Hamilton 751 Bearing replacement - Insulated?

[ijw1234]

Hi all,

I've finally got back to my project boat - 751 with a rover v8 engine :D
I need to replace the main bearing(+housing) which i have purchased from Hamilton, at the princely sum of 450 pounds...However the inner-race of the bearing is not electrically isolated from the housing - according to the Hamilton workshop manual for the 750 this is BAD!

Has thinking changed on this, as the laws of physics may have changed since the 70's when the jet was made - or is the bearing i have received defective?

Cheers!

[anthony goodson]

The outer ring of the bearing should be insulated from the casing ,and should arrive this way from the factory The electrical resistance measured between the shaft and the casing on an assembled jet with a DRY rear bearing should not be less than 1000 ohms

[ijw1234]

Got a reponse from hamilton saying that they no longer consider it neccesary to electrically isolate the shaft (as of 2004) - i have sent the bearing back and bought one from an automotive supplier (still a four point contact bearing!) for £36

I have applied a film of epoxy to the outer face of the bearing and pressed it into the housing so it is electrically isolated - not sure what i think of hamiltons reponse...if components last 20% shorter lives, they sell more components...? why would they change their minds after 25 years?

[anthony goodson]

Yes I think yours is a common sense approach why take a chance on immersing a mixture of metals coupled together in salt water I would insulate every time.