pistons!!! HELP!!!!PLEASE!!!!

[mrbeerbaitnammo]

Help!!!!
1991 YJ 4.0L 242 inline 6
my number 1 and 6 piston cracked between the first and second rings, any idea why? unbalanced crank mabey, and i want to retain everything stock ie. crank, rods, but can i use all the 242 stff and put 258 pistons on the 242 rods and use the 242 crank? i know the 242 pistons are a bigger bore size, so what over bore 258 pistons would i need if this idea would even work, unfortunatley i cant afford to do a stroker kit.... atleastnot on a soldiers pay!! i hope someone can help!!!

[hard core XJ offroader]

why do you want to use 258 pistons? your keeping everything stock just put the 242 pistons in. i don't know why or how, and i can't believe you cracked 2 pistons.

[hard core XJ offroader]

btw welcome to the board. oh and jeeps don't have rev limiters so watch the rpm's. thats the only thing i could guess that would blow 2 pistons

[mrbeerbaitnammo]

i bought it as a restore/build up project when i got back from iraq, i bought if off of a fellow soldier, who didnt take care of it, i found the 2 cracked pistons upon disasemble, thanks for the welcome, but the reason for asking about the 258 pistons is they seem to be more readily available and easier to find than the 242 pistons, unless you have any ideas, also i am having problems finding a new camshaft block plug, since i am changing cam bearings and had to pop the old one to remove the bearing.

[OhioYJ]

Where are you looking for pistons? I can go to my local Autozone and get 242 pistons, roughly $20 each when purchased individually.

The plug you maybe able to get at a parts store but you'll need the measurement of it, as they won't be able to look it up.

I'd be talking to a machine shop, when I can't find something at the parts stores, I get prices from the dealer (which many times is quite reasonable), then I call up the machine shop. The machine shops around here, don't have any problems selling me various parts and pieces.

[mrbeerbaitnammo]

i wish it was that easy, i am stationed in Germany, so i have to mail order everything, and some places wont deal with us military guys who are overseas even though we have a USA mailing address, i will try autozone website though, thanks

[trainbrainmike]

Originally posted by mrbeerbaitnammo:
i wish it was that easy, i am stationed in Germany, so i have to mail order everything, and some places wont deal with us military guys who are overseas even though we have a USA mailing address, i will try autozone website though, thanks Check your Yahoo email for an offer. :D

[dillonjm]

Originally posted by hard core XJ offroader:
btw welcome to the board. oh and jeeps don't have rev limiters so watch the rpm's. thats the only thing i could guess that would blow 2 pistons Newer ones do.

[edudley]

Yes Jeeps do have rev limiters. I know all 97 and newer do. This is when the ODBII engine management system came along. I also know that YJs with 2.5s do as well. I have a fellow Jeeper who frequently wheels hard and you can here the 4 banger bouncing off of the rev limiter. I think the 2.58 pistons may well have a different deck height than the 4.0. Good Luck with your hunt.

[hard core XJ offroader]

oh well i had a 1990 4.0 that did not have a rev limiter and i have a 1996 xj with a 4.0 and it too does not have a rev limiter. and it is OBDII. the 4 bangers might have had the rev limiters though.