91 HO or Renix 4.6? Getting mixed advice.

[johnj92131]

Bonkers,

 

Mechanically, I don't think it matters if you stroke a Renix or an H.O.   Even think the cam is the same (cam timing is different).  That leaves the electronics/fuel management system as the important difference.  In my view, the Renix system is the older and less supported system.  Electronic parts are discontinued for the most part.

 

The H.O. electronics are at least a generation newer starting in 1991 and by 1996 had moved forward to OBDII.  So the newest H.O. electronics are at at least 12 years younger then the Newest Renix electronics.  Something to think about for reliability going forward.

 

Next, having used my 91 H.O. to tow another Comanche a couple thousand miles, I would advise you to use 4.11 gears.  My 3.55 and AW4 managed all the Rocky Mountain passes.  But the cooling system was sometimes over taxed.  And this was a standard 4.0 engine - no speed parts or non stock upgrades.  The Gear change to 4.11 from 3.07 will increase your at the wheels torque by about one third all by it's self

 

With respect to getting 300+ lb/ft of torque, I suspect it will take than just a simple long stroke crank in either the H.O. or Renix engine.  Other (read expensive) additional tuning parts will be required.  Don has done a great job of documenting each of the changes he has made over the years.  Take a good look at all that Don has done - including going to 4.11 gearing.  Remember that Don gained about 2 mpg when he changed to the 4.11 gears!

 

The change in stroke from 3.413 inches to 3.895 inches is a 14% increase in displacement, by it's self worth maybe and extra 31 lb/ft or torque (14% of 220 = 31).  The rest of the gains come from other changes Don made and paid for.

 

Bottom line:  It depends on how much money and work you are willing to put into the truck. 

[Eagle]

53 minutes ago, Bonkers said:

 

No, I'm planning on spending a $#!&load of money on this

build. I already have more planned on the rear axle than i

originally spent buying the entire truck.

 

Is this what you intended to write, or did you mean you're NOT planning on spending a lot on the build?

 

Building a stroker engine is going to be basically the same whether you do a Renix or an HO. You'll need the same stroker crankshaft, the same rods, and the same pistons. What you do to the head will be the same, whether it's a Renix head or an HO head. The basic question is, do you want to build the engine and drop it in, or do you want to undertake rewiring the engine compartment while the engine is out?

 

You have an additional option that hasn't been discussed - rebuild a stock engine and put a different cam in it.

[Jeep Driver]

1 hour ago, Bonkers said:

 

ARB told me when i asked about lockers for the 3.07s. They

told me the highest ratio kits for the D30 and D44 had to be

at least 3.55/6 but preferrably 3.73+. Clearly I'm no mechanic,

but when the guys who build the product tell me it doesnt 

exist, i tend to believe them.

 

Also, i was under the impression that there was no difference

in stroking a 4.0 renix vs 4.0HO. So do you think stroking both 

the 91 HO motor AND swapping in the components would be 

the more ideal choice? Or are you saying to swap in a stroked

97 HO (which would be a huge PITA since I'm not changing the

interior to that crummy soft-edge look.)

Based on what you said here-

 

Money. 

 

ARB will run you $1000 per axle.  Thick gear or change carrier, without looking it up, $300 per axle. You said you are not a mechanic, $800 minimum for install. 

Then you'll need air and plumbing. 

 

Both axles- $3600, not including misc, such as bearings and seals and brakes. 

 

Then you'll move on to the engine...........$4K minimum for anything beyond stock, stock replacement, $2k++

 

 

Just giving you a little perspective..........not raining on your parade. 

[Bonkers]

34 minutes ago, Eagle said:

 

Is this what you intended to write, or did you mean you're NOT planning on spending a lot on the build?

 

Yeah, i was being ironical... this jeep will be the 3rd most expensive

car ill ever own and i have no regrets about that.

 

Please understand my confusion - if stroking a renix and HO is 

"basically the same" then why would having an HO Stroker the 

"best of both worlds."

 

Starting in the next couple of weeks, Gracie is being stripped down

to uni-frame. Everything comes off and out. I bought a 91 HO to

rebuild and swap everything over once the bodywork is done. I

was told before to ignore the strokers because they were not reliable.

[Bonkers]

4 minutes ago, Jeep Driver said:

Just giving you a little perspective..........not raining on your parade. 

 

Thats actually a lot less than I'm expecting.

 

So, back to the topic. Driving from delaware, to florida,

to alaska, and maybe bolvia... will a stroker be able to

handle the endurance?

[Jeep Driver]

Just now, Bonkers said:

 

Thats actually a lot less than I'm expecting.

 

So, back to the topic. Driving from delaware, to florida,

to alaska, and maybe bolvia... will a stroker be able to

handle the endurance?

If you're asking me..............?

 

 

Build a high-end stock engine, best parts you can buy.

 

Build it right. Drive it. 

 

 

[Bonkers]

1 hour ago, johnj92131 said:

Take a good look at all that Don has done - including going to 4.11 gearing.  Remember that Don gained about 2 mpg when he changed to the 4.11 gears!

Sorry John, i didnt see your post on page2 at first.

 

But didnt Don add a lift and 32s to offet the gearing? Thats

not a plan for me, but I'm not opposed to 4.11s. Its just

sounds like alot of gear for 80mph dashes through the corn

feilds of mid-america on 29s/30s... 

 

If towing is going to be a defeating factor i can certainly drop

that from the equation.

[johnj92131]

31 minutes ago, Bonkers said:

 

 

was told before to ignore the strokers because they were not reliable.

 

Just my observation:  Problem with unreliable strokers is the unreliable engine builder.

 

Don''t forget - the original stroker engines were build by the AMC factory in Mexico - VAM in the 1970's  282 cubic inches

[Pete M]

35 minutes ago, Bonkers said:

 

Please understand my confusion - if stroking a renix and HO is 

"basically the same" then why would having an HO Stroker the 

"best of both worlds."

 

 

 

mechanically they are equivalent.  But the HO other stuff gets the nod for being an improvement over the older renix stuff.     Chrysler was better than AMC at putting together a wire harness.  

[Jeep Driver]

11 minutes ago, Bonkers said:

Sorry John, i didnt see your post on page2 at first.

 

But didnt Don add a lift and 32s to offet the gearing? Thats

not a plan for me, but I'm not opposed to 4.11s. Its just

sounds like alot of gear for 80mph dashes through the corn

feilds of mid-america on 29s/30s... 

 

If towing is going to be a defeating factor i can certainly drop

that from the equation.

4.11 is not a lot of gearing.

[Jeep Driver]

Just now, Pete M said:

 

mechanically they are equivalent.  But the HO other stuff gets the nod for being an improvement over the older renix stuff.     Chrysler was better than AMC at putting together a wire harness.  

That's debatable.

[Pete M]

indeed it is.    there are pluses and minuses to both.

[HOrnbrod]

1 hour ago, Bonkers said:

Starting in the next couple of weeks, Gracie is being stripped down

to uni-frame. Everything comes off and out. I bought a 91 HO to

rebuild and swap everything over once the bodywork is done. I

was told before to ignore the strokers because they were not reliable.

 

That's not quite true. Mine's 13 years old and I've never a problem. You get into gray areas when you push the limits, like higher compression with dished pistons and shaved cylinder heads, over-boring, too aggressive a camshaft, etc. Since you are planning to rebuild your donor 91 engine, why not throw in the 4.2 crank, some stock pistons with not cylinder boring (unless needed), maybe a mild cam, the 01 intake, new injectors, a bored throttle body, and keep close to the stock compression ratio with the rebuild? It won't be many more $$ and you'll gain at least a 40-50 ponies minimum and maintain full street reliability. I get 21 MPG on the highway cruising at 70-75, but only 13-14 around town mainly because some fool puts excess pressure on the skinny pedal.

 

There's nothing wrong with keeping it a Renix, but then you'll have the parts scarcity problem which is only getting worse. If you didn't have an HO donor, I'd go along with just rebuilding the Renix engine right. But since you do, go HO. All that's up to you, we can only advise.

 

EDIT:  And yeah, I went from 3.55 to 4.10 only because I went with 31" tires. Final drive ratio is just a tad lower than stock. It'll cruise all day at 70MPH and get great mileage.

[HOrnbrod]

23 minutes ago, johnj92131 said:

Just my observation:  Problem with unreliable strokers is the unreliable engine builder.

 

^^  Words of wisdom right there. That's the main reason I went with Hesco. 

[Bonkers]

1 hour ago, HOrnbrod said:

 If you didn't have an HO donor, I'd go along with just rebuilding the Renix engine right. But since you do, go HO. All that's up to you, we can only advise.

 

And i really appreviate that advice. Once the build begins 

I plan on researching the hell out of these details, but in 

the prep stage theres just too much information to sort

through... especially for someone like me.

 

Are there any other builders worth looking into? Hesco and

I are not on good terms because of their shipping practices.

 

 

[Eagle]

2 hours ago, Bonkers said:

 

Please understand my confusion - if stroking a renix and HO is 

"basically the same" then why would having an HO Stroker the 

"best of both worlds."

 

 

As others have commented in this thread, parts availability for the Renix system is drying up. Take what my colleague, Hornbrod, says with a small grain of salt -- he's a staunch advocate of the Chrysler HO platform. I don't have any "HO" vehicles, I have three Renix MJs, a Renix XJ, and two 2000 XJs. The 2000s have OBD-2, which is even beyond the HO diagnostics -- but the few times I've had to actually use the OBD-2 diagnostics, the text that was supposed to "explain" the code I was getting was less than helpful.

 

The engine work, as I posted earlier, is going to be the same. The advantage to doing an HO stroker is simply the newer system. Is it worth it if you already have a functional Renix vehicle? Only you can decide. Speaking for myself only -- if I were replacing an engine on one of my Renix vehicles, whether I was going stock or stroker I would not even consider swapping out the entire wiring harness to get the Chrysler system. To me it's just not worth the labor and hassle. Among other things, with close to a half million miles among the several Renix Jeeps I own and have owned, I find them to be just as reliable as the newer ones, easy to work on, and they give better gas mileage.

 

But -- if I came into possession of a nice HO Comanche would I change it to Renix? Heck, no! Each has its advantages and its disadvantages. I'm just too old to feel like swapping out a complete wiring harness when the one in the vehicle gets the job done just as well.

[HOrnbrod]

40 minutes ago, Bonkers said:

And i really appreviate that advice. Once the build begins 

I plan on researching the hell out of these details, but in 

the prep stage theres just too much information to sort

through... especially for someone like me.

 

Are there any other builders worth looking into? Hesco and

I are not on good terms because of their shipping practices.

 

Hesco has the best stroker rep in the business. They are also the most expensive. I couldn't / wouldn't recommend anyone else, especially since I hang around the Strokers forum and read the horror stories about most of the other builders. Everyone rips Hesco because of their prices, but nobody ever rips the quality of their builds. You might pay more up front, but over the long haul you'll save $$ in the end.

[Keyav8r]

Just my 2c.  I don’t have a stroker, but if I were to get one it would be from HESCO.  Can’t say anything from experience about their pricing but knowing their work I would not be at all surprised if they are higher.  I do know Lee Hurley personally (he’s retired and Joe is running the show, I hear) and know his insistence on quality and that quality is still the name of the game there.  

Chrysler chose HESCO to build and package the throttle body and distributor upgrade kits for Jeep products (I’ve seen the kits being packaged in Mopar boxes).  Chrysler chose HESCO to build their show MJ (one really stout, good looking truck).  And hundreds of classic, performance, and exotic car owners/collectors have chosen HESCO as the only shop that touches their cars.

So, if I wanted a stroker for my MJ I would go to HESCO.  Your money, your choice.

[HOrnbrod]

1 minute ago, Keyav8r said:

Just my 2c.  I don’t have a stroker, but if I were to get one it would be from HESCO.  Can’t say anything from experience about their pricing but knowing their work I would not be at all surprised if they are higher.  I do know Lee Hurley personally (he’s retired and Joe is running the show, I hear) and know his insistence on quality and that quality is still the name of the game there.  

Chrysler chose HESCO to build and package the throttle body and distributor upgrade kits for Jeep products (I’ve seen the kits being packaged in Mopar boxes).  Chrysler chose HESCO to build their show MJ (one really stout, good looking truck).  And hundreds of classic, performance, and exotic car owners/collectors have chosen HESCO as the only shop that touches their cars.

So, if I wanted a stroker for my MJ I would go to HESCO.  Your money, your choice.

 

Lee's a character isn't he? Under that gruff exterior beats the heart of a pussycat. He did all my dyno runs personally (probably for everyone else too) and explained in great detail why he had it screaming at over 6000 RPM at times while I'm waiting for everything to blow up.    He always took the time to answer all my questions and I learned a lot from him. He has a soft spot for Comanches. Ever see the yellow Hesco supercharged 4.9L stroker "delivery truck" MJ? I think it's retired now and sits in the Hesco museum. Tried for the longest time to get that manifold and Eaton supercharger, but it was always "not for sale".

 

Didn't know he retired as he's still active on the Hesco forum. He helped me with a fuel delivery problem recently. Joe is a good guy too. Haven't seen either of them in years..

[Keyav8r]

That’s the truck he built for Chrysler.  When they got through showing it they were going to crush it but Lee talked them into letting him “store” it for them.  I think he finally managed to get a title on it.

There’s a good “Lee” story about a supercharged Firebird but it’s too long and off topic for the forum.  

I ran into him in a Mexican restaraunt at lunch a few months back and he told me he had retired.

[Bonkers]

Yeah, sorry, but Hesco lost my business back when

i was looking into strokers the first time. I can't 

remember who it was, but they quoted me a price 

on a built motor, then added shipping, THEN they

wanted me to pay for building the shipping crate. 

I don't care how good of a builder you are, but if my

potentail $5k+ isnt worth your time, then i couldnt

agree more. 

[75sv1]

You might look at Russ Pottenger at Bishop-Buell racing. He has a good rep on the Stroker board as far as I know. I did go that route. I still need to get the block done etc. I do not have any issues with HESCO, though. I plan to get their water pump.  I will be using an '01 block, and probably a '95 head I did some years back. I am planning 4:10's and mine is a manual. It might not be the correct gearing for a manual. Might have to go with bigger tires, bummer. As for a block, the older RNIX might have better strength. Very debatable. I do not know what casting techniques they used in the latter years. Some used to say the RENIX Mexican block might be stronger. I think for what you are doing, its a wash. I am going with 0.030 over bore. That is the min. through Bishop-Buell. I wanted some amount of longevity. So, a thicker cylinder wall should help.

            I do have a '98 XJ with 4:10 and 31"s. lifted 4.5 +. Its probably 5.5 to 6 in the rear. Its fairly nice on the highway. It is a stock motor though. I did tow a vehicle, but only a few miles. I would look at a HD radiator and a trans cooler.

[cruiser54]

Never hurts to search "poor man's stroker" either. 

[HOrnbrod]

15 hours ago, 75sv1 said:

You might look at Russ Pottenger at Bishop-Buell racing. He has a good rep on the Stroker board as far as I know. I did go that route.

 

I thought Russ just worked on cylinder heads.

[75sv1]

3 hours ago, HOrnbrod said:

 

I thought Russ just worked on cylinder heads.

No, He sells parts and kits. Also, break in oil. I have not checked into what his cylinder heads cost.  I bought just about everything but the water pump and harmonic balancer for roughly $2,700 shipped. I did upgrade to the nitride cam. That does include gaskets. The latter ones, as more $$. Also, very generous with advice.

      I did look at E-Bay and his were a bit more for say rotating assembly. His post seemed to me knowledgeable (very), but not over board. Happy so far with the way I went.  

       As to the budget vs 'long rod'. I think the budget is the same MPG as the stock. The long rod a few more MPG. If I were the OP, I'd look to see if he has two ribs on the lower block by the oil pan or one. I think two are Mexican blocks. A bit thicker castings supposedly than HOs.  Add the latter crankshaft caps ladder or cradle. 3.73 for the 30 inch tires would probably do for a bit more MPG. Check a thread on Jeep Forums about MPG by Charlie. Long, Long thread.