[C38] Transmission

Mon May 14 18:23:54 EDT 2012

PYI is  located in the Seattle area they make a lot of  stuff
http://www.pyiinc.com/  they are also a customer of mine.

Steve

From: listserve-bounces at catalina38.org
[mailto:listserve-bounces at catalina38.org] On Behalf Of Mark Lewis
Sent: Monday, May 14, 2012 3:20 PM
To: tdtron at earthlink.net; Catalina 38 Listserve
Subject: Re: [C38] Transmission

Tom,

What is PYI?  A trans company?  Where are they located, and how much
money are we talking about?

Mark

PS.  My conversion to propane was very smooth.  Burners are working,
just need new thermostat for the oven (the PO reported that mine didn't
work under CNG either, so it has nothing to do with the conversion.  It
didn't cost me anything to convert the range ( my propane supplier
redrilled the orifice holes after capping them for free...I bought my
shutoff solenoid, hose, pressure gauge and fittings through them for
$142 which includes the hose and adapter for my Magma grill).  Still
working on the fridge.

On Mon, May 14, 2012 at 12:46 PM, tdtron at earthlink.net
<tdtron at earthlink.net> wrote:

Hello Larry,

I'm no expert on transmissions but I may have some answers for you
anyway.

The "clunk" you refer to is usually caused by two things. The Hurth
transmission uses a spiral input shaft with matching driven plate that
allows the torque of the shaft to engage the drive plates like a nut on
a
bolt.  The rotation of the input shaft actually tightens up the drive
plates when you shift gears.  This is how our transmissions shift so
easily
when a manual transmission car or truck will have a pressure plate and
throwout bearing and clutch pedal which we don't have.  The reasons cars
and trucks don't use spiral input shafts like our boats do is because
you
can't "slip the clutch" with our systems, our systems are either totally
engaged or totally disengaged so they won't work on street vehicles.

Another source of a clunk sound is the slack in the gears which
increases
from wear.  All of these components with slack combine to cause the
clunk
but with a good flex plate, this clunk sound should not be a problem.

As regards to the "sweet spot" your technician was telling you about, it
is
the truth.  Every engine has resonant vibrations that are more
pronounced
at certain RPMs and less at others.  Having only three cylinders
compounds
the problem as does being diesel.  Idling is much more detrimental than
motoring but low speed in either case increases gear chatter and wear.
Sometimes speeding up or slowing down  will reduce but not eliminate the
resonant vibrations.

I replaced my Universal flywheel flex plate with the PYI unit and my
engine
was noticeably quieter and smoother at all speeds.  Another extremely
important benefit of the PYI flex plate is that the engine will continue
to
drive the transmission even if the flex plate fails, unlike the steel
springs Universal unit.  The PYI shaft coupler also offers this same
benefit of positive engagement even with cushion failure.  I replace
both
my flex plate and shaft coupler and it was like I had re-powered to a
smoother engine with more cylinders.  The results were nothing short of
incredible.

Universal flex plates have a history of fatigue failure of the cushion
springs which can break like glass after they fatigue leaving your
engine
without thrust.  All of those pieces of the steel springs have no where
to
go but around and around inside the bell housing causing havoc to your
aluminum bell housing, starter pinion, flywheel and ring gear.

PYI claims their synthetic material isn't prone to fatigue but even if
the
cushion material ever did fail, you would still have thrust in both
forward
and reverse because the metal dogs are captive with the synthetic
material
acting as a cushion between the steel dogs but if the cushion material
somehow magically disappeared, the dogs would still propel the boat.

One problem I did have with the PYI flex plate was that when I tried to
install it I couldn't get all of the flywheel bolts started without
slightly filing the plate holes with a small rat tail file to help get
the
bolts started.  I don't know if the bolt pattern irregularity was from
the
flywheel,  the PYI flex plate, or both but the amount of material I had
to
remove was only a thousandths or two of an inch so there was no balance
or
concentric alignment problem.

I know money doesn't grow on trees and PYI flex plates and shaft
couplers
aren't cheap but the PYI upgrades were some of the best improvements I
ever
made to my boat.  With the upgrades we could idle back to our slip with
almost no vibration or noise  and sometimes I thought the engine had
died
because it had become so quiet and smooth.

Tom Troncalli

> [Original Message]
> From: Larry Malmberg <Larrypi at roadrunner.com>
> To: Catalina 38 Listserve <listserve at catalina38.org>
> Date: 5/14/2012 12:28:52 PM
> Subject: [C38] Transmission
>
> A very special Thank You to Jay Sorensen for coming through with a
used
> transmission.  Picked it up Sunday and am taking it to the shop today.
A
> quick question though regarding transmissions.  Does every one with a
Hurth
> transmission get that "clunk" when you put it into gear?  Also, the
> transmission guy tells me that there is a "sweet spot" for engine rpm
when
> idling, this so called sweet spot causes less wear on the damper and
gears,
> what's your experience with this?  My idle is set at about 900 rpm
which
> apparently is a bit too low?  I'm told the damper was worn from
"engine
> chatter" as well as a few of the gears, the engine chatter is
apparently
> from the idle being set too low.
>
>
>
>
>
> Best regards,
>
> Larry Malmberg
>
> 7231 Boulder Avenue Suite 507
> Highland, CA 92346 PI 15211
> Telephone  909-208-1847
> FAX           909-991-7568
>
> E Mail  Larrypi at roadrunner.com
>
>
>
>  
> Life is short, Break the rules, Forgive quickly, Kiss slowly, Love
truly,
> Laugh uncontrollably, And never regret anything that made you smile..
>  
> "The American Indians found out what happens when  you don't control
> immigration"
>
>
> "Life is not a journey to the grave with the intention of arriving
safely
in
> a pretty and well preserved body, but rather to skid in broadside,
> thoroughly used up, totally worn out, and loudly proclaiming; WOW--
What a
> Ride!"
>
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