What about those Blue Globe Impellers? They seem much better that the neoprene 
style of old, and seem to be a silicone blend, or something. They seem to hold 
up much better, and they also have a hardier Red Impeller, which I believe is 
intended for Diesel, and I think Higher Temps.

 

Bill Coleman

C&C 39 Erie

 

From: CnC-List [mailto:[email protected]] On Behalf Of Chuck 
Gilchrest via CnC-List
Sent: Monday, April 30, 2018 3:56 PM
To: [email protected]
Cc: Chuck Gilchrest
Subject: Re: Stus-List Fresh Water Conversion Yanmar 3HM

 

Fred, 

Mine was Jabsco as well.  My engine tech said he’s concerned that a Jabsco 
rubber impeller wouldn’t be up to the task of the heat in a circulation pump.  
Any thoughts there?  I suspect it would need to be checked often just like the 
raw pump impeller.  Maybe I just need to inspect the Sendure exchanger for any 
blockages, change impeller and get the boat in the water.

Chuck Gilchrest 

Half Magic

83 35 LF

Padanaram MA

Sent from my iPhone


On Apr 30, 2018, at 3:04 PM, Frederick G Street via CnC-List 
<[email protected]> wrote:

Chuck — my 1979 Landfall 38 (Middletown-built) appears to have come with a 
factory-installed Sen-Dure heat-exchanger and added circulation pump (a Jabsco, 
which I have since replaced with another Jabsco, rather than try to rebuild).  
I also have the challenges of no access (V-drive).

 

— Fred


Fred Street -- Minneapolis
S/V Oceanis (1979 C&C Landfall 38) -- on the hard in Bayfield, WI   :^(





On Apr 30, 2018, at 1:39 PM, Chuck Gilchrest via CnC-List 
<[email protected]> wrote:

 

Silly me.  Since I bought my 1983 Landfall 35 a bit over 2 years ago, I had 
been under the assumption since there was an “expansion tank” on the engine 
that had coolant in it, that it was a fresh water cooled engine from the 
factory.  It is a Yanmar 3HM 30.   No (F) on the engine tag.  I had never even 
bothered to look..  Yeah, the heat exchanger looked a bit different from the 
one in the Yanmar manual, but since I’d been having a marina commission and 
decommission my engine each year, changing water pump impellers as necessary 
(“go ahead and do it”), I thought all was OK.  I even had a raw water pump 
changed out when the old one was demolished due to the “cam” screw backing out 
and galling the inside of the pump.  Turns out there’s more going on.

 

Low and behold, this year, when the mechanic looked around the engine, he 
mentioned that it was the first time he’d ever seen a small diesel with not one 
but two raw water pumps.  As it turns out, the engine appears to have had a 
fresh water conversion which was made by Sen-Dure, (thus the Sen-Dure expansion 
tank/heat exchanger) and a second external pump running off a belt.  So one of 
the two coolant pumps is actually a circulation pump (the one down low on the 
engine) and the other is a raw water pump..the one we replaced last year.

 

Has anyone ever heard of C&C converting engines from Raw to Fresh at the 
factory (Barry Carroll, Middletown RI built boat), or is it more likely an 
owner conversion?  My mechanic says that the rubber impeller on a raw water 
pump will never hold up to the heat of the interior engine coolant and will 
always burn up  impellers prematurely if I keep things as they are.  At one 
point Yanmar made a fresh water conversion kit for 3HM engines, but very 
unlikely there would be any availability considering the motor hasn’t been 
built since 1983.

This engine is somewhat dastardly in that it is installed backwards with a 
V-Drive, making access to the “front” of the motor a really tough job.

Right now, I’m at a crossroads which involves:

a.      Finding a suitable circulation pump that is up to the job for the 
existing system, since I just de-scaled the heat exhchanger and bought a new 
stainless mixing elbow
b.      Finding the needed parts to do a Yanmar factory Fresh water conversion
c.      Keep the boat out of the water this year and save up to re-power. 
Lavishing multiple thousands at a 36 year old diesel may not be the best way to 
spend money.

Any suggestions would be welcome..

Chuck Gilchrest

S/V Half Magic

1983 Landfall 35

Padanaram, MA

 

 

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