Hurth Transmission - bent fingers on coupling

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Hurth Transmission - bent fingers on coupling

The original shop hired to install a PSS dripless system bent the fingers when parting the prop shaft coupling.  The fingers are on the transmission side.  The shop lost their lead then passed off completing the work to another shop.  Said completing the job was beyond them.
Shop #2 pointed out the original bronze (brass?) prop shaft was worn by the stuffing box and out of tolerance required by the PSS.  New SS prop shaft and cutlass bearing ordered.  Upon reinstalling the new parts, shop #2 said the coupling would not join because of bent fingers by shop #1.
Shop #2 talked to the tech at shop #1 who explained an incorrect procedure for separating the coupling.  Shop #2 talks to a transmission shop about removing the coupling from the transmission.  Transmission said the transmission needs to come out (requires pulling the motor to remove the bell housing, then unbolt the transmission, bolts accessed from inside the bell housing), case split, try to locate an obsolete but working condition flange and reinstall.  10 hours labor (not counting labor to remove and reinstall engine and transmission).  Shop #2 suggested it would be cheaper to locate a used transmission and install that.
A #3 diesel shop working on a s/v on the hard next to mine and offered a consult.  They also determined bent coupler fingers.  Shop #2 returns while shop #3 is there.  All good w/ all four mechanics in the aft birth saying shop #1 bent the fingers.  Both shops agreed saying the ductile iron fingers could yield/break when bending back, the races/shims/bearings/etc in the transmission would be damaged if banging on it.
Shop #2 and I agreed there is not much to loose, to draw the couplings together with the bolts, measure, hammer out the bent fingers w/ punch, etc.  I called shop #1 to discuss the scenario / conundrum.  Shop #1 agreed it was worth a try to reassemble the coupling with potential damage to the transmission.
Shop #2 was successful at reassembling, but said it required a few big hits from the dead blow hammer.  7 thousands was the best they could do, wanting 2 thousands.  No possibility to shim/adjust to motor with the fingers not square.
Questions 1) 7 thousands - much vibration or okay?  2) Should there be no vibration and transmission appears to be working fine, would flat races or shims present right away or something that could take a few hours?  3)  Who has a transmission for sale?  4) Suggested recourse with shop #1.  They need to be bonded and insured to work in the yard.

Best,
-Russell

Russell Green
S/V "GoodwiII"  #759
1987 C36 MKI TR/WK M25XP
Moored: Deale, MD

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Pretty important that those fingers are square to begin with.  Hitting with a hammer is not good for thrust washers.  Faces not square and flat will manifest in difficulty in obtaining good shaft alignment.  Even if you get alignment, it might not be "true" resulting in vibration / rapid cutlass bearing wear.  If the hammering damaged the thrust washers, then the failure may not be noticed for some time.  Latent symptoms might be shifting difficulties.

I agree with shop #2, i.e., worth a try to put into service and monitor.  If vibration is excessive, then one recourse is to find a HBW-50 transmission suitable for rebuild and get this done.  Not sure if on a MKI the engine needs to be moved or removed.  Someone else needs to weigh in on this one.  Good luck.

Nick Caballero
Retired C36/375IA Mk II Technical Editor

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Need to purchase a new or rebuilt Hurth HBW-50 transmission.  Any reason not to purchase from Foley Engines?  Are there other options?
Pulling the M25XP looks straight forward, but if someone could point me to a thread with pointers, that would be helpful.  I searched to no avail.

http://www.ebay.com/itm/Reman-ZF-Marine-Hurth-Transmission-ZF5-HBW50-/300575549607?hash=item45fbb2e8a7:m:mHJ0Q0SDqIXGJY65hIW4D1w&vxp=mtr

Russell Green
S/V "GoodwiII"  #759
1987 C36 MKI TR/WK M25XP
Moored: Deale, MD

Maine Sail
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Posts: 324

[quote=down_shift]Need to purchase a new or rebuilt Hurth HBW-50 transmission.  Any reason not to purchase from Foley Engines?  Are there other options?
Pulling the M25XP looks straight forward, but if someone could point me to a thread with pointers, that would be helpful.  I searched to no avail.

http://www.ebay.com/itm/Reman-ZF-Marine-Hurth-Transmission-ZF5-HBW50-/300575549607?hash=item45fbb2e8a7:m:mHJ0Q0SDqIXGJY65hIW4D1w&vxp=mtr[/quote]

Please, please, please DO NOT DO BUSINESS WITH FOLEY ENGINES. You WILL be sorry if you ignore this advice...

 

-Maine Sail
https://www.marinehowto.com/

 

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[quote=Maine Sail][quote=down_shift]Need to purchase a new or rebuilt Hurth HBW-50 transmission.  Any reason not to purchase from Foley Engines?  Are there other options?
Pulling the M25XP looks straight forward, but if someone could point me to a thread with pointers, that would be helpful.  I searched to no avail.

http://www.ebay.com/itm/Reman-ZF-Marine-Hurth-Transmission-ZF5-HBW50-/300575549607?hash=item45fbb2e8a7:m:mHJ0Q0SDqIXGJY65hIW4D1w&vxp=mtr[/quote]

Please, please, please DO NOT DO BUSINESS WITH FOLEY ENGINES. You WILL be sorry if you ignore this advice...

 [/quote]
Maine Sail, thanks for the feedback.  After further research, I landed on Trans Atlantic Diesel who had a new ZF-6M for a better price.  Researching further, I located your feedback that "new" ZF boxes are $hit and to head over to Bata Marine and the TMC-40.  Spoke with Farron who took the time to address my questions and email technical literature.  Ordered a TMC-40, shifter bracket, damper plate, and globe drive saver from them today.  All for a better price again.

Russell Green
S/V "GoodwiII"  #759
1987 C36 MKI TR/WK M25XP
Moored: Deale, MD

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Hurth is no longer in business, so new HBW-50 is not going to be possible.  Foley might have available a rebuilt HBW-50, they may carry the drop-in replacement, the ZF-5M, but I think this has been discontinued in favor of the ZF-6M, which I understand to be 1" longer, both otherwise identical.  Best to give them a call a see what they recommend.

Nick Caballero
Retired C36/375IA Mk II Technical Editor

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TMC-40 installed.  Issues with the shifting geometry and trows being sorted out.

Russell Green
S/V "GoodwiII"  #759
1987 C36 MKI TR/WK M25XP
Moored: Deale, MD

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Russel
I big fan of the TMC 40. I had one in another boat.
Please let us know how it all works out. I think you'll love the transmission.

Chuck Lennox
97 MKii Ventura Ca
Island Girl Hull #1611

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Shifting linkage is now worked out. The horizontal bracket that came with the transmission was modified to include the bellcrank to reverse the shifter throw.  The hose connecting the exhaust riser to aqua lift tank was bad.  Replacing with a hump tube from CD.  Already lost two months of sailing over this issue.  Can't wait to get out this weekend.

Russell Green
S/V "GoodwiII"  #759
1987 C36 MKI TR/WK M25XP
Moored: Deale, MD

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