Hurth Transmission

[Betterdays]

The clutch on my Hurth  HBW 50-2r is shot.  I need to get a new as the part to rebuild my existing one are not available or so prohibitive its cheaper to get a new one.  I'm leaning towards the new one.  Any thoughts ?   

1992  Compac 27

Thanks
Stephen

[deisher6]

Hey Stephen:
I don't have any solution(s) for you but am always interested in required repairs on C-27's. 

I had thought that there was a synchronizer of some sort to allow the gears to mesh without grinding, rather than a clutch.

Please continue to blog about the problem and your solution.

regards charlie

[Betterdays]

From the research ive done, There is a clutch. I didn't take it apart, my yard is handling the repairs.  There is another cp 27 in the yard not sure the vintage.  But he had some linkage issues with the cable to the transmission lever.  You have to make sure the cable pushes the lever completely forward.  Mine engaged in forward but not fully and burned up the clutch, the fluid got so hot it evaporated.  It was only a 1 hour trip.  And everything appeared and sounded normal.  No fun docking in 25 mph winds with reverse only. 

[Tom L.]

I had a hurth on a 74 Tartan 37 and it was important that the linkage be adjusted so that the shift would literally slam into gear. Forward or reverse. Sounded terrible but that's the way it has to be.  If it is adjusted to shift softly it will not fully engage the clutch and will overheat the clutch.

Tom L.

[Allure2sail]

There is one in the consignment shop located in Wickford, RI. It has been there a few years. I know it is the right one because it looks just like my spare trans from my parts boat.
Bruce
S/V Allure
I should be boat shopping for a bigger boat by the end of the season, then everything from the parts boat goes with Allure.

[Betterdays]

the replacement for my transmission is either zf or twin disk  zf is almost double  twin disk.  1100 m vs 2100.  So, does anyone have an opinion on twin disk transmission?  Or zf vs twin disk ? 
Thanks
Betterdays

[Allure2sail]

Hi:
Sounds like your intent is to buy new? I'd check into the used one I mentioned before spending that kind of money.
Of course only my opinion.
Bruce

[Harrier]

I replaced my transmission last year.  I bought a Tmc 40 from Joe DeMers at
Sound Marine Diesel.  He used to rebuild the hurts, but stopped because in his opinion it is a poor design.
According to Joe;
The TMC 40 is a much better gear, because of the below reasons.

1] simple cone clutch construction. [ he Hurth uses a multi disc type clutch, more complicated, more expensive, and unreliable]

2] Overbuilt for 20 hp [ this gear is standard on our 30hp engine ]

3] direct replacement of the Hurth [ just bolt it on ]

4] 1 year warranty when buying a new gear [ Hurth /ZF is known for making any warranty claims a BIG HASSLE]

5] much less $ than a Hurth / ZF gear

So far I have been happy with new tranny.
Some other things to consider if you go this route. 
Replace the damper plate, on my boat it was made by SACHS.  It has 6 springs, a 5 bolt pattern and 10 tooth spine.  The diameter is 6-3/16" to the OD.  The bolt circle is ~5 5/8". 
Part number on the damper plate is 1866 061 001.  Joe had a replacement.
The shift linkage moved from starboard to port, so you will need a different mounting bracket for the linkage.  Joe also had this.
If I recall, this tranny is about 1/4" longer.  So your shaft will slide back slightly.
Last, it is a tight fit.  I had to jack engine all the way up to make room sliding out the old and installing the new.
All in all, it was only about a two hour job.  Good luck.

[deisher6]

Hey Harrier:
What is a damper plate? 

Does it go between the transmission and the engine, or between the transmission and the shaft? 

Thanks........I am not feeling as secure about my 30 year old transmission as I was before I started reading this thread!

regards charlie

[Harrier]

The damper plate goes between engine and tranny.  It is simply a torque transfer device that has springs in between the input and output.  The springs absorb the shock of shifting into gear, etc.

With respect to my trans, it was a gradual failure.  I almost made it a full season with it temporarily slipping.  It started as a lack of torque.  Then occasionally it would take several attempts of slamming into forward before it would engage.  It was always the worst pulling away from the dock when the fluid was cold.  By the time I got out of the marina, I'd be in good shape.  Finally one day I backed out of my slip and there was no forward gear.  I did a 360 spin in reverse and pulled it back into the slip. 
Reverse always worked fine.

Some thing else I learned from the experience....
I used to always leave the trans in neutral when under sail, thinking that was best for sailing performance.  Apparently that creates unnecessary wear on things.  I now leave it in reverse gear.  I do reverse, instead of forward, so that I'm loading up the least used gear.

[deisher6]

Hey Harrier:
Thanks for the scoop about the damper plate and description of your trans failure.
I have heard about putting the transmission in reverse while sailing.  Some even mark the shaft so that they align the prop vertically behind the keel to minimize drag.

Stephen, please continue to blog about the repair.

regards charlie

[Betterdays]

I'm working with Joe as well, with Sound Marine.  Everything Harrier has posted is the same situation, down to the 1/4 inch.
Installation not complete yet.  Joe has been exceptional, his knowledge of the situation and his patience were great.

Stephen

[deisher6]

Hey Steve and Harrier:
What was your cost?  Will Joe send me the parts?  Steve did you do the install yourself?

I have arrived.

I noticed on my trip this week that there was not full power being transmitted to the prop. The boat was not moving as fast as the rpm's indicated.  It seemed to work a little better if I backed off the throttle and shifted back into neutral then forward then eased the throttle up.

Checked the fluid.  The level was a little high but it had been that way for the past 18 months since I last changed the fluid.  The fluid was a little dirty in that you could see some black specks in it.  The transmission was not hot after using it for 45 minutes. 

[Betterdays]

guessing about 2 k
1200 transmission
need new cable and bracket
need new damper plate
new motor mounts
That's not including labor.  It took them a while. They couldn't get the shaft off,  they used lubricant, heat, puller, etc.
I'm pretty handy put this is beyond my ability, and I don't have all the special tools needed. Some of the parts were on back order so it took a while.  I got impatient and ordered from universal distributor and should have waited for Joe, would have saved some money.  The Universal distributor dealer complete rip off.  Wanted 70 bucks for v belt that I got at auto store for 4.   Fits perfectly exact same belt.
The new transmission is great. Shifts silky smooth and quiet and I am glad I didn't go with hurth

Stephen   

[Betterdays]

May be too obvious, check the prop  for marine growth, may boat is usually  a knot slower because of a sloppy bottom and growth on prop.

Stephen