[AMC-list] Hmmm for GM's DIS Ign... what about a crank angle sensor?

[Jesse <j2sax@xxxxxxxxx>]

Hey guys, 

I was reading about the tricky mods for DIS and wondered if it might be easier and less risky to mod a crank angle sensor (looks like a dist with no spark plug wires) so that there would be something to drive the oil pump where required.  I have never looked into it, but it seems to be an answer to a couple of issues, as long as there is a unit out there that similar critical dimensions to the AMC Dist.  Won't have time to check into it myself for about 5 years I think, but thought I would throw it out there!  


Jesse
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Message: 1
Date: Sun, 11 Oct 2009 11:55:25 -0400
From: Frank Swygert <farna@xxxxxxx>
To: amc-list@xxxxxxxxxxxx
Subject: Re: [AMC-list] Adding TBI fuel injection to a...
Message-ID: <4AD1FFED.4090905@xxxxxxx>
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You could use the distributor based GM system from a pre 87 2.5L four. Convert a V-6 distributor, gut it and mount in the AMC case. 

I don't think the TPS values are the same, but you can probably adapt a GM TPS to the Ford throttle body if necessary. Some of the 4.0L guys do such things all the time, I know the Jeep TPS is adapted to a Mustang GT TB sometimes. This article will help: http://www.angelfire.com/my/fan/MustangTB.html. If you have to make an adapter, which is relatively easy, use whatever TB is the correct size. I still think the GM 2.5L TB is about right for the 196 and even a stockish 232/258. I'd make a new plate for the 196 instead of an adapter -- just as easy to do!

The balancer is drilled off the car. HESCO does the same thing for their CPS relocater kit for the 4.0L. Basically you mark where the "gaps" need to be then drill down into the balancer 3/8" or so. One Jeeper that I was in contact with back in Gulfport, MS, made his own, copying a friend's HESCO unit. It's something you could do with that vertical mill, or someone with a real good drill press and vice could do, but not for the feint of heart! Easy to mess up a balancer. If a bolt on wheel could be found that would be best -- just use the balancer puller screw holes to mount it. Would require a spacer for AC cars though. 

The reluctor wheel on the 2.5L is INSIDE the engine on the crankshaft. You'll have to disassemble an engine to get the degrees apart for the holes. I don't think diameter would matter -- degrees apart should be the only concern. That would be degrees apart at the beginning and end of a gap, I think. A larger diameter would need a wider gap, smaller narrower.... right? 


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Date: Fri, 9 Oct 2009 23:31:33 -0700
From: tom jennings <tomj@xxxxxxx>

OK, I just went through Tedd Brown's Corvair TBI conversion page. I'm sold.
He did a great thing, and it's about 95% right for Rambler sixes (and v8's,
for that matter). I've only got two unknowns at this point:

* precisely which throttle body to use, that's easiest to adapt physically.

This is just junkyard hunting, there's the '87 Ford Tempo body, but I have
to figure out if the throttle position sensor is directly GM compatible. The
same GM body Tedd used is actually pretty close to right for a 1 bbl
downdraft carb. Adapter required, but it's just a flat plate at each end of
a tube.

* details on how Tedd handled the reluctor for the crank position.

First, DIS (GM's wasted-spark) system is overwhelmingly the way to go. I
won't bore you with the details, but it's 40KV at all speeds, zero timing
jitter, donors are all GM V6's from 87 - 00, all parts are CHEAP (Rambler
Mentality). Absolutely no distributor needed, for the 195.6, just plug the
hole, it doesn't drive the oil pump. THe catch is of course you need that
ECM to control it.

THe catch here is that it reads crank position with a notched wheel that is
of critical precision. Tedd Brown did a very clever job -- onto the harmonic
balancer, he bolted a saw blade that was notched to drive the DIS crank
sensor. He then ran the engine with his normal ignition, but used a timing
light connected to the DIS system to adjust the crank sensor to the precise
location, then using marks made with that test, drilled holes in the face of
the harmonic balancer to drive the sensor.

He didn't describe the process, or how many holes he had to drill, on or off
the car (I suspect on-car, as he was avoiding engine disassembly all along).
It's a sweet trick, and the only complication in the whole thing.

-- 
Frank Swygert
Publisher, "American Motors Cars" 
Magazine (AMC)
For all AMC enthusiasts
http://farna.home.att.net/AMC.html
(free download available!)
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