Beta 38 coolant change

[Chunk]

Hi,

I have just replaced the old hoses on my keel cooled  Beta 38, refilled the system and bled the keel coolers.

After running the engine on tick over for a couple of minutes  the hoses are still stone cold? It seems like the coolant is not being pumped around the system, presumably the water pump self primes when you refill the system? Is there any way of checking prime on the pump or manually priming it.

Thanks

[Tony Brooks]

The engine thermostat will all but prevent flow through the main keel cooler pipes until the engine and the calorifier have reached a certain temperature. This takes more than a couple of minutes. The calorifier pipes are likely to get warm first but think 10 minutes or so.

There is no nee to prime the engine water pump. If it has air in it so does the engine block and that would mean you did not fill it.

Run for longer at about 1000  to 1500 rpm with the filler cap off. Keep looking down the filler cap as air bubbles are ejected. If a big blob of air comes out you may need to top the system up. Keep manipulating any bows in hoses to help any air trapped in the bow to move into the skin tank or header tank. make sure the skin tank is properly bled. A few are self bleeding.

Edited August 3, 2017 by Tony Brooks

[Chunk]

Tony, thanks for the reply I will try again this morning.

 

[Chunk]

I ran the engine again and after a while noticed one skin tank is warming up and the other isn't, the inlet and outlet hoses just tee off to each tank.

The hose runs are longer to the tank that is cold and the water outlet tapping is positioned higher up the tank?

i have bled the tank numerous times, it looks like the flow is taking the shortest easiest path through one cooler but I don't know if this is how it was before as I didn't check

Afer running under light load for around 30 mins I had block temps approx 70c, cooler inlet 50c and outlet 30c with the other cooler inlet and outlet at 19c.

i don't know if the higher outlet tapping position  on the cold tank is due to the surface area cooling calculation, maybe a few hours cruising will sort things out, but any advice would be great thanks 

 

 

 

Edited August 4, 2017 by Chunk

[Tony Brooks]

The only advice I can give is that I do not feel simply Teeing to feed twin tanks is a good idea because, as you say, it will allow coolant to bypass one tank if it wants to. I  think a good cruise will help to clarify things. keep manipulating the skin tank hoses in case air is still stuck in one.

[Chunk]

I'll take it for a cruise and see, thanks for the advice.

[Chewbacka]

I have two skin tanks and they are in series, so even under heavy load the engine stays at a steady 80c.  The worry I would have, which is what you are finding is that water from the 'primarary' skin tank is returning to the engine hotter than you would wish and this can only result in a hot engine.

[Chunk]

Thanks for the reply Chewbacka, I will look at re-piping in series, my two tanks together would be way over the surface area recommended by Beta but I guess bigger is better?

[Chewbacka]

I don't think you can have too much as the thermostat will regulate the engine temp, so extra skin tank area will not over cool your engine.  The only concern is to check that the coolant pipes are a decent size as it is possible that the builder used small bore pipes assuming the water would be flowing through both at the same time.  When the shell was built I asked the shell builder to ensure there was plenty of cooling as I would be frequently going up river against the flow, and the last thing I wanted was an overheating engine on a flowing river, so we agreed on two skin tanks, one on each side, in series.  Never had a problem.

[Tony Brooks]

I agree with all Chewbacka says above. If it were my boat I would definitely be re-piping it with the tanks in series.

[Chunk]

I have re-piped the tanks in series and thinking about it that's the only way it can work properly, who knows why the tanks were in parallel but now the outlet temp of the second cooler is way down at 19c.

thanks for the advice

[Chewbacka]

Time to give it a good thrash for 30 mins to confirm............