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If you had a rod knock, what would you do?


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As the title states, I've got rod knock and want to know what you guys would do. Others' opinions are always nice when debating options.

My options right now are:

Sell it

Drop in a used/rebuilt 4.0

Drop in a 4.6 stroker

Mod a 5.3 in

Mod a 4bta Cummins in

or...?

 

All of these, (except maybe the 4.0) will include the obligatory paint, lift, axles, and wheels. :thumbsup:

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for now, drop in a used 4.0 so you can get your ducks in a row for a bigger build.

Unless you have another car to drive while its down.. then the skies the limit.

 

Use your rod knock motor as the base for the stroker build since it will be out and sitting there anyways.

Can do the 4.2 also, don't always have to go 4.6. I mean... at 225 ft lbs of torque our stock motor isnt exactly lagging...lol.

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for now, drop in a used 4.0 so you can get your ducks in a row for a bigger build.

Unless you have another car to drive while its down.. then the skies the limit.

Transportation would obviously come first. I'd arrange it with parents' cars and carpooling to work with my best friend. Or maybe buying a cheap commuter. It's all up in the air atm.

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Well IF you can get a bread truck to snipe everything from, you can do it for cheap, but the issue is how much torque it makes. Youll need beast axles and Tcase to use all the power. (as in atlas and 14 bolts)

Prob have to reinforce the entire front of the truck, and then getting it up and running with all the bells and whistles.. its not a cheap endeavor... to put it lightly.

Not that ive done it, but i do have friends who have done it to their full sized chevy trucks, and it is no joke.

The path of a baller, for sure.

 

With as bad @$$ as our stock engine is, and the truck was made for it, i don't see any reason to do a 4bt other than to say 2 things... A i have more power and torque than i could ever use and i like to $#!& parts out the back often... and B my dick drags behind me on the ground. lol

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just a heads up, a 4bt swap will cost you upwards of $20,000, just to be driveable.

:eek: Where the hell do you get that estimate? I was estimating 5-6k doing all the work myself

 

4bt swap forums, you need a minimum of 4.5in of lift just to clear the oil pan and have stock suspension travel. tons of mods to get the engine itself to fit, and an engine alone usually costs around $2500. iirc, just getting the engine to fit in the bay is roughly 8000 in labor/parts. thats just making it fit right. and parts are god awful expensive. example being the injection pump is ~4000

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you have listed some very differnet options there... some easy and practical to some not. If you were to do a cummins or a 5.3 Id say only do it if you REALLY REALLY want it. It isn't that practical, yeah its cool but not practical unless its a purpose built rig. It sounds like yours is you DD? without having a second vehicle I would stay away from doing such a long drawn out detailed swap. Id drive your truck till she blows and have a used 4.0 on hand. once you get it going back again id say start saving and building for your stroker... thats just what i would do. but I enjoy reading builds so go crazy! :wrench:

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Id drive your truck till she blows and have a used 4.0 on hand. once you get it going back again id say start saving and building for your stroker... thats just what i would do.

:agree:

I would not attempt to do any lavish motor swap in my only DD. It will never go as easy as it should and problems will always sneak up and get you. Now, if you have another DD and can live without your MJ for quite some time, go for the 4bt.

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I'd ignore the knock and drive it til it dies. :yes: then swap in a junkyard block. There's no telling how long the old Jeep engines can go. it might never die on you. :dunno:

:agree: them things are tough as nails. You could get another 100k out of it with a knock. I have a cherokee with a knock and havent once thought about replacing the motor. Its kind of a f-it til it dies thought, but seems to run good enough.

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Used 4.0. They are a dime a dozen compared to most other engines and WAY cheaper than the other options you list. It can be done in a day when most of the swaps, despite one's best laid plans, often stretch into a years or more or more or more...

 

Are you SURE it is a rod knock? I have personally seen 4.0's ( and heard of several others) that the owner said had an engine knock when in fact a converter bolt had backed out and was hitting the block at every revolution. A long shot especially as you have a stick instead of the auto but worth checking....?

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I'm not positive it's a knock, I plan to take it to a machine shop to make sure. Either way, I plan on rebuilding or replacing just because of the shape it's in now.

 

Stuck between a ls1 or stroking it. Both are pricy, but a stroker would be a hell of a lot easier.

 

Thanks for all the input Thus far guys. :)

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I saw on YouTube where a guy had a knock after a few seconds from starting it.. he found out that it was a cracked head in the #3 and #4 cylinder.. I can't remember the name of it but it was a green 97-01 Cherokee

 

Very helpful video

 

Goodluck

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probably a 2000 or 2001 for the cracked head. the redesigned heads they used for the coil-on-plug assembly is known for cracking, but they corrected the problem in 2002 from what i've been finding. but reguardless, your truck probably doesn't have a cracked head, that's pretty rare for the 4.0s in MJs.

 

to answer your question, i'd get a "core" 4.0 used, one that might also have a rod knock but still ran decent. rebuild it into a 4.6, pack it with some oil to keep it from rusting and bag it in plastic until you need it, then swap when your 4.0 goes.

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Pete: It has a "rod knock" took it to a local shop and that's what they said. As well as tons of blowby and leaking oil assumably from multiple places.

 

Mountain: I was looking at those as well. Rather cheap. Debating if it's worth the money to stroke it, or pull a cheap ls1 and rebuild it.

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don't get me wrong, if you're set on replacing it, go right ahead. :thumbsup: I'm just saying that with the 4.0: blow-by is normally an easy fix, oil leaks are usually an easy fix, and rod knock is usually just another noise. if it makes good power, then I'd run it. :D the 4.0 in my 88 has been starved of oil twice, overheated severely twice, has horrible blow-by, lifter tick and other noises, dirties the oil so fast it needs to be changed inside of 3k, had 200k+ miles and then I drove from MI to Utah and back to go wheeling. :yes: they just aren't like most engines out there. they are tough ol' buggers. comanche.gif

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well dedaw.. my advice is to pop in another 4.0 now/asap and then set to doing the LS1 or other custom conversion over time.

So you have a car while you scheme the new setup.

Cause an LS1 isnt just going to fall into place like another 4.0 will. lol.

 

OR.. i don't know about you but in my area... cherokees are like ritz crackers. Everyone has or has had one. They are for sale everywhere for as low as 400 on up to another ultra low of 1200.

You could buy a whole nother jeep to drive while you "build" this one.

Thats my plan, I'm gonna buy a chero and beat the $#!& out of that. Keeping my nice LWB manche in the minty condition its in.

It will end up being VERY capable, but i won't cave the whole truck in like i would a dime a dozen cherokee. I just don't see hurting such a nice truck to go wheelin super hard.

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My options right now are:

Sell it

Drop in a used/rebuilt 4.0

Drop in a 4.6 stroker

Mod a 5.3 in

Mod a 4bta Cummins in

or...?

I vote "or."

 

The simple option you omitted is to drop the pan and install new bearings. Getting the pan off the first time is a nuisance but, overall, this is an easy fix. Do the rods and mains, and the rear main seal all at the same time.

 

That will resolve the knock and probably help with the oil leaks -- then you can buy that used 4.0L and build it up as your stroker. You should be able to do the bearings with the engine in place over a weekend.

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