4.0L clean up

[Pookapotamus]

The engine in my xj is getting tired and burning oil quite badly. I have found a donar engine from a 95 xj with only 195,000 on the clock that seems to be in fantastic shape, not sure if it has been rebuilt, (no rebuild stamp on it) but it is very clean and seems tight. I am thinking it has been rebuilt recently because there is very little wear in the cylinders and the lifters and cam look pretty much new. Plus there are marking on the cylinders, but I have never seen any one use letters instead of numbers and can't figure out what they might mean? So here is a pic and if you have any idea please let me know.



And top of the piston markings as well, can some one explain these for me please? I get the arrow and frt its obvious but what does the 50 mean?

[Knox]

The 50 means you need to use a $50 bill as a gasket. Don't cheap out and try to put a $20 in there and don't bother with a $100 either as the different colour doesn't stand up to the temps as well as the recommended

Red/pink is for high temperature. Let me know if you have any other simple questions you need looked after.

[JackstandJohnny]

wel sounds like knox answered your questions in full.



or maybe it was rebuilt and the block was bored .050 over?

[Knox]

yeah I was only fooling around...

if you take that image and drag it into a google search box, this comes up, the Haitian children should answer all your questions
http://images.google.com/search?tbs=sbi:AMhZZiuBwdSQ8mH4rOwtAGKe_1OaMceO8ZOh4X8NTT90wYBP9bxOexQQicFHPydKM_1DfRrXICgBDLjMHf8qrpuxRWUDidVKS_1wgNM0SPMS46kjdIfObxqK00T6zt7I6eCaoAgvF6JGwDXsAxtwkr09pZLn-PWHVH3CjkdDShuNCfiAaJHZ318v7SF4Nd55cXfcajOJkDOnnG_1JH4y0dVHX8g8oTEt3iKkqOQUmX5drJ61EyVh0A20b3mv2oIzgMHhEfhhtmca1CmFxkzO1KvU1HfHdsLBYFd-JTPVs1eUgYTyjTADBeClK52TgGI_19c0ytlgWjsxSBzS7Hx38uZa-DHt5z4G8NGA2qeeovorj2oHz97qnBFPGYcXl2N9QwWAs38acW3MzqIlVhwIN2S9Bg57AHjngiIA-kZjp_1ciNJm3aiijVrs1EW53Zv23T5-3ZK0F5zxucqt4KeW3hxnrCT5jDhBnFHzxAD2Ev8M6sUzJIoHQ_1S9odzYbv5OqXlf2LJ-svi4mveVlYQrO50mRdAkqfXqbAO-l4MWvyMai4gmWec8DkZWTI3nXEarYxMjR1Nwsskgcxt3gH46kUqfbXjKZzvzVNAAhDvnDyYoxYEJi26MLKq8-MpERdflK8fYklya-iVrNjWEJrqZDrkay-UUbWqQayyUM0dYLJ7R8M8cwTxU4MOUA9d_1ZsFd4-2jljbyD0_1GJyw3P21RvVe7wH8Mzet3PrxB3o-KmIHi5Nta2M0yaeiQlPQn4yZDVBfKsH7-UlF-mJmELADqZZ-Mu9cDODjEVXqLAN5bHpIkjGvB07eemUlJkpk6xEjss33lZYcn2EqRQ0vIZ8WRSQ_1J1ISxoRhJKBL02DcEs0-CxBbb0rni4yXeqnc8WBXmUH65ct2ee_1b36VVStGWOVneUPDMuw8DlOCsFBWMoJwGnQdEpISge5YLa5_1hrA4hFY3-PoMRho7oqidDaNRQ8UtsFy5xFNkWXr_16ExrsPeehfBCFaj4P8aYa_17XyVfPP8isLMx3k4GSkFbT5TWC46cGvhpT3UyLjbK8edIGuEN1fS8AH1u56Q9i8vP0NossG_1Aoz1antZq3t3vMs-BOPKWHZDlshkws0RRvyX58rlk6xR887WdN8bHJYDVTqBdW_1exFg-rVXlW4FgTjJUIjO3yWAe660NiP4JK54iKMWmO7Gf-16Letg8HgjBcgDcJBNiNATFPJzXksD4rX7OiXrz2uVHRRywh4WBTYSFsgJRDNuiw3ce-OoG7lu5vffNJHt-IbjVndByLj43xumZjEERe4nae13rCtX0wWVh00ig&num=10&hl=en&bih=1068&biw=1814

[Pookapotamus]

Any intelligent answers out there?


And steve you better be nice or I wont weld up your fender! 

[Knox]

Hey I tried to be helpful

But seriously that part has a 50 cast in it, so if it had been bored recently then I'd assume that part should look newer which it doesn't so I have no idea.

[The Machinist]

All 2.5 and 4.0 pistons have a 50 cast in to the piston.  Can't see the pic from my bb but you'll need to measure the bore.  It is very unusual to take one of these apart and not have to re-bore it.

[The Machinist]

Ok, most of them do.  50 is not the oversize.

[Pookapotamus]

thanks jamie, i measured them today and they are all 3.875" just what the book says they should be. And i have figured out that the letters on the side are most likely from the factory when they were installing the pistons. so... now i am contemplating having the block bored!

any one recomend a good shop to have this done?

[tubby]

any one recomend a good shop to have this done?

Jamey only recommended Precise Engine Rebuilders when he couldn't do the job himself. They have a lot of experience with the Jeep 4.0

[JENSSEN]

Jamey only recommended Precise Engine Rebuilders when he couldn't do the job himself. They have a lot of experience with the Jeep 4.0

They did some headwork on the big jeep, great price, very fast and great customer service I would highly recommend them. Now that being said does the block need to be bored?

[The Machinist]

Yes, I would take it to precise.  They still have a 4.6 stroker short block kicking around there from over a year ago, might be worth looking in to.  Are the pistons scored on the skirts?  Check the clearance from the skirt to the bore, if it is more than a few thou I'd rebore it.

[Uboatcmdr]

Stroker?   

[cLAY]

Stock crank gets replaced with one that has more offset on the piston rod journals thus causing the piston to go farther up and down, increasing the stroke.  Increasing the stroke effectivly gives you more cylinder volume thus more power. Stroker. Combining this with boring out the cylinder takes a 4.0L to 4.6L. With the right cam,intake,exhaust and injectors you can then go out a make fun of stock 5.0 Mustangs and Grand Cherokees.   

[w squared]

Combining this with boring out the cylinder takes a 4.0L to 4.6L. With the right cam,intake,exhaust and injectors you can then go out a make fun of stock 5.0 Mustangs and Grand Cherokees.   

Don't you go putting fanciful idee-ers in that innocent pookapotamus head now Clay. That's just plain durn mean.