GM HEI Swap

[jafo]

I recently bought a new aftermarket GM hei distributor. It seems like a straight forward install. I have seen some threads some time back concerning the cam gear being worn down by some hei dist gears. The listing says that it has the "correct" gear. That's the main reason I went with this one.

For those who have done this swap. What gear did you wind up having to use? Just in case I want to play it safe and go with a different gear.

 

[jafo]

I hope this worked. But here is the hei dist I went with.

http://www.ebay.com/itm/201359638185

 

[Hedgehog]

Please for goodness sake, don't trust their gear, use your old one, it's easy to swap and you will be able to sleep at night ..... that is unless you want a new engine.

 

[gr8dain]

I used my old one as well

 

[mtnwhlr]

Please for goodness sake, don't trust their gear, use your old one, it's easy to swap and you will be able to sleep at night ..... that is unless you want a new engine.

If you don't use your old gear you will be sorry.

 

[gr8dain]

By the way, the coil in my “amazon special” HEI died within a year. Replaced with another cheap one. It died within a couple of months. Put an MSD coil in the cap and have been trouble free for a few years now. Knock on wood.

 

[Lumpy Grits]

LG

 

[jafo]

Thanks for the input. I will swap the gears as advised.

I have a good MSD external coil. I heard it's not hard to change the hei over to an external coil setup. May look into doing that. Hei's are notorious for frying from excessive heat to the module. Moving the coil externally takes some of that heat away. What do you all think?

 

[Hedgehog]

There are thousands or even millions of GM HEI distributors in use everyday. The ones made by GM and DUI get the job done. It's the inexpensive knock offs that are trouble. Replace the cap, coil and module on your dist. and you should be alright. I paid the price for a DUI and it flat works, besides, one full 12v wire and a tach. wire are all that is needed to run. Neat and clean. An MSD system works, but it reminds me of the old 1970's stereos. A piece here, a piece there, pieces over on the other side all with wires running between. It does work and people love them.

 

[jafo]

Ok. I hear ya.

Finally. I I have not gotten too deep into this jeeps wiring harness, but what guage wire did you go to for ample voltage support to the new hei? 12 to 14 guage? Also, which wire is the tach wire? I have a factory tach and want to keep it. Is it the green wire off the other side of the old coil?

 

[Hedgehog]

My old '75's wiring harness is less than in good shape so I ran my own wire for the tach to the tach plug in the DUI dist. cap. Find a good wiring diagram for your CJ, the tach wire color should be fairly easy to find. As for the coil wire, the instructions that came with your distributor should tell you. I found the coil wire before it got to the resistor tied in the same size and as close to the same color wire and ran it to the distributor plug in the cap. Both distributor power and the tach plug in should be side by side.

To be honest I've heard terrible things about the cheap E-bay distributors and I've heard good things. Those guys essentially replaced the poor quality parts with good and kept the mechanical parts of the distributor. They usually replaced the coil, the module and if I remember correctly the cap/rotor. These things are easy to do and not all that expensive. Of course they used their original cam gear.

 

[Tinman22]

Factory hei dist. From a 250 six cylinder remove the shaft extension, install your old gear. For under 50 bucks at a local yard you get factory parts. Most every 250 ive seen has had low miles.

The ignition curve is nearly spot on, machanical and vac.

It is where i went when the ebay unit went too in short order. The junk yard part is still running 4 years now.

 

[jafo]

Thanks. Every little bit of info helps.

I believe the green wire to one side of the coil I believe is the tach. The red is the power. I took the red wire that was about a 16 to 18 guage wire back to the point where it split at the fuse block. Cut that wire out and put a 14 guage wire comparable to the connector that came with the distributor. Ran a new green tach wire also.

Gear swapped over fine. But what I seen on the rebuilt distributor from Orielly's blew my gord. Drove the pin out, slid the gear off and the pin hole in the old shaft was slotted out. Looking straight on it slotted down to about 4 oclock. The opposite side of shaft was fine. Crazy

 

[jafo]

Oh looked down at the drive gear on the cam and it looked fine. The hei is extremely tight. It is the fuel line and power steering pump. Might have to get a longer belt when it comes time to install the cap.

 

[jafo]

Ok. Pulled out the plugs, regapped to .044. This HEI cam with a set of new 8mm Packard plug wires. Not real impressed with them but theh work ok. Got it timed and test drove. I wish I would have just went this route in the first place. From the first fire up, I could notice the difference. I read articles about other routes to take on CJ jeep ignitions, I honestly can say the hei is much much better than the duraspark ignition. I can tell on take offs and it runs out better down the hwy. This thing was super easy to install too. I now have to figure out what to do with the wiring from the old system.

Would highly recommend this swap if your looking at upgrading your ignition system.

 

[Lumpy Grits]

Did you upgrade the coil?
Many of us still have to play the SMOG test inspection game.
Some of these ign change overs are not SMOG legal in, some states.
The MSD is 50 state SMOG legal.
Good to hear the conversion worked so well.
BTW-Those 8mm Packard wires are very good wires. They do a good job of RFI suppression.
LG

 

[jfmcj7]

I hope this is not of topic, but I did the HEI conversion a few months ago and I don't think the shop put the old gear on the new one. Ever since I have timing problems and 2 shops can't mail it down. Can that be the problem??

 

[Torxhead]

A camshaft distributor drive gear wearing down due to a bad distributor gear can affect ignition timing. To verify this an inspection would be required, the sooner the better. I believe MSD makes the proper tempered gear for the 258.

 

[Belizean]

I've got a question on this subject. If and when I get to this point, I'll have a rebuilt engine with new camshaft. Not sure if I will be going back with the original distributor or something new. If I go back in with the old, I probably should be going back with a new gear, what gear or brand would be good ?

 

[Hedgehog]

With a new cam it is easy enough to install a MATCHED set of gears, MSD sells them. That's the problem, a stock cam gear and a new dist. gear are not a matched set, they haven't been lapped together as a matched set will be. I.E. Matched sets are MADE to live together.