Cummins B3.9-P; hole in block from balancer weight

[wrwtexan]

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?

 

[Bluox]

Kinda hard to find information on something they don't have.
Bob

 

[wrwtexan]

?? Engine Model; B3.9-P Family; 2CEXL0239AAC , SN; 46250290 80 HP @2500 RPM

 

[Wes J]

Sign up for a Cummins Quickserve account. You can get info on up to 5 serial numbers for free.

 

[Old Doug]

I think it has bolt on counter weights on the crank.

 

[kshansen]

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.

 

[DIYDAVE]

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:

 

[kshansen]

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!

 

[wrwtexan]

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.

 

[Bluox]

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

 

[kshansen]

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.

 

[wrwtexan]

Don't know who has the 4B but this one is the B3.9-P and it definitely has two shafts in the pan.

 

[kshansen]

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?

 

[GregsHD]

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!

 

[wrwtexan]

**** 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.

 

[Cmark]

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.

 

[Wes J]

All the patch needs to do is hold in the oil. I've brazed in patches before. It works fine.

 

[wrwtexan]

Hole is just under heat exchanger on right front lower corner.

 

[wrwtexan]

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!

 

[rondig]

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...