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Can this be fixed if the broken piece is missing? It's the motor mount boss /water pump hole, any ideas how to repair (weld)? It not a critical portion of the block but I would like to have it repaired while the engine is out of the boat.
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Attachment 18929
That needs attention! Your motor plate mounts there, I wouldn't want to run it with one bolt holding that corner of the engine.
If I were you I would give it the whole engine to that westernaero guy and go build yourself something new. :biggrin:
Seriously, I would have it welded, and then you can drill it thru all the way to the fuel pump rod stop hole. Then re-tap it thru and it should be fine. You'll need to run a longer bolt that almost enters the cross hole.
;)Quote:
Originally Posted by WESTERNAERO
Can a welder build the entire area up with a big blob of weld, then drill and tap it? I am not sure if that will work with cast iron. The rear plates use 4 bolts for each side (which includes the water crossovers).
If the plates go all the way to the water ports then you are in much better shape. I would still have it welded but i don't think it's all that necessary. No you really can't build it up with weld but you could make a small chunk and have that welded on. It was repaired before, you can see where it was drilled in areas to get the JBweld to stick better. I would still drill and tap all the way thru.Quote:
Originally Posted by 78Southwind
Yep...they go all the way to the water ports.Quote:
Originally Posted by WESTERNAERO
Attachment 18935
Are you handy with a jig saw or do you have a band saw? I would make a new motor plate that is one piece. Connected in the middle so those aren't trying to spread apart. May be the reason that boss is blown out to the side to begin with.
Something like this maybe.
Attachment 18945
That's the first thing I thought since my jet boat's motor plate is a one piece with an arch. They used a two piece so that there would be enough room to hang the water pump and the alternator on each side of the engine.
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Water pump? Do you have a sea pump, not a cam driven pump?
never mind your pics came up.
Yep...Sea Pump. This engine was originally in a Cat.Quote:
Originally Posted by WESTERNAERO
Attachment 18959
I would almost just suggest replacing the block if you had some reason the engine was going to be out and apart. I don't think it can be properly welded without heating it up, and then properly bringing temperature back down after it's welded. You might want to find out what it costs too. One time I had a block repaired, and I made the guy promise it would not distort the cylinders out of round. I took it straight from being welded to the machine shop where they stuck it on the Sunnen hone, made a couple of passes with the stones and showed me that it had been pulled out of round. The welding shop didn't charge me, but I had to get another block machined and start over.Quote:
Originally Posted by 78Southwind
I believe he has a Dart block and I doubt he wants to spend that kind of money on a new block. The area where its broken can be fixed without over heating the block. Really it just needs to be drilled thru and tapped. If he has the piece that broke off it would be even better for a repair. But, if he makes a new motor plate I wouldn't even bother with the repair and it would need just the drill and tap.Quote:
Originally Posted by obnoxious001
What is wrong with the current mount setup that put so much stress on the corner of the block?
My opinion on how it broke to begin with is the the holes drilled in the motor plate were not quite in the right place. Probably drilled with a 7/16 drill and no clearance. When the bolt was run it it was putting a side load on the casting and popped that piece off. The aluminum is stronger than the cast iron right there so something had to give.
When this was Greg's engine he drove his Spectra from Site Six to Laughlin then back and then to Havasu Landing (over 100 miles), the mounts got loose and one of the loose bolts did the damage. It is a Merlin II block and when this happened he had different plates on it that only had 2 mounting bolts per side. His fix was to change out the plates to 4 mounting bolts per side utilizing the water ports. Everyone that I have talked to seems to think that running it with it's current set-up (4 mounting bolts per side) is strong enough and I should not have any problems.
I am just a little different when it comes to doing things and if the block can be welded without creating other problems then that's what I want to do. However, Barry has brought up some good points that welding the block may create other problems.
Well that could break it too. :D:DQuote:
Originally Posted by 78Southwind
Just drill and tap it thru. That's what I would do, but what do I know.
It could be through bolted, but I looked at a regular GM block and a GM bowtie block that I have sitting here (sorry, no Merlin to verify on), and looks like there may only be 3/8" of iron to drill through, might be just a marginal fix.