Volvo 290 AQ / SP compatibility?

[Radon17]

Hi,

I have a AQ 290 with the wrong lower end ratio (2.15:1) for my V6 (4.3). Pictured below, I found a SP 290 complete unit (1.61:1 lower) and just lower unit for sale. I noticed that the SP looks like a short hub.

Assuming I stick with the old transom plate, can I just swap the complete unit? If not, can I swap the lower unit?

Thanks,
A.V.

 

[billbayliner]

Re: Volvo 290 AQ / SP compatibility?

Hi,

I have a AQ 290 with the wrong lower end ratio (2.15:1) for my V6 (4.3). Pictured below, I found a SP 290 complete unit (1.61:1 lower) and just lower unit for sale. I noticed that the SP looks like a short hub.

Assuming I stick with the old transom plate, can I just swap the complete unit? If not, can I swap the lower unit?

Thanks,
A.V.

View attachment 140356View attachment 140357View attachment 140358

Just an FYI here. There is no 290 SP drive. It may be a 290, 290A or an SP drive as shown in your photo.
The 4.3L can use the 1.61:1 V-8 ratio, or the 1.89:1 for slightly larger hulls.

All lower units can be interchanged when the right shimming is done. If you use a C or later lower, you might run into a short vertical shaft. If you do, then the long vertical shaft spline coupler is used.
See the OEM service manual for the A and B dimensions for the shimming.

I am not following you on the short hub comment. The hub pertains to the prop, not the drive.
All 280, 290, SP s/p drives net the same length of prop shaft when the right spacer-line cutter is used.


BTW, this is a C or later drive.
Notice where the hydraulic cylinders attach to the suspension fork compared to your 290 where they attach to the anchorage bracket.
This drive will also have the A style transmission bearing box.

 

[Radon17]

Re: Volvo 290 AQ / SP compatibility?

Thanks Bill,

The picture below is the transom plate I have with the square end hydraulics. Will the drive in the picture (SP) fit, even though it will connect at the suspention fork? I would rather buy the complete drive if it will fit, rather than just replace the lower only. The complete new drive is $2500, seems like a deal if it will work.

 

[billbayliner]

Re: Volvo 290 AQ / SP compatibility?

Thanks Bill,

The picture below is the transom plate I have with the square end hydraulics. Will the drive in the picture (SP) fit, even though it will connect at the suspention fork? I would rather buy the complete drive if it will fit, rather than just replace the lower only. The complete new drive is $2500, seems like a deal if it will work.

View attachment 140392

AV, the 290, 290A and first SP drives use a small suspension fork hinge pins. The cylinders also mount differently.
So to make the C drive work as is, you'll need the C transom shield and cylinders and I believe that the Y-pipe also changed again.

It may be possible to install your 290 suspension fork, anchorage bracket and reverse latch to the C drive intermediate housing. I don't know because I have not made this change before.

FYI, the C transmission has the large diameter bearing retainer, so it won't fit onto your 290 intermediate.
The lower unit will.