Tech

We are now in the final phase of the electrical stuff for this engine transplant, a 2003 GM 3400 V6 in a 1976 TR6.
The ECU is going to be reprogrammed shortly. The programmer brought up a issue. The front cover, A crank sensor (24 teeth) and dampner has been removed in order to go with a 1987 Camaro front cover, water pump, pulley and dampner. The car will run off the internal B crank sensor ( 7 teeth) but not as nicely as with the A sensor. The photos I have attached are of the 2003 GM front cover, dampner and crank sensor.





I am thinking of getting my machinist friend to make a 24 tooth crank wheel but I am not sure where or what type of crank sensor to get as the existing one fits inside the wheel. Can anyone help me on this?
I will post pictures of the Camaro pulley and dampner in the next posting.

The following photos are of the Camaro front cover and the pulley/dampner.




I am thinking that the notched wheel could be attached to the front of the pulley. If any of you guys have abetter Idea I would appreciate it.
When the engine harness was stripped we never removed the wiring or the plug for the front A type sensor so it should be the issue of making the notched wheel, finding an apropriate crank sensor and making a bracket to hold the sensor.

Thanks for your time and consideration.

Cheers
Byron

The sensor that GM uses is just a simple hall effect sensor.
Lots of other sensors can be substituted for it.
The crank sensor for a LS engine comes to mind as an easily adaptable replacement.
I would send your crank balancer out to your machinist friend and have him drill 24 equally spaced 0.50" holes around the circumference.
Make up a bracket to aim the sensor of your choice at the balancer and you're good to go.
Nice,tidy and easy.
Cheers
Fred

Hmmm. Thinking back to when I first installed Megasquirt on the old International SV series engine, it originally ran on the Pertronics module so that was 4 pulses per crank revolution from the distributor (V8). Eventually I upgraded to the Ford EDIS and MS-II but it was more because I wanted IAC control than any limitation with the trigger as I recall. The question that comes to mind is, what exactly are you giving up by running off the seven pulse trigger? If per crank revolution that is twice the resolution the old IH had and it ran pretty darned good. Can your controller still advance the timing? If it can and it is just a question of how quickly the controller can react to transitions, consider that at 1000rpm it is picking up a trigger pulse 116 times a second and you my friend, cannot tell the difference between one cylinder firing and the next, only 10 milliseconds apart. You certainly will not be able to feel a slight shift in the advance of one cylinder before the next one comes around. Yet the OEM's have seen fit to go to 24, 36, 72 and higher count trigger wheels, I think I've even heard of one instance of 720 teeth. Admittedly there has to be a reason for that but I suspect it has more to do with emissions than anything else.

Fred's suggestion is probably the best one, although you can buy all sorts of trigger wheels these days. Put it in front, behind, even on the flywheel. Be mindful of the possible need for a pulse to indicate TDC, as that can affect your balance.

Jim

The GM program will run with either crank sensor signal missing.
But it reverts to batch fire instead of sequential and it uses a safer timing curve.
You end up being down 15-20 hp and using more fuel.
The trigger wheel for this engine doesn't have an "odd tooth" to signal tdc so no issues there.
But I don't know how the timing count down is initiated so you might want to make the sensor mount adjustable to vary it's sync position.
Cheers
Fred

Fred , Jim thanks for the input I appreciate getting a confirmation to what the programmer has been telling me.
I plan on switching out the front cover to a 93-95 Camaro front cover, 3 wire sensor, and harmonic balancer with the reductor wheel. The programmer told me that the sensor has to be located the way it came from the factory in order for the thing to work. Using the newer front cover with the mounting holes in it will ensure everything will work.





"sigh" I paid an arm and a leg to get the 87 front cover. Does anyone need one? Finding older Camaro stuff here in Alberta is really hard and you end up having to buy it from an outfit that hoards this stuff and rips every body off. This time I will buy this stuff from the USA and with shipping it will still be cheaper.

Cheers
Byron