Repair? Rebuild? Or Replace 1988/89 2.6 L Power Ram 50 4X4 MT

[Soular]

200K+ miles, The old boy is struggling, It runs like the proverbial...

My main questions Are:

1. Should I pay 1700 and just get a 'new' motor and call it a day?
2. Should I have the machine shoppe do this head job and Pray to Carb that All is well?
3. Can I swap a more powerful Later year MightyMax/Ram50 motor in to the frame an mount it up to the 4x4 Trans? Getting the best of both worlds with a new Engine and New Power (Can a 90's era V6 4x4 fit in to an 89' 4x4?)

I mean the truck is an absolute bad ass. So I want to keep it as long as I walk this Earth.
I appropriate any feedback and guidance on this matter. - Thank You All!

Original Plan
I think I have burn exhaust values and was planing to have the machine shoppe fix all that to see if if the Truck gets back its strength and puts out another 200k miles..

The Value and Head job is 700$ installed which I think is fair (I could do this myself but I have way too many project going so ...)

Issues
Backfiring
No Power
The Truck Bleeds Oil like its been stabbed in the belly (poor thing)
I can hear coolant bubbling into the overflow after a drive
Engine Sounds Rough
Needs a new Exhaust system as everything past the cat has rusted through
(That was next on the to-do list before the other issues started)

Background (long)
Installed /Low Psi Epump and weber carb
Installed New Plugs New Wires New Distributor
Installed New Starter

The truck drove tops for a good while until it started to whistle.. turn out I need to
apply Thread lock to the carb bolts... so it started to leak air. I had been driving it a while like this because I
could not figure it out. Until one day it decided to not start.

I replaced the Plug wires and Distributor after I fixed the Carb because the truck was now very
low on power.

It starting backfiring violently through the carb so much so it has burned a hole thru the air filter foam.
The back fire stops when the engine comes up to full temp (I fear in the winter time this process will be brutal if not addressed)

It's getting harder to start as the starts are weak... almost like starting an prop driven airplane... it just stumbles as the starter spins it to life and then weakly fires. As stated it backfires through the carb and has no power until the engine comes up to operating temps.

After that 60mph to 65mph (and that's pushing it) is my max speed available (That may be gearing limits though)
Hills are a struggle without some creative gear shift action. The Truck is dying.


Added the pics here as well:

[tortron]

you are going to want to get the head checked for softness and cracks before deciding to rebuild it

[Soular]

Thank you for the info.

[Soular]

Well word came back from the shoppe that the head is cracked and the block is ruined beyond repair. So... thats a wrap.
Thanks!

[B-Line]

Check the head or find another one in the junk yard. That would help minimize down time if you had a fresh one to install.

[tortron]

what was the damage to the block?

might be able to pull an engine from a junk yard for much less than the $1700 quoted (they are about 400 here)

[Soular]

The Block Damage according to the shoppe was that the cylinders where torched to a point that they could not be bored to stock size.
I have not picked up the truck yet.. so I have not seen the damage I did ... but I drove the truck knowing that it something was not right... I mean like for 10 month or more off and on (so I murdered the poor thing... )

I found a motor from a 89 MT 2.6l 650 shipped so... I just need to make sure the shoppe puts on my weber and all the goodies I had on the old engine...

So far I am in for $800+ ($200 for the shoppe so far... not sure what they will charge to drop in the engine just yet.)
$605 for the engine...

Gosh I do hope it fits, the truck had an engine from an 86 in it according to the lady that sold it to me. She said she put it in a few years back like 2010 or so. So it had a engine from a year back now it will get a engine 2 years older... hopefully all MT 2.6L mate up to the transmissions... Fingers cross that she did not pull out the the wide block stuff for narrow block stuff...

I do have a 6 bolt 4G63T sitting around that I got for my 2G Eclipse should the 7 Bolt's crank decide to take a walk.
but for now fingers are crossed!!

Thanks all!

what was the damage to the block?

might be able to pull an engine from a junk yard for much less than the $1700 quoted (they are about 400 here)

[claych]

what was the damage to the block?

soluar , pictures please !! Thank You

[Soular]

Will do!! Once I get it back from the shoppe give me a few days and I will have a full post mortem

[85Ram50]

Get a price for sleeving the bores from the shop, it might be cheaper than another used motor. With sleeves you've basically got new cylinders. If you did not know they make steel sleeves to line old cylinders that cannot be ground any longer.

[Soular]

Dang it ... I did not know that!!?

Well the motor is in transit now. What I will do is keep that block if it can be repaired... I will post pictures and get opinions.

Thanks again for all the good info!

[geezer101]

Not meaning to get up on the pew so to speak, but you need to start wrenching. You'll save money (from some to a LOT), you'll get to know your truck and you'll learn sumpin' along the way. The D50/MM is a relatively simple beast to work on and being a rear wheel drive you actually can get your hands down either side of the block to reach stuff. It's annoying that some Mitsubishi second gen engines suffered from crankwalk, so going back to a 1G will make it tough

I have found a few online articles about 2G crank failure and some have gone into depth about what is eating thrust bearings in them. This one is a good write up on theory and diagnosis -

https://magnusmotorsports.com/crankwalk-theory/

[Soular]

I do most of my own work... my problem is that I have way too many projects in the works..
I could not take on another. 2 second gen Eclipse (420A and 4G63T) a VW Karmann Ghia and a G35 Coupe keep me busy.

So I decided to let the shoppe knock this out for me. Old Cars man old cars...

[SubGothius]

It's annoying that some Mitsubishi second gen engines suffered from crankwalk, so going back to a 1G will make it tough

I have found a few online articles about 2G crank failure and some have gone into depth about what is eating thrust bearings in them. This one is a good write up on theory and diagnosis -

https://magnusmotorsports.com/crankwalk-theory/

The Mitsu crank walk issue was all about 2nd-gen DSM coupes (Eclipse/Talon), no relation to 2nd-gen trucks, and the affected engines were 7-bolt 4G63Ts never fitted to any trucks as factory equipment. Granted, any engine can develop crank walk, and doubtless some other Mitsu engines have, but the notoriously prevalent issue affected that particular engine built at the US DSM factory.

[geezer101]

The Mitsu crank walk issue was all about 2nd-gen DSM coupes (Eclipse/Talon), no relation to 2nd-gen trucks, and the affected engines were 7-bolt 4G63Ts never fitted to any trucks as factory equipment. Granted, any engine can develop crank walk, and doubtless some other Mitsu engines have, but the notoriously prevalent issue affected that particular engine built at the US DSM factory.

Yeah, I know it was directly in relation to DSM engines (but not limited to). That's why guys get confused about 1G/2G - Gen 1/Gen 2 references. It would be more accurate to use 6 bolt/7 bolt references but 7 bolt cranks weren't in the equation on US market Mitsubishi trucks. As far as I can figure out, the Mitsubishi 4G6X engines don't just 'crank walk' and fail - the crank walk is the result of excessive thrust bearing wear which is a symptom of another problem (random oil pressure drops). It could be from crap maintenance, mixing mineral and synthetic oils without flushing between oil type changes, debris and junk jamming oil squirters open - the 'crank walk' isn't a predetermined design flaw.

[SubGothius]

That's why guys get confused about 1G/2G - Gen 1/Gen 2 references. It would be more accurate to use 6 bolt/7 bolt references but 7 bolt cranks weren't in the equation on US market Mitsubishi trucks.

Which is why I wanted to clarify, lest anyone get the mistaken impression that the stock engines in Gen 2 trucks were any more susceptible to crank walk than any other engine.

[Soular]

As Requested Pictures:

Rest in Peace Ol'chum:

If you want to see any more pics let me know.
Is there anything I should save from the old head or block before I send it to be melted down?


Is there anything anyone needs or wants from it as well.

Thanks.