performance distributor for 4.0 ?

[BADASYJ]

Hey guys I'm looking for a performance distributor for my 4.0 stroker and the only ones I can find are for the 258. I was told some slight modifications needed to be made for it to fit the 4.0 but not to sure on the differences. I plan on running the MSD 6A ignition on the jeep.
I'm leaning towards the MSD billet distributor. Is anyone running one of these or any other aftermarket dizzy?

[gmakra]

Yes I run that setup and nope problems at all with the installation or running.

[1bolt]

what mods are needed? I always thought of they would be the same but obviously never tried swapping one...

The 258 dizzy is basically just a Ford (literally motorcraft) Duraspark II ignition and distributor.

[TurboTom]

Be sure to check the timing on every cylinder with an MSD dizzy. I build distributor machines and have never gotten an MSD dizzy out of the box that was not at least 1-4 crankshaft degrees off on at least 1 cylinder.
I do not believe there is any differences in the 4.2 and 4.0 dizzys. other than some of the 4.0 models bolt in in 1 place. (can't rotate the housing) but that can be fixed also with a little grinding.

[1bolt]

Did Mallory ever make a 258 Unilite? Tom how do you feel about Mallory? I've always liked them (without any scientific testing albeit) I have a Unilite in my 65 Mustang that replaced the old points dizzy and I always felt it was a big improvement over 60's points technology. There are people who say the modules are fragile, but when using the proper coil (i.e. internally resisted) or ballast I've never had a problem. And I've always suspected that people who don't heed Mallory's specific setups are the ones ending up with dead modules.

[John]

Catalog shows them here http://www.who-sells-it.com/cy/prestoli ... pages.html
John

[Jeep4xb4u]

This is interesting information. I was checking out the 258 MSD dizzy a year or so back and instantlly quit my dreaming due to the fact that the only ones i saw were for carbs w/vaccum advance. Is this not true. And if so how would this work with the cam sensor in my current stock motorcraft unit. Did i miss a step here, if so im sorry you can tell me to read more if need be.

[TurboTom]

Did Mallory ever make a 258 Unilite? Tom how do you feel about Mallory? I've always liked them (without any scientific testing albeit) I have a Unilite in my 65 Mustang that replaced the old points dizzy and I always felt it was a big improvement over 60's points technology. There are people who say the modules are fragile, but when using the proper coil (i.e. internally resisted) or ballast I've never had a problem. And I've always suspected that people who don't heed Mallory's specific setups are the ones ending up with dead modules.

I like the Mallory stuff. The biggest problem with modules (and this goes for the earlier Pertronics stuff) is they were usually killed by leaving the switch on with the engine not running. If the engine stops in the right position they will act just like the points would if they were closed. With points, the coil would get hot (maybe even ruined) but the points would not fail. Modern distributor electronics can carry high loads for short periods of time, and can do a far more accurate, powerfull and reliable job of firing the coil. But when left in the "on" state those same loads will "let the smoke out".
I have been working on an fully adjustable ignition that will fire the stock coil pack using a modified Jeep dizzy. But it got put on the back burner until I get my race car engine done for some testing.

[1bolt]

Did i miss a step here, if so im sorry you can tell me to read more if need be.

We're talking non-stock fuel and spark setups, either carb'ed or fuel computer and ignition.

Everything I've seen says the factory ignition is more than enough for any street application or off-roading... And probably even more but there are applications (such as putting carbs on) where aftermarket may be the way to go. Maybe some High RPM applications where an billet dist. might have some machining tolerance, and stiffness advantages over OEM's.

Tom is the local authority and he may know something I don't about this, so I'll just say billet MSD and Mallory dizzys are SUPPOSED to be more accurate, consistent and less flexible than OEM parts. Meaning they're supposed to stand up to long high RPM blasts with less gear wear, less chance of catastrophic breakage and better timed sparks. Like everything with the Performance Aftermarket that aint always so, and there have been whole truckloads of Aftermarket parts since Hot Rodding began that were far worse performing than hum drum factory parts... Hell you could fill a couple Semi's with bad Offenhauser Intake manifolds alone. So I guess what I'm getting at is it's maybe not that surprising to find out that MSD Billet distributors aren't all that they want you to believe.

Tom the MSD you tested was it a "pro billet" or a billet? The difference being the normal one has a black plastic adapter base from the top of the shaft to the cap where the pro is aluminum all the way to the cap.

[TurboTom]

Most have been pro billets. The problem is not in the shaft or housing it's the reluctor wheels and the 1970 ford 6 cylinder pick up. The reluctor wheels are not even. I don't know wether they get bent in manufaturing or assembly. but I have never found one that was not off. MSD uses a Variable reluctance type sensor that outputs a sine wave. Mallory and the stock jeep stuff puts out a square wave (hall effect). With a sine wave the electronics in the ignition box have to sense where on that sine wave to trigger. With a square wave it's either on or it's off. Which I believe gives a more accurate timing. We did some testing on a dirt track engine on the dyno. With the MSD ignition the timing would jump around 3-4 degrees at 4000 rpm. Switched it to a Mallory dizzy and box and the timing was rock steady. Made about 6 hp more on the Mallory.
MSD cornered the market early, but I am not a huge fan of the way their stuff works. I have a 6A box on my race engine, but it is triggered by the MegaSquirt and a reworked Jeep dizzy.
Nascar engine builders actually bend the reluctors to run different timing on different cylinders.
My MSD box was free

[cal]

Hmm.

I'm pretty sure I've got a box at home that is labeled mopar performance distributer for the 4.0.. ?

If i can remember I'll dig it out this weekend and get the part number, see if I can find more.

[dwg86]

Not mine, but found on craigslist
http://atlanta.craigslist.org/pts/1094840771.html

[Plechtan]

Why don't you just lose the distributor and use a Megajolt. Probably cheaper than a distributor and MSD box.
You could use a 2000+ cam sensor in place of the distributor.


http://www.autosportlabs.net/Megajolt_Lite_Jr.

[Bodo]

looks like it's made for a Ford system? How would that work on our Jeeps?

[Plechtan]

It uses ford parts, but it will work on any car. you have to mount a trigger wheek on your damper, you can get these on ebay for about $35.00 You need a crank sensor for a Mustang or explorer, these are about $19.00 at autozone. You can then either go to a junkyard and pull off the EDIS module and Coil form a V6 ford vehicle, ($50.00 maybe?) or buy all new stuff. The new stuff is not cheap, the EDIs module new is $150 and up (Rock Auto), coil is around $50.00 I think you can get an Accell coil on ebay cheap.

here are some links to installation on other ( non jeep) vehicles

http://www.justdrive.ca/gt6/josh/distributorless.html

This is a gerat description for installation on an inline 6. All inline 6 engines have the same firing order, so you can use the wiring diagram from this for your Jeep.

http://www.dctra.org/wp-content/uploads ... _part1.pdf

http://www.dctra.org/wp-content/uploads ... _part2.pdf

Hope this helps explain things.