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Rebuild or Replace 1976 Merc 454bs

A

andy

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" I bought a 1976 Bertram 35 t

" I bought a 1976 Bertram 35 this year that has original Mercruiser 350HP 454's with about 1100 hours each, fresh water operation only. Both engines start and run smoothly, with minimal smoke and only a little oil slick seen after idling for several minutes. Both engines reach 4500 rpm easily with similar throttle settings.

One piston has compression about 115psi, others all 130-150, so I am thinking of doing an overhaul to see what's up with that piston (ring problem, I think).

What should a "major" on these engines and VelvetDrive transmissions cost? Does it make sense to rebuild engines this old? Are there parts available for 1976 Velvet Drive transmissions? What would you do? "
 
"Andy, if the engines are run

"Andy, if the engines are running well, with normal oil consumption, temps, and the oil and water are staying separated, I wouldn't do an overhaul based on the 115 psi cylinder alone. If the cooling systems are raw water then rebuilding blocks and heads that old is questionable. A machinist could tell how much meat is left in the cylinder walls, etc., but of course they would have to be torn down to get that info.

You might consider giving them some thorough TLC, look hard at the exhaust manifolds & risers, and just run them until something happens to justify more drastic action. I don't run Velvet Drives, but all hydraulic gears benefit from fresh fluid and a good heat exchanger. Again, I'd follow a preventive maintenance program and run them. Can't help with the cost estimates.

"
 
" Thanks, croozertoo;

The e

" Thanks, croozertoo;

The engines are FWC, so the blocks and heads have only ever seen coolant. I replaced port manifolds in the spring, and will do starboard and risers this winter. Everything else seems OK, so I'll wait another season, get to know the engines better, and see what happens. "
 
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