I had bad lick of luck with my trusty montero ls, it has the 3.0 6g72 engine. the day before i left for emergency services to ny for the hurricane sandy she popped her timing belt. I am not too sure if it was a interference engine but it seemed to have bent valves as well as the engine has 226k on it, so i decided to upgrade to a newer engine.. I was only able to locate a 1997 diamante engine which on the block it says 6g74m?, the heads are bigger, but i have the 3.5 manifolds now .however the intake said it was a 3.0 but shortblock cast said it was a 6g74m. ive run into some major problems. the 4 bolt main gate is too wide for the other oil pan. and ive been thinking of using the 2 bolt main gate that holds basically the main bearings and everything in. i may not do that tho but can i install without changing the oil pan? ive already had issue with plumbing but decided to weld the pipes after cuttin them for the rear u and also supply for the heatercore on the now rear side of the block. im hoping to get away without using the old 6g72 pan as the engine is more beefy and the simple 2 bolt standard engine dont work..maybe in future ill get a set of t6 turbos but for now any suggestions from the other montero lovers that have swapped. any suggestions? never have heard of this type of swap being successful. would spacing the engine mounts from frame with block washers to lift the engine work? who knows right? well thats why i just bought a 220v welder.
the engine isnt a "bolt on" if your going the route with a diamante 4 bolt main 6g74m, shes a little different, not much same block with some differences ive noticed, ...
so heres a rundown of the things that have to be replaced with 6g72 montero parts as well as from the diamante ive done so far. bear in mind its like 27 degrees in new mexico right now and we are getting snow, ergh. i need my garage back from being turned into a man cave room ergh.
A:driveplate, and retainer. note the driveplate bolts (8 bolts)on crankshaft rear on automatics are shorter, so u have to use the shorter ones as its recess is not tapped deep.
B: rear plate in between the driveplate and block needs to be rplaced with montero one as the bolts wont fit on the lower part when u install to transmission RWD
C:sice the heads are taller u need to use 3.5 exhaust manifolds federal because u will come up short on the exhaust at the cat or at the manifold, either way if u try using the 3.0 manifolds yoyu will be short. i had this problem
D: you will have to use the air intake manifold spacer plenum that the injectors plug into off the diamante and also plug the egr intake on it or u will have a air leak and she wont run correctly with the air to fuel ratio on the 3.0 6g72 ecu. flashing is pointless and on the 6g72 it didnt have that egr feed so its like putting her back to stock.
E: use the injectors off the 6g72 as the diamante will cause issues. get aftermarker if u want to get more horse.
F: you can and have to use the montero 3.0 intake on it as the other will face the firewall from being a fwd engine.
G: engine mounts can be used however u need to use heavy duty spacers to make them correctly seat on the engine as the 6g74m's block is a bit different same tapped holes but the mounts will not sit totally flush. it wont compensate the mounts tho theyll line up u just have to add 3 washers to one between the mount and block.
H:on the diamante 6g74m the rear of the block the water plumbing is spaced more because of the bigger heads and the u pipe that connects both heads in the cooling system that also supplies the heatercore wil have to be replaced with the diamante 6g74m one. you will have to plug one hole. its where the thermostat was, other than that u can reverse the facing of one of the caps to connect to the large pipe coming from the front of the water pump on the front topside that runs to the rear on passenger side. note u will have to mod this pipe and secure it to something to keep it from flying off when under pressure. one of the other pipes on the old diamantes system is also needed. this will serve as the supply to the heatercore. if all goes will it should be water tight. i used jb stickweld and it worked. 9000psi tensel stregnth as it says.
I: you will have to replace the front crankshaft pully for belts but the timing gear is still usable. (note the engine says its a 3.0 but strangely its stamped 6g74m. you have to use the 3.5 timing belt as the heads are taller.
J: you will have to use the montero valve covers and not the diamante covers as the oil port is different as well as a few things. they are interchangeable.
K: i used clay to make a cast of the old head where the cam position sensor is behind the pully, then i used that cast to put jb weldstick in it, then on the new head 6g74m i pushed the casting on it, it lined up perfectly, and beforehand i scored the new head surface for tensil stregnth, hit it with a 3lb hammer and she wouldnt budge even after heating metal around with blowtorch a bit it didnt loosten from heating or cooling. but its temp until i rewire.
K: you have to use all the electronics from 6g72 engine, including ignition.
L: replace the cam gears on the 6g74m with the ones from the 6g72
M:you cant use the 6g74m oilpump and assembly. you will have to use the one from the 6g72 montero however it has its ports a bit different it will work, make sure to use new gasket.
N: on the diamante 6g74m's engine its distributor ran, nowever this is not a problem if you have the old heads from the coilpack ran engine the factory put a bolt on plug. guess they used the same head for sistributor and non distributor can engines so that is a 5 min job just make sure to seal it with form a gasket.

tonight im gonna try to install her without changing the oilpan, its fat in the front and longer but might just work. shes almost done, gaveup on idea of changing to a 2 bolt main, it would be too dangerous with a nice crank tensile strong engine like this.
i noticed the cams in the engine are stamped #7

i will include a list of the hp differences in them all for u guys since everyone is newbies to this
In the 6G74 engine, these are results:

#4 Cams will produce around 124fwkw
#6 Cams will produce around 130fwkw
#7 or #15 (Galant, 380, Ralliart Magna) Cams will produce around 137fwkw

The cam number can be found on the engine of the cam (on the gearbox side)

Note 6g72 cams are stamped #3
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#7 Cams are found in the 6G74 that was fitted to the Ralliart the engine =) i got also has a heavier and a nitrided, forged steel crankshaft (the original was cast iron or mild steel in the 6g72's) still I was absolutely floored when I took the oil pan off of my 74 that it was a 4 bolt main like the 6G72TT engines were.From what I understand these might be the same engines they use in the 6G74TT, this is turning into a sweet turbo project <img src="/forums/images/graemlins/cheers.gif" alt="" /> <img src="/forums/images/graemlins/butwiggle.gif" alt="" /> <img src="/forums/images/graemlins/nana.gif" alt="" /> <img src="/forums/images/graemlins/evil.gif" alt="" />

6g74 is a 3.5. 6g75 is a 3.8. I think you have the 3.5 sohc 24v motor. The block should be 19mm taller than a 3.0.

FWIW, the 6g72 is NOT an interference motor. I think you are going to find that there's interference with the crossmemember and the pan. There is with the 3.5 dohc rwd motor and the pan.

SRTNate is in the process of doing such a swap (dohc 3.5 into a gen1), but I haven't seen him post in a while on it. I think he's busy playing with remote control helicopter drones

the interference on the crossmember is apparent i ran into that a hr ago, im now in process of having my buddy cut some metal slabs to space the engine mounts and trans mounts to lift her up. the engine said it was a 3.0 tho on the intake manifold from the diamante. im confused, but hell if its a 3.5 maybe i can get that part for the rear cooling system. ive already modded the orig. so far shes going well but only time will tell in a few hours. thx for the info i need it this thing is driving me nutz

If the block is taller, it's either a 3.5 or 3.8...

i measured the block from the 6g72 and also the block from the 6g74m, its same from the end where the pan hits to the top of the short block. i also removed a head bolt from both and the new one is longer, from the marks on it where the head hits the block and the head gasket are longer i need to get a micrometer, as well as look up some serials on it asap i would be extremely happy to find out its a 3.8 but i can wish even if its a 3.5, hell ill just be happy when shes in, i have it on cherry picker now just taking a small steak and beer break, but the heads are larger strangely enough and both motors are dohc. this thing is hiding something, i had the cell number from the guy i got it from, it was already removed from the vehicle it was in and he said it was a diamante but it has 3.0 on the intake manifold from the diamante, someone mighta done work to the other car but it only had 41k on it supposedly a grandmas ride that was rear ended. shes getting bolted in right now. ill post what happens <img src="/forums/images/graemlins/scared.gif" alt="" />

just hit a problem, the torque converter isnt sitting far enough out from the crankshaft, crankshaft is shorter somehow, not by a large amount, like maybe 4-8 mm but that means alot when u got transmission fluid pressure running, but im gonna figure out how to space it more, maybe use the retainer from the other engine, i wondered why i had to use shorter bolts from this engine and not the ones from the 6g72 for the driveplate. the engine that this was off was a standard tho, i hope this is the last bump but she fit in there, only have like 4 bolts in the engine to transmission,hit the starter and held it down and had a buddy thats drinking and helping me watch for anything bad as well as listen to the valve train and put in some marvel mystery to lube her up since she hadnt been started in so long and is bone dry. wasnt a good surprise when red trans fluid was coming from the bell housing. this damn things going in tonight. its snowing tonight and i aint playing tomorrow in the snow with it lol unless its running anarchy kicking up mud and grass and dirt from the neighbors front yards <img src="/forums/images/graemlins/evil.gif" alt="" />

just hit a problem, the torque converter isnt sitting far enough out from the crankshaft, crankshaft is shorter somehow, not by a large amount, like maybe 4-8 mm but that means alot when u got transmission fluid pressure running, but im gonna figure out how to space it more, maybe use the retainer from the other engine, i wondered why i had to use shorter bolts from this engine and not the ones from the 6g72 for the driveplate. the engine that this was off was a standard tho, i hope this is the last bump but she fit in there, only have like 4 bolts in the engine to transmission,hit the starter and held it down and had a buddy thats drinking and helping me watch for anything bad as well as listen to the valve train and put in some marvel mystery to lube her up since she hadnt been started in so long and is bone dry. wasnt a good surprise when red trans fluid was coming from the bell housing. this damn things going in tonight. its snowing tonight and i aint playing tomorrow in the snow with it lol unless its running anarchy kicking up mud and grass and dirt and getting xmas lights hung up on the bumper from the neighbors front yards jk, i just want to get it done <img src="/forums/images/graemlins/mrt.gif" alt="" />

decided to give up for the night people. i need to get a new seal for the transmission also some things from early tomorrow, my vacation is almost done. for anyone who needs some parts ill be parting out the old engine, also i have a spare transfer case from a montero ls 1994, also may be parting out my other montero sr. anyone whos interested lemme know, i also have new arm rests for rear bench w cup holder, a new turn signal switch and also cruise control etc, both sides as one unit, and side mirrors as well as a spare metal cattleguard from a 1995. i have one but its got mount for wench so other is just standard front end protection. also have extra set of front headlights and also have interior center bezel that has alternator, oil pressure and inclinometer im going to post pics of all work done so far as well as parts and my 1995 montero sr i am parting out or selling as a whole. she starts but there is a clunking in engine, she builds normal oil pressure as well as idles fine

she lives. it wasnt as bad as i thought, posting from phone but other than a little valve chatter its running good, lost low end but damn it leaps now from mid to high range, bit hard on the transmission tho. <img src="/forums/images/graemlins/cheers.gif" alt="" />