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HRW3 cooling problem


MtB

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Ok, I now have the starter motor fixed and back on the enjun, and it starts and runs like a dream. FANTASTIC!

 

Slight problem with the heat exchanger though. It has indirect raw water cooling and there is no water flow though the raw water circuit.

 

Disconnecting various pipes etc revealed a ton of waxy greasy stuff blocking the the rigid pipes. I've poked it all out but there is still no flow because the heat exchanger also seems to be blocked, with the same waxy grease.

 

I've run the engine up to 80 degrees C so the thermostat opens and heats up the heat ex but the wax won't melt to the point where the Jasco water pump pressure will shift it. (I can't image how this engine ever passed its functionality tests when installed in the lifeboat. I'm bloody glad it was never needed in anger, with the dead starter motor and blocked cooling circuit!)

 

Anyway, is anyone here familiar with this type of blockage? Is there anything simple I can do to unblock the heat exchanger or do I have to remove and dismantle it, and get the pipe cleaners out?

 

All advice most welcome.

 

:)

 

MtB

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I have had to clean heat exchangers many times in the day job so normally do the following. If it is just a greasy type mess then remove the end caps and rod out all the passageways until clean, If there is any build up of scale/crusty marine growth then it will probably need acid dipping or ultrasonic cleaning.

Edited by martyn 1
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Has fixing the starter motor caused this thing to grow an extra cylinder, then?

 

Impressive!

Lol no.

 

I typed "HRW2" in my post title but the forum software changed it into "HRW3" after I pressed 'Post', obviously...

 

:)

 

MtB

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I wonder if this waxy gunk was some sort of wax-oyl material used to inhibit the engine during long-term storage.

 

Perhaps it never got cleaned out properly when put back into commission.

 

What you cant clean out by hand, try heating it all and blowing through with comprssed air at low pressure.

 

Also try dissolving a lump of this goo in some sort of solvent, like white sprirt, petrol, parffin/diesel or meths. Which ever sems to work best - half fill the HX with that, plug the ports, a leave in the back of your van for a while to shake loose and dissolve this stuff.

 

The silly thing is that a lifeboat engine would spend long periods out of use on standby but when the flag drops ..... it needs to be 100% reliable.

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I wonder if this waxy gunk was some sort of wax-oyl material used to inhibit the engine during long-term storage.

 

Perhaps it never got cleaned out properly when put back into commission.

 

What you cant clean out by hand, try heating it all and blowing through with comprssed air at low pressure.

 

Also try dissolving a lump of this goo in some sort of solvent, like white sprirt, petrol, parffin/diesel or meths. Which ever sems to work best - half fill the HX with that, plug the ports, a leave in the back of your van for a while to shake loose and dissolve this stuff.

 

The silly thing is that a lifeboat engine would spend long periods out of use on standby but when the flag drops ..... it needs to be 100% reliable.

 

 

Yes I wondered that too. There is a lot of it though. A 3/4" copper pipe two feet long was completely full of it!

 

Some of it is just like normal grease in nature, in other places it is more like soft(ish) candle wax. The odd thing is it doesn't liquify when heated up with a blowlamp, hardly softens at all in fact. I think I'm gonna have to clean it out manually.

 

I agree with the lifeboat comment. Anyone needing this engine would have been out of luck. Too much compression to hand start, busted starter motor and totally blocked cooling. So much for the twice-a-year testing it supposedly had.

 

MtB

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Thanks Tim. That sounds exactly like what's in the pipes especially the bit about the waxy crumb-y nature of the residue once the higher fractions have evaporated away.

 

I wonder how it got inside the raw water circuit in the first place. I imagine it must have been pumped through the circuit to flush out sea water after each testing. Then left for a number of years.

 

I'll dismantle and soak it in white spirit as you suggest.

 

MtB

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When I was in the forces, all the parts for the main battle tanks were coated with this stuff. We found the only thing that would remove it before fitting was petrol. (Sometimes a box of matches helped as well).

Edited by andyb116
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