Igntion upgrade help needed.

[dave123]

I totally changed my plans. I sold the AMC 304 and bought a AMC 258 i6 / 4.2l that I've now rebuilt.

I decided to go with a GM HEI distributor out of a 250 inline 6 cylinder chevy but with the backward cut gear so it'll work in the AMC 258 i6 / 4.2l , but I ran across a great deal on ebay for a brand new HEI that is already set up for the AMC and comes with everything including the cap rotor and coil for only $59 with free shipping!!!!!

I received it just 3 days after I ordered it and couldn't believe what a great deal it was!

I considered the HEI before going with the "team rush" upgrade. Here are some of the quotes I got about HEI's that may make you reconsider. Most of quotes are from "JeepHammer", a team rush guy over at JeepForum. A very smart guy that walked me through the job.



Wouldn't use the cheap HEI distributors.
You could very well wind up with something that will hammer your engine to death with wrong timing,
Or a hardened distributor gear which will tear the camshaft gear out of your engine.

Several places have 'Cloned' the HEI with a stem that will fit AMC engines, but they have all the problems of an HEI and some extras, like cheap hardened gears and other problems.
Most places did a really poor job of adapting an HEI type head to an AMC shaft.

With an HEI, they have a very WEAK trigger internally, that triggers a module that is inside the distributor cap. The module works much better when you get it out of the distributor cap where it isn't being 'Zapped' all the time by high voltage,
But the trigger HEI uses isn't worth taking out to skip it across a lake!

GM put the module in the distributor, a bad thing for the module.
It picks up a lot of 'Noise' in the cap, often 'False Fires'.

The issue with that is you have a 14 Gauge feed wire to your existing ignition,
And to work properly a GM HEI need about a 10 Ga. wire to feed it correctly.

HEI comes with a lot of problems, from advance curves (Which we haven't covered here) that will knock the valves & Pistons out of your engine,
Or hardened distributor gears will eat up your camshaft gear causing MAJOR repairs...

You can trouble shoot most of the Jeep/Motorcraft system with a $6 test light from the local discount parts store very easily.
You can't do that with a HEI distributor.

I would not touch the Hei Distributors, too many issues.

The HEI coil is an energy hog, it's MUCH less efficient than the Ford E-core coil is...


p.s. You pulled out a AMC 304 for a AMC 258 i6 / 4.2l ?

 

[Rescue Diver]

I considered the HEI before going with the "team rush" upgrade. Here are some of the quotes I got about HEI's that may make you reconsider. Most of quotes are from "JeepHammer", a team rush guy over at JeepForum. A very smart guy that walked me through the job.



Wouldn't use the cheap HEI distributors.
You could very well wind up with something that will hammer your engine to death with wrong timing,
Or a hardened distributor gear which will tear the camshaft gear out of your engine.

Several places have 'Cloned' the HEI with a stem that will fit AMC engines, but they have all the problems of an HEI and some extras, like cheap hardened gears and other problems.
Most places did a really poor job of adapting an HEI type head to an AMC shaft.

With an HEI, they have a very WEAK trigger internally, that triggers a module that is inside the distributor cap. The module works much better when you get it out of the distributor cap where it isn't being 'Zapped' all the time by high voltage,
But the trigger HEI uses isn't worth taking out to skip it across a lake!

GM put the module in the distributor, a bad thing for the module.
It picks up a lot of 'Noise' in the cap, often 'False Fires'.

The issue with that is you have a 14 Gauge feed wire to your existing ignition,
And to work properly a GM HEI need about a 10 Ga. wire to feed it correctly.

HEI comes with a lot of problems, from advance curves (Which we haven't covered here) that will knock the valves & Pistons out of your engine,
Or hardened distributor gears will eat up your camshaft gear causing MAJOR repairs...

You can trouble shoot most of the Jeep/Motorcraft system with a $6 test light from the local discount parts store very easily.
You can't do that with a HEI distributor.

I would not touch the Hei Distributors, too many issues.

The HEI coil is an energy hog, it's MUCH less efficient than the Ford E-core coil is...


p.s. You pulled out a AMC 304 for a AMC 258 i6 / 4.2l ?

Sorry but I have to call Shenanigans here. I'm not a newbie at building engines by any stretch of the imagination. My 69 Vette ran 11 second quarter miles all day long at the strip with a pertronix igniter module INSIDE the distributor. It did well enough to get my car in the local drag strip's commercials. Let's also not forget that Mallory and most other aftermarket ignition manufacturers place the module inside the distributor. I have no idea who this guy is or what he's smoking, but an HEI will work just fine for what I'm doing with this AMC 258 i6 / 4.2l .

 

[dave123]

I too have had good luck with FACTORY HEI's. I ran one in my 350 engine for many years without any trouble.

Don't forget that HEI's were around before the Duraspark. Many argue, and it makes sense, that Ford pretty much waited until GM did all of the research and development, then took the good points of the GM HEI, and designed out the bad parts of the GM HEI to come up with the Motorcraft/ DuraSpark Ignition. The biggest draw back to the GM HEI is the coil in the cap, and the module in the cap design.

Coil in the cap means that all of the Radio Frequency Interference, and Electro-Magnetic Interference that the coil produces is directed at the module and the pick up trigger coil. That is why Ford fixed this by moving the module and coil outside.

check this out:
GM HEI vs. Motorcraft/Duraspark ignitions (very long) - International Full Size Jeep Association

The AMC 258 i6 / 4.2l , like my AMC 304 , is not a high performance engine and this would probably not be a noticable problem in a properly maintained vehicle.

I think the problem is the aftermarket cheap HEI's, more than the factory ones used in the engines they were created for. Since you got one so cheap, I think it is something you should be on the lookout for.

The problem with gear wear is well documented as well.

Best of luck, I hope it gives you many years of trouble free riding, this was just a heads up.

Dave

 

[Rescue Diver]

I too have had good luck with FACTORY HEI's. I ran one in my 350 engine for many years without any trouble.

Don't forget that HEI's were around before the Duraspark. Many argue, and it makes sense, that Ford pretty much waited until GM did all of the research and development, then took the good points of the GM HEI, and designed out the bad parts of the GM HEI to come up with the Motorcraft/ DuraSpark Ignition. The biggest draw back to the GM HEI is the coil in the cap, and the module in the cap design.

Coil in the cap means that all of the Radio Frequency Interference, and Electro-Magnetic Interference that the coil produces is directed at the module and the pick up trigger coil. That is why Ford fixed this by moving the module and coil outside.

check this out:
GM HEI vs. Motorcraft/Duraspark ignitions (very long) - International Full Size Jeep Association

The AMC 258 i6 / 4.2l , like my AMC 304 , is not a high performance engine and this would probably not be a noticable problem in a properly maintained vehicle.

I think the problem is the aftermarket cheap HEI's, more than the factory ones used in the engines they were created for. Since you got one so cheap, I think it is something you should be on the lookout for.

The problem with gear wear is well documented as well.

Best of luck, I hope it gives you many years of trouble free riding, this was just a heads up.

Dave

The good news is as you said, the AMC 258 i6 / 4.2l isn't a high performance engine. The redline is only 4000 RPMs. The HEI will work fine. As for it being a cheap aftermarket one, well at least all the parts are interchangeable. You can't swing a dead cat in a U-Wrench-It without hitting a car that has an HEI for parts. I plan to grab a spare module and coil from one of those to keep in my jeep tool kit. I haven't really heard anything bad about the gears on them. I'd be interested to know more about that if you can get me a link. Again, I'm not too worried about it though since this is only a 4000 RPM motor. After all, a lot of the people that do the HEI swaps for their Jeeps are taking their stock gear and grinding it shorter and putting it on a GM 250 distributor. I'd be more worried about that causing cam damage than an aftermarket gear that was machined to be the right part in the first place. I really like the HEI because it's a simple one wire hook up, and you can get replacement parts anywhere. I'm going for the simplest bullet proof settup that I can put together. The HEI fit that bill perfectly.

 

[Rescue Diver]

Here's a pic of the new HEI.

 

[dave123]

You can google AMC Gear HEI. Here are a couple quotes I got from one link. I think a gear from a AMC V8 may fit your HEI, which should solve the problem. Of course you would have to line it up perfectly, and you may need a spacer, etc. All my experiance is with V8's, I not sure about your AMC 258 i6 / 4.2l . Like I said, this was just a friendly "heads up".

Link below the quotes.

"The problem is that the AMC cam gear is made of cast iron. Some HEI distributors being sold for use on AMC engines have hardened steel gears that will eat up cast iron cam gears."

"Their are NO matching gears on any aftermarket HEI units that will work with any cam gears no matter where you get them

This unfortanate state and the fact that their isnt any other set that fits together besides MSD (Which can be marginal if you dont have a 10 gear) has brought us alot of business. What your seeing is a Crown cam gear or OEM (Crown is extremely soft) in the 6-10Rc range and a distributor gear that is in the lower 60's for RC hardness. With a 20 point spread you can use any material and grind it to a cutting tool. This is a over 50 point spread on those gears. This is very common and we get maybe 15 calls a week on it!! Yes the 6 cylinder one from 4WD and CRT are made by a company that imports them from China. They both have an extremely hard gear that will not could but will eat your camshaft gear 100% of the time."

Caution: HEI gear problems (pics) - JeepsUnlimited.com Forums

 

[Rescue Diver]

You can google AMC Gear HEI. Here are a couple quotes I got from one link. I think a gear from a AMC V8 may fit your HEI, which should solve the problem. Of course you would have to line it up perfectly, and you may need a spacer, etc. All my experiance is with V8's, I not sure about your AMC 258 i6 / 4.2l . Like I said, this was just a friendly "heads up".

Link below the quotes.

"The problem is that the AMC cam gear is made of cast iron. Some HEI distributors being sold for use on AMC engines have hardened steel gears that will eat up cast iron cam gears."

"Their are NO matching gears on any aftermarket HEI units that will work with any cam gears no matter where you get them

This unfortanate state and the fact that their isnt any other set that fits together besides MSD (Which can be marginal if you dont have a 10 gear) has brought us alot of business. What your seeing is a Crown cam gear or OEM (Crown is extremely soft) in the 6-10Rc range and a distributor gear that is in the lower 60's for RC hardness. With a 20 point spread you can use any material and grind it to a cutting tool. This is a over 50 point spread on those gears. This is very common and we get maybe 15 calls a week on it!! Yes the 6 cylinder one from 4WD and CRT are made by a company that imports them from China. They both have an extremely hard gear that will not could but will eat your camshaft gear 100% of the time."

Caution: HEI gear problems (pics) - JeepsUnlimited.com Forums

Thanks for the info. A while back, before I ordered the aftermarket HEI, I read somewhere that a factory Mopar 360 distributor gear will work with a GM 250 HEI in an AMC 258 i6 / 4.2l without any other modifications. The gear is only supposed to cost about $30 new.

If we ever go to war with China, I hope their military is using the same parts they like to sell us!

I doubt that the gear would cause problems in such a low RPM motor, but thanks to your info, I think I'll play it safe and replace the gear.

 

[Rescue Diver]

I read a little further into the thread you supplied the link to. It looks like 4wd.com sells aftermarket HEI distributors and they acknowledge a problem with the gears, but they say it's only with the V8 gears, and that the AMC 258 i6 / 4.2l distributors haven't been a problem. I might just leave the gear on it and check it a few times for wear. Or maybe I could use the gear from the stock distributor and have it machined shorter to fit. That way I'd know I'm using the original gears that have always worked together!

Here's the post.

"
Here is the answer from 4WD:
I am aware of the problems out there. We recently switched manufactures on these and have not had any issues. Just pay attention to the gear mesh. A lot of people will either run a single gasket or no gasket at all. Sometimes ( in V-8 models) it helps to double the gasket up. These aren’t a precise distributor such as the DUI. Sometimes they will take a bit of setting up. The outcome is well worth it though. If you want a simple installation, I would recommend going with the DUI set up. Also, for either set you will need to purchase the DUI live wires.

The live wires are the spark plug wires the HEI uses. They have different ends on them. Its been a good six months since the distributor change. You can do one of 2 things. 1) double your gasket up and you should have no problem. 2) use the Mallory gear we sell, if it does shred it will disintegrate because of the material its made of.

You could make the gasket if need be. It is just a paper circle. They do not come with the distributor. They are usually included in gasket sets for the timing. If you have any parts stores over there they should have them. We carry the gear. Yes you would have to purchase it.

Oh, you have the AMC 258 i6 / 4.2l . Sorry, didn’t check the link. Haha The six cyl. ones we had no issues with. Its always the V-8 ones that have the gears chewing up. You shouldn’t have any issues. Just run a gasket under it.

I have only heard of the V-8 issues. Just double up the gasket. The gear chewing usually happens when the mesh is too tight. What I am saying is that most of the reasons that the gears are getting chewed is the mesh is too tight. There is no way to tell what gear is on there. You should be able to compare the gear to your stock gear as far as mesh goes. "

 

[dave123]

Yeah, all my experiance is with the V-8's, but if you can get the gear for $30.00, I would consider that cheap insurance.

I would put some bluing on what you have and turn it over a few times to see how it is meshing.

Don't forget you need a 10 gauge wire to the ignition.

best of luck with the swap.

 

[Cheepjeep85]

rescue diver i've had this argument i too run a CHEAP hei its been on my daily driver CJ7 for over nine months now and it works and runs with no issues, its simple, it does the job and best of all its cheap, it looks exactly like yours. go with it man, theres no convincing some people of the benefits. run what you like and we'll let others do the same. as i've said before i bought my dad one for the 350 in his k5 last june and its still goin strong with no issues. not all things cheap are bad.

 

[Rescue Diver]

Yeah, all my experiance is with the V-8's, but if you can get the gear for $30.00, I would consider that cheap insurance.

I would put some bluing on what you have and turn it over a few times to see how it is meshing.

Don't forget you need a 10 gauge wire to the ignition.

best of luck with the swap.

I've now read several threads on this. They all seem to say the same thing. The hardened steel gear on these aftermarket HEI's is definitely a problem when used with the soft, bolt on cam gear in the V8 AMC motors, but shouldn't be a problem on the AMC 258 i6 / 4.2l I6 cam since its gear is actually a hardened part of the cam. Of course, once in a while someone will chime in and say that the problem also affects 258s without any proof to back it up.

 

[Rescue Diver]

rescue diver i've had this argument i too run a CHEAP hei its been on my daily driver CJ7 for over nine months now and it works and runs with no issues, its simple, it does the job and best of all its cheap, it looks exactly like yours. go with it man, theres no convincing some people of the benefits. run what you like and we'll let others do the same. as i've said before i bought my dad one for the 350 in his k5 last june and its still goin strong with no issues. not all things cheap are bad.

Thanks. It's good to hear from someone actually running one of these. Is your motor a AMC 258 i6 / 4.2l ???

After everything I've read, here's my plan. I'll run the gear that came with the distributor after making sure it's not binding on the oil pump. If so, I'll add a second gasket to rais the distributor a little. I'll also use bluing to check the mesh before I start it. I then plan to check the condition of the gear several times over the first few weeks to look for signs of wear. If after a reasonable number of miles everything looks good, I won't worry about it any more. If I see any signs of wear, I'll switch to a factory V8 gear for $30 and again check it several times to be sure everything is ok.

I really want to keep things as clean and simple as possible under the hood. Having only one wire to the distributor besides the tachometer wire, and not having extra bolted to the wheel well is exactly what I'm looking for.

One more thing I do plan to do before starting the engine, and I would suggest you do this too, is buy some heat sink paste from radio shack, like what is used between the heat sink and the processor in your PC to put between the module and the distributor body. HEI's are know to have module failures because of heat. A couple bucks spent on this past might keep you from being stuck beside the road some time.

I'm guessing that the company making these distributors so cheap is probably cutting corners everywhere they can, and they probably aren't using heat sink paste.

 

[Cheepjeep85]

yeah its a AMC 258 i6 / 4.2l my motor was rebuilt last summer so i wouldn't take a chance on screwing it up, i have complete confidence in my cheapo distributor.

 

[Rescue Diver]

yeah its a AMC 258 i6 / 4.2l my motor was rebuilt last summer so i wouldn't take a chance on screwing it up, i have complete confidence in my cheapo distributor.

That's great! One person who's actually put the part to the test in the real world is worth a thousand people that heard something somewhere.

 

[nyeti]

I have seen these threads turn really ugly on other forums....its nice to see a civil discussion.

While I very much appreciate the benefits of the Team Rush conversion, for my needs, I am looking for pure simplicity...one wire, and no extra stuff to mount anywhere. I have had very good luck with HEI on numerous vehicles, so I trust the system. I have a AMC 360 in my CJ7 now, with a 401 being built to eventually replace it. I almost bought the Summit HEI the other day, but I got scared off due to the gear issue.

Has anyone here run the Summit HEI and does it have the non hardened gear?

Also, I just wanted to confirm that there are no issues at all with the DUI unit. I have no problem spending the extra money for the DUI if I am guaranteed years of problem free performance with no negative effects or wear. Thanks for any input.

 

[Cheepjeep85]

if i were you and where concerned about it i'd just buy a new factory gear for your new hei. you can also take the gear off of the factory distributor and put it on a new hei dist. if its not in bad shape

 

[Petescj]

Im on the other side of the fence for now on this issue. On the Salvage CJ7 I did the Team Rush with a flamethrower coil and a Mc2100. On my Scrambler I used a Hei I got off Craigslist and also put on a Mc2150.The Salvage CJ7 now runs like no other AMC 258 i6 / 4.2l Ive had before. The Scrambler has very similar issues to the "Uphill Battle" thread.

Now being I did two mods at once Im not sure if its the carb or the dizzy causing my issues. If I have everything in my shed I'll put the original back in over the weekend and update you. Im pretty sure this is a cheap Hei dizzy and Im leaning toward it as the culprit.

That's great! One person who's actually put the part to the test in the real world is worth a thousand people that heard something somewhere.

 

[Rescue Diver]

Im on the other side of the fence for now on this issue. On the Salvage CJ7 I did the Team Rush with a flamethrower coil and a Mc2100. On my Scrambler I used a Hei I got off Craigslist and also put on a Mc2150.The Salvage CJ7 now runs like no other AMC 258 i6 / 4.2l Ive had before. The Scrambler has very similar issues to the "Uphill Battle" thread.

Now being I did two mods at once Im not sure if its the carb or the dizzy causing my issues. If I have everything in my shed I'll put the original back in over the weekend and update you. Im pretty sure this is a cheap Hei dizzy and Im leaning toward it as the culprit.

I'm looking forward to hearing the outcome. I'd be surprised if you're getting poor spark from an HEI, but who knows? Maybe the module or cap and rotor are suspect since it's the cheap HEI? HEI's have been around for a long time and they're well proven, even in performance high rpm applications. If I have issues with mine, I'll try swapping in a different module before I scrap the distributor. The only thing I was concerned with on my new HEI was the gear eating issues, but that seems to only be a problem with the V8 AMC applications where the bolt on cam gear is too soft for the hardened distributor gear. I'm running a AMC 258 i6 / 4.2l inline 6.

Have you checked to see how your mechanical advance is working? That could be the cause of your problem. Advance kits are easy to come by for the HEI......