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billybobbooth

National / rn thermostats

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Just wondered if anyone is running a thermostat on there national or rn?

If so what temp is the thermostat?

I did find a 40deg one but i now cant find the link, the easyest lowest one i can find is between 50-60deg

Ill be running a open loop system. I.e. loops the water round till at temp then draws in raw water till below temp.

 

Edited by billybobbooth

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Now then

 

The "Instructions for Erection and maintenance of national "D" series engines" says

"The temperature of water as it leaves the engine  should not exceed 130 t0 140 deg F (55 to 60 deg C) at which temperature it should just be possible for the hand to be held on the outlet water pipe."

The oil cooler as per your diagram is a good idea, if my inlet blocks causing an overheat the water temp soon comes down once flowing properly however the oil pressure at idle remains lower than before not really recovering until the engine has been stopped for some time and the heat dissipated.

Hope this helps

Bob Tidy

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Once again bob perfect ill get a 55 deg thermostat mean it cant get over 55 ive designed a bypass for the thermostat by a tap so i can adjust lower than 55 if needs be.

It use to get semi hot but that was with the bolinder water intake but this had to be swapped to to leakage so its now got a 2 inch ball valve that even cracked open lets more water in than the bolly could fully open meaning the engine never gets hot.

Oil cooler again on a bypass is off a car. I dont really have a problem with oil temp or pressure but if im raising the engine temp its best to alow for some oil cooling as at present the lowest oil pressure i see is 15 psi its normally around 25 psi this is all sence i ran it at over 80psi cleared all the oil ways of the old gunk oil as was backly like oily grease i then cleared the sump and original oil filter and flushed it. Sence then ive seen good oil pressure as before even cold i only saw 10 psi.

1 minute ago, linnit said:

Mine runs a 60°C

Thank you has confirmed a 55-60 is the way to go.

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Better to have a manual  regulating valve in the water bypass. That way YOU have control. Experience  and a temp. gauge will soon tell you best setting. Thermostats and  aged  raw water cooled  diesels are not a happy pairing.

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Yes plan was to put a bypass in past the thermostat and a shut off valve at the pump this way by open one and shut one the system runs as present.

My plan in 4 way tee off water outlet pipe

1 goes to thermostat that then goes to outside.

1 goes to valve over thermostat then outside. (Allows thermo to be bypassed) also help draining at winter.

1 to bypass running down to water pump again shut off just at pump with bleed to drain for winter.

I do have a temp gauge on way but not sure best location was thinking over 2nd cylinder output hole so will read temp coming out of both cylinder but get a direct temp read of second cylinder closest the thermostat.

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When running a direct cooled engine with seawater cooling then a low temperature is necessary. But why limit an engine with fresh water cooling? And if you fit an old engine to a boat with a skin tank do you still have to stick to low temperatures (and why)?

 

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Sea water when hot can cause the salt to react more.

Old engine arnt fully designed to run at full temps like car engines due to more heat = more pressure and alot of old engines head gaskets ect arnt designed for the pressure on the water holes some are re designed so you can.

Fresh water

other thing you get is stopping the water from boiling on raw water as you cant add a pressure cap. Higher pressure lowers the boil point but you have an open system due to outside so lower temp thermostat needs fitting.

If its a fully closed system as long as you can cool the tanks and the gaskets and pipes are upto it you could run the engine at 80-100 deg be far cleaner and more fuel efficient. But not all engine can run that hot due to components.

Some engine when running raw cooling run hot naturally and dont need a thermostat you can control there temps by air intake divertions like on 15hp bolinders these run hot with no thermostat.

Hope this semi answers you question.

Edited by billybobbooth

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Hi all

Just a thought as stationary engines they were cooled by a large tank, the quote is "should not exceed 130 t0 140 deg F (55 to 60 deg C)"

Ideal temperature is not quoted, RN may have view on this but we are dealing with a variation on a Mk1 RN and the RN design has been improved over the years all RNs are not equal

My personal preference is to use raw water directly (with a tap to restrict the flow if required), using a thermostat is fine if the spare water then continues overboard without going through the engine. I would be concerned if a thermostat system results in no water exiting overboard until operating temperature is reached.

My reasoning for all the pump is able to provide to go overboard is:-

by being able to visually monitor  the output you can then identify if the inlet strainer is becoming clogged before you start to overheat.

A temperature check by hand is always available.

You can check for a good flow when entering a lock when it is easy to clear the strainer with the screwdriver kept in the ticket drawer for the job

Given the choice I would have an inlet on both sides of the boat because when the mop fails to clear the leaves etc the towpath is without fail on the wrong side and at 6ft 1in tall the strainer is way out of my reach from a town class engine hole door.

Having a tap gives the ability to remove the restriction when things start to warm up however  running into a shallow stretch causes a noticeable rise in temperature  with or without a bit of rubbish on the strainer all taken care of by the spare cooling capacity, Battersea never overheats unless the outflow has dropped to a trickle, when its getting dark you can hear the outflow splashing back into the canal, very reassuring.

Battersea runs without restriction and maintains an exit temperature that is pleasantly warm until the strainer starts to clog when it can soon reach as hot as you can keep your hand in, if the mop fails (never a bridge when you want one) it will soon start to steam, which running old cars in my youth always seemed to cause the thermostat to fail.

Keep things simple works for me.

 

Edited by Bob Tidy
typos

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This is what i have been doing and my old bolly water intake was good for this but due to a wooden boat and years of corrosion and the never ending wood rott this then became a sinking boat situation and had to be removed and no there is little chance of it going back on, but with this on it was easy to control the temp but as said the new valve even virtually shut is open more than the old one at wide open so a water intake control of flow has gone out the window.

This has now caused me to change the system. Ive designed it with clear pipes so you can visualy see the flow and bypasses so if all goes wrong it can be put back as is. I did look at a 3 way adjustable valve but this was hours of tiny adjustments all day and i need to keep it easy to use if fam use the boat.

I dont get a problem with blocked intake its far to low down. Havent you still got the 2 intakes on Battersea?

Hopefully the system ive designed is up to it its all 1 inch bsp pipe side so should be fine and wont add any extra stress to the water pump or pressure in the system at this size. The thermostat being used also as 2 small bleed holes in so will alow a tiny bit of water past so will dribble out over the side too.

Edited by billybobbooth

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Interesting you are to far down to get blocked, we were in dock at backend of last year and reinstated, cleaned/overhauled the bottom pipes and valve on Battersea intending to use it as a backup, and reshaped the sieve on the top intake.

On the way back to the mooring the top intake didn't block (well it wont now we have a 2nd option :)) but the lower one did remain clear when i checked it, I thought it would get full of dead leaves/mud off the bottom. I would be interested to know which one others use and their views, possibly I should run the bottom with the top as reserve, at least i can reach it from the lockside with my shirt sleeve well rolled up.

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Its a 2 inch pipe copied from the original with about 20 holes in it never blocked once. Even on Dane it only blocked up we we had emence duck week but was also more it blocking up the mud box.

I can just reach mine if my ear is nearly lapping the water.

20170215_211819.jpg

Its easyer to find now can reach from back but on the boat moving a brush is easyer. But i also have the mud box so has a while to go before it stops sucking water.

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True, current balasting is about half way down from Empty so I suppose I have a choice, Top clearly works ok now the strainer isn't flat so more than 4 holes can work and the bottom valve opens fully with pipes not blocked by the remains of something long dead. I will try the bottom next trip on my way round to the Audlem gathering and see how it goes.

Edited by Bob Tidy

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