A customer brought me a trailered water pump powered by a Cummins B3.9-P four cylinder engine with a hole in the block by #1 rod but still running. I figured it pitched a rod but good and still had clearance to run on remaining 3. The plan was to replace engine with a long block. Not finding what I wanted, I thought about doing a rebuild and fixing the hole (weld/braze/patch with sealer) and went out for another look. Upon further inspection, it didn't pitch a rod but instead, through the hole, looks to have chucked a balancer shaft weight which went out the side! The block repair looks very feasible now but I can't at the moment find any info on the counterbalance shafts or what they will take to fix. Any experience with these?
Kinda hard to find information on something they don't have. Bob
?? Engine Model; B3.9-P Family; 2CEXL0239AAC , SN; 46250290 80 HP @2500 RPM
Sign up for a Cummins Quickserve account. You can get info on up to 5 serial numbers for free.
I think it has bolt on counter weights on the crank.
Not seeing the engine hard to say but if it's not a critical area high stress I might be tempted to clean it off real good and then make a patch out of say 1/8 steel and drill a series of holes around the outside of the patch and tap holes in block for 1/4 inch screws maybe a inch apart. Then install the patch with a good grade of silicon sealer rated for hot oil. This would all depend on how critical the engine is and how deep the pockets of the owner are.
As kshanson said, not seeing where the hole is, makes any prescribing of remedies harder, but I had a similar thing on an old JD 440 tractor. Block hadda crack, in the side, about 4" heading up from one of the oil pan holes. Worried that it might be into the water jacket, I had a friend at the local machine shop bring his magna-flux kit and light over, and he set it up, we checked, I took a center punch, marked about a quarter inch farther up, made a mark. Then I drilled some holes, and tapped them to 5/16" fine. Bottom line that I'm coming to, is any time something exits the block at a high rate of speed , best to do the crack check with a magnaflux unit, and the black light, to see the network of cracks, it produced. Once you see where the cracks are, you can see if any cracks are heading toward any oil galleries, or the water jacket, drill the appropriate holes, then cut the and form the plate, and use the holes you just drilled and some dowel centers, to mark your plate for drilling... Here is the theory: And here it is in practice:
wrwtexan, any chance of a couple pictures of this one? I'd be interested in knowing if there was damage to the crank or what ever the balance weight was connected to as that could be more of a problem than the block. You don't want to put a lot of time and effort into patching the block only to have something fly off and damage the patch job!
We are having a last of winter cold blast so we'll be stuck in shop and get it out of the frame over next couple of days. My plan is to remove the pan/counterbalance shafts frame and lay the block on its side for easy fix whatever that may be. The hole is a clean break out on right side just below oil cooler and above pan joint line and not in any galleries or structural webbing. The owner said it was still running when they found it! As far as the balancer shafts, one looks to have some scuffing on it where the weight was so it will likely get replaced but the rod looks good. I had figured the rod had slapped the weight out but what I can see, it wasn't touched. I'll take and upload some pics as we get into it.
I guess you have never seen a 4B cummins before since they don't have a balancer shaft. You must be looking at the oil pump pickup tube. Good luck with putting new weights on that. Bob
I must be missing some thing here! Who is working on a 4B Cummins? The original poster right in his subject line says B3.9-P. I only had a passing knowledge of the B3.9 as the one we had in a sweeper only ever needed an oil change while I was there so I went to an online service manual and found this: So that tells me at least some of the B 3.9's DO have balancers.
Don't know who has the 4B but this one is the B3.9-P and it definitely has two shafts in the pan.
So the pictures in my attachment are showing the engine upside down? Or is that the Australian version of the engine?
The 3.9L B series Cummins or whatever you want to call it in some Case equipment have those balancers. (Eg. Series I 580M and SM) Pretty silly design having the weights bolted on, lot of centrifugal force there!
**** off Bob! I'm not going to hold back on here anymore. Moderators; kick me off or deal with the know it alls. If you'll reread my post, you'll see its not a 4B! And yes, it does have balancer shafts as we just got the damn thing out. Stay out if you don't have anything useful to say. To everyone else, we dropped the pan and it has a balancer setup similatar to some Perkins of German IH engines. one or two weights flew off and one of the needle bearings had disintegrated and come out of the frame. I'll have to get a complete unit as I wouldn't risk trying to rebuild this one. I'll post pics soon.
I once found a block with a hole repaired with sheet metal and pop rivets. Only discovered it when it was steam cleaned and the paint and body filler came off.
All the patch needs to do is hold in the oil. I've brazed in patches before. It works fine.
Hole is just under heat exchanger on right front lower corner.
After going through several people at the Dallas area Cummins dealer, a service tech was finally able to identify the balancer and send me a complete parts breakdown with numbers for it. It will take a shaft and needle bearings to fix, but this little engine will be back in service soon with a patch in the block and a rebuilt balancer!
Your gonna need a lot of bubblegum on that hole....yikes....would like to know final solution though...i have jb welded cracks before...but nothing like that...good luck though...
agreed rondig!. Funny thing is that the owner said it was still running when they found it like this. they thought it had pitched a rod.
After seeing that hole, more than ever, I would recommend that you magna-flux to see if any cracks go up, toward that closest bolts, above the hole!
I've patched blocks before and welding was not successful the entire edge of the patch. Very few individuals can successfully braze anymore. I'd be tempted to clean the paint off around the hole with paint stripper and form a metal patch. Metal surfaces need to be surgically clean. Then use 3M body panel adhesive to glue the patch on. Same thing the OEMs use to glue on car door hinges. Good stuff! Still may have a nuisance oil seep, but more cost effective than block replacement.
I think he takes his time and manufactures a cover for that window in the block using some epoxy as sealer it will work just fine.
That is my intention. I was thinking of acquiring some Devcon or the like and either sandwiching the block between two plates with screws and sealer or the other screw and patch methods others have mentioned. It appears to be a very clean breakout between structural webs and I would be afraid of trying to do a heat and fuse based repair as the integrity of the block seems fine. If it doesn't work, the project would still go back to the original plan of a longblock or running unit so not much to loose.
I've seen and used Belzona for that purpose. It used to be an approved fix for marine engines. I've been out of that industry forever but if it worked then it should work now.
Set it up in a trade school to show how things work in a diesel.....charge admission and get your client a free engine...
Am figuring you don't have the missing piece.....but if you did: There is a company that mfg's stitching "contrivances", has a hooked thread and a smooth finish to the bored hole, pretty trick. Lock n Stitch out of Turlock, California. http://www.locknstitch.com/index.html
oceanobob; sadly no. If it were mine, I would have looked for the pieces but alas, his crew didn't have the forethought to find them for a patch. The call went; 'Hey Wes, I've got an irrigation skid that needs a new engine as it threw a rod and has a hole in the block.'
What a **** poor design for a counter balance set-up. That engineer should be standing in front of a firing squad.
I finally have an update on this hunk of junk. A service tech at Dallas Cummins was kind enough to find a parts breakdown of the offending balancer. With all our rain, I am getting some backlog and stale projects out and I made a call to see about parts. The balancer needs a shaft, 2 flyweights, and several needle bearings for a rebuild. NO ONE I talked to had EVER seen or dealt with one of these! Here is the kicker; the shaft is $1,100 and no availability. Best the parts man could tell me is it would be a build to order item! At this point, I decided to see if it could run without it as a Shibaura engine I just put a crankshaft in could, I was told, be run without the same style balancer. To verify my idea, I got through to a Service Tech out of the Ft Worth shop who also had never heard of or seen one. He said it would likely throw a rod as this engine is externally balanced (balancer unit) instead of a crank snout harmonic balancer and internal crank balancing. So... now on his concurence to mounting and drive parts interchanging with a 4BT, I am now in search of a complete running 75HP non turbo engine to drop in and be done with it.
If in fact your water pump will mount up to a 4BT that would sound like a good option. Just doing a quick Google search shows rebuilt units going from $3,000 to $5,000 so if you could find a running take out of something your pump would mount to I would think you would have a much better setup than a patched together B3.9. Only dealt with a few 4Bt's and but those gave almost zero problems. Think that was the engine in a 1989 Case skid steer at work that was still going strong in 2015 when I retired with no real repairs!
Almost every 4b I ever fooled with did not have the balancer. They usually only came in automotive applications like ups and bread trucks. With harded mounts in industrial applications the 2up 2down vibration was not as noticable. Watch out for those Chinese "Cummins" out there, they are not the same
Is there any obvious visible difference that would help us avoid these?
The engines look the same and parts are interchangable. They are actually Cummins engines manufactured in China. The parts have Cummins parts numbers. When you see a new long block 3.9 5.9 or 8.3 for a good deal , that is what they are selling. I have a customer that runs 7 or 8 old machines with the 5.9. He wants these engines because of the price. When the cam or crank breaks he just gets another one. As long as you go into knowing what you got , it works for some.
I just looked through the first page , so just clear things up a little . The 4b is 3.9 liters. The 6b is 5.9 liters. 4b naturally asperated 4bt turbo 4bta turbo , after cooler Not that it matters...
Example All that changes when you get into the QSB and ISB s.
Then a 4B is what I need. I have seen several on facebook marketplace for 1500 to 3K running. What I understand is a B3.9 is the ugly stepcousin to the 4B (3.9L) series. The 4's with no harmonic balancer must be drilled and counterweigthed internally.
Again, not that it matters, but for the sake of conversation; I have believe the step cousin is the B3.3 Cummins. It is identfied by the single rocker box. May have also been a B3.9 , just never run up on one.
The B3.3 is Japanese through and through and appears to have nothing to do with the 3.9. I would like more info on the 3.3 but I only have ever seen maybe 3 of them. With Stanadyne pumps, very strange for a Japanese engine.