volvo penta 280 SP leg upper swap to a DP-D or E lower

Hi everyone, I own a 1981 28 ft Campion with a command bridge, 350 small block chevy with a 280 stern drive SP, and a 1.61 lower ratio. I just purchased a DP-D or E, gunmetal grey in color, (perhaps a 290?) lower leg, and according to the numbers on the large(forward) shaft, the gear ratio is 1.78(3861458 part #), and the housing has the diesel type exhaust outlet(it's below the cavitation plate, oval shaped, not the same as the gasser exhaust like my original 280 lower)
Now, I've been reading alot of forums and talked to a few volvo penta mechanics, and I'm getting discrepancies between what I am reading and what I've been told. I was told that the DP-D or E won't work with the upper, the only reason I was told as to why it may not work is due to the ratios from the upper to the lower are not quite compatible, and things may "break", but that doesn't make any sense really IMO, to yes it will work no problem(with some shimming required for the tapered roller bearing). By what I can physically see is, the lower DP setup I just bought, looks really close to the 280 lower SP setup, mounting surface, size(the DP cavitation plate is slightly longer) and looks are almost identical, I even test fitted it to the upper and it bolts right up to all the mounting holes, the ONLY obvious part that's different is the vertical shaft, the DP is shorter, and the SP is longer, I was told that all I need to do to fix that is to install the longer sleeve in place of the short sleeve.
My question is, should there be any issues with this type of swap? I just don't want things "breaking" falling apart, ect while out in the middle of no where, or did I just waste my $ on something that will only work as a paper weight...BTW, I am willing to change out parts, convert, whatever it will take to make it work...

Ricardo will give you the specifics but you need to properly ID what you have. Take some pics and rick will tell you what you can do.

Hi there, thanks for the response, will Ricardo answer me here? or do I contact him instead? let me know...
thanks
in the mean time I have pics of what I have so far...

I see a few things that you need to be aware of.
Your 280 would be the s/p (lower case characters) which means single prop. The SP drive is a later and similar model.
If you bought a DP -E lower unit, there are several more things that you will need to know.

I’ll have more time in the morning to make a few suggestions.


.

Hi Ricardo, thanks for the quick response!
Oops, sorry about that, you're right, it's just a single prop & not an SP model, according to the volvo penta pdf service manual i found on google, it's an AQ 280, i wish I could give more info on the tag that sits below the helmet, but it's pretty hagard and impossible to read. keep me posted, sir...
thanks again!

SP=single prop DP=double prop I’m pretty sure

kimcrwbr1 said:

SP=single prop DP=double prop I’m pretty sure

Click to expand...

To indicate a single prop lower gear unit, we would use "s/p"......... SP is a model and is a s/p drive.
DP = Duo Prop.

BCCI said:

............ I own a 1981 28 ft Campion with a command bridge, 350 small block chevy with a 280 stern drive SP, and a 1.61 lower ratio.
FYI.... the 1.61:1 reduction is an over-all reduction.
In other words, it is a combination of the transmission (upper gear unit) reduction plus the lower gear unit reduction.

I just purchased a DP-D or E, gunmetal grey in color, (perhaps a 290?) lower leg,
the 290 DP is a candidate for your drive, but it is not the same as the DP-D or E lower gear unit.

and according to the numbers on the large (forward) shaft, the gear ratio is 1.78 (3861458 part #), and the housing has the diesel type exhaust outlet (it's below the cavitation plate, oval shaped, not the same as the gasser exhaust like my original 280 lower)
Yes, that is correct. The E drive is for a diesel engine system.

Now, I've been reading alot of forums and talked to a few volvo penta mechanics, and I'm getting discrepancies between what I am reading and what I've been told. I was told that the DP-D or E won't work with the upper,
Bad info..... it will work but will not offer the correct over-all reduction.

The E transmission gears are unique. The E transmission gear set gives this transmission an additional reduction, which in turn creates a unique over-all reduction and avoids using the less stout 2.30:1 or 1.95:1 lower gear set.

The diesel engine offers more torque.
So.... in order to see an over-all reduction of 1.95:1 (for example), the E transmission along with a 1.78:1 lower (a much stronger gear set), gives a reduction of close to 1.95:1 without using a 1.95:1 lower gear set.

the only reason I was told as to why it may not work is due to the ratios from the upper to the lower are not quite compatible, and things may "break", but that doesn't make any sense really IMO,
See above.

to yes it will work no problem(with some shimming required for the tapered roller bearing).
Yes..... the A and B dimension must be taken, and the correct shimming above the tapered roller bearing race must be done.
However, there is a problem.
Your small V-8 needs a 1.95:1 reduction. It will not work with a 1.78:1 lower unit because the reduction is not great enough for your hull.

By what I can physically see is, the lower DP setup I just bought, looks really close to the 280 lower s/p setup, mounting surface, size(the DP cavitation plate is slightly longer) and looks are almost identical, I even test fitted it to the upper and it bolts right up to all the mounting holes, the ONLY obvious part that's different is the vertical shaft, the DP is shorter, and the SP is longer, I was told that all I need to do to fix that is to install the longer sleeve in place of the short sleeve.
This lower gear unit will indeed bolt up to your 280 s/p Intermediate housing.
During and after the DP-C, all DP vertical shafts became short, of which requires the long vertical shaft spline coupler.

My question is, should there be any issues with this type of swap?
Yes..... the 1.78:1 is too tall for the SBC engine and your heavy 28 ft Campion SDN F/B boat.
However, it can be made to work in a very light weight hull.

I just don't want things "breaking" falling apart, ect while out in the middle of no where, or did I just waste my $ on something that will only work as a paper weight... BTW, I am willing to change out parts, convert, whatever it will take to make it work...
Changing a 1.78:1 DP gear set to a 1.95:1 gear set will be cost-ineffective.
A gear set alone will run you about $1,800+ .
Now add new bearings and 6 to 8 hours set-up time, and you can see that is does not pencil out very well.

Do you also have the E transmission and the E Intermediate housing?????

Click to expand...

Hi Ricardo,
thank you! very informative! you just saved me a truck load of headaches , was worried that what I have won't work at all, period, so I do have options to make this setup work for my application, great to hear that I can change out the gear ratio on the lower unit that I just bought, which you mentioned that it's not cost effective, and I can understand that, however, after looking online for a complete duo prop with the 1.95 ratio, I'm looking at $3500 and up just on the lower unit, so I guess it's safe to say that either way I have spend a small fortune on getting my lower leg re-geared to the 1.95 or buying another dp with the proper gears.

Unless, I build a 350 stroker AKA the 383, would the 1.78 gear ratio now be adequate for my boat? for I found out that the 1.78 ratio is also used on the 7.4L 454 bbc, and the 5.8L 351 ford, hmmm, interested in hearing your opinion ...

Do you also have the E transmission and the E Intermediate housing?????

no I don't have the E transmission or the E intermediate housing, just the lower piece, is that something that is a must for this application? or is that something I need that will aid to this build and keep cost down? please let me know,
thanks

...........................

BCCI said:

Hi Ricardo,
thank you! very informative! you just saved me a truck load of headaches , was worried that what I have won't work at all, period,
Correct....... the 1.78:1 reduction is incorrect for your SBC Engine.
You will need the 1.95:1 lower DP unit.

so I do have options to make this setup work for my application, great to hear that I can change out the gear ratio on the lower unit that I just bought, which you mentioned that it's not cost effective, and I can understand that,
Correct.... it is typically NOT cost effective to change from the 1.78:1 to the 1.95:1 gear set with new bearings and set-up time.
This work (should you do it) needs to be done by an experienced AQ series Volvo Penta technician, and by one who can offer you a guarantee.

however, after looking online for a complete duo prop with the 1.95 ratio, I'm looking at $3500 and up just on the lower unit, so I guess it's safe to say that either way I have spend a small fortune on getting my lower leg re-geared to the 1.95 or buying another dp with the proper gears.
If you consider buying another unit, be sure to pull the prop shaft bearing carrier and look at the gears/bearings.
You'll need to build one of my special carrier puller tools.
Nothing with regard to shimming is disturbed when doing this..... regardless of what anyone will tell you!
It will cost you 2 new carrier O-rings ONLY!
(see image below)

Unless, I build a 350 stroker AKA the 383, would the 1.78 gear ratio now be adequate for my boat? for I found out that the 1.78 ratio is also used on the 7.4L 454 bbc, and the 5.8L 351 ford, hmmm, interested in hearing your opinion ...
As I suggested earlier, the 1.78:1 reduction is too tall for the 5.7L SBC Engine.... especially in your heavy hull.
It will work with a correctly built 6.3L SBC (383 cu in).
(correctly built = incorporating a Q/E within the combustion chamber)
In other words.... NO GM style Full Dished pistons!

Rick said:

"Do you also have the E transmission and the E Intermediate housing?????"

Click to expand...

no I don't have the E transmission or the E intermediate housing, just the lower piece, is that something that is a must for this application? or is that something I need that will aid to this build and keep cost down? please let me know,

The E transmission uses the large diameter driven gear bearings. These bearing retainers will only fit into the C or later Intermediate housing.
In other words, you would need a C or later Intermediate housing in order to mount the E transmission.
With the E transmission, your over-all reduction should be closer to being correct for the 5.7L SBC engine!

All lower gear units will interchange ..... but must incorporate the proper tapered roller bearing "race" shimming procedure.
Likewise when swapping transmissions....... the correct shimming procedure must be followed!

thanks

Click to expand...

Oooops..... I forgot to post an image of my prop shaft carrier puller tool.

My tool works on either AQ series s/p or DP bearing carrier.

Be sure to use grade #8 7/16" NC all-thread and to use coupling nuts and/or grade #8 nuts!