Destroke? 199 crank in 4L?

[Cheromaniac]

Check with the JeepSpeed folks. They are doing Destrokeing for the class. Then turning around and running 6,000rpm plus with them.

I've been trying to find out which Jeepspeed class that is. The 1700 class rules state that:

4.1.5.2 Maximum engine displacement is 4097cc (250 cu in.) This would allow a 4.0-liter engine to be rebuilt with
.060 oversized pistons with a little extra for honing cleanup.
4.1.5.3 Stock block and cylinder head must be retained. It may be bored, honed, decked, and otherwise machined as
long as all other rules are adhered to. Stock block, cylinder head(s) and oil pan must be retained. All internal parts
are open. No dry sump lubrication systems, but oil pan may be modified to increase capacity.

[Plechtan]

I would like to destroked to 3.0L and put a supercharger on it.

Thats the plan for the Bonneville truck, 4" bore, 3" stroke 226 cid. Going with a turbo and 30 lbs of boost.

[farna]

Did anyone ever figure out the combination to put a 199 crank in a 4.0L or 4.2L block? I'm thinking of doing it for a different reason, but want a small displacement six.
What I'm thinking about is building an engine around 200 inches and putting a small turbo on it for gas mileage in a J-10. Low compression (8:1 would be fine), 5-6 psi (no more than 10 max, and don't really want that much), all boosted out by 3000-4000 rpm. So a four cylinder turbo will be fine, and also have little to no lag. I just want 4.0L power (around 200 NET hp @ 3500-4000 rpm -- that would be about 265 GROSS hp, off a crank dyno with no accessories) with a smaller displacement. With the turbo increasing power and torque this should mean having good power and burning less gas. Sort of like the Ford T-bird turbo coupe -- 2.5L four with the performance of a 5.0L V8 model (1985 model 2.5L turbo = 150hp @ 4400/240-lbs.ft. @ 3,400 RPM; 5.0L V-8 = 150hp @ 3,200 rpm/270-lbs.ft.@ 2,000 rpm). I've gotr a Ford turbo 2.3L with five speed in the back now --- maybe I should just drop that in the J-10? I wonder what 4x4 trans I could use -- Jeep CJ T-5?? The AX15 won't bolt to the T-5 bell housing, but I don't know what the input shaft length on the Ford 2.3L T-5 is (it's from a Merkur XR4Ti). Don't want to go 2WD, but I probably have enough length with the long bed pickup to do a divorced t-case... This might be a better post for an FSJ forum....

[SIXPAK]

Farna,
I was going to try to put together a combo like that for a fun sand drag motor. I have the donor 199 crank in the garage. First issue for me was the crank is made for a smaller .750 input shaft trans. More modern automatics are the more typical 1.812, which is what the 4.0 and the 258 is. I could have got past that. On the piston/rod combo I was going to have custom pistons made. So wrist pin postion would be just a matter of some math. With the shorter stroke of 3 inches I think I would have went with the shorter 258 set of rods. If you go with the stock 6.125 rods do not go with the 199's. Go with the factory 4.0's they will be stronger for you.

[sureshot007]

Fuel efficiency and power are mutually exclusive - especially with a turbo. And 10 psi or less on less than 9:1 compression won't give you the power you are looking for.

[crazygogo]

i did some R and D and found out that for the rod and piston combo stock off the shelf rods use the 2.6L turbo rods from a conquest tsi.. and the pistons from a chevy with a bore of 3.898 and a little machiing and your set there as far as the shaft size that i am still working on.......