Volvo 290A lower gear unit

[degerb1170]

Can anyone help me? I have a Volvo 290A outdrive mated to a Volvo V8. The lower unit has a 1:89.1 ratio. I have purchased a Volvo 280 lower unit that has a 1:61.1 ratio. I need to swap these. My question is since both lower units have came from operating outdrives is this just a a simple bolt on swap, that I can accomplish or is this best done by a Volvo dealer? Thanks Don

 

[captmello]

Re: Volvo 290A lower gear unit

The lower needs to be shimmed to fit the intermediate. If not done properly, you could have more problems.

If there is a good Volvo mechanic that you're comfortable using, and has experience working on the older outdrives, you may just let him do it. I don't think it is a big job, just requires careful measuring and a bit of experience. Or get the manual and try it yourself. Just don't bolt it on and go.

Good luck, and let us know how it turns out.

Also, I wonder why you have a 1.89 lower on your current drive when 1.61 is typically used on V8's.

 

[degerb1170]

Re: Volvo 290A lower gear unit

Thanks for your response! I have completely restored a 1967 Thompson 20' wooden lapstrake that had the original OMC stringer I/O installed. I had read good things about Volvo's 290 series outdrives and the one I found had the 1:89.1, I bought it knowing I would have to, at some point install a different lower unit. I didn't know for sure about the shimming since the lower tower shaft has a removable splined coupling joining the lower unit assy and the intermediate/top end unit. With that set up, It wasn't clear in my mind why shimming was necessary. Thanks Don

 

[Don S]

Re: Volvo 290A lower gear unit

With that set up, It wasn't clear in my mind why shimming was necessary.

Trust me, you have to shim it. The bearing height changes due to how the lower is shimmed internally.
When you remove the lower unit from the drive, you will notice the vertical shaft bearing race (and shims) are pressed into the intermediate housing. You must use the race for that bearing, don't just reuse the race in the intermediate to the bearing in the lower.
That race has to be shimmed to the bearing height of the lower you will be using.
Here is a link to the OEM manual you can download. http://www.4shared.com/document/R-C91eXm/280_to_DP-C_Drive_manual.html?dirPwdVerified=818cbd4e
It will explain how to shim it properly.

 

[zbnutcase]

Re: Volvo 290A lower gear unit

And you will need a depth micrometer to do it.

 

[degerb1170]

Re: Volvo 290A lower gear unit

:redface:Hey Guys thanks a bunch! I was strictly thinking shimming for gear tooth contact and not even considering bearing clearance! I think I better leave the installation up to a professional! I appreciate all the input.