Adivce on swappin out motors

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It may be just a ring. I don't know yet. At this point I'm thinking drop the newer motor in there and go through the older one later. I'm pretty confident that the motor switch will go well. I've never had an engine that big apart before. I've rebuilt some small 4 strokes and I'm sure its not all that different. I just don't have a lot of time to learn now. There is wood I could be moving right now! I talked to a Cummins rep today and he said an over the road motor would not be compatible with an industrial one. I usually take their advice with a grain of salt. Everything is always by the book with them. From there I called my Franklin dealer (whose advice I hold in greater regard) and he said he has never heard of it, but it should work. Its not going to have the low end torque though. As long as everything else matches up he said it will go. The front main seal blew out again (replaced it a month ago thinking that was the oil leak problem). Now its blowing out like 5 quarts an hour. The block is going to have to come off to change out a ring right? Would I be able to tell if its just a ring by taking the head off? Whats the best way to preform a leak down test on this thing? That should pin point the bad ring right? I had a guy tell me I may have a hole in a piston.
 
I doubt it's possible to see if the ring is broken without taking it out of the bore first. I'd do a compression check first thing to try and locate the bad cylinder(s). If it was a hole in the piston it's hard to imagine that it would even fire that cylinder with lack of compression that bad..

Even if you locate a bad cylinder with the compression check you have to remove the piston and rod out the top of the block which would require removing the head and oil pan, unbolting the rod cap and sliding it out. Reverse that for assembly... Do you have room to drop the oil pan with it in the machine?

I'm unfamiliar with leak down testing a diesel but it should be similar to any gas engine... Piston at BTDC on compression stroke and then pressurize the combustion chamber with air then isolate the air supply and watch how much leaks off over a few minutes. If it leaks air quickly then check intake/exhaust for bad sealing valve of air coming out crank vent for bad ring.
 
If you end up reringing it you will probably need a ridge reamer, cylinder walls wear funny and develop a lip at the top, making it difficult to pop out the old piston, ridge reamer removes this lip, should be able to rent one from a tool house or NAPA... Along with a cylinder hone.

Even a small ittle bittle hole in the piston will cause massive blow by 200-300pis blasting straight through the crank case and out the only hole available will take a bit of oil with it.

Lastly if it is a bad ring... which I'm voting for... it will generally **** can the piston with it, I.E. breaking off the groove the ring rides in, and then tearing the snot out of the cylinder wall, which means complete rebuild. Although you may get lucky and the rings are just worn and all you need is a couple of $20-$30 rings and a full weekend of learning by doing (not to mention $200 in gaskets and broken bolts;)).

In my horrible opinion, you may be better off getting a cheap motor and swapping it in. With some motivation you could probably have it licked in a couple of days and be back in the woods by monday. Then in your glorious amounts of free time (you know that 5 minutes between harrassing 153 rug rats and logging, in other words while eating...) you can get that other motor rebuilt properly and have a spare laying around for when that second hand motor tanks on you.:rock:
 
detroits....normaly can do just rings.....they like to break/stick rings. piston usually ok in them. like I said I have no time inside the little cummins. the 855 had more a water works problem and the top ends outlasted the rest.
 
Most of my motor experience is small engine, hondas etc, the rest is gasser ferds and chainsaws. I have blown my fair share up, witnessed a few more go...

You would think a detroit would eat the piston when it lost the ring what with those funky ports in the bottom...

Its a bit of a shame that bitz's cummins isn't a sleeve type, a rebuild would be a snap then, inframe and a fresh set of bearings, be almost like a new motor.
 
the oe liners in the old detroits are super hard. I have seen the piston come apart n the liner will be fine. if it not out of round just hone it n put her back together..........have done it on side of the road.....don't wanna do it again tho lol.
 
oh I just had a thought.......saw troit start doing this once.....there is a freeze plug type thing in the piston covering the wrist pin....came out n made base pressure to beat the band. not sure if the bt has this or not.
if this motor don't smoke it seems like it can't be that bad.......i'd love to see inside it.
 
If it's been mentioned I've overlooked
or didn't retain it.
One of the first things to look at.
Cutting the oil filter open can tell
Quite a bit...
 
Cylinder leak down tester is the proper tool to do a leak down test . You may want to also pull the the exhaust and intake and valve cover and spray with soap water and look for bubbles when pressured up . Possible you may have a cracked head or valve guide


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Kinda like a bad tooth, gotta come out one way or another.
Pulling vavle covers show condition of valve train and possible leaking past stem.
Pulling exhaust manf and intake tube might show which port(s) are oily/carboned.
If it's got good oil pressure hot and has been changed regular by previous owner, then psiton/ring might be a good fix.
Those 75 engines probly came out bread/laudry van. stop and go high hours if you follow.
that said there were some back 10-15 year that were from bankrupcy sales that had low mileage engines in them. Personally, I'd look at them with a Cummins mech there and runing hot. stuff sounds good free running but a load may tell different story, like saws maybe.
The upside is it's not December, snow and frozen mud. jmo
 
Well I looked at about 20 out of the 50 some trucks the guy had. About a third of those had the motor very similar to mine. It looks like I will have to swap a few parts from my old one, like the exhaust manifold. The intake and exhaust need to be switched around. He fired a couple of them up and I found one I'm going to pull the trigger on. She snapped over really well and sounded pretty good. I think it was a re-con because it had decent paint on it yet. Most of the rest of them were pretty rusty. It was built in 92. 2200 bucks and its mine. Like Northman already stated, I plan to throw this one in for now and take the other one apart during my spare time. I usually get spare time after everyone goes to bed. That gives me from about 10 pm until 6 am. Well that is as long as my wife is willing to get up with the little guy. I will let you guys know how it goes. I'm pretty curious what I will find in my old one. I'd really like to get away without having to hire anyone to turn wrenches for me. So learning when I'm not under the gun should help.

I appreciate all of the replys and I have taken all comments under advisement! Thanks again!
 
careful with exhaust manifold bolts, they like to break off, then you have to drill em and try an easy out,

Also I hope you have hoist that can handle the height to pull that motor

And lastly since you plan on rebuilding the old motor, You probably will need to have some machining done, bore and hone the cylinders if nothing else, turning the crank, and maybe line boring the cam, not to mention going through the head and reseatting the valves, and new bushings.

Anyway what I'm getting at is the machining itself is little different than having a gas pot gone through, the tolerances are a little bit tighter, so any reputable auto machine shop should be able to accomplish it without charging 2-3 times what a regular gas engine would cost. May be different out there, but we have several of them out here wont even touch diesels, there is one that will and they only charge a little more because of tolerances.

Good luck,
 
On the easy out on the exhaust bolts ,i do not advise this myself ,if the bolt was stuck enough to snap off the easy out more than likely will too ,if you have ever tried to drill an easy out that has been broken off ,i will save you the trouble ,they are hard or harder than your bit and will not drill ,i have has better luck with a center punch ,start with a 1/8 bit drill a small hole in the broken bolt ,then step up a bigger size till right close to the threads then just run a tap in there to clean the threads

also if you bust the tap off ,it will not drill out either ;) but a punch and a hammer will break it out in little pieces if comes to that
 
I think if you're gonna learn on a diesel engine, the 3.9 is a great choice. I had one in a chipper and did the head gasket on it. It was easy enough, I'm sure taking the head off isn't much more work. Parts are easy to find. The nice thing is that everything mechanical.

Industrial motors are a lot different than the on road versions, but there should be plenty of guys on the web to walk you through that. I know my local gravel pit put an industrial 5.9 in a ford pickup, lots of parts swapping involved, but it worked.
 
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