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275 swap to a dp

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weibs75

New member
I have a vp 275 leg pushed by the "chevy" 350 engine. A Bayliner cierra 2755. I am interested in turning it into a dp setup. I read awhile back that the lowers of the 275/280/290 are interchangeable. I came across a good deal on a 290 dp drive but I cant find much on instructions or directions on actually doing the swap. Anyone know where I can find some info??
 
All of the AQ series lower units will interchange when the correct shimming procedure is followed.
Your engine determines the over-all ratio, of which will be 1.95:1 for your engine.

You can use a 1.95:1 DP lower from the 280DP clear on up through the DP-C1 (or C2, I believe).
The C and later will use the short vertical shaft, which means that the spline coupler now becomes the "long" coupler.

See your Volvo Penta OEM work shop manual for the A and B dimensions that are required for the change to the shimming above the vertical shaft tapered roller bearing race.
This will be in the Workshop Manual 280 280DP 285 290 290DP, page 114.
This requires several very accurate and precision measurements to be taken.

This also requires five new O-rings, one phenalic gasket, and the gear oil now changes from 30/40W engine oil, to GL-5 gear lube.

Your shift arm must now be set up for a LH prop (i.e., rotates the eccentric piston CW for FWD engagement)

DO NOT forget the prop thrust spacers/washers!

Here is the FWD prop washer.

Here is the AFT prop washer.

When left out, the prop takes out prop shaft bearing carrier........... $$$$$$$$$.
I've repaired several of these from the owner failing to install the thrust spacers ahead of the propellers.

Neck braces required! :D


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Thank you such a fast and detailed response. I know may handling and fuel efficiency will increase tremendously . Do you have any idea on my top end gain?
 
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