can I swap two piece lower unit for one pice?

[volundur]

hi!

I just realized that my 1979 70 hp Chrysler has a broken lower unit, the upper piece is cracked and the gear housing has also suffered damage.

I have a donor engine that is a 105 hp 1977. It has a nice one piece lower unit.

Do you guys think I could swap the whole motor leg from the 105 hp to the 70 hp?

This is the motor leg on the 70 HP - http://www.**********/parts/search/Merc2/Chrysler/70 (1979)/709H9A/MOTOR LEG/parts.html

This is the motor leg on the 105 HP - http://www.**********/parts/search/Merc2/Chrysler/105 (1977)/1059HG/MOTOR LEG/parts.html

 

[volundur]

Re: can I swap two piece lower unit for one pice?

dang - the website is masking my links so I'll mention the serial numbers instead.

1059HG - this is the donor engine, 105 hp 1977 model.
709H9A - this is the one with a broken lower unit. 70 hp 1979

 

[Frank Acampora]

Re: can I swap two piece lower unit for one pice?

NO! The bolt pattern is different AND the drive shaft on the two piece lower is one inch longer. They are designed completely differently and will not swap. You can not even swap in the gears.

HOWEVER, your engine dates confuse me. The older one should be a 2 piece lower while the newer one should be one piece.

A couple of photos might clarify things.

 

[volundur]

Re: can I swap two piece lower unit for one pice?

Hi ! thanks for your input. - I realize the bolt pattern would differ, but how about if I swap the whole leg, including the mid section?

Pics of my newly rebuilt Chrysler SKIER:


The donor engine with one piece lower unit:

 

[Frank Acampora]

Re: can I swap two piece lower unit for one pice?

Yes, the bolt patterns for the engine block and all the cowlings are the same. So, you can swap the complete midleg/lower unit assembly. It is not a too difficult task. Back a couple of years ago I did just that to prove that indeed the one piece was faster. The post should be floating around somewhere.

Just be aware that the two piece lower unit is about 3 MPH slower and it is one inch longer. You SHOULD see an slight increase in speed with the one piece lower unit. AND--- It looks prettier too! Plus, it is easier to find props. Do not worry about the one inch shorter leg. On most hulls it makes no difference and in fact you still may be able to jack the engine another inch to put the anti-ventilation plate one inch above the bottom of the hull.

Your REAL problem may turn out to be the power tilt/trim. These tend to corrode and almost weld together making them a bear to swap.

 

[volundur]

Re: can I swap two piece lower unit for one pice?

Thank you so much for the info Frank, now well deal with it with confidence

I'll try and find the thread you mention.

All the best.

 

[Frank Acampora]

Re: can I swap two piece lower unit for one pice?

See my private message to you!