Full Size Jeep Network

Blake wrote:ALWAYS match AMC stock dizzy gears to the AMC cam gear.

Unless of course, your AMC dizzy gear is a thrashed POS. Then go with the new one because you don't have much choice unless you want to go in and replace both gears. Which is what you should do if the dizzy gear is a POS.

So. ALWAYS? NO. Not really.

fulsizjeep wrote:

Blake wrote:ALWAYS match AMC stock dizzy gears to the AMC cam gear.

Unless of course, your AMC dizzy gear is a thrashed POS. Then go with the new one because you don't have much choice unless you want to go in and replace both gears. Which is what you should do if the dizzy gear is a POS.

So. ALWAYS? NO. Not really.

what are you doing in a fuel injection thread?

thinking about making your rigs run the way they should?

Nice attempt at deflection but no. I am trying to save someone a headache by revealing when you would not use the original AMC gear.

In retrospect, every dizzy gear failure I've ever had (4 of them) we're proceeded by a new timing set. It's why I rag on the oil grooves that have been added to all the after market timing sets available. Since both my running engines have new MSD cam and dizzy gears I can't say this for sure, but I think matching the gears is disproportionally blamed for the gears failure. I filled the grooves on the 401 timing set and added an oil sprayer to the 304 timing cover. Not a whole lot of op-hours on either, so nothing to report there.

Blake wrote:you will keep your existing dizzy gear and put it on the new HEI shaft. ALWAYS match AMC stock dizzy gears to the AMC cam gear.

I know there are a lot of choices out there for HEI dizzies. I can't remember which one I have, but it seems to work fine.

I can find HEI dizzies but no info regarding 7 or 8 pin

All the GM HEI (that fit AMC v8) are 4 pin.

The 7 pin module kinda sorta bolts in place of the 4 pin because they are almost exactly the same size.

Blake wrote:All the GM HEI (that fit AMC v8) are 4 pin.

The 7 pin module kinda sorta bolts in place of the 4 pin because they are almost exactly the same size.

Ah! This makes sense now. What should I look (vehicle wise-at the parts store) for to find the 7 pin module?

Still toying with just modding the oem dizzy if it works just fine. Less $$$ is MORE better. Haha.

IF you want timing control.... you will use the 7 pin ignition module and hook things up like GM says you should. :- )

THEN you will hook up your Streetfire MSD box as if it was being connected to a GM TBI system because, well, it IS being connected to a GM system.
:- )

So, yes, you can use both. But, no, you can't hook them BOTH up like you did previously.

Clear as mud, yet? :- p

Stock dizzy, 7 pin module under TFI cap, Streetfire to GM HEI 7 pin.

Am I getting clean in the mud?

IIRC, it's not too complicated. You wire the Streetfire in-between the coil and the plug from the ignition module.

They have a harness that you can buy that plugs in between the coil and the plug, too, I think.

FSJ Guy wrote:IIRC, it's not too complicated. You wire the Streetfire in-between the coil and the plug from the ignition module.

They have a harness that you can buy that plugs in between the coil and the plug, too, I think.

Except, I would run the black and orange to the coil?

Or is all of this even needed? Simple is good with me.
I can always just stash the streetfire in storage.

Your plan was JY system, so get module when get harness.
No need to hack up harness to run a 7 pin module.
Use stock GM coil, module, and wiring.

stock amc motorcraft distributor w/ advance locked out.
remote mount stock GM TBI module next to streetfire on heatsink.
do not need aftermarket HEI distributor, it offers no improvement IMHO, just extra $, and potential for cam gear trouble.
Use the junkyard TBI ignition module or new ACDelco.
Parts store modules are usually cheap china junk.

Okay. Let me see if I have this. Looking at schematics on Binderplanet. My eyes hurt.

GM ignition module on aluminum and grounded.

+ and - from module to dizzy

dizzy is stock/TFI mod with advance locked out.

4 pin connector from module to ecm

2 pin connector on module to GM coil. I wire in the streetfire here. Is the streetfire even necessary?


Also, I'm assuming phasing is also needed inside the dizzy? http://www.binderplanet.com/forums/inde ... up.114498/

I'm wearing you guys out. I just like to know and plan heavy for whatever I dive into.

Thanks for your patience.

That diagram looks correct for an HEI, but I've never hooked one up. But as mentioned, you can just use the stock distributor. No HEI needed, since that's sort of what the GM coil is, anyway. If you want to keep it simple, install it without the Streetfire. Then if you want to use it, use the harness from MSD and it sits in-between the coil and the factory coil plug. Aside from wiring the supply voltage, it is plug n play.

As for rotor phasing, I have not bothered with it. Binderplanet will disagree with my opinion, but I don't think it's necessary. When you have the distributor at rest (not spinning), and the vacuum advance not engaged, the distributor "phasing" should be at zero. If you want to get technical and adjust your rotor phasing, knock yourself out.

But it has been my experience that it is not necessary. There are better and more useful things to pull your hair out over.

Planning is good. You're asking good questions and it shows that you're reading.

A "junkyard" TBI system requires TONS of reading. That is the tradeoff (aside from money!) versus a turnkey system. No worries.

X2 on not bothering with phasing. I've never done it and the folks I've help convert their engines over to TBI have not done it either. Same goes for the VSS. It's simply not needed.

The whole debate on retaining the stock dizzy VS using an HEI is spiritual one based upon semantics.

In the end, its personal preference. I do believe it's safer to run the stock dizzy (and stock cam/dizzy gears) rather than gambling with the much cleaner HEI installation. My experience with broken dizzy/cam gears was (at least in part) due to the bulltear timing cover that I had which I believe was mis-machined causing my only failure. I've since been running stock mis-matched gears on a stock cover with HEI for years now.

and ya, ditch the streetfire. either way, you are gonna end up with either a ford TFI coil on your stock dizzy or HEI and both have plenty of juice to run the old iron.

on another note related to TBI, I have a VW sandrail with duel Kadron carbs. well as a TBI guy I simply despise carbs and I'm looking into converting it over to twin 1 barrel TBI connected to a 7747 ECM. Seems pretty straightforward: twin TBI but only one has the MAP and TPS. the other will only have the wiring for the single injector. I will run the stock VW dizzy (welded) and a 8 pin module. The trick will be wiring it up and keeping the ECM from getting (too) wet.

Okay, so ditch the Streetfire and the phasing, everything else I posted is correct?

Install dizzy at 0* base timing and start from there.

The VSS is useful should I want cruise control, though, right? Stock soup can is inop.

The TBI VSS has nothing to do w/ cruise control.

While a VSS is not required, it will run better with one installed.
There is a LOT of logic in the programming that uses VSS input.

Okay. Went back to JTR and read about the vss again. It improves driveability while at speed under light/no throttle cruising. Basically, the same spot my 2150 is currently screwing up and trying to surge/bog/die at.

Considering, I like to drive economically, I'll want to hook the VSS up.

Guessing I'll probably need the Speed Sensor, # 2PRS for my conversion, correct?

(The two-pulse square wave unit for all passenger car TBI installations, all computer controlled carbureted engines, and 1985–1989 TPI engines. 7/8–18 thread, .104" square drive.)