New engine? Son of a BEEEP!

Joopin

Joopin

Super Moderator
Well I brought my YJ to a mechanic this morning to get the rear main seal fixed he told me it would be done today around noon. I just got a call from him thinking it was finished, and the first thing he said was "you ever think about putting a new engine in this thing?"

So what happend i guess is the rear bearing is crap which caused the rear main seal to go. He also said that the jeep doesn't run like there is a bad bearing, but he said if one goes then they all go... then your engine will eventually go. So I asked him just to replace the bearing and the rear main since its all open and I will just cross my fingers

Worse case senario, I will have to put another engine in or rebuild the 4.0... but I do have a 289 I could put in it if I can find an adaptor for the transmission... so is this guy just making it out to be worse than it is? Or should I be looking for an adaptor. Is there anywhere else that sells adaptors besides advanced adaptors?
 
Well I looked into it and Novak doesn't sell the conversion plate I need. He suggested I buy a T18 transmission out of a ford truck to put in and buy an adaptor for the tcase. Advanced Adaptors said I need to get a bell housing from a f150 and a new slave cyl, master cyl, and brackets. If I go with the Advanced Adaptors option I would get to use the AX 15 which would save me money, but the Novak guy said that transmission wouldn't hold up that much longer with a V8 infront of it. Thoughts?
 

Torque kills driveline components not horsepower. When you mention the words Jeep--Swap--V8 all in the same sentence, most peoples minds are automatically filled with the image of a Chevy smallblock. There is a HUGE difference in "natural" torque production between a 3.48" stroke Chevy350 and a 2.75" stroke Ford 289. Your 4.0 puts out more torque than most factory hydraulic cammed 289s did.....really. If you aren't going to build the 289 too radically, I would trust an AX-15 behind one. Novak won't tell you that because they don't offer the kit. If you want a Ford engine in your YJ and you don't want to worry about the AX15, the early bronco would be a good place to look for a transmission and Tcase. Driver's drop, no adapters, and you KNOW that combo will handle a smallblock Ford.
 
yeah... the ax15 MAY hold up to moderate use of a v8 spinning it... but... i wouldn't go that way.... you're going to spend as much, or more, by getting an adapter plate versus getting a transmission/Tcase combo from a ford...

plus... you have a good ax15 np231 SYE and CV shaft... you can get some good bucks from that... its just too bad you put all that money into installing the sye... the combo of ax15, np231, sye, and shaft will get you AT LEAST $1000.... and i'm sure you can find a ford drivetrain for $500... which will leave you with $500 to toss around... the other way, you'll be spending money, and still have the weaker drivetrain
 
Well the 289 was rebuilt 2 summers ago and I put a 4barrel, new cam, timing chain, intake, ported... anyway its got about 280 HP and 300 ft. lbs. of torque. My transmission was rebuilt right before I bought it a year ago. So your saying this transmission will not be able to take the v8 grunt? How much torque does the 4.0 push out?

If I do go with a different transmission and engine both from ford that will probably lengthen my driveline by tons. Like you said snitty I could probably get some good money for my existing driveline, but that is a project I can't even fathom since I just did all that work.

Advanced adaptors said they have a the thing i need for 270 and this other company Z and M has the rest of what I need for this exact swap that is 800 bucks. So... who knows
 

The AX15 is marginal for that kind of HP, it may work, MAY. I'd suggest swapping in a transmission built for a v8.

Having said all that, I used the Peugeot BA10/5 behind the 350 I put in my '88 YJ, no problems. ANd you hear all the bad things about the Peugeot :roll:
 
Oh shoot, I was wrong earlier. A 289 has a 2.87" stroke not 2.75".

What engine combo are you running on that 289? And at what rpm do those peak numbers occur? If that 289 is making a 300# peak, then considering the narrow torque curve and the rpm required to do it in a 289, then your 4.0 is probably making as much or more torque in the rpm ranges that you would actually drive the Jeep. You could tear up the AX15 pretty easily with your 289, but making it live wouldn't be hard. I wouldn't do it, although there are lots of guys running them behind stroked 4.0s without problems. A properly matched 4.5-4.7 stroker just flat out eclipses a Ford 289 in torque production.
 
Those #s are around 5500 RPM... so the peak torque does occur later than the 4.0s peak. I've never heard of a 4.0 stroker, sounds like an idea. If I had a garage I would do it.

I guess I'm kinda jumping the gun right now though, I don't even know when the engine is going to crap out... it is still running and I am just going on the word of the mechanic I brought it to. I am picking it up today and hes gonna show me the fried bearing. That should give me some idea.
 

Brown Mountain ORV

the 4.0 stroker has been discussed here a few times... i've looked into it quite a bit.. if you think you might be looking toward that... lemme know
 
Why Snitty, do you know how to do it? I know a guy that could rebuild the enine and stroke it out for about a grand... whats the specs on a stroked 4.0?
 
yeah.... its pretty straight forward... its a basic rebuild, but using parts from a 258.... don't go 4.7... go 4.6 at most... that leaves some cylinder wall for future rebuilds
 

Stalled and I can't get up

hey im doing a 4.0 stroker everything is the same other than the crank, rods and pistons, the crank and rods are from a 4.2 and the pistons are aftermarket, bore it .030 to make a 4.6 and .060 to make a 4.6..
im going .030 and domed pistons with a big cam. iv read from plenty of mags and articals on the net that they can produce up to 300 horses, everything shoule be also strengthened to hold the power.
im planing to do a 4.6 thats .030 over milled heads domed pistons and a full roller cam. high volume oil pump with an oil cooler, aftermarket throttle body spacer with an after market throttle body and cold air pipes going to a snorkel.. with that a fully tuned exhaust.. im planing to peak out around 250 horses to the ground....
 
careful with your compression, there... and... while it is out... if you want some more torque... get yourself an inertia ring made.. just a ring of heavy metal around the block side of your flywheel to keep momentum going... less acceleration... but WAY more momentum/torque for low speed crawling, and coasting
 
hey jeepin916, you said everything needs to be stronger to handle the stroker, what are you doing to the Ax15? Or are you going with something else?
 

There are several different ways to build a stroker, and probably even more thought up on a regular basis. Custom machining makes anything possible, well anything within reason that is. The 258 crank and rods with a 242 piston will leave the piston too far down in the bore(.020"-.022") in a 242 block at TDC. This kills the effective quench area and disrupts a clean burn in the combustion chamber. Custom pistons with a lowered pin hole will fix that problem, but so will decking the block although that will raise compression. Domed pistons with shaved heads and a high lift cam will require some massaging to avoid valve to piston interference(not good!).

Jeepin916-- Are you using custom pistons made for the stroker or are you using domed pistons made for a 4.0? With domed 4.0 pistons, you still have the piston too far down in the bore and the dome will only compound quench problems. It would still outperform the 4.2 or the 4.0, but it won't be one of those 300hp+ units you have seen. You sound like you know what you're doing, so I'm not questioning you, I'm just curious. What roller cam are you going with?
 
Well it looks like the 4.0 will last a little longer... for now. I went and picked it up yesterday, and it seems to be running fine if not better than it used to. The guy showed me the bearing (it was toast!) and he said I should just keep an eye out for anther rear main leak, drop in pressure, or a knocking toward the back of the engine. When that stuff starts happening then its time to throw in a new engine. I think I am going to go with the 289 though, I will just have to find a new transmission and shorten the driveshaft. To build a 4.0 stroker would be too much money for me and stupid since I have a brand new 289 waiting to be beat on.
 
That's what I would do too, since you already have the 289. Really though, I know you have put alot of time and money in your NP231 but a C4 automatic and Dana20 transfer case from a first generation Bronco would save you some money if you can find one. The Ford version of the Dana/Spicer20 tcase has something like a 2.46:1 low range and it has a drivers side drop. The C4 is about as compact as you could ask an auto transmission to be. All you will need are some mounts, no adapters, and after all the other work you have done I'm sure you could handle fabbing some mounts. The manuals used in the Broncos are good too. A fullsize Ford transmission/tcase will work too, but unless you go with a newer model aluminum tcase you will suffer the unneeded weight penalty and crappy low range of the NP205.
 

Well if I were to go with a C4 I have one of those that I rebuilt too, but I want a stick in my jeep, I was thinking of just getting an adaptor for the tcase though since I did put that sye on it, not to mention using the np231 with an adaptor is pretty common. If I do find a deal on a tcase with the transmission with a fixed yoke I will have to spring on it, like you said, it would be nice to have no adaptors at all. At least the 4.0 is still running and giving me time to find all this stuff... thanks for the info people!
Joop
 
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