Repairing Drilled Engine Block

[5030]

Interesting thread with a lot of good fixes, however, something isn't Kosher.

I work part time at an authorized Kubota dealer and I know for a fact that if you buy a reman engine from Kubota, for any reason or even a short or long unused engine, Kubota has to have documented proof the original engine was destroyed and rendered not useable or rebuildable. Documented proof for Kubota is detailed pictures of the destruction and or valid receipts from a scrap company.

I've destroyed more than one failed engine and in my dealer's case, that involves using a sledge hammer or torches and destroying it, not drilling a hole in the block that can be repaired. Like I said, Kubota requires documented proof as in pictures or scrap dealer receipts that the engine was rendered not useable or repairable, except for scrap value. Corporate policy. I have no idea about an independent non Kubota rebuilder or shop, only a Kubota authorized dealer.

The OP in his first post states a Kubota dealer drilled the hole and I'm very suspect of that.

Kubota revised and adopted that policy when the emissions engines came on the scene to prevent an owner of a failed engine replacing it with a non emissions engine.

Give me no pleasure in destroying a rebuildable engine but corporate policy is corporate policy anyway and at least the dealer I work for don't want to loose his franchise over an engine.

I will say, using a 15 pound sledge on one renders it junk real fast. That and using it for target practice with a high velocity round.

If you buy a long block from Kubota you cannot remove anything, a short block, you can. Not sure about other brands, just Kubota.

 

[ruffdog]

So the drilled hole goes through solid cast iron all the way to the cylinder? If this is the case then this old machinist thinks it could for sure be tapped and plugged. If it was mine I would tap the hole for a tapered pipe plug from inside the cylinder. Use a steel or cast pipe plug so that it has a similar amount of expansion as the block heats up. Install the pipe plug with red Loctite. The hard part will be grinding down the part of the plug that extends into the cylinder so that it is flush without damaging the cylinder. Any competent engine shop could do the work for you and then use a boring bar to remove excess plug material. I would then have a shop turn a piece of cast iron or steel just a few thousandths smaller than the hole and install this with green Loctite. I think the correct number is 609. 635 looks to be an even better choice. Cut the plug so that it is just slightly longer than the depth of the hole so that you can use a punch and hammer to swage the end of the plug so that it cannot possibly come out if the Loctite ever fails, which it won't if used properly. Use Chlorinated brake cleaner, if you can get it, to clean the hole before applying the Loctite. Make sure the cleaner is completely evaporated before applying the Loctite.
Eric

Agree but loctite 620 is more high temp.

 

[etpm]

Agree but loctite 620 is more high temp.

Your post is why interaction is great. High temperature resistance is probably most important rather than the highest strength. Especially since I suggested swaging the rod in the block. Belt and suspenders and all that. If I had that block I would be sorely tempted to repair it and then use it for something.
Eric

 

[f2000ez]

When you go to get parts for the rebuild and give the engine serial number, it’s going to raise a red flag showing the engine was “destroyed”. Kubota could come back to the dealer and give them a very hard time.

 

[DigDoug]

I had the dealer install a new engine in my Kubota L4740 when it spun a bearing

In order to get the new engine from Kubota, they required the dealer to drill the block

Now I would like to rebuild this engine and am wondering what it would take to repair the drill hole

See pics

Are you friendly with the mechanic at the dealership? Just ask him exactly what was done to the engine. Take some of the guess work out your project. I can’t imagine they would have a problem with you wanting to rebuild the engine…….

 

[Massey convert]

Why are to trying to save this old block? Even if a reliable fix were found, you'd still have the original spun bearing issue to fix. Cost prohibitive, IMHO.

I would agree. After you repair the drilled hole, you still have the same issue with the spun bearing, which would be more of a challenge.

 

[Cycledude]

Seems like a lot of time and money wasted

 

[Fueler]

Engine machinist/builder here.
The first move is to get it apart to assess if the rest of it can be machined and rebuilt.
The outside wall hole is not critical to operation or engine life if tapped and plugged. Don't over think it.
If concerned about the serial number when acquiring parts the aftermarket does not care.

It used to break my heart when Chevy would sledge hammer a perfectly good 427 vette block.

 

[boatmoter]

I had the dealer install a new engine in my Kubota L4740 when it spun a bearing

In order to get the new engine from Kubota, they required the dealer to drill the block

Now I would like to rebuild this engine and am wondering what it would take to repair the drill hole

See pics

I would tap some threads into it and install a pipe plug with Teflon tape

 

[WinterDeere]

I would tap some threads into it and install a pipe plug with Teflon tape

Oh no... now you've started a whole "tape vs dope" debate, that'll take us through the next 3 pages.