Great debate: Oberdorfer vs. Sherwood

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crieders

So my boat started her life with the Oberdorfer
Replaced it with Sherwood that cooled well but was hard to access
Went with new Oberdorfer and in a strong headwind, against the tide on a hot day, engine gets up to 185-190. Makes me nervous
Thinking of going back to Sherwood
Any new views on this?
Cliff Rieders, c34 tall rig, 1990, hull #1022

KWKloeber

Quote from: crieders on September 05, 2014, 06:39:21 AM
So my boat started her life with the Oberdorfer
Replaced it with Sherwood that cooled well but was hard to access
Went with new Oberdorfer and in a strong headwind, against the tide on a hot day, engine gets up to 185-190. Makes me nervous
Thinking of going back to Sherwood
Any new views on this?

Yes, but first...

What's your:

Engine model?
Thermostat temp rating?  Checked it lately?
Hx size - 3"?
Location - ie, water temps?
Ob pump model?
Size of inlet hose - 5/8"?
and outlet hose?   5/8"?  (7/8" on the B engines?)


-Ken
Twenty years from now you'll be more disappointed by the things you didn't do, than by the ones you did.
So throw off the bowlines.  Sail away from the safe harbor.  Catch the tradewinds in your sails.
Explore.  Dream.  Discover.   -Mark Twain

Roc

My friend with a C350, same engine as C34 (M35B), converted to this Oberdorfer.  Apparently, there are different Oberdorfer pumps and you need to get the one with 1/2" fittings (-16 model).

Roc - "Sea Life" 2000 MKII #1477.  Annapolis, MD

crieders

I have the 25xp and yes I did check all those other items
I noticed that the Oberdorfer does hava a smaller impeller or so it appears
Cliff Rieders, c34 tall rig, 1990, hull #1022

KWKloeber

Quote from: crieders on September 05, 2014, 03:02:51 PM
I have the 25xp and yes I did check all those other items
I noticed that the Oberdorfer does hava a smaller impeller or so it appears

So what Ob pump model do you have?

Ken
Twenty years from now you'll be more disappointed by the things you didn't do, than by the ones you did.
So throw off the bowlines.  Sail away from the safe harbor.  Catch the tradewinds in your sails.
Explore.  Dream.  Discover.   -Mark Twain

DarthOccam

Both pumps have similar GPH ratings. If your engine is over heating, I would eliminate other possible causes first.  Are you getting a "normal" volume of discharge from the exhaust?  If not, could be clogged inlet, heat exchanger, or the impeller. All cheaper and faster to fix than a new pump.

More details on the symptoms and what you've eliminated would help.

Michael
Michael DeCamp
Serenity, #1703
Channel Islands Harbor, CA

Ron Hill

Cliff : You have thrown out a question to a form that 99.9% have either a Sherwood or an Oberdoffer !!

You are one of the VERY VERY FEW M25XP engine owners, that I know of that has used BOTH pumps :
1. On the same engine,
2. In the same boat
3. In the same environments,
4. With the same running RPMs.

You aught to be telling us the answer to your question - rather than asking us !?!  :!:

My thoughts  :?
 
Ron, Apache #788

Stu Jackson

Cliff, Ron makes a good point!   :D :D :D  All in good humor... 8)

It has been repeatedly reported here that the Sherwood pumps more water.  I have also repeatedly mentioned that in the 27 years our boat has had its Oberdorfer it works just fine.  Michael is right, check the other issues first.  If you're concerned about 185-190, either 1) don't worry it's normal; or 2) put a 160 thermostat in.  Before someone says it's bad for your engine, it isn't.
Stu Jackson, C34 IA Secretary, #224 1986, "Aquavite"  Cowichan Bay, BC  Maple Bay Marina  SR/FK, M25, Rocna 10 (22#) (NZ model)

"There is no problem so great that it can't be solved."

oldcatsailor

I was running near 200* cleaned the heat exchanger and replaced tired sherwood with a  model16 1/2 inch in=outlet oberdorffer
now the temp is usually below 180.ground off some metal as per the forums instructions and it fit perfectly.220, for a new pump compared to 370. for a rebuild,
Sail 1064 Tr wing keel 1990/

MarkT

I have the M25 which came to me with a Sherwood pump. Replacing it with the Oberdorfer was one of the first things I did after buying the boat. The design of the Sherwood is so unhelpful when it comes to changing impellors that there was no argument in my mind.  My heat exchanger did have the remains of several impellors in it when I cleaned it out. If you are not getting sufficent cooling then my first advice is to remove the end caps from the heat exchanger and clean it out.  Next check that there is no obstruction to the inlet. My experience has been that the Oberdorfer does a great job and pumps more than enough water for the efficent cooling of the engine.

3" heat exchanger, M25 engine on the Chesapeake bay

crieders

I have never opened the heat exhanger and will do that
Cliff Rieders, c34 tall rig, 1990, hull #1022

Stu Jackson

Stu Jackson, C34 IA Secretary, #224 1986, "Aquavite"  Cowichan Bay, BC  Maple Bay Marina  SR/FK, M25, Rocna 10 (22#) (NZ model)

"There is no problem so great that it can't be solved."