Is the 2.8l really that bad?

[omega_rugal]

On 4/1/2020 at 8:37 PM, Pete M said:

there is a running hypothesis that Jeep got... lesser castings.  just a rumor though.

 

they probably did, make the competition look bad... like the v8 ZJs getting a goods trans while the 4.0 got a $#!&ty one, that way the 4.0 ones would get a bad rep so the customer will get the v8 instead...

[cruiser54]

On 4/1/2020 at 7:37 PM, Pete M said:

there is a running hypothesis that Jeep got... lesser castings.  just a rumor though.

 

Nah. I lived through that era.

both GM and AMC got the same engines.

The issues were with 2 things. Both oil leaks.

Rear main seal was frickin rope!! Like old days.

They eventually changed that in production.

The other was the back of the intake manifold leaking and appear to be a rear main seal.

GM never addressed it. Jeep developed a fix!!!

[Pete M]

1 minute ago, cruiser54 said:

 

Nah. I lived through that era.

both GM and AMC got the same engines.

The issues were with 2 things. Both oil leaks.

Rear main seal was frickin rope!! Like old days.

They eventually changed that in production.

The other was the back of the intake manifold leaking and appear to be a rear main seal.

GM never addressed it. Jeep developed a fix!!!

 

yeah, the other hypothesis was that all early ones sucked and GM made them better later on but Jeep no longer used it.

[AMC86Kid]

but does the 3.1 bolt up to the same tranny as the 2.8 ?

[Eagle]

16 hours ago, AMC86Kid said:

but does the 3.1 bolt up to the same tranny as the 2.8 ?

 

Yes. (Same answer I gave the first time you asked.)

 

https://en.wikipedia.org/wiki/General_Motors_60°_V6_engine

 

 

[Pete M]

14 hours ago, AMC86Kid said:

but does the 3.1 bolt up to the same tranny as the 2.8 ?

 

 

not only yes to that, but you can reuse the exhaust, intake, accessories and motor mounts.  the block is 99% the same on the outside.  

[AMC86Kid]

Nice I’ve never seen a 3.1 I wonder if anyone has done the swapped and what there thoughts on it are 

[Pete M]

should be able to find something searching the build threads   

[Eagle]

I think I remember someone in NAXJA doing a 3,1L swap "back in the day," but now? Why bother? The cost of a junkyard 3.1L is likely the same as a 3.4L so why get the smaller engine when you can get the bigger engine?

 

[cruiser54]

19 minutes ago, Eagle said:

I think I remember someone in NAXJA doing a 3,1L swap "back in the day," but now? Why bother? The cost of a junkyard 3.1L is likely the same as a 3.4L so why get the smaller engine when you can get the bigger engine?

Uh, yeah.....

 

 

[Pete M]

7 hours ago, Eagle said:

I think I remember someone in NAXJA doing a 3,1L swap "back in the day," but now? Why bother? The cost of a junkyard 3.1L is likely the same as a 3.4L so why get the smaller engine when you can get the bigger engine?

 

 

nowadays it's most likely a matter of which you can find in the junkyards or on craigslist.  mid 90s cars aren't exactly as plentiful as they used to be.

[Eagle]

1 hour ago, Pete M said:

 

nowadays it's most likely a matter of which you can find in the junkyards or on craigslist.  mid 90s cars aren't exactly as plentiful as they used to be.

 

True.

[Money_Pits]

The 3.1 was also used in other brands, like buick, making it a bit more common than the 3.4. Ignore this, I forgot those would all be fwd engines in the buicks, making them useless here.

 

Also, Isuzu had their own 3.2l and 3.5l engines with the same transmission bolt pattern as gm's, but are entirely different engines with different electrical/fuel injection. The Isuzu 3.5l has oiling problems in the cylinder since it was just an overbored 3.2l, but as long as you keep up on oil changes/watch your oil level, it doesn't seem to lead to engine failure. However, this swap isn't recommended in any way because those engines are even more rare, have no write ups that are easily found or are comprehensive, and don't provide anymore power or fuel efficiency than a 4.0l. I'm only mentioning them in case you stumble across them in your search (like I did, as I also own the 2.8l). I have personal experience with the 3.2l, as my sister owns one in a rodeo, and it is the only engine she hasn't been able to kill through neglect (and it was neglected), so I entertained the idea for the shortest of moments. If any engine you are looking at is going to require relocating the engine mounts, just go 4.0. It will likely be the easier, cheaper, and better option in the long run.

 

 

I have yet to get my Comanche up and going, so I can't comment on the 2.8ls performance or reliability.

 

[omega_rugal]

 

want a challenge?

[WesD]

Why bother?  If the 2.8 sucks, just drop a 4.0 in there, or search for a TBI setup from the S10/Blazers of that day,  grab the engine wire harness, ECM,  throttle body, fuel pump, and associated sensors and it should all fit up no problem.    Gives another few HP and a much better driving experience.    Plenty of write ups of GM TBI all over the net, I've done one conversion and it's simple.    One might have to do some wiring mods to make it work with the bulkhead connector.   There used to be aftermarket kits available just for the 2.8s, might even be able to do a Holley sniper kit or similar.     

 

The 2.8 V6 was just fine for the period it was made in.   The oil leaks Cruzer mentioned I had to address on mine.  My rear main didn't start leaking until the quick lube place overfilled the oil.     The intake seal let go some time later, again it wasn't difficult to change just a little messy.   

 

I worked with a guy who owned an 86 Comanche with the 2.8.   He was happy with it, bought it new.   

 

Heck, the later 2.8 engines with the MPFI were downright peppy (in the Beretta, 6000, Grand Am, Cavalier, Camaro, Corsica, etc).   The 2.8 then became the 3.1 which lived on til the mid 00s in the Impala/Malibu cars.

 

 

 

[Eagle]

2 hours ago, omega_rugal said:

 

want a challenge?

 

It's been done ... by one of our members.

[omega_rugal]

i wonder why no one else has done it, looks like a great swap...

[Pete M]

3 hours ago, omega_rugal said:

i wonder why no one else has done it, looks like a great swap...

 

 

Pat did a 3800 swap (thread should be in Epic Tech).  downside is he kept eating AX-5s, but the AX-15 swap should be able to handle it just fine.

[omega_rugal]

19 hours ago, Pete M said:

AX-15

 

dakota´s bellhousing?, i better start doing the list of item

[Pete M]

2 hours ago, omega_rugal said:

 

dakota´s bellhousing?, i better start doing the list of item

 

yup, you're going to need one.   car-part.com might be able to find you one if you search for a dakota 2.5L or ax-15 and then call the junkyard about the bellhousing.

[omega_rugal]

A Jeep pick up powered by a Buick engine coupled to a jeep tranny with a dodge sourced bellhousing... and with a Ford sourced 8.8 rear axle...i will call it the Frankenjeep...

[Green Mesa XJ]

That Dakota bell housing is a PITA to find, I used Hollander parts to get the Hollander parts number , 3 digest a dash then the rest of the numbers. ( example 300-05428B) . It’s in the web address when you find the right part. I’ll run that number on the ebay and other places looking for a junk yard or reseller listing it. I got lucky when somebody listed it by the mopar casting number didn’t know what it was.

You can put a lot of options place of the 2.8. 3.4 is the best option for drop in simplicity.

Part of the problems were bad carburetor and exhaust. Fix at least the carb.

Now my 2.8 I’ve beat to hell and back and it never failed, sounds crappy and the compression is not great, leaks all kinds of oil, but will not die. Probably not the original engine as it had a oil sender and temp sender meant for gauges my wagoner didn’t have, I had to put over 150k miles on the hunk of junk driving from the west back to my folks in Florida. Now that I think about it, that was kind of crazy how far and how long a road trip I would drive that Jeep. Used to take in to the desert and into the mountains any free time I had. Didn’t think a thing of it failing on the trail or the ride home. Never had that Jeep towed, didn’t have the money for one, kept some tools and a few necessities with it. Drive shaft exploded many miles from home and it drove home with a crimped fuel line and front drive shaft.
That’s my Jeep and why I bought other jeeps, still own it but hasn’t been on the road because I’m stalled doing the engine swap I intended to finish years ago, I fire it up every couple of months but the hydraulic clutch took a dump so it’s been stuck in the side drive way. Still my baby.







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[Green Mesa XJ]

Oh, some useless information about the 2.8

86 MJs have a mixed bag, in 1985 gm upgraded the heads, rear main oil seal, and crank,
Heads were used 1985-1995 , same head as a 3.4

Oil seal is a one piece rubber later gm motors got.

Crank has bigger oil journals and main bearings , I believe these main bearings are used until the end run of this block. Could be wrong.

These later 1985 block 2.8 could be rebuilt with newer parts, I want to say a 3.1 is just a stroked out 2.8 and the guts of the 3.1 engine can be swapped in to the later 2.8 block. It’ll have the same differences a 3.4 would, like internal vs external balancing. But if you’re going that far just put a 3.4 or something better in.

Here’s the catch for 1986 2.8 XJ and MJ owners, the later block would be more desirable, if any 2.8 could be considered that, but gm supplied their cars and truck first with the newest blocks and heads, so Isuzu and jeep got the left over 2.8 gm didn’t want to put in their vehicles. 1984 Jeep models got 1982-83 gm engines, 1985 models got 1983-84 and 1986 jeeps got a mixed bag of some getting 1985 improved engines.

But all this being said unless you’ve got to have a mechanical fuel pump, pull the original 2.8 out and don’t look back.



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