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View Full Version : 496 HO water pressure relief valve location?



Tborisch
05-25-2010, 09:35 PM
Ok. On the 496HO this is the flow path.

1. Raw water pump
2. Power steering cooler
3. Oil cooler
4. Fuel cooler
5. Heat exchanger

what one should I mount the pressure
relief valve before? I see lots of people put it right before the crossover on the raw water cooled engines. It seems like that would be the same as putting it right before the heat exchanger on this engine.

Help!? :)

Thanks guys!
Tom

gcarter
05-25-2010, 09:46 PM
I'd add a seawater strainer between the drive and the seawater pump and the relief valve right after it.
I think the pressure builds up from increasing speed in the water and the potential pitot pressure is the problem, not the seawater pump.
So the pressure needs to be relieved before the pump.

thehow33
05-26-2010, 08:38 AM
I'd add a seawater strainer between the drive and the seawater pump and the relief valve right after it.
I think the pressure builds up from increasing speed in the water and the potential pitot pressure is the problem, not the seawater pump.
So the pressure needs to be relieved before the pump.

Definitely the way to do it.
Only thing I have to add is the big offshore boats use a relief valve because pressure spikes happen every time the water intake leaves the water and then reenters along with higher speeds like gcarter said.

Tborisch
05-26-2010, 10:27 AM
Hey guys. Thanks for the input. I will put the relief before the pump. On the other hand, Im sure I don't need a strainer... In my 20 years of boating, I've never had one?

Tom

gcarter
05-26-2010, 10:35 AM
On the other hand, Im sure I don't need a strainer... In my 20 years of boating, I've never had one?Tom

Unfortunately, there's a first time for everything.

Tborisch
05-26-2010, 10:44 AM
Would it be your suggestion to run sea strainers on every boat?

Tom

gcarter
05-26-2010, 11:04 AM
Would it be your suggestion to run sea strainers on every boat?

Tom

If you think about it, every commercial/work boat has one or two.
Again, if you think about it, the typical Merc or Volvo engine/drive packiage is sold as a self contained package to eliminate as much work as possible in boat rigging.
We come along and pretty much finish up where they left off.
We add internal or external hydraulic steering, different exhaust, different/larger oil coolers,etc.
I think every offshore boat you'd look at would have one or two strainers.
They're invaluable in those unfortunate positions we find ourselves in.
I also like transom pickups because they eliminate the tiny little hose that goes through the gimbal assembly.
I don't think anyone who has these additions are ever sorry they made the changes.