Thread exclusively to discuss the best ways to build Jeep I6 Stroker motors

[Rescue Diver]

I know my AMC 258 i6 / 4.2l was rated at 110 peak hp stock, but I don't know what RPM's that is, or the torque numbers for that matter. Numerous sites say I should be making around AMC 150 hp after the 4.0 head swap, and based on feel of the pants, I believe it. If I make a conservative 200 hp on the highway with the 4.7 liter, that's more than enough to have some passing power above 65 mph, and the torque chart shows really good numbers starting around 1500 rpm's. Not bad for a light weight engine that I can actually carry the block around in my hands instead of needing a hoist.

 

[tarry99]

Good point. Im thinking the low rpm torque would be what Id look at.

Your right ..........torque is all that matters. Nobody is running around in the woods over 2 grand.

 

[coldair]

:driving: what octane are you going to have to run through this beast

 

[Rescue Diver]

:driving: what octane are you going to have to run through this beast

With all the sharp edges on the pistons and in the chambers smoothed and softened, some ignition tuning and jetting, I expect to be able to run regular pump gas, or mid grade at most. I'd definitely need mid grade or premium if I were running F.I.

 

[Rescue Diver]

Slight change in plans. Summit Racing emailed to say that the Sealed Power 677 pistons I ordered are discontinued.

I called to see what they could get for me and they're shipping me a set of H825CP60's and discounting them to let me have them for the same price as the 677s. I should have them towards the end of the week. As soon as they arrive, I'll bring them and the block to the machine shop.

The only down side to the 825 compared to the 677 is they have 2cc smaller dishes and a slightly lower pin height, so I'm looking at just a smidgen higher compression. It'll probably be in the 9.4 to 1 range.

 

[coldair]

Keep the info coming

 

[Rescue Diver]

I watched a few youtube videos on Jeep stroker building and they highly recommended a Comp 252h cam.

I guess I've taken one too many looks at the old 4.0 stock cam sitting in my garage with all the miles on it, and when thinking of re-using it with my new lifters, I just couldn't do it. I just pulled the trigger on a new cam. The stock 4.0 H.O. cam has .405" lift. The 252h has .433" which should work just fine with the stock springs. A few people on the Stroker forum have run the 4X 250h cam with its much bigger .485" lift on stock springs, so I feel pretty comfortable running the smaller lift 252h. After all, we're only talking about compressing the springs .030 more, and in a low RPM Jeep motor.

Comp Cams Hi-Energy 1000-4200RPM Hydraulic AMC Jeep 199-258ci 6cyl Cam #68-200-4

 

[Rescue Diver]

I found this great spreadsheet with specs on stock and available aftermarket cams for all the Jeep inline 6 motors. It's worthy of its own thread!

http://www.angelfire.com/my/fan/Jeep4.0Camshafts.htm

As it turns out, the stock cam from 1987 to 1995 has .424 lift, so I'm very comfortable using stock 4.0 springs with the one I ordered.

 

[IOPort51]

where did this chart come from??

Here's the torque chart they have posted. It lists stock 4.0, modified 4.0, and Stroked 4.0. I wish it had the stock numbers for a AMC 258 i6 / 4.2l included.

 

[Rescue Diver]

where did this chart come from??

I wish you'd asked that back when I posted it. I'll see if I can scrounge up the link.

Here's a really good article on stokers by Fourwheeler magazine.

1987-2006 Jeep 4.0L Inline Six - Four Wheeler Magazine

 

[Rescue Diver]

where did this chart come from??

Found it!

Stroker

 

[Rescue Diver]

Here's one more for you IO. Keep in mind that the dyno numbers provided are at the wheels vs. most of the Stroker dyno numbers going around that are measured from the crank.

Mopar 4.7L Stroker Motor Part 2 - Jp Magazine

 

[Rescue Diver]

I have everything ready to go other than the crank and rods that I still need to rob from my current AMC 258 i6 / 4.2l motor. The block is .060" over, so 4.7 liters.

 

[Rescue Diver]

I'm back. I got side tracked for a couple of months with the purchase of a boat, and a 2000 Cherokee to haul it.

Last night I finally got back to work on the stroker. I found a standard size crank and rods from a 1978 on Craigslist so now I won't have to cannibalize my current good running AMC 258 i6 / 4.2l !

I'll be dropping them off, along with the pistons at the machine shop this afternoon, and when I get them back in a few days I'll assemble the short block. Now that I can build the complete short block without stripping down the AMC 258 i6 / 4.2l , when it comes time for the install, it'll only take my CJ out of action for one day.

 

[Rippin]

I know its been quite a while, but you got any updates? Run into any more snags or did everything go pretty smoothly? I've got a line on a donor cherokee that I was gonna rob the top end off of, but this stroker sounds like a much better plan!

Sent from my A200 using Tapatalk 2

 

[Flabby]

Rescue Diver,
I have an 84 CJ and just picked up a 4.7L Stroker completely redone. I'm of like mind and keeping it carb'd vice FI. The MC 2100 as well as the Weber 38 have been recommended. What did you go with and what luck are you having? I'm also curious as to your electric fuel pump config and motor mounts. I picked up an aluminum 22 gal tank and I believe I'll put an tank pump to save any mounting issues. I'm going with the HEI DUI iggy/distrib and looking at Clifford intake/exhaust manifolds. Did you upgrade your radiator also?

Sorry for all the questions but I've enjoyed your thread and I'm wondering how things have turned out.

 

[caveman]

If you're going to buy from Clifford performance, Be sure they have it in stock before you pay for it. I ordered mine and payed for it over the net and they didn't have it in stock. It took six weeks for them to ship it and the quality was worse than any junk that you would expect to get from china. The quality that they used to be known for when the original owner had it is gone with the new owner. I also bought the carb adapter from them at the same time and even that was $hit. The stud holes were bored just enough off so the carb wouldn't go down over the studs.

 

[rufus1138]

anyone have a link to some info on AMC 258 i6 / 4.2l stroker or otherwise building vs 4.0 stroker builds?

 

[Flabby]

Thanks for the update Caveman. I've heard some of the same from others on other forums. Any other intake suggestions? I see you have a stroker, are FI or carbed?

 

[caveman]

Thanks for the update Caveman. I've heard some of the same from others on other forums. Any other intake suggestions? I see you have a stroker, are FI or carbed?

It's carburated. I just put a motocraft 2100 on it and haven't had a chance to test it out on the trails yet. I had a weber on it before and It was a good carb untill it got steep and it would flood out. I used the clifford intake when i finaly got it but had to modify some things to get it to fit. The power steering mount didn't line up and i had to modify my exhaust header to fit.
If i had to do it over again, I would use the 99 and newer intake manifold and buy , or have built, an adapter. If i had the milling equipment, I could have built a better one and i'm not a machinest. The clifford intake needs an adapter for any carb that you put on it anyway.