New to Pearson - survey advice

[Della and Dave]

We are planning on fixing the cooler and trying it out before we take on any tranny work.  I'm hoping it was just cold and grumpy and thick oil making the prop spin tin neutral.  Knock on wood.   

[Dale Tanski]

Dave,

The raw water flow on my boat is as follows however I have the Paragon transmission that does not have a heat exchanger like your Velvet drive apparently does.  Starboard seacock -> sea water strainer -> Walter V-Drive -> engine raw water pump ->  engine oil cooler -> closed loop engine heat exchanger -> siphon/vacuum breaker -> water exhaust injector. 

As for hose, I am a practical, logical person for the most part so this is just my opinion.  The entire engine and cooling system is below the waterline. That means that the water contained in the system is under pressure the entire time it is in the boat until it reaches the water lift exhaust system.  If someone does not believe that, just pull off a hose before the raw water pump and you will be amazed at the volume of water flowing into the boat. 

If anything, the intake side of the raw water pump is under slight pressure not negative pressure or suction even while it runs.  The pump is required to provide a flow and overcome the resistance of the various components in the cooling system and overcome any exhaust pressure that the exhaust system has at the exhaust injector.  The amount of water that would flow in through an open hose below the waterline far exceeds the water flowing out of the exhaust metered by the impeller in the raw water pump.  Speaking of pressure, for every foot below the surface of the water the raw water cooling system will be under approximately 1/2 pound pressure.  Given the depth below the waterline the cooling system is located, the static pressure on the cooling system is at about 1 psi.

This said, I used plane jane automotive heater hose.  It is good for over 212 degrees F, and the average cooling system in a car operates at 10 to 15 psi or 10 to 15 times the pressure encountered below the water line of your boat. I have never had a cooling system issue and never have had a hose suck shut from the supposed negative pressure generated by the raw water pump. Keep in mind, the impeller on the raw water pump consists of rotating flexible rubber vanes not a piston or gear design that has a positive displacement.

The engine oil hoses going to and from the oil cooler are another story.  They are the only lines that have any reasonable pressure and they need to handle engine oil pressure which is under 60 psi. For those hoses I went with crimped on threaded hose ends and a hose that is designed for oil, the anticipated heat.  They are rated at around 150 psi and can be seen in the picture below in blue.



Dale

[PeteW]

Dave,

If I can gauge human nature, I think there is a sensible reason why your transmission cooler is under the galley sole. Quite simply, after connecting it to the gearbox they needed to shove it somewhere and that's where it ended up. Out of sight, out of mind.  I don't believe anyone ever intended for you to go under there and actually work on it.

So to remove it, simply disconnect the hydraulic lines at the gearbox and pull on these lines to yank the entire assembly out from under there. I know a half baked installation when I see one , and the chance that it's actually mounted to anything down there is remote. If the raw water hoses get in the way just cut them off. You will be replacing all that anyway.

Most of the oil coolers I see are intended for closed loop cooling from the engine fresh water loop. These will have 1 1/4" inlets. These get connected with various pieces of molded radiator hose.  For raw water cooling the inlets should be 1/2 - 3/4" ID and there should be a pencil zinc screwed in, to keep it from turning green for at least awhile.

I've seen a variety of dual loop fresh water coolers that allow you to run engine oil through one loop and transmission oil through the other. Its a cleaner installation that trying to figure out where to mount a second oil cooler. This makes plumbing into the closed coolant system of your engine easier.

The last time I needed a custom hydraulic line crimped up,  I went to Napa Auto. These lines are stiff so after you mount your cooler to some point on the engine you will need to design these lines to the exact lengths. You can get 90 degree connector which might help in routing the lines.

Overheard at the marina and I believe this: "Everything on an old boat is either broken or about to break." 

Best of Luck,  Pete    365 Ketch, old hull #6

[Della and Dave]

Thanks again both Pete and Dale.  I got the box today in the mail and, other than a little shipping damage, looks like I now have two good almost new heat exchangers, one engine coolant and one new oil cooler that looks Like Dale's picture, just not as clean:-). 

I am thinking I can use engine oil cooler for the transmission oil cooler.  I figure the heat load of the engine must be higher than the transmission so if it is sized to work for the engine using warmer water by the time it gets that far down stream past two other exchangers, it should keep the transmission cool. 

Pete:  Where did you put your cooler when you converted? I saw your pictures but couldn't see the cooler.  I have seen others, that are on top of the tranny, but I was wondering if it would be happy at the top of the system?  Do you need to bleed out the air in the transmission fluid if you put it there? 

(Spell check wants to change tranny to tyranny, somehow I find that really funny..).

First of many boat bucks....   

[Della and Dave]

Well, we finally closed on the loan so Polaris is now ours! Lots of work to do over the next few months. Thanks to all for the great advice as we navigated this process. We'll be posting in the other sections now when we need help.

[Leo]

Dale, every time I see your bilge and drive train photos I get a little envious! Mine seem to have 30+ years of gunk permanently adhered to them.

Della and Dave, Nigel Calder's mechanical and electrical manual is a great resource. He goes through what type of hose you need for your application, Plus tons more. It was a go to book when I was refitting Sol.

Len