Volvo 280 lower unit, housing, interchangeability

[bwano]

I have a 1975 Skipjack 28 Flybridge w twin small block Chevy motors. The outdrive housings were badly corroded, but the inner gears looked primo, as new.

I bought some used, clean, 280 outdrives, that were for 4 cylinder engines, thinking that the lower housings were identical, but under the assumption, that the gears inside, were the only difference.

I thought I could put the V8 (B 1.6x:1) lower housing gears, inside the 4Cyl (D 2.15:1) lower unit, housings. A local outdrive mechanic, has told me this will not work.
He said the bores inside the housings are different, to accomadate different sized gears or bearings.

 

[Don S]

Re: Volvo 280 lower unit, housing, interchangeability

280 housings are the same for all 280's. Your mechanic must be an OMC guy, they (OMC) are the only ones that used different housings on 4 cyl engines.

You do understand you need to reshim and recheck gear patterns on the gears don't you?

 

[bwano]

Re: Volvo 280 lower unit, housing, interchangeability

Thank you sir, for the efficient response.

I guess, I know which mechanic, not to take the housings to.

This is good news to me, as I have one completely "New Old Stock" Outdrive. It is a "D" for a 4 cylinder, but I want to pay a reputable outdrive shop in southern California to put the gears from the original outdrive into the new or used housings.

The only problem, is I have been quoted, (rough estimate) $2500 per outdrive (x2) for this service.

I may have to bite the bullet, and just pay. I don't have the necessary tools or knowledge to under take the project.
I tried to post some images of the housings and boat, but i failed the process.

280 housings are the same for all 280's. Your mechanic must be an OMC guy, they (OMC) are the only ones that used different housings on 4 cyl engines.

You do understand you need to reshim and recheck gear patterns on the gears don't you?

 

[GilligansIsland]

Re: Volvo 280 lower unit, housing, interchangeability

I would be VERY cautious as to who I had do this work. Shimming is critical, and not easy work. Not many guys have a lot of experience in this area.