258 crank

[87manche]

currently I'm bidding on a 258 crank and rods. Man, I hope I can get them super ccheap. Right now it's $50. Once I get those then all I need is a rebuild kit and machine work and it's budget, low compression 4.6L

[DirtyComanche]

Good luck!

 

 

I might do that with mine when it kicks the bucket. Maybe. It might never die too.

[87manche]

well, I got a free renix block. I figured that if I was going to rebuild it then I should just stroke it. Right now I'm looking for a good HO head, and 99+ intake. Going with Speed pro hyperu whatever pistons. .30 over. Should get a CR of about 9.5 and upwards of 250HP. Gnarly power. Definitely what the Mj needs. of course I'm going to put in the AMC 20 with 4.10s first. I don't think that the 35 is gonna hold up to that kind of power.

[DirtyComanche]

I'd go to propane and go with about a 12:1 compression if I was to do it. I don't like paying for regular gas, much less mid or supreme. Yeah, I know, it'll add at most a buck a fill...

 

 

But I really like propane. So damn cheap here!

 

 

 

Oh yeah, port that HO head out yourself. It's easy, and worth a bunch more HP. And if you can't find one, port a renix one, it'll still work out okay.

 

 

 

Decided on a cam yet? Going to deck the block to get a .040" squench? Are you planning on using the renix computer/fuel injection? Apparently it'll take a little work to adapt to the 99+ intake.

 

 

And get your TB bored! It's going to be the big restrictive point otherwise.

 

 

 

Damn Jeeps, it all jsut adds up.

[87manche]

I plan on useing the renix computer. It's just so damned easy to fool into the proper fuel mixture with a map adjuster.

I'm doing the research now into adapting the TPS. That's not a big issue, just some work with a dremel.

The fuel rail is most likely my biggest issue. I've not seen the 9+ intake up close, so I'm not sure what's involved.

[DirtyComanche]

I was told just to snag the rail off a HO and adapt it to the renix, as opposed to trying to adapt the renix rail to the newer style intake.

 

Might want to pick up a fsm for a later model cherokee. It'd be a help.

 

 

Edit: Which crank are you getting? If you care, I had this written down:

 

Crankshaft - AMC 258 cranks

 

Year.........Casting No......Description

1971.........3199738.........For Borg Warner automatic

1972-80...3214723.........12 counterweights, 66lb, 64mm nose - Heaviest, best for lugging. Balances easy.

1981-86...3235477.........4 counterweights, 46lb, 64mm nose

1987-90...3727...............4 counterweights, 46lb, 54mm nose - Has nose length correct, shaving is needed on other cranks.

 

 

You need to cut an inch off the nose of most of them, but I assume you knew that.

[mjeff87]

Right now I'm looking for a good HO head, and 99+ intake.

 

Cast heads are $20 + core at my local U-pull (aluminum ones are $40, and I'm dropping the one I got for the MJ off today at the shop to get decked/cleaned).

 

If'n you're not in too much of a hurry for one, I can get you one down here (?)

 

Jeff

[pingpong]

For the amount of money you are going to spend to build a "stroker" you can build a 4.3 or a chevy v-8 with adapters for the same. Just some friendly advice. One of the guy in the club I belong to, did it, He only saved a few hundred bucks on what a built 4.3 or 350 would cost.

 

 

 

 

Just my opinion.

 

 

 

Patrick

[Pete M]

Depends on precisely how you build the stroker doesn't it? One could spend a whole heck of a lot on *any* engine build-up.

This is my plan: I have a ~$100 4.0L block and a $75 '76 258 block. Now I need to get the machining done and buy part of a rebuild kit, then some Mustang injectors from the junkyard, the MAP sensor magic, *maybe* a cam, and then some odds and ends (the timing chain is still original so that has to go, but the rest of the accessories that are on my 88 are pretty new and my alternator cost me a small fortune so I'd very much like to keep it).

For a Chevy 4.3 (the way I would have to do it):

A decent and complete 4.3L block from the junkyard (including harness and all the accessories) or a donor rig

+ AA motor mounts

+ AA bellhousing adapter

+ exhaust

+ wiring that bad-boy up (my truck is on a no-carb diet)

+ I haven't a clue what to do about the A/C (yes, that is important to me)

+ cooling system stuff

= well, the parts from AdvanceAdapters alone should exceed what I plan to sink into my stroker.

 

Now, there are plenty of other details depending on what condition the truck is in now, but those are the big ones that I would have to worry about. I need a new engine, and if I'm going to rebuild one, it doesn't cost much more to build the stroker. In my opinion, the true beauty of the stroker concept is that it all bolts back into my truck. :D Of course, when H.O. parts are used or when building for maximum HP, it can get complicated. All I want is an engine with the balls to pull my too-heavy truck uphill on the freeway without slowing down. :D

Jeep on!

--Pete

[comanchedude]

For the amount of money you are going to spend to build a "stroker" you can build a 4.3 or a chevy v-8 with adapters for the same. Just some friendly advice.

 

 

 

Shame on you!

Its a Jeep not a chevy :x

I think you should keep the Jeep all Jeep and never bastardize it with chevy parts. Bad enough that chrysler stole the company, better than Renault though

 

Yeah that’s my opinion 8)

[87manche]

I'm with Pete's situation. I got a free block and head. Speaking of which, does anyone need a Renix head that's in good shape?

I was just going to do a rebuild, but then the dark side of engine building seducedme, and all this talk of 300 ft lbs got into my head. Now I'm oing a stroker, and then I figured that if I was doing a stroker then I should put a higher flowing head on it, then if I was going to do the head I should put the 99 intake on it, and then, and then.......

Soon it turns into an expensive project, but I've never built a motor before, merely repaired them. I figured since I had the spare block I would use it. My motor is still quite strong, in fact it was probably rebuilt itself not too long ago. SO I can sell it to defray some of the cost when I make the swap.

Anyway, it's a long rambling post...

I went with the stroker because the MJ is my DD, and the swap will have to take place in a weekend.

Not to mention that if I went SBC or 4.3 then I'd have to get all new accessory brackets, and such.

[pingpong]

I should have known I was going to get flamed :roll:

 

 

All told my friend spent some where qround 1800 building his stroker. Where I live you can find a running s-10 with a 4.3 with relatively low miles for an mid 90's motor for around 1000. Then all you have to do is adapt the np231 to a 700r4 tranny. Sounds complicated, but it is doable. Or if you want to get fancy just find an older 3/4 or 1 ton and swap everything into the MJ :twisted:

 

 

I am sorry that I feel this way... If you look at my rig, it is allready basterdized, but it does what I need it to do.

 

 

 

Patrick

[87manche]

I completely see your point, but I don't have acess to welders and such to make new mounts and everything else.

It may cost more money to do the stroker buildup, but it's within my skill level.

That and I want to get a sticker that says 4.6 litre on it :-D

FOrgt to mention, got outbid anyway, someone on NAXJA was competing. sucks.

[pingpong]

I will keep my eye's open for a 258 crank. From time to time I come across some smoking deals in my area.

[87manche]

yeah, my neighbor has a TJ, and wheels with a guy that's got two cjs he's making into one good one. He's got one with a 304 and one with a 258, so I'm hoping that he stays with the 304 and ditches the 258 and I can get the crank and rods for a song.