3.0L Mits engine swap

I have an 87 1/2 Caravan with one of the very first 3.0L Mitsubishi
engines.
At 130K highway miles I have finally been bit by the slipping exhaust
valve guide gremlin.
I'm off the line like a fully loaded cement mixer but can maintain 60
MPH on the flat, more downhill when I get going! Now it's parked and I
must make repairs.
NO smoke out the tail pipe. I have already been bit by the harmonic
balancer removing the key and keyway from the crank. I had to machine a
colet to hold the balancer on the crank. (it may never come off)
The van looks NEW Great paint perfect inside always garaged so I think
it's worth a DIY repair.
It seems this engine had many faults the first few years then was a
real winner. The punchline is if I wanted to swap the entire engine
with say a 96-2000 engine what problems would I have? My dad has a 97
Caravan and I was looking it over and his 3.0L looks the same. Except
the intake plenum is a little lower for hood clearance. So I may try
and find a 3.0L from a salvalge yard.

old computer should work fine. I only question the fuel injector wiring
/ interface though. I have all the factory shop manuals and the pull is
out the hood on these early models. Soooo it seems to me the entire
engine swap may be a lot less trouble than replacing the heads plus I
can change the timing belt on the new engine before I install it.
Anyone done this before? Will this job require me to purchase a $50.00
bottle of Tequila about 1/2 way through? Or should I just opt for a set
of newer heads? It sure looks easy to pull the entire thing out and pop
a newer one in.
Thanks, Bill

 

Even if the nuts and bolts between engines all match up there could be
issues with different flavors of computers, sensors, fuel delivery systems,
etc. Be careful in your selection.

 

Thanks Steve,
I have read that the throttle body and fuel injectors should be moved
from the old to the new to get the new to run on the old computer.
Possibly the Distributor also. From what I can see this is the worst
case and the injectors are only swapped if the new engine has the newer
dual fire sequence type as they have a different electrical resistance.
I should also use the 87 fuel rail as it has better flow that the newer
ones.
Bill

 

A few years ago my brother and I put the engine and transmission from a
1988 caravan into a 1990 caravan (both 3.0L). There were a few
differences in the throttle body and related parts as well as a couple
of other things I don't entirely remember. In all cases when something
didn't match, we simply used the part that matched the van I was going
to be driving. I'm pretty sure that the basic engine is the same under
all the accessories. In the end this was a very dependable vehicle with
no problems. This was the opposite of what you plan to do. I put an
older engine into a newer van.

If something doesn't look right, maybe you should stick with an engine
closer to the correct year. There may not be any problems at all with
the engines that are ten years off, but I would feel more comfortable
not going past 1990. One of those years around 1990 the computer was
changed to a newer model with twice as many wires. You can look at vans
in the junkyard to see when they changed.

 

Thanks Robbie,
I worked on it today and my balancer fix was so good it just won't come
off.
So I feel a bone yard 3.0L is the way to go.
I have all the factory manuals including the classroom controls manual
for this 87 engine.
It looks like if I put the entire 87 manifold on a newer engine I'm all
set.
The other sensors are pretty simple swaps. Oil sending and switch are
on a tree that bolts into the block. The distributor should drop in.
The older fuel injection system should work.
I guess I'll find out.
Bill

 

The basic short block (block, heads, etc) are the same. Just put your
accessories and intake on the new motor, and your set.

I would recommend getting a 94 or newer motor, as they had the most
updates to the heads.. (IIRC).

If you get a junkyard motor, it might be a good idea to freshen it up
a bit. New rings and bearings, valve job (with maybe a 30-32 degree
backcut on the valves for a little extra flow), and new gaskets....
even if you dont want to do rings and bearings, at least replace all
the gaskets...... save yourself a future headache...

Also put on a new timing belt and pulleys, water pump, water transfer
tube, and any other thing that is harder than hell to do with the
motor in the van.

Of course, you could always just drop it in, put your stuff on it and
GO!

 

....and cross your fingers!

 

Thanks for the info. I'm in Austin Texas and there seem to be many of
these around.
I found a 97 listed at a local bone yard as "fire on top" I'm going to
go look at it and see how bad the fire was seeing I'm going to replace
the intake system anyways. But a fire on an engine with Alum. heads
could be trouble. Just worried that it may have debris in the
combustion chambers. Stuff that won't come out like melted plastic that
fell down the cross flow path into the intake ports. In the past I have
used a shop vac in the spark plug hole for this kind of issue. They
also have a 98 but it was hit in the front so I have to go look at it
also. One question is will my 87 optical pick-up distributor drop into
the newer engine (valve train). I think I will need do this to make the
87 computer work as I'm sure they must have changed them in 10 years. I
plan on a new water pump and timing belt while it's on the shop floor
and easy to access.
Bill