Long stroke motors do not like to be over reved.
You also have to stop it.....
Steve AKA Dr Deuce
----- Original Message -----
From: DaveCole <davidcole@tk7.net>
To: Military Vehicles List <mil-veh@skylee.com>
Sent: Tuesday, June 27, 2000 7:21 PM
Subject: Re: [MV] CCKW 270 Upgrade
> 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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>
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