Mike,
>From my Mil-veh experience with my M51 gas dump (1962), I'd say the only
practical way your CCKW is going to go at 65 mph consistently is on the back of
a flatbed trailer. My newer M51 has a difficult time maintaining 55 mpg and I
have a state of the art 1962 602 cu in gas engine in good shape. These things
just were not made to go fast. It goes great at 48-53 mph but that is about
it. It goes really good at about 2 mph in low first and can pull itself through
all kinds of slime and crud.
I don't mean to rain on your parade, but I gave up on 65 mph about a month after
I got it.
Good Luck,
Dave
Mike D'Ambrogia wrote:
> > Of all the bits to change........
>
> I was waiting for that... <smile> Overall I like the idea of the original
> engine/transmission configuration, my feeling is that the engineers who
> designed this put it together that way for a reason and used the best
> combination of reliable parts and engineering that was available back in the
> day. But, since the motor has been sitting for over 40 years its bound to
> need some work and that will mean downtime for the truck - that and the fact
> that highway driving (3 hours or more at a streach on CA 65 mp/h freeways)
> will be plentiful concerns me for the safe running of a 270 engine in good
> shape.
>
> >The 6 x 6 drivetrain is rather lean for the existing horsepower. My
> >experience (watching DUKWs mostly) is that either the intermediate diff
> >goes or the intermediate output from the transfer case - one takes out the
> >other not figured out which. As a completely separate problem the pillow
> >block which takes the rear drive over the intermediate axle goes west if
> >it isn't maintained and leaves you seized by the side of the road.
>
> This is my big concern, overdriving the drivetrain with more HP than it was
> designed for.
>
> >The only bits of the system which never cause trouble are the gearbox
> >(unkillable if unfortunate in the ratios) and the engine. My advice would
> >be to stick to the stock engine and drivetrain, with particular attention
> >to careful maintenance of the transfer case and pillow block. One good
> >point is having a matched set of rear tyres which seems to help a lot.
>
> Ok, maybe I need to approach this from a different direction. If one needs
> to drive the 353 at freeway speeds on a regular basis what would you
> suggest? It seems like the transmission drive ratios are the keeper of
> reduced speeds. The primary motivator for the swap is the engine, getting
> it out and taking the time to rebuild it nicely while getting the truck on
> the road quickly, and not burning it up while running on the freeway. I
> love the idea of keeping the transmission in there (i must be one of the
> sick one who smiles at the idea of double clutching and I agree, the thing
> was bullet-proof), is there a list of motors that bolt directly up, or a
> source of adapter plates?
>
> >If you must upgrade go for a newer version of the same engine. I think
> >Jack Tomlins DUKW had the 302 which had more grunt in basically the same
> >engine, and if you need to upgrade the engine figure on at least using a
> >transfer case and drive system from a newer 6 x 6.
>
> urrrghh, hoping to keep it simple by just swaping engine and trans and
> having a new driveline manufactured between trans and xfer case. what kind
> of xfer case would you suggest/recommend? Have any mpg comparisions between
> the older 270 and the 302 been submitted?
>
> > You can fit larger
> >diameter tyres for more road speed if you need it - several suppliers have
> >11:00 x 18 singles which have more plies in the construction and a bigger
> >rolling radius.
>
> good point, need to dig out the tire to speed calculator...
>
> >Maybe I'm being a bit gloomy - properly serviced and used the 6 x 6 will
> >go anywhere anytime, just remember transfer cases can be noisy, and can
> >scream all day but still work properly....
>
> No, not at all - I can easily respect the purist view. The truck is going
> back into service vs. being restored so my mindset is not finely tuned to
> keeping it all original. I appreciate your thoughts.
>
> Mike
>
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This archive was generated by hypermail 2b29 : Sun Jul 02 2000 - 23:51:32 PDT