Re: [OMC-Boats] Outdrive Gear Ratios v6 versus v8

Hi Lee and list members:

Thanks for reply.  I'm thinking about bidding on a cheap '67 rogue on ebay right now,  mainly because it has great seats identical to the '68 sportsman seats, and because it's only 50 miles from my Sportsmans in Michigan.  But the cost has reached $360, so it would be great if it had significant other parts I could use - like the outdrive.  Hence my question on whether it is practical to switch gears in the upper gearcase.  I figure if I wear out a Sportsman outdrive, hopefully its upper gears can be transplanted into the outdrive from the Rogue.

Anyone wanting a '67 Rogue in good condition should take a look.  This one has a lot of life in it and should not be a parts boat.  Says the engine does not start, but also says it has sat for 10 years unused.  I'd withdraw if someone on the list wanted it to restore:

http://tinyurl.com/67Rogue

-Doug Julien

--- On Sun, 4/12/09, lks@... <lks@...> wrote:
From: lks@... <lks@...>
Subject: Re: [OMC-Boats] Outdrive Gear Ratios v6 versus v8
To: dfjulien@..., "Evinrude & Johnson Boats of the 1960's and 70's" <omc-boats@...>
Date: Sunday, April 12, 2009, 7:20 AM

Hi Doug,
 
So let's be clear about your goals?  Your
asking if it's possible to take the outdrive assembly from a V8 and replace it's
UPPER GEAR SETS (21:16; 21:17, 21:18, 21:19) with UPPER gear sets from
the Buick V6 (25:25) ratio's ?  I'm unclear because your footer lists
68 and 69 Sportsman's which probably already have V6 (25:25) stock gear
sets?
 
First make sure you have what you think you have:
Is your V8 unit a four or five bolt cap unit? You want the later five-bolt cap
units introduced after 1967. Secondly is it a long-shaft or short
shaft?
Short shaft's usually came off later Ford V8's
(170-190-235hp)  which had different ratios (see my chart). You notice they
all share common lower gear sets of 15:23. It is the upper gear sets that
vary.
 
I've never personally done this job, I understand
it can be complicated by year-to-year changes and differences in shims,
bearings, etc. Mixing and matching usually leads to problems.
 
What I did was to exchange the entire power unit
without cracking open the units. At my altitude, I considered the fact that my
21:16 V8 gearing is a little tall, but I have enough room to still compensate by
running a relatively short 13-inch SST prop. The 21:19 set used in the 165-hp,
straight six Chevy is ideal but hard to find. The 302 Fords came in 175-hp @...
21:18, and 190-hp @... 21:17 but were usually as I said before short-legs. Remember
I have a 24 per cent power loss when I run at 7000 feet, so I seriously
considered running lower V6 gearing in my V8. The benefit of running the taller
V8 gearing is I get fantastic cruising fuel economy, (that is provided I'm not
into the secondaries of the QuadraJet.)
 
So to summarize:  Find out exactly what you
have, by counting teeth, or precisely counting input to output rotational
relationships. And either exchange entire down-leg units or find someone
mechanically familiar with rebuilding the outdrive with the desired gear set
ratios.
 
Happy Easter
 
Lee Shuster
 

  ----- Original Message -----
  From:
  DOUGLAS
  JULIEN
  To: Evinrude & Johnson Boats of the
  1960's and 70's
  Sent: Saturday, April 11, 2009 10:51
  PM
  Subject: [OMC-Boats] Outdrive Gear Ratios
  v6 versus v8
  

  
    
    
      Hi Lee and list folks:

Lee, when you upgraded from
        the V-6 to the V-8, did you change the gears in your outdrive?  Per
        your prop page, these engines used different ratios in the upper
        gears:

http://hhscott.com/evinrude/props.htm

I'm
        wondering how to do the reverse - to change the V8 gears in an outdrive
        to gears designed for the V6.  Is it a simple matter to switch
        these things out?

Thanks for any info.

-Doug Julien, '68
        and '69 Sportsman 155's
  
  

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Received on Sunday, 12 April 2009