Going to look at a possibly seized engine tomorrow

[BaltimoreSailor]

I'm going to look at a MerCruiser 470 tomorrow that might be seized, but I'd like to shoot in some PB blaster or similar and see what I can do. What I'd like to know is if there's a nut on the flywheel I can get hold of, and what size it is. If anybody knows, I'd appreciate hearing so as to be forearmed.

Thanks!

 

[dubs283]

Don't waste your time

A seized 470 is something you do not want

 

[BaltimoreSailor]

What if it's not seized?

 

[dubs283]

Do a search for 470 engines here on iboats. They are a mixture of mercury manufactured engine block with a ford 460 head and require closed cooling. Outboard charging system with some nla parts

Many repair shops won't work on them these days

Even people with a decent knowledge about them avoid them for the most part

I have heard they are popular engines for some dirt track racing but it could have been false or me mis-remembering

 

[BaltimoreSailor]

The hull is in good shape. Is there another engine that would take the lower unit, or better to rip it all out and mount an outboard?

 

[dubs283]

Depending on vintage a 4.3 L gm based mercruiser engine with some stringer work should work for the ratio in the drive, close enough if not the same

How big a project are you willing to take on

 

[matt167]

470 can be swapped with a 3.0L as a near bolt in if you don’t mind a major HP loss. 4.3L replaced it but will require mounting adjustments.The 470 is a cool peice of engineering that mercruiser abandoned before it had all the kinks worked out. 40 years later, it should really be avoided…. A fiberglass boat which hull is in good shape, means nothing as fiberglass does not rot. The wood structure however is usually toast