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HELP ! ! ! BLEW MY MOTOR

A

ARBOGASTER

NAXJA Forum User
Location
Cincinnati OH
Somehow my valvetrain ticking turned into something worse. I ran some seafom and later ran some ATF fluid to clean her out per some suggestions from here and now have blown a hole in the top of the piston #3. Ahh well stuff happens. . . . So I need to know what my repower options are. Do I try to save the motor and rebuild it as a stroker 4.6L. Do I trash it and get a junkyard 4.0 with less than 100k miles. What are my pro's and cons with these choices and what motor years and jeep models am I limited to with a swap. IE can I swap a 1999 4.0 from a grand Cherokee in or a 1998 4.0 from a wrangler. I can get a motor for about 600-700$ a jasper is about 2000$ and I have no idea what the stroker costs.

Thanks for the help
 
Is there any modification to the motor I should make befiore putting it in? The Jasper website said they use a different oil pump due to chronic oil pressure problems with this motor. I'd rather spend a few bucks more and get a newer engine with 60k or less but that puts me into the newer motors. I need to know what the cutoff is for the 4.0 as far as compatibility if their is one. Thanks guys keep the coments coming.
 
Get an OBD-II short block (1996 and up,) put your cylinder head on it, and drop it in. I'm fairly sure there are some mild sensor changes, but that will be addressed with the head swap anyhow, and I'm assuming you already have it off (since you mentioned a hole blown through your piston anyhow.)

There were some internal revisions due to NVH concerns made by ChryCo (and misplaced consumerism. Honestly, I like a little road and vehicle noise - if I wanted quiet, I'd have a Caddy out front!) with the most significant being the addition of the main cap girdle about 1996 or so, I think. Apart from that, the 4.0L block is externally identical from 1987 to 2007, with the only change being that the small boss on the driver's side oil sump rail going undrilled/untapped from 1991 on (since ChryCo deleted the knock sensor along with the EGR valve...)

5-90
 
I would take my time with the swap. I would get the junkyard 4.0L it would be nice if you could get it running at the junkyard to do a compression and leak down test. If not just use your best judgment and get the best looking lowest miles engine out there. Since you have the motor pulled already you might as well take you time and do it right. I would plan on a rebuild of the junk engine but if its still in really good shape just re-ring it. If you want to go the performance route now is your chance to put a new cam etc... into it since the engine is already pulled. Please don't use a NAPA head gasket or any NAPA gaskets go with OEM for all gaskets. If you have the manual transmission put a new clutch in again since you can get to it really easy now. Again don't use NAPA clutch spend the extra dough for a centerforce or OEM from dealer. Overall just do what you want but I would take my time and do it right. It will save you a lot of hassle and future problems down the road.
 
how about the motor from a '98 XJ del. to Cinnci. for $350? Has around 64,000 miles.
 
ARBOGASTER said:
Somehow my valvetrain ticking turned into something worse. I ran some seafom and later ran some ATF fluid to clean her out per some suggestions from here and now have blown a hole in the top of the piston #3. Ahh well stuff happens. . . . So I need to know what my repower options are. Do I try to save the motor and rebuild it as a stroker 4.6L. Do I trash it and get a junkyard 4.0 with less than 100k miles. What are my pro's and cons with these choices and what motor years and jeep models am I limited to with a swap. IE can I swap a 1999 4.0 from a grand Cherokee in or a 1998 4.0 from a wrangler. I can get a motor for about 600-700$ a jasper is about 2000$ and I have no idea what the stroker costs.

Thanks for the help
Click to expand...

Stroke that puppy! Once you get used to a 4.6 stroker, you'll never want to drive a 4.0 again. Depending on the parts that you use, it could cost anything between $1000 and $2000 to complete the rebuild. You'll only find out when you tear the engine down and see which parts are damaged.
Take a look at the "recipes" on my stroker page. Once you've asssessed which parts of your engine need replacing, you can start drawing up a shopping list. I'll help you.
 
5-90 said:
Apart from that, the 4.0L block is externally identical from 1987 to 2007, with the only change being that the small boss on the driver's side oil sump rail going undrilled/untapped from 1991 on (since ChryCo deleted the knock sensor along with the EGR valve...)

5-90
Click to expand...
I don't think this is accurate. I am going from pictures as I didn't have time to look at the engines at home. The 96+ has a cast in extension for the tensioner for the serpentine belt. The '03 block I have has additional changes. Two of the engine mounting bracket bosses are at different hieghts than the other blocks I had/have (88, 95, 00). The oil pressure sensor boss is towards the rear of the passenger side of the block and not on the oil filter boss. The water pump bolt pattern is different. It has one extra hole and one of the other holes isn't in the same place. Still, these changes don't prevent these blocks from being used. I modiffied the bracket and added a spacer to fit the '03 into an '88 Comanche. TO the original poster, I would stick with a 96+ block, unless you find otherwise on the serpentine belt setup. The serpentine belt setup is different between the Cherokee/Comanche, Grand Cherokee and Wrangler. Still, the different bracket should bolt onto the block.
Tom
 
Ah. If you have the blocks available to you, I'd appreciate pictures (for my own edification...)

As I recall, though - I had mentioned that it would be best to stick with an OBD-II/1996 and up block, just to simplify things.

Given that most of an engine swap's maintenance is mainly keeping track of the donor vehicle, you are quite correct that the changes should not affect anything (this from a guy who once wedged a G/N turbocharged 3.8L V6 into a Volkswagen Beetle...) but this sort of thing is nice to know...

Pictures and discussion may be referred to JeepI6Power AT yahoo DOT com, if you would be so kind. I'd always like to know more...

5-90
 
5-90,
I do have a few pictures showing the serpentine belt tensioner or lack there of. They should show the bracket bosses, but its a height issue. I don't think I have the photos of the modified bracket developed yet. I'll send the photos and any explanation I can think of. I'll see if I have any of the water pump bolt hole pattern and the oil pressure senor boss.
Tom
 
Outstanding - thank you! If, when referring to bracket heights and such, you could also include something for perspective, that would be appreciated. It doesn't have to be a ruler (although that's usually best...) but something of known and constant dimensions would also be useful - say, a 4"x6" index card, or something like that. Just a constant reference that moves from picture to picture...

5-90
 
5-90,
I sent a few pics. I had an e-mail problem notice. I took out a few pics. Let me know offline if you got one or both e-mails. It would take awhile for me to get pics of stuff. The engine is now in the vehicle. I take pics with a disposable camera and have the pics put on CD. I do remember the spacer on the passenger (distributor) side was about .915-.965 in height. I made it from a spacer of 1 to 1-1/8 diameter with a 9/16 hole through it. The other side on of the 'ears of the bracket had to be cut off and welded in the same plane(height) as one of the other ears.
Tom
 
They came over - I'm waiting for them to load in MSIE now.

Total of seven pictures, with explanatory notes in each message, yes?

What email problem were you having? Just curious - if it's attachment size, it's probably set by your IT guys (since I routinely get attachments anywhere from 1/2Mb to 10Mb in size...)

5-90
 
I get a Deamon e-mail failure. I think it was the file size as to many JPEG files. Yes, there should be 7 pics with explanations of the variations of the blocks.
Tom
 
I need to correct my information. I was looking at two '00 blocks last night and neither has the cast bosses for the tensioner. I am not sure which year they were added. I would guess '02. Sorry for any confussion.
Tom
 
Re: HELP ! ! ! BLEW MY MOTOR (Me too)

Hey guys...great info on replacement engine options. I have a slightly different twist, in that I have a 1992. Up to what year can I do a relatively easy swap? Thanks!
 
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