642B Blown Motor Question

[crash3d]

The motor in my machine blew. It is the 4G32. It is froze solid. Will a motor from an 80's Dodge Colt be a direct drop in? Motor in Colt is a 1600cc turbo'ed job. I will probably have to change the head out, and not use the turbo as I do not get the brain box with this motor. Or, can I use existing brain box? Old motor was not turbo'ed. Any info would be greatly appreciated!! Shawn

 

[crash3d]

No ideas?? Someones got to know! lol

 

[OldMachinist]

No ideas?? Someones got to know! lol

Give it some time. A lot of people work all day and don't have time to check the forum. There are a few members with 742B's and 642B's around and I believe this question has been asked before by one or more of them.
Read this post.
http://www.skidsteerforum.com/DesktopDefault.aspx?tabid=54&frmView=ShowPost&PostID=48401

 

[crash3d]

Give it some time. A lot of people work all day and don't have time to check the forum. There are a few members with 742B's and 642B's around and I believe this question has been asked before by one or more of them.
Read this post.
http://www.skidsteerforum.com/DesktopDefault.aspx?tabid=54&frmView=ShowPost&PostID=48401

Thanks for the reply! Prior to posing my question, I did do a search of the site, and came across those posts you referred to, but they don't answer my questions. They say the block is slightly different, but not what makes them different. Some parts are not the same, but will my existing external parts(starter, manifold, carb,etc) bolt on the new motor. Are the mounts the same? All kinds of questions unanswered in those forums, so I decided to pose my own question in hopes of getting a definitive answer. Thanks!

 

[jeepcreepcj]

Thanks for the reply! Prior to posing my question, I did do a search of the site, and came across those posts you referred to, but they don't answer my questions. They say the block is slightly different, but not what makes them different. Some parts are not the same, but will my existing external parts(starter, manifold, carb,etc) bolt on the new motor. Are the mounts the same? All kinds of questions unanswered in those forums, so I decided to pose my own question in hopes of getting a definitive answer. Thanks!

I first tried finding a car motor as a replacement for my 642b. I was unsuccessful in finding one as they are so old, no junkyards have them anymore. I would suspect that they would be similar as far as mounting holes in the bellhousing area and manifolds. I think the car motor may have had a balance shaft? If you can find a used running engine from a car, it would be worth attempting. It is not likely that Mitsubishi would have completely changed the block for industrial applications. Actually, when I look at the one from my bobcat, it seems unlikely that the block was changed at all. the motor mount points on the mid-sides are angled like they were meant for a rwd car chassis, and bobcat designed angled mount points to work with what was there. You would probably have to use your oil pan, sump, manifolds flywheel maybe water-pump, pulleys and other brackets for the alt and governor. Is your motor not salvageable? If you are planning on keeping the bobcat for any period of time it may be worth rebuilding instead of putting in another 25 + year old motor.

 

[crash3d]

I first tried finding a car motor as a replacement for my 642b. I was unsuccessful in finding one as they are so old, no junkyards have them anymore. I would suspect that they would be similar as far as mounting holes in the bellhousing area and manifolds. I think the car motor may have had a balance shaft? If you can find a used running engine from a car, it would be worth attempting. It is not likely that Mitsubishi would have completely changed the block for industrial applications. Actually, when I look at the one from my bobcat, it seems unlikely that the block was changed at all. the motor mount points on the mid-sides are angled like they were meant for a rwd car chassis, and bobcat designed angled mount points to work with what was there. You would probably have to use your oil pan, sump, manifolds flywheel maybe water-pump, pulleys and other brackets for the alt and governor. Is your motor not salvageable? If you are planning on keeping the bobcat for any period of time it may be worth rebuilding instead of putting in another 25 + year old motor.

Thanks for the helpful reply! I did find a motor for it, but did not want to buy it until I knew if I could make it work in the bobcat. Although it is an old motor, it only has 89K on it so it will be fine to put in there. I do intend to keep this old girl around for a long time, as I use this one in the woods for my firewood business. I like the gas engine in the woods because it will start at -25 degrees, where my diesel ones wont. Perhaps I will rebuild this engine, but that is to be worried about another time! Thanks again!

 

[crash3d]

Thanks for the helpful reply! I did find a motor for it, but did not want to buy it until I knew if I could make it work in the bobcat. Although it is an old motor, it only has 89K on it so it will be fine to put in there. I do intend to keep this old girl around for a long time, as I use this one in the woods for my firewood business. I like the gas engine in the woods because it will start at -25 degrees, where my diesel ones wont. Perhaps I will rebuild this engine, but that is to be worried about another time! Thanks again!

Well, that motor would not work. Now, it looks like a rebuild may be the best move. Dang it, was hoping for an fast easy fix!

 

[jeepcreepcj]

Well, that motor would not work. Now, it looks like a rebuild may be the best move. Dang it, was hoping for an fast easy fix!

What was different between the two that would not work? They were both 4g32 engines, correct?

 

[crash3d]

What was different between the two that would not work? They were both 4g32 engines, correct?

The opening for the starter was on the wrong side of the engine, for one thing. I was also a little leary of the compression, or rather, lack of. I could turn it over easily with a 3/8ths ratchet. Barely felt the compression stroke. I believe that engine was a G32, not a 4G32. I have the old engine ready to pull, as soon as I get a hand to do it. One question, is there anything holding the motor to the pump, other than the engine mounts? Doesnt seem to be. Thanks!

 

[jeepcreepcj]

The opening for the starter was on the wrong side of the engine, for one thing. I was also a little leary of the compression, or rather, lack of. I could turn it over easily with a 3/8ths ratchet. Barely felt the compression stroke. I believe that engine was a G32, not a 4G32. I have the old engine ready to pull, as soon as I get a hand to do it. One question, is there anything holding the motor to the pump, other than the engine mounts? Doesnt seem to be. Thanks!

The engine is coupled to the pump with splines on the yoke, it will just slide apart once everything else is undone. So the g32 had a casting in the block for the starter to mount to? If I remember correctly, the starter in the bobcat is positioned and attached by the motor mount plate where a bell-housing would have been. It could have been oriented anywhere there was room as long as it is on the same plane as the ring gear and the same distance from the center of the crank.

 

[mhorsman]

The engine is coupled to the pump with splines on the yoke, it will just slide apart once everything else is undone. So the g32 had a casting in the block for the starter to mount to? If I remember correctly, the starter in the bobcat is positioned and attached by the motor mount plate where a bell-housing would have been. It could have been oriented anywhere there was room as long as it is on the same plane as the ring gear and the same distance from the center of the crank.

I rebuilt the 4g32 motor in my 642b a year ago and it is worth rebuilding, it now runs like new. My engine had also seized at one time but was loosened up with a pipe wrench and hammer. The worst part of the rebuild is the head. It is aluminum and the cam rides directly on the the aluminum, no bearings. If you find a good machinest they can insert bearing material and line bore it. Most of the parts( water pump, star, alternator, etc) are the same as the cars. i buy parts for a 79 dodge colt for mine. The pistons and cam are different. The motor will pull right out after disconecting the mounting bolts. I did it by myself. I made a platform the sam height as the floor of the engine compartment and pulled it out onto it. Goes back in just as easy. Good luck!

 

[crash3d]

I rebuilt the 4g32 motor in my 642b a year ago and it is worth rebuilding, it now runs like new. My engine had also seized at one time but was loosened up with a pipe wrench and hammer. The worst part of the rebuild is the head. It is aluminum and the cam rides directly on the the aluminum, no bearings. If you find a good machinest they can insert bearing material and line bore it. Most of the parts( water pump, star, alternator, etc) are the same as the cars. i buy parts for a 79 dodge colt for mine. The pistons and cam are different. The motor will pull right out after disconecting the mounting bolts. I did it by myself. I made a platform the sam height as the floor of the engine compartment and pulled it out onto it. Goes back in just as easy. Good luck!

Thanks for that info! This one has not come free yet. I put some oil in the cylinders to try to free it up. I am really curious to see what went wrong in there. I am wondering if it is related to tipping it on it's side about 3 weeks prior to the engine failure. ( found a stump in some brush that had been angle cut! how nice!) It was only on it's side for about 5 minutes, and it had been shut off within a second of landing on its side. But that could have caused something to go wrong, I just don't know what. Lots of possibilities. I have seen car motors have trouble with that head setup you are talking about. One has to wonder what that engineer was smoking when he came up with that design!

 

[Tazza]

Thanks for that info! This one has not come free yet. I put some oil in the cylinders to try to free it up. I am really curious to see what went wrong in there. I am wondering if it is related to tipping it on it's side about 3 weeks prior to the engine failure. ( found a stump in some brush that had been angle cut! how nice!) It was only on it's side for about 5 minutes, and it had been shut off within a second of landing on its side. But that could have caused something to go wrong, I just don't know what. Lots of possibilities. I have seen car motors have trouble with that head setup you are talking about. One has to wonder what that engineer was smoking when he came up with that design!

I wonder with the topping if it allowed oil into the cylinders and it locked up and bent something?
If it was shut down fast, it shouldn't have burnt a bearing, but its possible.... If a bearing locked up, it will lock the entire engine. Removing the sump will tell you a lot more. You can then remove the pistons and see if they have stuck in the bores or not.

 

[crash3d]

I wonder with the topping if it allowed oil into the cylinders and it locked up and bent something?
If it was shut down fast, it shouldn't have burnt a bearing, but its possible.... If a bearing locked up, it will lock the entire engine. Removing the sump will tell you a lot more. You can then remove the pistons and see if they have stuck in the bores or not.

Well, I got it pulled out and torn down. The rod bearings were bad - real bad on 2 of them. The pistons all seem fine. Looks like I will need 2 piston rods, rebuild the crank or replace it, bearing kit, gasket kit, and who knows what else! There is an engine builder in Mpls, will take the crank there and see if they can fix it or not. Probably should cook the block too, to make sure all of the metal pieces are removed.

 

[PharmD]

Well, I got it pulled out and torn down. The rod bearings were bad - real bad on 2 of them. The pistons all seem fine. Looks like I will need 2 piston rods, rebuild the crank or replace it, bearing kit, gasket kit, and who knows what else! There is an engine builder in Mpls, will take the crank there and see if they can fix it or not. Probably should cook the block too, to make sure all of the metal pieces are removed.

As I posted in another thread about the 642b 4g32 Mitsubishi engine, you can buy a crank kit from Autozone for $150 which includes bearings. The rods can be purchased on Ebay for about $40 each. That's what I did on my 4g32 and all is good now.

 

[crash3d]

As I posted in another thread about the 642b 4g32 Mitsubishi engine, you can buy a crank kit from Autozone for $150 which includes bearings. The rods can be purchased on Ebay for about $40 each. That's what I did on my 4g32 and all is good now.

Thank you Pharm! I was just about to do a search for your previous thread about that. I knew I had read it one time, so was just a matter of finding it! I am going to see what they would charge me to fix it, knowing that a new one is only 150.00. The rods have to come from a 4g32 or g32? either one work?

 

[PharmD]

Thank you Pharm! I was just about to do a search for your previous thread about that. I knew I had read it one time, so was just a matter of finding it! I am going to see what they would charge me to fix it, knowing that a new one is only 150.00. The rods have to come from a 4g32 or g32? either one work?

The rods are the same in a 4g32 g32b and 4g37. The only differences I found, and I bought the wrong one at first, is that the end of the rod on the piston side is square on some rods as opposed to round which it should be. The forging # on the rod should be G3. I bought a B&P Reconditioned rod sold by thompson-engine on ebay. Part cr345.

 

[wings5j]

The rods are the same in a 4g32 g32b and 4g37. The only differences I found, and I bought the wrong one at first, is that the end of the rod on the piston side is square on some rods as opposed to round which it should be. The forging # on the rod should be G3. I bought a B&P Reconditioned rod sold by thompson-engine on ebay. Part cr345.

Glad to hear you are making progress. I am sure you will think of it, but rather than assume I thought I would throw this out there.
While the engine is out, you will have the easiest time ever for greasing the U-Joint to the hydro unit! ;-).
The 4G32 I have is doing well but I know it received an overhaul at one point in its past. Have fun,
John

 

[ZackaryMac]

Glad to hear you are making progress. I am sure you will think of it, but rather than assume I thought I would throw this out there.
While the engine is out, you will have the easiest time ever for greasing the U-Joint to the hydro unit! ;-).
The 4G32 I have is doing well but I know it received an overhaul at one point in its past. Have fun,
John

crash The cam-in-aluminum-head design has been around a long time, and built properly, it works well. Motorcycles used them for a long time. PROPER maintenance goes a long way to keeping things running a lot of hours, as they certainly aren't forgiving to poor/dirty oil. It seems that it started out as a Japanese thing, but has become much more common today.