MikeH

iTrader: (10)

I think thats what its called...Its right under the rotor has the magnets on it. Ive been chasing down a weak spark. ON the dyno the graph would disappear between 2300/3400. The data on the dynometer is taken from spark. I replaced the ignition coil and that really seemed to help. I think that was the problem but havent had the car back to the dyno to find out for sure. I want to be sure its solved before i go back. I go back in a few weeks. Ive rebuilt the distributor with a new pickup coil and module,cap,rotor,
wires. I tried to clean the rust off with a scotch brite pad as much as i could and gave it a shot of PB blaster. But its still pretty pitted. When i turn the shaft you can feel the magnets grab on all the points. Do you think its okay? Or should i replace it?

Also When I would disconnect the bypass wire to set my initial timing with the MSD hooked up. It would start on the first crank (hasnt been doing that lately). But it would run for a second then die. It had a funny smell to the exhaust lean maybe. But if i disconnect the msd and run my stock ignition it would run fine and i could set the base timing. It seems to take more turns to start then it should. With the bypass wire disconnected it starts faster. Why wont it run with the bypass wire disconnect and the MSD hooked up? The timing is at 6*

Ive disconnected my MSD for now I think there was a problem in the box too. The car seems to idle smoother and have more power.

Any ideas or comments would be helpful. This ignition stuff is driving me nuts.

Thanks for reading!

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90 IROC
SuperRamed 406
Trickflow 23* heads

Vader

Mike,

In a word,, yes.

The pickup coil pole core relies on a sharp rise and cutoff of the moving pole piece to induce a slight current then sharply end it. This trigger signal to the HEI module should be as clean as possible, and the rust can cause a poorly defined start and end to the signal. The HEI module switching transistors are highly compliant, and will transfer any of that "noise" generated by the pickup and moving pole piece to a similar high current signal to the ignition coil. For best spark generation, the coil needs to be sharply turned off, with no "ringing" (sinusoidal decay) of the power signal.

A rusty core and/or reluctor can cause poor cutoff that mimicks the problem of a failed capacitor (condenser) in a Kettering (breaker point type) ignition system.

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Later,
Vader
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If you want to beat the World, it might reach up and pull you down...
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MikeH

iTrader: (10)

Hey Vader....What would I need to do to insure the distributor is in good working order then? Should I just buy I rebuilt one? I already have a new pickup coil, And module. Is this piece replaceable?

What would you do?

Thanks!

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90 IROC
SuperRamed 406
Trickflow 23* heads

Vader

Mike,

The reluctor can be replaced, but the distributor shaft needs to be removed to do it. If you're going that far, you might as well plan on new bearings for the shaft if there is any excessive clearance. If you've already replaced the pickup coil, you've already been there. IIRC, the movable pole piece is shrunken onto the shaft. If you have a bearing heater, the new one should be relatively easy to install. If not, a replacement distributor might be in order, since pressing or driving the reluctor on might create excessive clearances and a poor fit. You don't want it to slip later.

Trying to find the replacement reluctor could be a problem, however. You might not be able to get one at the local Auto Zone, but a dealer should have a bin full in their system.

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Later,
Vader
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If you want to beat the World, it might reach up and pull you down...
Adobe Acrobat Reader

MikeH

iTrader: (10)

Thanks for your help Vader ...I think I will look into a rebuilt one. Just to be sure its working properly. Or maybe a partial one and use my module/pickup coil.



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90 IROC
SuperRamed 406
Trickflow 23* heads

Guest

I used to work at a 'real' parts store (not Autozoo, Schlep boys, etc.) and we carried reluctors in stock. Dont be surprised if you find one other than at the dealer.

MikeH

iTrader: (10)

Hey Madmax...Thats good to know... getting the reluctor on and off the shaft would be the problem. If I could buy just the reluctor and shaft as one unit. But I still would have the outside piece around the recluctor its rusty too. Unless that comes with it, I cant remember how that piece was attached.



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90 IROC
SuperRamed 406
Trickflow 23* heads

Vader

Max,

Thanks for the tip! I used to get them at the dealer, and haven't had a need for one for quite a while (knock on wood). Oh, heck - I'll probably forget it all by then.

Umm, what were we talking about, anyway?

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Later,
Vader
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If you want to beat the World, it might reach up and pull you down...
Adobe Acrobat Reader

Guest

Dont know what the heck you are talking about Vader, that was more than a minute ago.

I do believe its riveted to another part and pressed onto the shaft. Course it was a while ago I looked at one so, who knows...