can i change things around ?

[wolfie-uk]

Hi all,

to set the scene............. just bought a 5.4m rib and need an engine to suit, my preferred choice is a good old Chrysler. The RIB needs a 80 to 90 hp to run at its best.

my dilemma -

i have a 1980 Charger 85 that runs like new - SHORT SHAFT

i have a 1979 Skier 70 that needs a major overhaul - LONG SHAFT

Well the boat requires a long shaft setup,

SO can i just transplant the charger power head and gearbox onto the long shaft mid section, obviously using the Skier drive shaft / water tube and gear selector rod ? did Chrysler use the same mid sections for these engines ? and is it do able in your collective knowledge, really hope so because i think it will make for an exciting package, a 700lb boat being pushed by a 85 Charger.

regards in advance

Neal

 

[jerryjerry05]

Re: can i change things around ?

Powerhead's an easy swap.
The lower unit needs to be re-shimmed if your gonna swap gears and shafts.J

 

[Frank Acampora]

Re: can i change things around ?

Well, Let's see: First, if you mean a 20 inch shaft as short shaft (which is actually long shaft) and a 25 inch shaft for long shaft (which is actually extra long) then I understand you.
The 25 inch shaft will have 8 bolts on the bottom cap of the kingpin and the cap will be twice as long as the 20 inch cap, while the 20 inch shaft will have only four bolts. The midleg of the 25 incher will be 5 inches longer than the 20 inch midleg, but the engine bolt pattern and the lower unit bolt patterns are the same
Why not simply swap the complete powerhead onto the bottom of the 79? Everything will fit with no problem and you don't need to change the lower unit.

If the 79 lower unit is no good, you can swap driveshafts BUT you will need to change the shim package and pinion. If the 79 lower unit only needs seals, it would be better to do them than swap out the driveshaft into the 80

 

[wolfie-uk]

Re: can i change things around ?

hi Frank and Jerry, dont know why i mentioned swopping gearbox's, same gear ratio etc yes? so just a powerhead swop it will be, and to clear things up, short shaft is 16" and longshaft 21"

 

[jerryjerry05]

Re: can i change things around ?

Just remember if you take it apart and swap parts (lower)it will need to be re-shimed.

 

[wolfie-uk]

Re: can i change things around ?

well i have hit a snag already, came to start sorting things out, and the gearboxs are totally different, the charger 85 has a one piece gearbox, and the skier has a 2 piece gearbox, the fixings to the leg look the same ( have not yet dropped either to see if they line up when swopped) everything else such as mid section / tray and powerhead look identical, so the question is as per original post, is it do able ? Did chrysler change just gearbox design oram i going to find internal differances when i get round to changing things.

 

[Sprky]

Re: can i change things around ?

Just swap powerheads and leave eveything else alone. Wouldn't that be the simple thing to do.............

 

[Frank Acampora]

Re: can i change things around ?

Well, then, your 1979 is not a 1979 because here in the U.S. Chrysler changed from a 2 piece lower unit (gearbox) to a one piece lower unit in 1978-79. (Perhaps in the U.K. they continued it later.) The 2 piece and one piece lower units are different designs and NOT swappable--they have a different bolt pattern-- AND-- The internals are different too, so you can not swap gearsets, driveshafts, and propshafts from one case into the other. The 2 piece lower unit is about 3 MPH slower than the one piece lower unit and props are more difficult to find. However, the good news is that the upper drive shaft splines are the same so the powerhead can still be swapped.