How to repair a hole in 4cyl engine block

I have a Perkins 704.30T with a hole nest to crank were #4 connecting rod came loose.

Need advice on best way to weld it. Nickel Rod and preheating?

How hot to preheat and can it be done with a torch and IR thermometer.

Yair . . . Family Man. I believe that nothing you could weld in there would add to any stiffness or integrity of the block, therefore all you are setting out to do is stop it leaking oil.

If the area is relatively regular with no extreme angles or hills and hollows it is usually possible to fashion a patch out of 1/8" annealed sheet. It should be formed in place to a nice fit and drilled around the edges with (say) clearance holes for 1/4".

You can counter sink or use roundheads and the holes should be on no more than 1" centres.

When it can be offered up and its fitting sweet mark the holes and drill and tap. I don't use a gasket and just bed them down on a high grade epoxy (back in the day a good one was put out by "Devcon").

As always cleanliness is king. You want the mating faces absolutely spotless and degreased with acetone or some such. When you screw it down you should have the compound extruding evenly all round.

It is much easier to have the block set up so you can get at the inside and outside and clean off the excess before it dries.

Properly done such a patch becomes part of the engine block and would go unnoticed by a casual observer.

If acute angles and webbing are involved I have had success building a plasticine dam and casting a patch with a compound such as "Chockfast" but that is a whole different procedure.

These comments are just my opinion of course and, using advanced techniques it may well be possible to weld a block . . . if so I am sure there are folks on here who will know.

Cheers.

I have on several occasions just brazed it up with oxy/acet & good low temp brazing rods..2 of the repairs have outlasted the machines the motors were in..

My father and I welded the pieces back into the hole in a IH 684 block after a rod came loose with nickel rods, lots of time and a needle scaler for stress relief. No preheat, weld an inch, let it cool, relieve stress, weld some more. Worked fine.

What resources did you use to weld the pieces back into the hole..?

On an old Detroit 4-53 a number of years ago we fixed a 1-1/4" block hole near the starter by drilling it out with a hole saw and threading in a 1-1/2" pipe plug. It was still running and doing fine the last time I seen the owner a year or so ago.

Helenhagan; I picked up the pieces under the tractor. It had a loader on it and the side plates kept them from flying off to parts unknown.

Last time I had that problem we went with the sheet metal patch & silicone .
https://www.heavyequipmentforums.co...5-Wabco-c-pull&p=342574&viewfull=1#post342574

Yair . . . Good stuff td25c. It is obviously not necessary to go overboard as I mentioned with screws on one inch centres . . . and I find it interesting that some folks have had success with welding.

We never even tried to weld. Any that I have seen welded or brazed ended up with hairline cracks and an oily greasy mess and the sheet metal and screw caper fixed a few of those.

Cheers.

Yeah Scrub . No point in overthinking it . I was on site at the time of the trouble and needed a simple patch repair to continue on wit the project . Funny thing ... I tell the farmer ( who I was building the lake for ) about what size patch piece of sheet metal I needed and sure enough he shows up with it and it fit perfect . LOL !

The sheet metal patch method works good. I've also had success with brazing using Rockmount Brutus-G filler rod. It's hard to make it 100% leak free, so I cover the inside of the repair with A thin coat of Belzone. Sometimes you can't find all the pieces, so then the patch works better. If its a crack, instead of a hole, the metal stitch kits using the drill and plug method work good. Fixed a couple of cracked Cummins ISB blocks that way.

These are by no means structural repairs. Just a way to cover up a hole.

coaldust

wrwtexan said:

Helenhagan; I picked up the pieces under the tractor. It had a loader on it and the side plates kept them from flying off to parts unknown.

Click to expand...

Dod you get any problem while fixing those plates?
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