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block surgery

Posted: Sun Sep 12, 2021 11:41 pm
by geofflena
The Wipac Silver Century I had had on the rail of my main boat as an emergency engine got a check over - and a I saw the block was developing a crack right on the impossible to clean area next to the inlet port.
Otherwise a good clean block ( I did this engine a few years back as a atrip and re-assemble job ) - it seemed a shame to let it go to waste.

My reckoning was to drill some holes to facilitate cleaning the area - and also to relieve any current built up stress. The crack was about an inch long - quite fine and level - but was obviously going to get worse !

I drilled three holes in the side of the exhaust flange - and two on the flat top. These enabled me to drill out the stubborn black sediment inside.I opened the crack slightly and filled it with thickened epoxy.

To plug them after tapping I used my worst condition old head bolts and cheeses heads - sawing off small threaded sections and cutting a slot for fixing.
After degreasing the tapped holes I just screwed them in with non setting black loctite.
If you cut a good deep slot they will file flush after inserting.
I could have fleathered them off with filler - sanded flat and painted ? - but they looked quite good, so I left them as they were. !

surgery-1.jpg
surgery.jpg

Re: block surgery

Posted: Mon Sep 13, 2021 8:13 am
by Charles uk
That port is actually the exhaust port.

That is a strange place for cracking to start, it's normally up inside the port.

Did you remove the head & what did that look like, are there any photos of the contents of the water jacket?

Re: block surgery

Posted: Tue Sep 14, 2021 9:52 pm
by geofflena
Yes - at the time I completely rebuilt it - ie undid and checked everything - even the drive bearing ! ) The jacket was cleaned out with head off as best as I could do or reach ! To be fair it been sitting on the rail of the boat for years ( with a cover on ) - but sat out in salt estuary.

The inside of the port is fine - the crack was on the face where I drilled the two holes and just reaching the edge. It was very solid in there ! Had to drill it out really - hence the three side holes as well.

My feeling it would at least relieve any stress - and with the gunge inside cleared a little - will probably keep it intact ?
Its an engine I keep for emergency 'large boat moving' - and one more shed ornament at present !

I will probably regret that its not on the rail if I do have a main engine go on me !
If it gets in the way in the shed it may go back on the boat !

Re: block surgery

Posted: Sun Sep 19, 2021 8:57 am
by Journeyman
Nice fix Geoff, another engine saved! :)
Did a similar fix on a French engine block, drilled and taped each end of the crack and then ran some braze over it to seal.

Dave.

Re: block surgery

Posted: Wed Sep 22, 2021 9:16 am
by dandrews
Nice work.
Below is a kingfisher block, and you can see how seagull solved the problem in the next generation of QB's by opening up the water channels to the exhaust flange and then covering them with the inner exhaust flange.