I have been working over the last week on swapping a hyundai 3.0 into my 91 LWB Montero. I have read several other posts and thought this wouldn't be a bad swap. Especially because you can find those engines with fewer miles on them and cheaper. Everything went pretty good.
I tore the engine down to the short block and swapped over the oil pump, oil pan, and oil strainer (the main bearing assy did not have the holes machined for the two other bracing holes for the oil strainer - not a problem - I believe the it will hold with the two upper bolts in). I also swapped over the cam shafts with the drive gear for the dizzy and the alternator bracket. I grinded off the two locater pins where the A/C bracket goes on the drivers side of the engine. My biggest surprise came when installing the engine mounts. That was the largest problem.
On the drivers side there was only on hole on the block that was machined for the engine mount bracket. On the passenger side it was one hole short. I had to replace both
my motor mounts (completely fell apart when I pulled the engine). I just decided that one bolt will have to do since there was really nothing that was holding it on before. I guess I could always take it later and have it welded if it all works out. So far this is the only issue. I have yet to get it cranked though. I am now in the process of putting the engine back it. It is a bit## trying to mate the tranny and engine up. I am going to get a engine leveler and hopefully make the job a little easier. That pilot hole from the torque converter to the flywheel is unforgiving. I polished it and I am going to lube it up before trying it again.
Issues:
1: Swap over oil pump, oil pan, and oil strainer.
No holes on Main Bearing Assy for bracket on oil
strainer.
2: Grind off locating pins on Driver side of engine
Where a/c bracket goes
3: Change over fly wheel
4: Changed over alt bracket and drive gear for Dizzy
5: Only one mounting hole on drivers side for engine mount
and one hole short on passenger side for engine mount.

Sorry, I wish I would have taken pics but I was in to much of hurry to get it done. My truck has been down for about two months and I need to back on the road. It all started with a broken spark plug and then it just went down hill. Lost both back cylinders and a valve. Which probably why it was running rough to begin with and not the plugs. LOL

The reman shortblock I have in mine didn't have the hole for the oil pickup/strainer either. It's hanging on by the bolts at the oil pump. Not much leverage on it ,,,but I don't like it. I should have drill some holes.

Why did you put the Montero cams in the Hyundai engine.
Was the Hyundai distibutorless? The cams should be the same from what I've researched.

I was keeping an eye out for a Sonata engine. I didn't know about the motor mount holes not being there.
I guess you should check for hole for those brakets that bolt from the Transmission to the block.

If I wouldn't have been in such a time crunch I could have drilled and tapped the holds for the Motor mounts. The tabs are there for them they were just not machined. So it could be done pretty easily. All in all it was still a cheaper conversion. I can find a lot of Sonota engines with less than 100K on them for less than $500.00. I only paid $350 for this one which included my core charge, bcs I wanted to keep my original engine. It was also closer to where I live. The others would have been a 200 mile round trip and a day off of work to get them. It had a little over 100K on it.

a question?

clarify for me:

did you just swap over the distributor adapter housing? Or did you swap the whole camshafts over from the old montero engine? and why?

I went ahead and swapped over the Cams. Since I had to swap over the valve covers and put my lifters in and wanted to use the orginal Montero timing gear pulleys I just assumed it would be easier to just change over the whole Cam. Especially since I didn't have the tool used to hold
the pulleys in place to loosen them or tighten them.
I did finally get the egine in and mated up to the tranny yesterday. I should have it running by the weekend. I did have to have new engine mounts and just used the same ones as the 2.6L uses and they worked perfect. It is a bit of a tedious task when you are doing it by yourself.

I also found that one of the tabs for the the A/C compressor bracket was not drilled and tapped.

The engine is in and running but smoked pretty bad. I checked the compression and all the cylinders had good compression. I did this before I cranked it - so I guess
it is the valve stem seals. Probably from sitting up so
long. If it doesn't stop I will probably change them out next weekend. Still seem to have a pesky water leak from
where the tube runs into the water pump housing though. I will have to work on that later also. I need to find a new
housing.

Balkamp P/N 605-1779 ~$38. Available at NAPA. Or, Dorman P/N 902-000.

Kind of off topic. But I noticed the sonata runs a mitsu 110 AMP alternator in those years with the 3.0 SOHC. Looks kinda like the 90Amp Diamante alt that I'm running in my 89. From the pics it looks like it possible could fit a montero. I'll have to find one in the yard to investigate further.

Both of the water pump housings listed are for the cars and will not work on the Montero. It lists them as they fit, but they will not. I have all ready been down that road. Try explaining to an auto parts place that their system is wrong. I had to show them mine to make them believe me and I think they still thought I was crazy.

Yea, your probably getting the one with the big hole in the back right?