Tbi/distributor help

[flawlessfailure]

Hello, I am collecting parts for my junk yard gm tbi conversion on my 88 wagoneer. I saw a write up on it that uses a chevy hei "big cap" distributor, but does not elaborate on if any mods are required to use it (gear swap ect) or if it just drops in. So basically I'm asking should I use the hei distributor or retain the stock one, and if I use an hei (which I would prefer) what do I have to do to it to instal it? This is my first fsj so kind of new to them

[Bill usn-1]

I have write ups for both distrs in the injection forum on binderplanet.
I much prefer the factory Duraspark distr over the large cap.
Much simpler conversion and cleaner and it's a factory part not an aftermarket item.

[FSJ Guy]

I prefer the OE distributor. Remove the mechanical advance springs and weld it to lock it in place. Just leave the vacuum advance line disconnected and the vac advance will not move.

Some people like the HEI, but I have no personal experience with one.

As for the factory distributor, if you ever need to replace the pickup sensor, it's available at parts stores.

[jaber]

You can use 89 Ford 460 dizzy cap, cap adapter, rotor and wires and get HEI performance out of the stock dizzy...

[flawlessfailure]

Thanks for the advice, I will probably keep the factory one, seems like the easiest route, kind of new to these fsj's, I'm a chevy guy but im really starting to like the grand wagoneer and I can't even drive it yet, so I think I will be doing a lot more to it after its running

[Nikkormat]

You can hook the duraspark to a gm 4 pin HEI module. Works great, better than a gm hei dizzy because the ford distributor because the trigger produces a "crisper" signal.

http://www.hotrod.com/how-to/engine/131 ... to-gm-hei/

[tgreese]

You can hook the duraspark to a gm 4 pin HEI module. Works great, better than a gm hei dizzy because the ford distributor because the trigger produces a "crisper" signal.

http://www.hotrod.com/how-to/engine/131 ... to-gm-hei/

You can use the HEI module - it can be driven by any variable reluctance (VR) distributor, like the HEI or Duraspark or whatever Chrysler called their system. But crisper? Seems unlikely. Any of these modules are just a big transistor on-off switch - there's no conditioning of the spark like in a CD module like a MSD. On or off. You can eliminate the resistance wire, but I would expect that the HEI module is also internally current limiting, and there can be no hotter/sharper/crisper spark as a result.

But the HEI module is said to be more reliable than the Duraspark, especially than the generic Duraspark replacements.

[Bill usn-1]

I think you guys are going off track here a little.
IIRC the question was if he could use the large cap HEI distr for EFI. Can it be converted or would he be better to use the stock distr.
I provided the information to do both with the preference for the stock Duraspark distr conversion over the large cap HEI.

The 4 pin module originally used in the large cap distr is not compatible for timing control when doing an EFI conversion. It has to be converted to the 7 or 8 pin module as specified in the write ups I referred to.

I think discussing all the 4 pin module options is just confusing the original discussion.
It would be relative if you would like to simply discuss ignition upgrades for use with a carb, but then why are you discussing it in the injection forum?
Just trying to keep the discussion "on track" for any others that may search for the correct answer in the future.

[flawlessfailure]

Thanks for all the help guys, and thank you bill for clarifying that you need to use the 7 or 8 pin, that's what I have read but thought if I could use the 4 pin now I know I cant, and I am already converting the gm hei now

[Nikkormat]

I was un aware that the 4 pin module wasn't a viable option bill, thanks for setting me straight. I will look closer at your posts regarding the subject in hopes of educating myself.

[Nikkormat]

You can use the HEI module - it can be driven by any variable reluctance (VR) distributor, like the HEI or Duraspark or whatever Chrysler called their system. But crisper? Seems unlikely. Any of these modules are just a big transistor on-off switch - there's no conditioning of the spark like in a CD module like a MSD. On or off. You can eliminate the resistance wire, but I would expect that the HEI module is also internally current limiting, and there can be no hotter/sharper/crisper spark as a result.

The Ford reluctor produces a higher quality signal than the gm design. Dwell readings using an oscilloscope are much more stable. We won't discuss the spark conditioning with the 4 pin module here. As bill said, its my bad for thread jacking away from the original question and solution.

[flawlessfailure]

It's cool, all still good things to know