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4.0 hei/carb

D

DonnMcc

NAXJA Forum User
Location
West TN
Last edited:
kevin s said:
Step
awayyy
from
the
keyboard.

You are way overdue for this morning's Bloody Mary.:kissyou:
Click to expand...

what's wrong with hei?1 wire to hook up,sweet. I grew up building fast fords with my dad and got exceptionally good at holley carb tuning.I love them.I sit here and think about the infinate tuning possabilities with the carb and hei and it makes me smile like I'm back at the track.being able to adjust timing,advance,cam,compression,maybe even a blow thru turbo.lol,I do have some small t/c's laying around.just kidding.the simpilcity and reliability are what appeals to me.
 
If you are familiar with holley carbs you know you either love them or hate them.I love all the changes you can make to them,squirters,jets,accelerator pump volume,pump cams,4bbls are even more fun to play with.
should I post this in the modified forum?
 
just think if it was hei...it won't start,got spark..no..it's in the distributor.no really,coil and module are in the dizzy.easy.
 
So far I've read that a 258 dizzy will fit.I'm gonna make a parts list and figure prices.if anyone has any info I'd love to read it.
I know you may think I'm moving back in technology but hey I've never went 3 weeks tracing down a no start situation.I know search and you will find,yeah right I've joined every xj forum I could google and have yet to find my problem.I have had some great help too,thanks.Gonna still work on getting it going with it's currant ignition system but I'm making me a list.
going this route has got to make mods alot more friendly and tunable
 
DonnMcc said:
what's wrong with hei?1 wire to hook up,sweet. I grew up building fast fords with my dad and got exceptionally good at holley carb tuning.I love them.I sit here and think about the infinate tuning possabilities with the carb and hei and it makes me smile like I'm back at the track.being able to adjust timing,advance,cam,compression,maybe even a blow thru turbo.lol,I do have some small t/c's laying around.just kidding.the simpilcity and reliability are what appeals to me.
Click to expand...

No offense intended. As you say, you are going back in technology, but if you want to be able to dial in everything yourself, then your idea has some merit. The ignition system on an XJ is already very good. It already has fuel injection. Those are the things that the 258 guys covet. I am in the middle of trying to get my "new" scrambler dialed in. I have upgraded the ignition, Nuttered the computer away, but don't have the knowledge to get it just right. You sound like you might have the smarts to do it. My son has a brand new 4.7 stroker ready to go, but doesn't have the time to put it in, figure out the wiring & fuel injection,etc. He is considering throwing the 258 intake and Weber 38/38 on it and calling it a day. That is not to say that he has actually researched the fitability of the intake....:doh:
 
Let me as you this - and do please take it in the spirit intended:

"Why do you want to do this?"

This is a valid question - what is the problem you're running into, and why do you think stepping back in engine management will help you? There may be a better way to solve the problem - but I can't figure out a better way to help you if I don't know what you're trying to solve.

As far as the HEI on the 4.0L, it shouldn't be a problem. The bottom-end parts commonality between the 199/232/258 and 242 is fairly high, even to cranks and cams.

If you look up "Davis Unified Ignition" (or "DUI",) you'll see that the GM six-cylinder HEI has been adapted to the AMC six, so that's a possibility already.

However, since you're working with a 1995, you're going to hit your head on OBD, unless you're looking at a total system refit (and elimination of pretty much all of the OBD-I control system. Sounds like that's what you're trying to do, tho.)

I know about the adjustability/tunability of Holley carbs - I've used dozens of them in performance applications. However, while I wasn't a huge fan of early FI setups, I have come around and realised that there's a good deal you can do with port fuel injection (like on the 4.0L) that can't be done with carburettors - and I like the ability to run a "dry" intake as well.
 
5-90 said:
Let me as you this - and do please take it in the spirit intended:

"Why do you want to do this?"

This is a valid question - what is the problem you're running into, and why do you think stepping back in engine management will help you? There may be a better way to solve the problem - but I can't figure out a better way to help you if I don't know what you're trying to solve.

As far as the HEI on the 4.0L, it shouldn't be a problem. The bottom-end parts commonality between the 199/232/258 and 242 is fairly high, even to cranks and cams.

If you look up "Davis Unified Ignition" (or "DUI",) you'll see that the GM six-cylinder HEI has been adapted to the AMC six, so that's a possibility already.

However, since you're working with a 1995, you're going to hit your head on OBD, unless you're looking at a total system refit (and elimination of pretty much all of the OBD-I control system. Sounds like that's what you're trying to do, tho.)

I know about the adjustability/tunability of Holley carbs - I've used dozens of them in performance applications. However, while I wasn't a huge fan of early FI setups, I have come around and realised that there's a good deal you can do with port fuel injection (like on the 4.0L) that can't be done with carburettors - and I like the ability to run a "dry" intake as well.
Click to expand...

lol,I hear ya man.I'm just getting frustrated.If I was racing the jeep,yeah I'd do it and throw some boost to boot.mopar products and their unique ignition systems with everything tied in to everything is making me insane.I'm working on it got a few guys shooting me some solid advice.I know(yeah right)it's only a matter of time before I narrow it down.I'm closer than I was when I bought it.lol,I know the guy who sold it to me is laughing now.but soon I will be driving past his house in his jeep.He could of atleast given me a heads up on what had been done/tested/replaced.Guess that's asking too much.I'll get it I am a very persistant man that has a "i gotta know"complex.I know alot of you know what I mean.
I agree efi has come aways,back in the day retroing efi was unheard of.now it's has numerous benefits.I'll let you know what those are after this jeep gets going.
 
I've read swapping in the amc v-8 dizzy gear on the gm 6cyl dizzy is a bad idea.the gear doesn't engage the cam all the way and could/will eat your cam gear up.I figured if I was going to do it I'd do the frod dura spark dizzy.it's easy to hook up to anything and very reliable.I'm not wanting to go that way,but when you are stumped it's nice to have another option to keep the hopes up.
 
kevin s said:
No offense intended. As you say, you are going back in technology, but if you want to be able to dial in everything yourself, then your idea has some merit. The ignition system on an XJ is already very good. It already has fuel injection. Those are the things that the 258 guys covet. I am in the middle of trying to get my "new" scrambler dialed in. I have upgraded the ignition, Nuttered the computer away, but don't have the knowledge to get it just right. You sound like you might have the smarts to do it. My son has a brand new 4.7 stroker ready to go, but doesn't have the time to put it in, figure out the wiring & fuel injection,etc. He is considering throwing the 258 intake and Weber 38/38 on it and calling it a day. That is not to say that he has actually researched the fitability of the intake....:doh:
Click to expand...
I'm not sure about the intake,I know the 4.0 head fits the 4.2(20-40hp supposedly)I know the 4.2 intake fits the 4.0 head and distributor also.There is a small fitament prob with the intake with the alighnment pins of the 4.0 head.From what I read so far it's no big deal.The 4.0 head needs water jackets filled when swapped.I would think going carb would cost me more time and trouble with the other things...a/c,cruise,speedo meter,gauges.I'm sure it all can be worked around.I'm not trying to get into another wire testing marathon though.if you or your son needs some swap info I bookmarked alot of it.the more I read about the strokers the more I want one.be awhile though.
I'm lost with this efi system though.I know what everything does but damn does it all have to be hooked together?My old ford had just about every sensor bad,no oil pressure at idle,rattling rods and still ran. I miss the old days when a bottle of lucas fixed your probs for awhile.
 
Quick thought...is this a street driven Jeep? IE, does it need to stay registered and street legal? Out here in CA, you're not allowed to mess with installing an older engine than what came in the vehicle or modify emissions equipment in any way at all. If it may cause worse emissions it's outlawed out here...You probably have different rules in TN, but might be something to look at.
 
By the way, addressing the original question in a way:

I was having a bit of sputtering at high RPM on my 95, and in diagnosing it I realized that I had not bothered to look at the spark plugs for over 100 thousand miles (really!). I took out the plugs, and found that what little remained of the electrodes gave it a gap approximately 2 1/2 times what it should be. It had continued to start and run fine up until high RPMs. My conclusion was that the ignition delivers high enough energy already.
 
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