Impeller bits filter

zoidberg

zoidberg

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A friend is stuck in Palma while local engineers fish bits of fragmented impeller from his heat exchanger. This is certainly a commonplace problem, with an expensive solution.

Has anyone come across a filter arrangement downstream of the raw water pump/impeller which would trap such debris, but not impede water flow?
 
What engine? Usually the bits of the impeller stop just before entering the little holes of the heat exchanger "insert" (don't know how is called) and you simply remove the end cap to gain access to it. If they get inside the little holes you will need to remove the "insert" completely and clean it. It's not an expensive solution.
 
zoidberg said:
A friend is stuck in Palma while local engineers fish bits of fragmented impeller from his heat exchanger. This is certainly a commonplace problem, with an expensive solution.

Has anyone come across a filter arrangement downstream of the raw water pump/impeller which would trap such debris, but not impede water flow?
Click to expand...

Some Volvo Penta engines have a filter mounted on the front of the engine just after the raw water pump as here https://www.marinepartseurope.com/en/volvo-penta-explodedview-7738870-26-3437.aspx

Www.solocoastalsailing.co.uk
 
My TAMD40b's have a metal pipe from the strainer to the oil cooler, so would need serious modification.

I have just had a glassful of bits fished out of mine, and it makes a lot of difference to the engine sound and exhaust water flow!

Makes changing impellers ever so important for sure!
 
pvb said:
So it does! What an odd arrangement.
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Not odd at all I would think, my TMD40s have the same arrangement. It does ensure that any impeller bits are trapped BEFORE they get to the heat exchanger/oil cooler. There is a easily cleaned seawater strainer on the inlet seacock which picks up most weed etc before it gets to the pump.
 
You have a choice.

Either the impeller acts as a macerator for all the cArp it sucks up, or bit of impeller go into the oil cooler.... :ambivalence:
 
zoidberg said:
A friend is stuck in Palma while local engineers fish bits of fragmented impeller from his heat exchanger. This is certainly a commonplace problem, with an expensive solution.

Has anyone come across a filter arrangement downstream of the raw water pump/impeller which would trap such debris, but not impede water flow?
Click to expand...

YES

I have a Perkins 4326M Low line and have had a Vetus Water strainer fitted between the sea water pump outlet and the heat exchanger inlet for about 6 years now and it works a treat.

Checking the strainer is part of the daily engine check. As soon as you see bits in the strainer, it is time to change the impellor. I do 200 hours + a year and find the impellors last about 2 years
 
pvb said:
So it does! What an odd arrangement.
Click to expand...

That setup is normal for outdrive boats where the water pickup on the leg acts as a first line filter to remove larger debris. That's what I have and it's nice when you shred an impeller to remove all the bits from the strainer in a couple of seconds :D
 
CLB said:
That setup is normal for outdrive boats where the water pickup on the leg acts as a first line filter to remove larger debris. That's what I have and it's nice when you shred an impeller to remove all the bits from the strainer in a couple of seconds :D
Click to expand...

Outdrives?? Whatever next?:rolleyes:
 
john_q said:
YES

I have a Perkins 4326M Low line and have had a Vetus Water strainer fitted between the sea water pump outlet and the heat exchanger inlet for about 6 years now and it works a treat.

Checking the strainer is part of the daily engine check. As soon as you see bits in the strainer, it is time to change the impellor. I do 200 hours + a year and find the impellors last about 2 years
Click to expand...

This is interesting. I change the impeller when it has done between 500 and 700 hours, when it's convenient. This is usually 3-5 years. Every single one over the last 30 years has come out looking in good condition. Never had one fail. This is a Johnson F5B pump using Johnson impellers. Any ideas why some fail and others don't?
 
SlowlyButSurely said:
This is interesting. I change the impeller when it has done between 500 and 700 hours, when it's convenient. This is usually 3-5 years. Every single one over the last 30 years has come out looking in good condition. Never had one fail. This is a Johnson F5B pump using Johnson impellers. Any ideas why some fail and others don't?
Click to expand...
+1
Actually had one impeller fail (broken vanes) and it was one of those costing a fraction of Jabsco/Johnson impellers, never used the cheap ones again, I replace the Jabsco/Johnson ones every 300h or so but just as a precaution, they still look perfect.
Ah another failure I had was the rubber vanes body detaching from the inner bronze body, the pump shaft was turning but the rubber impeller did not, happily noticed there was no more water coming out of the exhaust; it must be one of those noises deeply entrenched in the subconscious, it sends a subliminal signal as it stops :D
 
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