Pegasus my old 38LF had been converted to fresh water cooling. Dont remember who made the heat exchanger. It used the cam driven vane pump (old raw water pump) as the recirculating pump. Replaced the impeller once in 10 years of ownership. Yes access did suck. Never had an issue of that pump failing. Only overheating issues I had was when the heat exchanger tubes became clogged. My 39LF has the engine installed the right way (no vdrive) and good access to everything except the dripless shaft packing.
Doug Mountjoy Rebecca Leah LF39 Port Orchard YC, WA. -------- Original message --------From: Chuck Gilchrest via CnC-List <cnc-list@cnc-list.com> Date: 4/30/18 11:39 (GMT-08:00) To: cnc-list@cnc-list.com Cc: Chuck Gilchrest <csgilchr...@comcast.net> Subject: Stus-List Fresh Water Conversion Yanmar 3HM 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: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 elbowFinding the needed parts to do a Yanmar factory Fresh water conversionKeep 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 GilchrestS/V Half Magic1983 Landfall 35Padanaram, MA
_______________________________________________ Thanks everyone for supporting this list with your contributions. Each and every one is greatly appreciated. If you want to support the list - use PayPal to send contribution -- https://www.paypal.me/stumurray
