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4.0 ideas


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So its come time to where I need a new 4.0. Mine is knocking and miss firing (no thanks to the water that may or may not be inside :shake: )

 

So I need some options. I can go with a full rebuild but I'm not sure what all is good or not good with this motor. If I chose this way, what rebuild kits are best to use? This is a great time to upgrade should I think about having my crank shaft balanced and any after market parts added like lifters? Any and all info and what to get, and where to get it would be great!

 

I can put in a junk yard Renix 4.0 but that would be a 50/50 shot if its gonna last more then a year. Do you think this would be worth it?

 

Could go with a HO swap but don't know what all is needed in this kinda swap, any and all info on this would be great. And would this kind of swap be worth it?

 

Or I can go with a reman 4.0, If I do this what company should I get one though?

 

Thanks again for any and all info ya'll give!

 

Brandon

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I know ive talked to a place in Tampa who quoted me $2,500 be for taxes to do that but thats if I take the motor out, bring it to them and put it back in. I don't have that kinda $...

 

Btw the place was called engine lab of tampa

 

Brandon

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Stroker or rebuild, the cost will be about the same. The stroker just takes a bit more research. The Renix system responds much better to a stroker motor vs. OBDI. $2500 for parts and labor sounds about right for a long block rebuild. If you have the machine shop do a short block and you install the cam/lifters/etc you might be able to save some money, but you really need a dry shop.

 

If $2,500 is too much to swallow for a rebuild, it sounds like you need to find a used motor and stick it in. Machine work is expensive. The valvetrain components can add up real fast too.

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First thing to do is find out whats wrong with the engine you got now. Make sure a 'simple fix' won't do the job. If it is in fact toast, then find a wrecked vehicle with a 4.0 engine in it.

Look for , in preference, a rollover, tail ended, T boned. Only consider a head on if you can insure the engine isn't busted. It's best if the Jeep is still drivable or at least be able to hear it run. I just finished a project doing this. 1989 XJ with a busted engine. Nice shape so worth fixing. I got a 1996 ZJ that had been rolled for $400 and a 100mile trip. Advertised and sold the transmission and rear axle for $300. $50 for the radiator, $50 for the seats. $10 for the hood, it was heavily scratched, and $20 for the good tail light. That's $430. Swapped the engines and got a good running '89XJ. Threw the busted XJ engine in the back of the ZJ and hauled it across the scales.2,700lbs. Another $275. However if you've got deep pockets and want a new engine, any auto parts house can fix you up for $2500, plus installation. :wrench:

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Brandon

I bought a rebuild from titan motors out of Ocala last September. put it in the manche and about 3 days later drove it all the way to north Carolina.since then i've drove it back and forth between Nc and florida 4 times. i average around 75 mph on these trips.on a daily basis i drive it about 20 miles 1 way to work back and forth. I think with tax and all, i paid 1400.oo for the long block.They also have the strokers there i think they are 1000$ more.I havent had any problems with the motor at all.

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The Renix system responds much better to a stroker motor vs. OBDI.

 

Whaaaa? Please elaborate. :huh???:

Knock Sensor.

 

Obviously OBDi will work just fine with a stroker. From my research, the Renix system is more forgiving to the shade tree mechanic.

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If you are looking at purchasing a built engine, I'd highly recommened S&S Engine Reman located in Washington state.

 

www.rebuilt-auto-engines.com

 

Will cost you just under $1500 according to current prices on their website which includes shipping both ways. Few years back I restored an 85 CJ7 and purchased a rebuilt 4.2 from them. Customer service was excellent, engine was packaged extremely well and came with a new oil pump and full felpro gasket set.

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If you are looking at purchasing a built engine, I'd highly recommened S&S Engine Reman located in Washington state.

 

http://www.rebuilt-auto-engines.com

 

Will cost you just under $1500 according to current prices on their website which includes shipping both ways. Few years back I restored an 85 CJ7 and purchased a rebuilt 4.2 from them. Customer service was excellent, engine was packaged extremely well and came with a new oil pump and full felpro gasket set.

 

Great link. I'm going to save it for future reference.

 

-mel

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Knock Sensor.

 

Obviously OBDi will work just fine with a stroker. From my research, the Renix system is more forgiving to the shade tree mechanic.

 

That's a point; good feature on the Renix. But the HO computer does that now once it "learns" the settings and compensates. If it's a built stroker and out of the computer's range and still pings, bigger injectors with an adjustable fuel pressure regulator does the trick.

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I can put in a junk yard Renix 4.0 but that would be a 50/50 shot if its gonna last more then a year. Do you think this would be worth it?

 

 

Brandon

 

If budget is a big concern then I suggest looking in a reputable? :dunno: JY.

 

The 4.0 is known to run 300k miles, easy. My 87 knocks on start up, occasionally take it to 4k rpm, still hanging in there.

 

Find a motor, see if they will warranty it for any amount of time, if it smokes or knocks after install, get a different one

 

from them or get your money back.

 

In any case, a decent JY won't have a problem with letting you pull the pans to inspect the internals.

 

Lots of goo or carbon - bad, clean decent looking internals probably means regular oil changes and taken care of.

 

I think you should be able to find a decent 4.0 for 3-4 hundred $ just take your time don't buy the first one you find.

 

Do your homework, shop around, pull the pans. Your a smart kid, you'll do fine with a JY motor.

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  • 2 weeks later...

 

I can put in a junk yard Renix 4.0 but that would be a 50/50 shot if its gonna last more then a year. Do you think this would be worth it?

 

 

Brandon

 

If budget is a big concern then I suggest looking in a reputable? :dunno: JY.

 

The 4.0 is known to run 300k miles, easy. My 87 knocks on start up, occasionally take it to 4k rpm, still hanging in there.

 

Find a motor, see if they will warranty it for any amount of time, if it smokes or knocks after install, get a different one

 

from them or get your money back.

 

In any case, a decent JY won't have a problem with letting you pull the pans to inspect the internals.

 

Lots of goo or carbon - bad, clean decent looking internals probably means regular oil changes and taken care of.

 

I think you should be able to find a decent 4.0 for 3-4 hundred $ just take your time don't buy the first one you find.

 

Do your homework, shop around, pull the pans. Your a smart kid, you'll do fine with a JY motor.

 

 

Yours knocks on startup too? Mine has a rattle (I assume it's a knock) for 1-3 seconds when it starts, and then it starts to make the noise again when I get up in the 3k+ RPM range. New knock sensor did nothing - maybe the connection? Maybe just the way Renix is?

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This week ill be at scout camp all week, so I just broke down and paid the guy who's helping me make my bumpers and helping me with the 4x4 swap, to take my old one out. He's also goIng to install one for me when I get back and find one. The junk yards around here wanted 700+ for one and a 60 day warranty :ack: so I've found one Comanche for sale near here that from what I hear runs good For about $400 so I might end up choping that one up for mine. If that does not work then a guy on here pm'ed me about his 4.0 that he's taking out with in the next two weeks for his V8 swap. Either way I'll be 4x4 and driving with in the next two weeks. I'll let y'all know how every thing turns out. Thanks again

 

Brandon

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I can put in a junk yard Renix 4.0 but that would be a 50/50 shot if its gonna last more then a year. Do you think this would be worth it?

 

 

Brandon

 

If budget is a big concern then I suggest looking in a reputable? :dunno: JY.

 

The 4.0 is known to run 300k miles, easy. My 87 knocks on start up, occasionally take it to 4k rpm, still hanging in there.

 

Find a motor, see if they will warranty it for any amount of time, if it smokes or knocks after install, get a different one

 

from them or get your money back.

 

In any case, a decent JY won't have a problem with letting you pull the pans to inspect the internals.

 

Lots of goo or carbon - bad, clean decent looking internals probably means regular oil changes and taken care of.

 

I think you should be able to find a decent 4.0 for 3-4 hundred $ just take your time don't buy the first one you find.

 

Do your homework, shop around, pull the pans. Your a smart kid, you'll do fine with a JY motor.

 

 

Yours knocks on startup too? Mine has a rattle (I assume it's a knock) for 1-3 seconds when it starts, and then it starts to make the noise again when I get up in the 3k+ RPM range. New knock sensor did nothing - maybe the connection? Maybe just the way Renix is?

 

 

Pretty sure my knock on start up is from a tired rod bearing, when the oil pressure comes up it takes up the clearance and

 

the knock stops. The only reason I keep running it is because 1. it still runs well

 

2. I have it's replacement on an engine stand ready to go 3. Too many projects, too little time.

 

I think rod bearings can be replaced with the motor in the truck ,if the crank journals aren't damaged from being hammered

 

on, that's another subject in itself, IMO that is just a band-aid buying time for a worn motor.

 

 

And Brandon, $400 for a complete MJ with decent motor sounds like a gold mine for guys like us, hopefully you won't have

 

to sacrifice a rebuildable truck though.

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More Lilly then not it will be taking the parts of of my truck and put them on the "new" one. But we will have to see. There's a reason it's $400 bucks tho and when I get back to take a look at I'm sure I will find out why...

 

Brandon

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