Replacing head 1980 CD27

Warren Kaplan · Post by **Warren Kaplan** » May 31st, '10, 15:08

I'm considering either upgrading or replacing the head on my 1980 CD27. According to the manual for CD yachts, the CD27 came with Gross Mechanical HC PB head. Gross Mechanical is Groco.

Groco now sells the HF model which they say is a great improvement over the old HC model. They have an upgrade kit that is supposed to upgrade the HC to an HF with a 15 minute procedure. Does anyone have any experience with this??

Second...if I decide to just replace the old HC model, does anyone know of one that would be an exact fit, so I can use the same mounting holes? Perhaps the new HF model will fit the bill but I'm not sure.

Any other recommendations are welcome. The less I have to modify the head compartment for a new head the better off I will like it.

Thanks

Joe CD MS 300 · Post by **Joe CD MS 300** » Jun 1st, '10, 05:36

Warren,

I replaced the original Groco head in 2005 shortly after buying Quest with the HF (which I'm assuming is still the current model). There were two improvements if I am remembering correctly. The base was changed from plastic to bronze and there was some type of improvement to the pump innards said to reduce maintenance.

The mounting hole were slightly different. Two of four matched up. No change in the hose attachments, or not enough to matter.

Joe

Warren Kaplan · Post by **Warren Kaplan** » Jun 1st, '10, 05:48

Thanks Joe. I have to check out what ails the old head a little more before I commit to a new one. The trouble may actually be with a "clogged" raw water intake seacock.

Seems I'm not getting any water with the "Wet Flush" setting. But the the flush dry setting works okay. If its not the seacock or a clogged intake hose I imagine the problem has to be in the "guts" of the pump cylinder.

The boat is afloat and I have to be prepared to check the seacock in case there's trouble there. So it won't get done until this weekend.

Joe CD MS 300 · Post by **Joe CD MS 300** » Jun 1st, '10, 16:37

Warren,

I had the same problem. There is a little "flapper" valve in the pump that creates a vacuum so that you can draw in water. I think there is a little spring that gets weak over time that is to help make the seal. They have a rebuild kit. You can also "prime the pump" by filling the bowel to the rim with water. It may work for a while after doing that.

Joe

Cathy Monaghan · Post by **Cathy Monaghan** » Jun 1st, '10, 16:51

Hi Warren,

Ours was upgraded to the HF but that was so long ago I couldn't tell you what was involved. And I've replaced nearly every part since then except for the bowl and the seat. I think the seat will be next.

Cathy
CD32 Realization, #3
Rahway, NJ
Raritan Bay

Mike Raehl · Post by **Mike Raehl** » Jun 1st, '10, 19:17

Warren,
I replaced my original Groco HC with a new HF model after a "rebuild kit" failed to correct the problem. The PO had given up on the head and had installed a porta potty in the v berth. As mentioned in an earlier post, two of the four base mounting holes are an exact fit. The other two are about one inch wider than the HC model. To avoid drilling additional holes in the fiber glass liner, I put a 3/4 inch thick teak "transition block" between the new head and the fiber glass. The two mounting points that did not align were bolted to the transition block with SS machine screws and tee nuts. Then the new head with attached transition block was mounted to the liner using longer screws through the original holes in the liner. The two screws that did align capture the head mounting tabs and then through the block.

Cathy,
My First Mate insisted that we keep the original seat from the HC model since she found it to be much more comfortable. So I have an almost new HF model seat with lid in case you are interested. Seems that not all changes are improvements.

Jim Walsh · Post by **Jim Walsh** » Jun 1st, '10, 19:31

After installing a rebuid kit I was still not getting the suction I should have and I found a hairline crack in the body of the cylinder housing. A new cylindar assembly was so close to the price of a new HF that it was an easy decision to go for a new head. The new HF is great.

Steve Laume · Post by **Steve Laume** » Jun 2nd, '10, 06:55

Same experience as most above, except I bought the rebuild kit and then a new head.

I had called Groco and they were great! Before you decide to rebuild, take a very close look at the plastic flanges around the base of the pump. Most likely they are cracked or soon will be. I am a rebuilder in general but this is one case where I would definitely recommend a replacement.

I was surprised to find lag bolts holding a rather heavy and vital object in the boat. One of the things I did while drilling the slightly new bolt pattern was to add an inspection port just aft of the head. This allowed me to get my hand under the shelf and bolt the new head in with big fender washers and self locking nuts. I just didn't trust those little lag bolts, Steve.

Warren Kaplan · Post by **Warren Kaplan** » Jun 2nd, '10, 07:09

Steve,
Did you replace and Groco HC with an HF?

Bob Luby · Post by **Bob Luby** » Jun 6th, '10, 20:17

We replaced the Groco HF with a Raritan atlantes Raw Water electric flush toilet in our cape dory 36. The head is free to a good home. It does need a new seat.

Toilet is in Wallingford CT.
________
NASH METROPOLITAN HISTORY

rtbates · Post by **rtbates** » Jun 7th, '10, 08:42

I did the HF for old HC switch years back. The HF still had issues with the pump being a wimp. Finally I threw the HF out and bought a LAVAC with the Henderson Mark5 pump. That's a pump...Two years later it still flushes tennis shoes...haha

rorik · Post by **rorik** » Jun 7th, '10, 17:40

I really like the Lavac I put in my CD28.
Simple design. Easy to use. The only parts to go wrong are the seat seal and the pump diaphragm. And those are easy to replace. Couple pics of mine here:
http://capedory.org/board/viewtopic.php?t=26782

The Cape Dory Board

Replacing head 1980 CD27

Replacing head 1980 CD27

The new HF is great

HF Free to a good home.

Lavac FTW