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Blown motor, what would you do?

F

foress_89

NAXJA Forum User
Location
quebec, canada
Hi guys, new subscriber here! I've had my jeep comanche for almost a year now, roughed it up alot, dide some trails. But it's solid, for a 1986 canadian truck. I'm pretty sure I blew the motor on it, it doesn't turn anymore seized up. The oil got very very dark. I've yet to check it, I'm thinking crankshaft bearings...

Now I'm thinking, 1986 2.8L. I could take it apart and fix it ascheapaspossible. I've heard that the best you can do in these is to replace it with a crate engine 3.4L. But then I'd have to get an intake manifold and carb. And I've heard that the AX5 is not very capable and that the AX15 would be better, do you guys think a 3.4 would be too much for that AX5?

I'm screwed for the moment anyway. Can't even work on it, won't stop raining. At least it was a wonderful trail.

Give me your two cents.
 
if you are going to do a swap then you might as well just put a 4.0 and aw4 in it. if not just fix what you have for cheap and keep going. if the trans works then wait till it blows up for a swap. on a vehicle that old you might as well ride it till the wheels fall off.
 
After thinking about it, I decided to replace it with another 2.8, since otherwise well I'd have to change transfer case and tranny and costwise I won't be able to bring my boat to the river this summer!! The motor is almost out, only have to unbolt tranny and motor mounts, and I've called the scrapyards they have some 2.8s :)

If I don't fix the truck, where will I put that nice NAXJA sticker I just received? On my hyunday? yeah right.
 
Might want to widen your search to the 3.1 and 3.4 that GM put in the Camaro. While you would be stuck using the 2.8 manifold/carb/etc (unless you want to try to hook up the FI from the newer engine) the later engines have improvements in the oiling system that make them more reliable.

Just a thought. Any way around, good luck with the swap.
 
tbburg said:
Might want to widen your search to the 3.1 and 3.4 that GM put in the Camaro. While you would be stuck using the 2.8 manifold/carb/etc (unless you want to try to hook up the FI from the newer engine) the later engines have improvements in the oiling system that make them more reliable.

Just a thought. Any way around, good luck with the swap.
Click to expand...


I got a stupid question...I am the king of those...:yap:

The Camaro has the reputation as being one of the biggest POS cars to ever hit the road. Why would one want to pull its engine out and do a swap?

I am a JP subscriber and they recently had a similar article about possible engine swaps. Most of them came out of cars that should have never existed.

I plan to ask them the same question.

Not trying to be argumentative, just curious.

Boris

BTW, I watched Top Gear last night and Jeremy reported that Honda put one of its engines in I dont remember off the top of my head how many millions of cars and no one ever had a problem with it. Thats just amazing.
 
The car being a pos does not automatically makes the engine a pos. The 3.4 from the camaro is basically the same as the 2.8 except it's improved, and a little bigger. It's just that they are harder to find used in my area. I have not yet bought any motor so I'm still looking!

And as for a bigger V6 (GM) or L6(4.0), please clarify "cheap"? I'm quite picky and want to keep the truck standard, and I've heard the 4.0 does not fit very nice in the older MJ/XJ model (under 87). I think the 4.3 would have been a great motor but like I said too much money involved to change tranny and transfer case.

Unless someone here can tell me the AX5 would actually hold up on a 4.3? I've read everywhere that it wouldn't... If someone thinks it would, tell me about it.
 
I finally took my motor apart...

Picture%252520032.jpg


Picture%252520031.jpg

This, is the oil pan...

Picture%252520029.jpg


Picture%252520038.jpg


Picture%252520039.jpg


Picture%252520034.jpg


Picture%252520033.jpg


Picture%252520035.jpg


Picture%252520044.jpg



I don't feel like buying a junkyard engine for 500$, it'll be the same state or worse than mine was before I blew it... So I'm looking for a used crank and rods, or something reasonnably priced. :cry:
 
wow, smoked the bearings hard.

seriously consider the 4.0 swap, especially if you can find a donor XJ that's wrecked or something for cheap. Take all of the parts you need, scrap the rest, accomplish motor swap cheap.
 
If you poke around enough you never know what you may find. I went to Harbor Freight one day to get a floor jack and a guy had a 4.0 with AW4 attached in the back of his truck after converting to a V8. Sold the whole setup to me for 250. I rebuilt the motor and had a great inexpensive motor and the tranny is till sitting in my garage waiting to be taken away for free..
 
lol yeah I'll just scuff it and put ticker oil ;)


I've got a project in my head now, I've got an inline6 2stroke engine in my shed, for my mercury outboard... But we can't talk about that in OEM tech forum can we ;). If it get's serious I'll start a thread.
 
Personally, I would go the 4.0L/AW4 route. LOTS of them in the junkyards to be had for cheap. Parts are plentiful (and cheap), and its overall a strong combination for light to meduium duty wheeling.
 
I've decided to go the 4.0L AX15 route. I've bought a cherokee for parts, it's got everything I even have spare diffs and all that stuff, it's got a 3 inch lift too.

Does anyone have a good link to someone who has done a 4.0L swap in an older truck like mine? I've heard it might not fit perfect, I can manage but if anyone has a link or some tips!

I'm also wondering how to know what are the diffs on the jeep? I'm not sure of the exact year it says manufactured 1995 in the door.
 
I've read the pre-'87's need to swap in '87 and later front clips to obtain the additional clearance needed for the in-line 6 (4.0l).
You'll need the wiring harness out of the donor, including ECM, relays, etc. Probably need the donor's fuel tank, pump, filter, etc.
If the donor is a '95+, it's an OBD-I system, versus the older "Renix" fuel injection system; that's a plus. I don't know if the front clip off the '95 will fit the '86. Also, you may have to message the the fire-wall a bit.
I know I've read a thread discussing installing a 4.0 into a pre-'87, but don't recall were.
Do a "google" search for "jeep 4.0L" +"early xj"; try various combinations of search terms. I got this as a starter: http://www.jeepz.com/forum/jeep-performance/25390-newly-acuired-project.html
 
Last edited:
Just wanted to clarify a point in my previous post: A '95 engine control system would be OBD-I; a '96 and later would be OBD-II. I believe the first year that OBD-I capability was required by law, was 1991 (although many manufactures used "OBD-I" prior to '91). If your engine is a '91-95 Chrysler, then the OBD-I control system (ECM and sensors, etc.), would be applicable to your conversion.
 
you'll need the hood latches/core support stuff from the 4.0 Jeep. The reason the latches got moved to the corners was to make room.

You'll also note that the firewall is a touch different, you can make yours work with a BFH just fine. Jjust be sure there's enough clearance.

Other than the wiring it will pretty much just drop in. Things I would do while the motor is out:
valve cover gasket
main seals
check over the timing set
new harmonic balancer
new exhaust/intake gaskets.

all of those things are reasonably inexpensive and easy to do on a motor that's not in a Jeep.
 
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