4.0 rebuild kits which one

[sinkrun]

Ok tired old 4.0 needs rebuilt. Wish I could swing a stoker but just can't to much $$. Sugestions on kits quailty price etc. This is a 89 4.0 any cheap performance items I could upgrade to. Not sure I want to get into a ho swap at this time was going to keep the renix???

[wolfpackjeeper]

Ok tired old 4.0 needs rebuilt. Wish I could swing a stoker but just can't to much $$. Sugestions on kits quailty price etc. This is a 89 4.0 any cheap performance items I could upgrade to. Not sure I want to get into a ho swap at this timwas going to keep the renix???

 

the stroker should only cost you about $200 over any other rebuild. The only part that is different are the crank and rods. The kits for strokers are more expensive because people do not know any better. You can piece it together much cheaper. A crank and rods from a running 4.2L, have them polished and such if you want. Everything else is stock 4.0L stuff. WHen I priced it out before I did mine the only difference was where I bought a crank and rods.

 

Of course, this was assuming that when you said rebuild you also meant bearings and piston rings. If not and you are just doing gaskets then just get a master gasket kit from advance auto.

 

edit, even if you are doing a full rebuild most of the Kits are kinda on the expensive side versus buying what you need individually.

[Geonovast]

the stroker should only cost you about $200 over any other rebuild. The only part that is different are the crank and rods. The kits for strokers are more expensive because people do not know any better. You can piece it together much cheaper. A crank and rods from a running 4.2L, have them polished and such if you want. Everything else is stock 4.0L stuff. WHen I priced it out before I did mine the only difference was where I bought a crank and rods.

 

Not entirely true... in the motor pretty much yes, but unless you get a newer YJ crank, you need to have the snout machined down about 1/4". If you're running a stroker, you also need new(larger) injectors. If he's got a BA 10/5, he's also going to need to find an AX-15. BA 10/5 will not last long behind a stroker.

 

I did just a gasket set in my 88 4.0, which was all I need.

 

Why does your motor need a rebuild? I would tear it down, and see how everything is in there before you start buying stuff up. If all you need is gaskets and new bearings, it shouldn't run you more than $200.(If you do the work yourself)

[Pete M]

Why does your motor need a rebuild? I would tear it down, and see how everything is in there before you start buying stuff up. If all you need is gaskets and new bearings, it shouldn't run you more than $200.(If you do the work yourself)

 

I was just about that ask that. What about the engine makes you think it's ready for major reconstruction?

[sinkrun]

Not sure how to post a previous link I had a quetion about motor rap a few days ago most say rebuild or rebearing. Its has lower end rattle upon start up and low oil pressure for about 30 seconds I belive its rod or bearing rattle. This has a 4.0 auto 145,000 was driven about 300 miles in two years the guy did take care of it besides not running it. I have put about 4000 miles on it changed oil twice and alot of gunk does come out when I do this. Did not make this noise for about the first 2500 miles. The head has a small oil leak the exhaust manifold is shot and with the rap or rattle in it. I thought as long as this needs done and with the rap at least rings, bearings, maybe lifters, timing chain, Oil pump. I bought this as a ocasional driver but its in such nice shape so little rust for a nothern truck and so cool to drive my 99YJ just sits most of the time. I quess i just ran it to hard to soon. Maybe its time to post a build thread and some pics. Sorry about the gramer can't spell worth a darn and tying on a lap to does not help either!

[comanchedude]

http://www.flatlanderracing.com/

[Eagle]

Not sure how to post a previous link I had a quetion about motor rap a few days ago most say rebuild or rebearing. Its has lower end rattle upon start up and low oil pressure for about 30 seconds I belive its rod or bearing rattle.

Now hold on.

 

What you are hearing may not be bearing noise, it may be lifter noise. Even if it is bearings, it can't be too serious yet. Remember that the oil is thickest when the engine is cold. Most instances of bearing rap get worse and louder after the engine warms upand the oil doesn't provide as much cushioning effect. If I'm understanding you correctly, yours goes away after less than a minute -- which suggests that it's either tired lifters that need time to pump up, or a weak oil pump that isn't pushing oil to the bearings as energetically as it should. Does it rap once it's running and you're driving it down the street? If not, you don't have a serious problem. I've driven trucks with bad rod bearings -- when warm, when you drove down the street it sounded like there were fifty little guys inside the engine, beating on it with sledge hammers.

 

A LOT of 4.0L owners just drop the pan, put in new rod and main bearings, replace the rear seal while it's open, and button it up. You could go all-out and replace the oil pump while you're in there.

 

That ought'a do 'er.

[sinkrun]

No, it quits after about 30 seconds or so. I was wandering if the bearings could be done without pulling the motor. The guy offering to do this with me helping wants to pull it and rering to I may just take him up on it. This does have alot of crud in it I was afraid to put a engine cleaner in it??? But when I change the oil it does get a little better. I am changing again tommorw with a little heavier as its getiing near summer here. I will also try adding a low draw back filter. Is a napa gold the same as a wix?

[maddzz1]

Yes, the napa gold filters are made by wix

[BootsNTrucks]

I know this is a old forum but hopefully some of you wise sages will see it and spare your $0.02

 

We hydro-locked the engine when we went through a puddle and the hose that runs from the exhaust manifold to the air box was displaced by the water. 

It appears that only the first connecting rod is broke. I have yet to pull off the oil pan and check the others because that axle makes it just frustrating. 

 

I have another 4.0 out of a '89 XJ that I picked up for cheap. We were spinning it over and it had really good compression (68-75ish) in about 50% of the cylinders and horrible (5-28ish) in the other 50%. Tore into it and discovered the bearings were shot and whole lower engine looked worn inside, top looked ok.

 

Mine was a still a decent running engine at only 194K but started to get a little tired (still could do a peelout with A/Ts and Dana 44 LSD). 

 

From what I'm reading it sounds I have several options.

 

Door #1) Rebuild Kit

Pro: Have everything I would need. Truck should run for a long time.

Con: $$$, sounds like there are a lot of parts that I am not going to need (i.e. timing kit, oil pump, freeze plugs), less power

 

Door #2) Replace crank if bent (probably not a bad idea to replace just on principal), replace connecting rods, bearings, reseal pistons,  and replacing gaskets on my way back out.

Pro: Cheap

Con: If I'm in there seems pointless not to go the whole 9 yards and just do everything. Its easier to work on engines out of the vehicle that in it. Less power

 

Door #3) Replace crank and connecting rods with ones from a 4.2, replacing gaskets on my way out.

Pro: POWER, cheaper than rebuild and stroker kits

 

Con: Issues making all of the pieces work together correctly. 

 

Door #4) Stroker Kit 

Pro: EASY POWER, pieces should have no problem working together correctly, everything I need should be there, truck should run for a long time

Con: $$$$

 

Door #5) Combine the two engines using the best of both

Pro: Possibly the cheapest option 

Con: Need to have block machined, gasket set, lower of XJ looked like it had seen its fair share of miles, gamble on how well/long this engine will run.

 

The plan before this was to wait till I graduated college in a year or so, get a job and get settled then stroker the Jeep. Now I am at the point of do I just rebuild it and then possibly in a few years tear into it and stroker it or just bite the bullet and stroker now? I guess it comes down to how much more power does a stroker really give you? I assuming that just by rebuilding I am going to see quite an improvement.

What do you guys think?

[dustyinthedirt]

SOOOOOOOOOoooooOOOOOooooo.....Anybody?  I am gonna try and reawaken this post