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  7730 2.8 dizzy to dis conversion for old no crank sensor 2.8

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7730 2.8 dizzy to dis conversion for old no crank sensor 2.8 by f85gtron
Started on: 06-13-2015 07:44 AM
Replies: 8 (350 views)
Last post by: f85gtron on 06-15-2015 10:57 AM
f85gtron
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Report this Post06-13-2015 07:44 AM Click Here to See the Profile for f85gtronSend a Private Message to f85gtronEdit/Delete MessageReply w/QuoteDirect Link to This Post
I just had a light bulb go off in my head, and this time, it wasn't my ses!
1) The reason most 7730 conversions on stock 2.8 is because of no provisions for a crank sensor right?
2) I understand the crank sensor is two wire (magnetic), and so is the pickup coil on the dizzy right?
3) why not modify (shorten, like from an s10, install sensor) onto the dizzy shaft, maybe even use the existing pickup coil, just modify the ring to produce the expected signal for the $A1 mask, or $88 , whatever your using?
You'd lose the distributor cap and icm.
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ConvictedRedneck
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Report this Post06-13-2015 09:54 AM Click Here to See the Profile for ConvictedRedneckClick Here to Email ConvictedRedneckSend a Private Message to ConvictedRedneckEdit/Delete MessageReply w/QuoteDirect Link to This Post
Having done the DIS conversion myself and having to make a bracket for the pickup on the balancer, which was a PITA, I have to say I like this idea. I guess you'd have to figure out what the rotation ratio is between the balancer and the distributor shaft. Interested to see what others have to say about this.
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Raydar
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Report this Post06-13-2015 11:32 AM Click Here to See the Profile for RaydarClick Here to Email RaydarSend a Private Message to RaydarEdit/Delete MessageReply w/QuoteDirect Link to This Post
The crank will turn 2X for every rotation of the distributor, by design.
Since the distributor is adjustable, you will still have to time it. That may be a good thing or a bad thing, depending upon your outlook. (I've watched some of your other projects from a distance. I don't doubt that you will make it work. )
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phonedawgz
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Report this Post06-13-2015 01:49 PM Click Here to See the Profile for phonedawgzClick Here to visit phonedawgz's HomePageClick Here to Email phonedawgzSend a Private Message to phonedawgzEdit/Delete MessageReply w/QuoteDirect Link to This Post
You would need a reluctor wheel with the correctly (not evenly) spaced notches. Because the distance between notches is smaller your accuracy would need to be greater. Beyond that there is no reason why you couldn't do it.
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fierofool
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Report this Post06-13-2015 11:41 PM Click Here to See the Profile for fierofoolClick Here to visit fierofool's HomePageClick Here to Email fierofoolSend a Private Message to fierofoolEdit/Delete MessageReply w/QuoteDirect Link to This Post
Ron, something that comes to mind, along the line of what you're toying with---My 4.3 Chevy powered boat had an ECM. It also had a dummy distributor of sorts that appeared to be some form of solid state device with a harness coming out to the ECM. There was no crankshaft sensor used. I believe the 4.3 distributor is the same depth and tooth as the 2.8? If you can find an early 90's Yamaha equipped inboard engine with the Yamaha Engine Management System (YEMS), it may have the setup you need. Maybe not immediate but something to tinker with, down the road.
http://www.ebay.com/itm/Yam...em4ade391afd&vxp=mtr
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Patrick
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Report this Post06-14-2015 12:25 AM Click Here to See the Profile for PatrickClick Here to Email PatrickSend a Private Message to PatrickEdit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by fierofool:

Ron, something that comes to mind, along the line of what you're toying with...




Now that would be sweet. Distributors are so archaic.
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f85gtron
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Report this Post06-14-2015 01:28 PM Click Here to See the Profile for f85gtronSend a Private Message to f85gtronEdit/Delete MessageReply w/QuoteDirect Link to This Post
Proof of concept may only to be cut off the pickup coil fingers and bend until the correct frequency it's achieved? Anybody see a problem with this? I don't think it will blow up anything
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phonedawgz
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Report this Post06-14-2015 06:07 PM Click Here to See the Profile for phonedawgzClick Here to visit phonedawgz's HomePageClick Here to Email phonedawgzSend a Private Message to phonedawgzEdit/Delete MessageReply w/QuoteDirect Link to This Post
The 4.3 distributor from my 94 4.3 looked nothing like a Fiero distributor shaft. To start with there is no o ring on the 4.3 distributor. Different oil pump drive also.

You will have to get double, that is 14, notches spaced CORRECTLY on your reluctor. The different spacing of the first(last) notch is required for the ICM to identify which coil pack to fire. Of course this would have to be done twice on your reluctor since the distributor turns at 1/2 the speed of the crank.

[This message has been edited by phonedawgz (edited 06-14-2015).]

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f85gtron
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Report this Post06-15-2015 10:57 AM Click Here to See the Profile for f85gtronSend a Private Message to f85gtronEdit/Delete MessageReply w/QuoteDirect Link to This Post
The geometry's pretty clear there. What's the reluctor ring made out of? I could start with a round slug and start drilling and sawing. I haven't done the math, but I assume some of the notches will be duplicates and therefore won't need to be cut.
Duh. Nevermind. If the crank turns 2 to 1 dizzy, then all the dizzy notches will be unique.
Basically, just need to X0.5 all the degrees of notches? Am i looking at that right?
It can't be that simple, or it would have been done already.....
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