1990 vs 1992 4.3 block swap

Chris51280

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i will pick it up Friday. once I start the rebuild, maybe this can be renamed and i post my progress here. I also have my rebuild on the Restoration site. does anybody know how to put the link in the signature?
 

Chris51280

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I got the engine today and the casting number is 756. It turns out the engine is a '92 and is a replacement from the '87. Still no balance shaft since this is what I need. Probably less miles than the odometer shows. Odometer is 135k
 

Chris51280

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[No message]
 

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Chris51280

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Thanks. Lots to do for the winter. I might need some advice along the way. Sure keep you posted on the progress.
 

Chris51280

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Started tearing into the donor engine. We saw that it was a remanufactured one already. After taking the heads off, they are .060 over piston. I think this engine did not have alot of miles on it. Car read 135k total. I think I will put new gaskets on and new rings. Kiss the bores with a hone. Check bearings for wear with a gauge. Swap over the cam from the mercruiser and put it together. What do you think?
 

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Chris51280

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They are brass already but will change again. Do i need to put the black gasket sealer around it? They should seal by themselves but i think that would be additional insurance
 

achris

More fish than mountain goat
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May 19, 2004
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Brass is good, stainless steel better. ;) I use loctite master gasket sealer (515) around the edges. Same stuff I use to seal 2 stroke engine crankcases...
 

Chris51280

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I was thinking. If this has been bored over, there might be good chance that the crank has oversized bearings as well. I will measure and find out. The reason I'm asking is that All the rebuild kits I see have main and crank bearings in them. I would need different ones if I even need them. Since the engine has less than 135k miles on it, would it be too terrible to just change the piston rings and touch up the cylinder bores and get seals? Would you get a new oil pump too?
The mercruiser heads will get new valve seals for sure. I think they are in better condition. (Not as rusty on the outside)
 

Chris51280

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OK. I measured 2.220" on the rod journals. The manual says 2.2487-2.2497. I believe this means I need 0.030 oversize bearings. Is this independent from my connecting rods? Connecting rods are standard I believe
 

Lou C

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Did they ever change the oil? That thing is very sludged up. What does the oil pump screen look like?
 

Chris51280

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Screen was clear. This engine was sitting awhile with old oil in it. It's also 25 years old. There were some deposits but nothing too terrible. I still have to get the damper off and check the main seals on what diameter they are
 

Lou C

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Here's mine when I pulled off the intake to replace the heads and head gaskets. Blew both head gaskets and had salt water in it for a few days. I'm surprised the screen was clean. The small block Chevrolet did have a good oiling system!
 

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Chris51280

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Looks like there was no oil film at all. Looks very dry.
Is there anybody that restored the block with oversize parts?
 

Chris51280

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Starting to clean up the rust. A drill and wire brush work really good. I have to get the tool to remove the damper soon so I can get the crank off. I got some of the freeze plugs out.
 

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Chris51280

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I have been looking at gasket sets. Anybody ever used enginetech gaskets? Summit has regular gasket sets and marine gasket sets. I'm planning on using Felpro gaskets. Since my engine is already .060" over, can I use a regular head gasket? The top metal ring is not full round, kinda oval shaped. Any input from someone that rebuild one with oversize bore?
What about the rest of the gaskets? Do they need to be marine grade? I don't think so. Will see freshwater only!!!
 
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