[C38] RPM for smooth transmission change

[Tom T.]

Hello Rob Cornelsen and salty Catalina 38 mariners,

The Hurst transmissions have an ingenious method of shifting where the 
rotation torque of the input shaft causes clutch disks on a spiral shaft 
to engage resulting in a solid lockup with only finger effort on the 
shift linkage.

If your transmission does lock up properly without slippage, the clunk 
you feel probably isn't the fault of the transmission.   The original 
Universal engines employed a damper plate that used steel springs that 
were prone to fatigue and failure.  If one or more of your springs have 
failed, it would result in a clunking when you shift because the damping 
effect would have been compromised.

I replaced my flex plate with a PYI plate which not only uses synthetic 
damper material instead of steel springs prone to fatigue failure but 
the PYI flex plate parts are captive to each other so a damper material 
failure will never result in a disconnect from the engine to the 
transmission.

I had the springs fail on my original Universal flex damper and it was 
like I was stuck in neutral.  This was really exciting because I was 
moving my boat to a hurricane hole as hurricane Charlie was bearing down 
on us and winds were already building and no towing services were 
available because all were working overtime moving other boats to safer 
moorings.

I don't want to be accused of presenting an arm chair diagnostics of 
your transmission problems but from my own experience I would expect 
your problems are with the flex plate and not the transmission.

Tom Troncalli
recovering ex-Catalina 38 owner, Hull #95 Renata





On 9/16/2013 6:04 PM, Rob Cornelsen wrote:
> Pierre,
>
> My experience is that engine RPM needs to be as low as possible. 
>  Throttle back until you feel the spring but not further or else the 
> engine will shut off.  This takes some practice :) Any higher and you 
> will hear the clank of the damper plate protesting the gear change. 
> With this said I experienced a bad shift yesterday after years of 
> practice :(
>
> Good Luck!
>
>
> Rob Cornelsen
> Catalina 38 #223
>
> ------------------------------------------------------------------------
> *From:* Pierre Patino <pierre.patino at gmail.com>
> *To:* Catalina 38 Listserve <listserve at catalina38.org>
> *Sent:* Monday, September 16, 2013 5:44 PM
> *Subject:* [C38] RPM for smooth transmission change
>
> Hello All
>
> I just read every posting since 2005 containing the word 
> "transmission" and I did not find what I was looking for.
>
> It seems to me that I need lesser and lesser RPM to effect a 
> transmission change, very close to the point of stalling. I don't have 
> an idle setup, the boat's stock throttle goes all the way down to 
> cutoff so it's a matter of listening to the engine which sometimes is 
> difficult in high winds.
>
> What could be causing the transmission's lack of proper shifting until 
> the RPM is very low? Is time to rebuild/replace/sell the boat?
>
> Thanks for your time.
>
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