[mmerlina]

Hey everyone, I've looked through the majority of the more recent topics on engine swaps.. but it still leaves me begging the question "what should I do?"

My jeep is basically useless right now, it just leaks every pint of oil I put into it from every possible angle.. it's 258 has just had it, it's become undrive-able because I can't keep a safe amount of oil in it.

Now I'm not afraid to get my hands dirty and I love to learn, but I am in NO way a master mechanic. I can put 2+2 together and figure out how stuff works.. but an engine swap is really intimidating me.

Does anyone have any suggestions for me here? Should I go with a newly rebuilt 258, or will I just end up with the same headaches in the end? Should I switch over to a 304? The 304 was an option for an 86 CJ7 right? So most of what I need to swap over is factory stuff?

Anyway I am really just shooting at fish in a barrel here and hoping for some expert opinion. I really don't know what's involved with swapping an engine, will I need a new tranny? Am I going to need to switch gear ratios? This is all the stuff I read but not sure if it's going to apply to me. A kick in the right direction would be a great help. I just want my jeep back.

Thanks guys

[HighCountry]

This is an ongoing discussion here... Personally, I have an 86 with the 258 and a T-176 4-Speed and am running 3.31 gears and 30" tires. Understand that I keep my 258 in 99% perfect state of tune, it is my toy and I drive my Cherokee or Suburban most of the time. That being said, the 258 has all the power I could ask for. On a level road, I can put mine in HIGH gear and let it idle along. Then I can ease in on the accelerator and it will just smoothly accelerate without a single sputter. By the way, it has the original Carter BBD 2 barrel carburetor which I prefer.

I have owned a CJ with a 304 totally stock that would break the rear tires loose on asphalt pavement and make a cloud of smoke while fishtailing madly! But in my world, a CJ is just not a 'hot rod' and I love those inline 6 cylinder engines.

Bruce

[mmerlina]

I'm with you there on the hotrod thing. I'm not looking for a racer, I'm looking for a daily driver. While I do hit the trail every now and again, not nearly as much as I'd like, it's more like dirt and rocks than steep mountains and rough terrain.

I've never owned a new 258 so the only thing I've ever seen them do is run like a tank and leak like one too. Think I should stick with the 6 (considering my knowledge of swapping here also, since logically it would require less skill)?

[wswartzwel]

How do you use your Jeep? Strictly off road? Daily driver?

I am thinking about a 304 swap in mine as well... But only because i need a little more oomph. My 258 6cyl 999 auto/.355 gears and 33.12.50's on a 4" lift will run down the interstate at 80 all day long with A/C cranked on high... unless there is a headwind or if I have my dirtbikes on the trailer..then 65mph is a struggle.
Mine has well over 90,000 miles and uses zero oil between changes... no drips in the parking lot.... I love the 258... but since mine sees some highway use as well as logging roads I am tempted to step into the never ending quest for more power.


Edit, just saw your post about how you are using yours.

[Bard]

Leaks can be fixed, just might take some time to find how they are leaking. I have fixed leaks which held for a 1/2 a day or 3 years. Depends on where and what is the cause of the leak. Sounds to me like the rear main is gone leaking that much. Some are straight forward fixes, others are a PITA.

Before you toss out the 258, do a compression test on the cylinders and see what you come up with. Most leaks can be fixed and when you do the pan seal, you can clean out the oil pump which might be a culprit.

I always liked the 258, but would probably go 4.0 which should be a direct swap with wiring and computer which should be a better DD IMO.

[Jeff5886]

Throw in a 360. In my opinion, that and the 304 are the easiest v8 swaps. And if your going to pull the 258 out; no use in throwing another 258 back in. just my 2

[mmerlina]

Originally Posted by wswartzwel

How do you use your Jeep? Strictly off road? Daily driver?

I am thinking about a 304 swap in mine as well... But only because i need a little more oomph. My 258 6cyl 999 auto/.355 gears and 33.12.50's on a 4" lift will run down the interstate at 80 all day long with A/C cranked on high... unless there is a headwind or if I have my dirtbikes on the trailer..then 65mph is a struggle.
Mine has well over 90,000 miles and uses zero oil between changes... no drips in the parking lot.... I love the 258... but since mine sees some highway use as well as logging roads I am tempted to step into the never ending quest for more power.

Edit, just saw your post about how you are using yours.

Yeah I'd classify mine as a DD. I would say 50% of the time, cause I have a 99 z28 otherwise. In the crappy winter months with snow and all, the jeep tends to get used far more often.

[mmerlina]

Originally Posted by Jeff5886

Throw in a 360. In my opinion, that and the 304 are the easiest v8 swaps. And if your going to pull the 258 out; no use in throwing another 258 back in. just my 2

Well Jeff, it's not that I don't like the motor, it works great for what I use the vehicle for. Driving to/from work at highway speeds (65 or so). The only problem I'm having is leaks.. from everywhere!

I've tried to fix the leak I have at the valve cove I don't even know how many times.. I've come to the conclusion that it's not going to stop. And it leaks right onto the manifold, so it's a nice and stinky oil burning ride everyday.

I've also spotted several leaks at the oil pan, and can't really tell if the rear main is gone because all the oil leaking at the pan is basically directed right towards that direction.

With 160k miles on the motor, how much time/effort should I spend trying to fix problem after problem? I'm just very torn between what I should do at this point. ;/

[jeepdaddy2000]

I'm with bard on this one. If you are looking to do an engine swap for a specific performance reason, that is one thing. If you have a basically sound engine that you are happy with, then fixing the leaks will be a simpler and less expensive proposition. Check to See if the PCV system is good, insure the valve cover and gasket are the right ones and are sealing properly. Many times it is easier to pull the engine and mount it on a stand. This allows you to do all the seals and gaskets as well as getting a look at the rear galley and cam plugs without having to fight the grill or lay on your back for the job.

[solitudetree]

The original 258 in my engine was at one point leaking oil badly. It turned out I needed a new valve cover. Once that was put on then the oil leak stopped.

When it was time to pull the original 258 to plan on rebuilding it, I had a used 258 put in. The problem with that was it had sat so long (18 months) that the front and rear main seals and valve cover gasket had dried out. Also, I needed a new oil pan since it had rusted out around the bottom The engine fired up with no problems but it was leaking oil badly.

Once the valve cover gasket and front/rear main seals and oil pan was replaced, no more oil leaks.

I like the 258. If you rebuild yours, I would recommend doing the 4.0 head swap (which gives you about 40 more hp) as well as the team rush upgrade.

You could also buy a remanufactured 258 and do the 4.0 head swap yourself as well.

[HighCountry]

I very much agree with the 'fix it' crowd! Many years ago, I came into an older car that had sat for about 10 years. I started it and it ran fine, but EVERYthing leaked! I pulled the engine and stripped it down to the heads and block. Replaced the Intake Gasket, Oil Pan Gasket, Timing Cover Gasket, Front Seal, Rear Seal, New Water Pump, New Thermostat, etc.,etc. I even knocked out ALL of the freeze (core) plugs and replaced them with Brass versions. When that engine went back in, it ran perfectly and was totally DRY for the three years that I drove it.

Another hint, I will use nothing but Fel-Pro Gaskets. Don't let the parts guy substitute the 'price leader' version on you, insist on Fel-Pro!

Bruce

[amcjeepman]

If I wanted to swap it would be for a 360, plenty of power typically no worse milage than the 258 and a very easy swap as swaps go. However if the only problem is oil leakes and the 6 runs fine I would just fix the leaks as the 258s are good long lasting engines.

[Keyser328]

If you are happy with it and you think it's fixable, stick with the 258... *if* you can fix it without pulling it out.

If you're going to pull the motor and strip it down, it'd make sense to do some upgrades, but before you get too far down that path, look at what you're spending and the net gain from that.


Personally, if you're going to pull the motor out anyway, put something else back in. The 258 is a stellar motor, but the version in the Jeep is plagued with some issues. Funky plumbing (die smog die), poor head design, and in my case, it's bolted to a HORRID transmission.

My plan is to find a donor chevy 4.3 out of an S10 or such, go through the engine, and stick the whole thing in Jeep. The 4.3 runs Vortec heads, uses 90% of the same accessories as a SBC (even the same mounts), and typically has fuel injection.

A used 4.3 with a 4L60E (700R updated with electronics) won't be very expensive at a yard. If you get lucky, you can get the transfer case as well and get that snazzy electronic push button on demand.

Maybe it's the geek in me, but push button 4x4 in a Jeep would be fun

[HighCountry]

Keyser, sounds like you are building a new JK with the 'mini van engine'!!! Sorry, just couldn't help myself...

Don't hit me!!!

Bruce

[Keyser328]

Pfft! Don't get me started on the JKs!

Nah, I like the 4.3 for the SBC form factor and accessories, and the Vortec design... it was good enough for the Typhoon/Syclone (=


~d-;