destroked

[crazygogo]

has anyone destroyed there 4.0? and what was the out come?

[Cheromaniac]

has anyone destroyed there 4.0? and what was the out come?

Destroking a 4.0 is only possible with a 199 crank but good luck finding one. You'd also need pistons with a 1.828" pin height, and with minimal dish volume to offset the lower CR that results from destroking.

[crazygogo]

ah.. the 199 crank is that hard to find? is the 199 crank just as strong as the 4.0 cranks?

[Root Moose]

Curious why you'd want to do this? Spec racer that requires specific engine size?

[crazygogo]

i have a toyota 2zzge engine in my celica and oh boy its a revv. happy.. i just wonder if i cud do this with a jeep engine? and to have a both type of engines for my jeep other being a stroker. and to have something that is uncommon.. just a thought i called and i can have the rods made for it and use chevy pistons i just don't know if there is a crank i can get ahold of??? since i guess there oh so rare....

[crazygogo]

anyone have a clue if it is possible ???

[Rockhound]

I know a guy that has a destroked Jeep 6. They race pebble drag hill climbs or something??? So the idea is make a motor rev to the moon, from what I understand. They love it, and did very well, until more modern motors have taken over.
Anyway....there must be a way!

[Cheromaniac]

I know a guy that has a destroked Jeep 6. They race pebble drag hill climbs or something??? So the idea is make a motor rev to the moon, from what I understand. They love it, and did very well, until more modern motors have taken over.
Anyway....there must be a way!

There IS. All you need is:

AMC 199 crank (as common as hens' teeth nowadays)
4.0L rods
Custom pistons

Displacement with this 3.00" stroke crank would be 215.6ci (3533cc or 3.5L) with a +0.030" overbore and 218.9ci (3587cc or 3.6L) with a +0.060" overbore.

[jeepxj3]

Destroking a 4.0 is only possible with a 199 crank but good luck finding one. You'd also need pistons with a 1.828" pin height, and with minimal dish volume to offset the lower CR that results from destroking.

IDK if you could get a piston made with 1.828" pin height for a reasonable price.
505 can get RaceTec custom forged pistons with custom pin height and dish. IDK if there is enough 'meat' on the forged slug to move the pin down 0.227".

If you could...- using 4.0L rods 6.125", 0.000"deck, 0.043"HG, 58cc Combustion chamber and +0.030" 1.828" pin height pistons = 215.58CID, 3.53L.
With flat top (no dish) SCR = 9.81:1 and with a stock '99+ cam DCR = 8.35:1.

Longer rods would really help. 6.30"-6.40" length rod would make it easier, but now you are talking custom rods, $$$$.

[crazygogo]

rods from a 4g54 engine has 6.528 and they jeu have to be machine very very little to fit the crank. and in stock form they handle very very well power.. the 4g54 turbo mode can handle 500 plus horsepower to the rods and that is a 4 cylinder. without going custom rods so running them in then run them in a 4.0 shouldn't be a problem. with budget pistons.