Best Crankshaft Choice

[mecompco]

OK, I've read the FAQ, I've read 5-90s book and all the stroker recipe threads. I've gotten some good info from my "wanted" thread here. But, I think I need a little more specifity in the choice of a crankshaft.

1) It is my understanding that with an auto tranny either 4 or 12 CW cranshaft would be fine (my application is off-road/DD, and I could care less about 1/4 mile times or top speed--max torque up to about 3K and max reliability is what I'm looking for).

True/False?

2) Within reason (chromed Hesco is out , what's the most economical choice w/o compromising reliability?

Remanufactured w/2" snout (which I guess would be a later-model, 4 CW--correct?)
Junkyard/Classifieds used (cheaper, but would need machining, and could be either 4 or 12 CW)
Other

3) Assuming I go with a used one, what is a reasonable amount to pay (let's also assume it's already been extracted from the engine) and are there any caveats I should be aware of?

I don't think it make any difference, but it's going in a '92 block. Thanks for any and all opinions!

[seanyb505]

Ive read and heard (no experience though) the 12wt is better for offroading. It unfortunately does not come in the 2" snout, you can either get it machined down or use a spacer. I ordered a reman 4wt from O'Reillys. That way if it was bad or anything just send it back. If you dont live near one dont worry; they have free shipping for orders over $75 and mine took less than a week to get here. I thought the price was fair too, the total came to 236 and shouldnt need machining (its at the shop right now being checked). If you did get one used and it needed machining, I would expect to pay around 140-150. The shop Im going to quoted me 165. Their expensive but high quality.

[John]

For the end use you describe, either crankshaft will work quite well and with the automatic transmission the lightweight crank would have a slight edge. The longer snout 12 cwt. would not be a issue at all and the spacer is extremely easy to make.

With a lot of shops wanting ~$280 for a re manufactured crank ($50-60 of that is core charge) you might consider looking around for a motor to remove one from. They are easy to find and usually quite cheap in my area. Machine shop prices vary but $120-$150 is common for a regrind.

That said, The last two cranks came my way with no cost except machining, Too many old Wagoners going off to the crusher, I keep a small trailer for all my steel scrap and donate it to one of the area junk recyclers and he lets me know anytime he gets a Jeep to take to the crusher. I get anything I want to pull myself. He pays 200-250 dollars for one that he is going to haul to the crusher and doesn't recycle parts himself. He gets a few trailer loads a year free and I get a few parts free.

John

[seanyb505]

Thats a pretty good deal! I decided I didnt want to deal with finding one (I couldnt) and just buy a reman. It was 181 with a 40 dollar core so it was 236 total. I didnt think it was a bad deal considering I would have preferred to not do much work with a jy engine.

[mecompco]

OK, I checked O'Reilly's:

PN: 25210 (I used an '82 CJ5 as the model to search for, w/258) $227.99 including core charge and free shipping.

Unless one could find a used one for under $50.00, that really seems the way to go, considering the machine shop costs.

I assume a reman'ed one would be ready to drop in with no extra work? Any caveats to be aware of? I assume checking all the machined surfaces for correct size would be a good idea.

[John]

Yes do check all dimensions, do scrub the heck out of it before using it. I use stainless rifle bore brushes to scrub the oil passages. If it comes with bearings, they will be the wrong ones for your 92 block, check this out. You might get them to swap for the correct ones if discussed in advance.
John

[mecompco]

If it comes with bearings, they will be the wrong ones for your 92 block, check this out. You might get them to swap for the correct ones if discussed in advance.
John

John, it didn't mention anything about bearings, so I assume they'd be extra. I thought I read in the FAQs that the 4.0 and 4.2 used the same bearings--perhaps that was rod bearings, not main bearings (or perhaps I'm misremembering entirely)? Is there a brand preferance? Clevite? Is there anything else I should order at the same time? Due to budget constraints, I'm doing this Johnny Cash style--one piece at a time. My goal is to have it done before my 4.0 calves (only 180K on it, so I think I've still got some time).

Michael

[John]

Rod bearings are the same, mains have a break, check our FAQ section for further details, Clevite bearings will serve you well, I like them a lot. Johnny Cash style...... when people see my YJ (with a CJ front clip) and ask what year, I reply which part. With only 180K on your Jeep clock, you should have no problems having a stroker motor ready.
John

[aaronkeiser]

I took this information from the Robert W. Bryce stroker build.

Bearing Selection
The 4.0L and 4.2L engines share the same main bearing dimensions and clearances. However, the main bearings list as different numbers. Should the 4.2L bearings that match the crankshaft be used, or should the newer 4.0L bearings be used? The tech guys from both Federal Mogul and Mopar Performance couldn't help us here. So our machinist looked up in his bearing book, and the only difference is in one alloy. The alloy used in the newer 4.0L bearings was recommended for off-road use, so the decision was easy.

[seanyb505]

The crank will come with both main and connecting rod bearings. (Mine did anyway)

[jeepinwi]

The best crankshaft to use is one from the motor I got off eBay for $5.50(not a typo). I picked up a complete running 1985 4.2L engine that supplied the crank, rods, and crankshaft snout spacer that are currently in my stroker. Even better, all bearing surfaces had less than .002" clearance, so I didn't have to get any machining done. I used the 4.2L harmonic balancer to make my 1cm thick snout spacer.

[mecompco]

The crank will come with both main and connecting rod bearings. (Mine did anyway)

Cool! I'll specify I want the 4.0 main bearings. Thanks for the info.

[John]

I used the 4.2L harmonic balancer to make my 1cm thick snout spacer.

That is the same way I get mine. Cheap & easy, you know the key way and bore are correct to start with.
John

[seanyb505]

Cool! I'll specify I want the 4.0 main bearings. Thanks for the info.

It will come with the 4.2 bearings. I dont know if you can choose which bearings you want.

[fedrusion]

I thought the 50 I paid for a good 4.2 was a great price.