Has anyone rebuilt there twin ford lemans in a Grand Banks 36 in the boat?

Just wondering if this is possible, not having to pull the engine, take the top end off and rebuild the bottom end in the boat.

Port side is blowing to much blue smoke for my liking and smoke out of the crankcase breather. Boat has sat for sometime, maybe stuck rings and running with a good detergent oil may solve the smoke.

Anyway just wondering, thanks

when I had my GB36 I did read it being done.

SteveK said:

when I had my GB36 I did read it being done.

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Thank you Steve I’ll keep looking, couldn’t find anything last night online

FWIW, a mechanic replaced the no. 6 pistons in my twin FL 120s on a GB 42 while on the water.

A full rebuild job including the crankshaft and lower end bearings is a much bigger job, in place or not, than a top end overhaul, which sounds like all you may need.

How is the oil pressure? That is a good indicator of lower end health.

And run it hard for several hours with the detergent oil. That may free up the rings.

David

DavidM said:

A full rebuild job including the crankshaft and lower end bearings is a much bigger job, in place or not, than a top end overhaul, which sounds like all you may need.

How is the oil pressure? That is a good indicator of lower end health.

And run it hard for several hours with the detergent oil. That may free up the rings.

David

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Headed out this am for some high detergent oil and give that a go first off. Thanks

Xlantic said:

FWIW, a mechanic replaced the no. 6 pistons in my twin FL 120s on a GB 42 while on the water.

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Thank you for checking in, so worse case, it’s doable

what are compression numbers for each cylinder?

Compression on diesels is a rather poor indicator of ring wear. Blow by is a much better indicator and the OP reports significant blow by on one engine.

David

SoWhat said:

what are compression numbers for each cylinder?

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We are not that far along, I’m just now starting to address the smoke, boat has sat for sometime. Oil is thick and coal black, be changing this afternoon. Just finished replacing all the coolers and heat exchanger on this engine as had no idea how old or condition. I’m a nub and slowly going through and changing out filters and such. Just replaced the thermostat that was stuck. Also the gauges are on and off again, so I’m using a heat gun for temps, and think I will replace the gauges and sending units for the oil pressure. This engine just had head gasket replaced, no water in oil, no oil in the water.

Previous owner stated many facts as to what was done and gone through on the boat, and I’m finding much of it was untrue.

Like the bottom paint that was done last summer, diver found that the paint job was an owner quicky, it’s rough and they even painted over the barnacles on the shafts. Don’t believe they did any prep work. We are going to have a haul out in beginning of may and do the bottom are selves.

Was just wondering if it was possible to rebuild in the boat, and not have to pull engine out, as I’m figuring out costs if worst case.

Well whoop de do, last eve after replacing all the coolers, hoses and heat exchanger, running the engine up to 1000rpm. She’s locked up this am, just a big clunk when starting, and can’t move the crank with wrench. She ran fine, no noises or anything, idled down, let engine settle down and shut off. Today seized, lol.

Could be hydrolocked, although I doubt it. Two days ago replaced thermostat, ran fine, fine yesturday other then the blue smoke, which was more then I felt was normal. I think she just finally gave it up.

Will check oil filter for metal and get an oil test. Move on from there.

Bummer, but been there too.
Your choice;
1) remove the #6 injector and see if you can hand crank it over. OR
2) remove the tranny and check the damper. picture attached of mine. After running great all day, next day seized, a spring from the damper jammed up the flywheel. Not overly hard to replace, an extra pair of hands would help lugging the tranny out of the way.