Raw Cooling Water Pressure

[MOP]

Randy (Big Griz) stated that a transom pickup generates more pressure than the drive, the drive water passages and where it comes though the shield is smaller restricting volume compared to the transom setup. That being said the transom setup is 100% more reliable, it does away with the worry of the hose between the drive and shield going bad. My kid went through two hoses in three seasons with a lot of usage, they are a real pain and can be bloody to replace. Done by a shop can be close in $$ to installing a transom unit. Phil

[Carl C]

So this thread raises an interesting question for me. If i don't open up the water pickup like Carl did on his lower, and just leave it the way it comes from the factory, and I'm running my 496HO at a top speed of 75 mph, should i have to worry about using a pressure release valve? My stock bravo lower has the side pickups, and the lower pickup.. and makes about 38 pounds of raw water pressure. I would think the imco would make about the same pressure as my bravo with the lower and side pickups.
I'm not anxious to be the next guy to have a $92,000.00 22 classic. I still want to have a skater some day
Tom

The Imcos are notorious for excessive water pressure at lower trim settings. Being closed cooled any damage would be limited to the raw water side but still I'd install a relief valve. Here is what I have on the way (the first two items on the page). It will easily splice into your existing raw water hose. You'll also need a through hull and 5/8 hose. Our transoms are fully cored so I will dump out the hull side.http://www.cpperformance.com/c-121-p...ef-valves.aspx

You can probably find cheaper but I try to buy the best

[undertaker]

Carl after the first time of reaching down and cleaning the sea strainer you will change your mind about it. I just ordered a Hardin Marine strainer to replace the same one you have on Carl Chase's boat. Its all stainless with a large T-handle and it will match your exhaust.

Brian, which one did you get for Carl Chase boat, looked on their site and they have a few to choose from....just curious....thanks..

Undertaker

[Tborisch]

The Imcos are notorious for excessive water pressure at lower trim settings. Being closed cooled any damage would be limited to the raw water side but still I'd install a relief valve. Here is what I have on the way (the first two items on the page). It will easily splice into your existing raw water hose. You'll also need a through hull and 5/8 hose. Our transoms are fully cored so I will dump out the hull side.http://www.cpperformance.com/c-121-p...ef-valves.aspx

You can probably find cheaper but I try to buy the best

Hmmm.. Thanks for the lead. I think those parts look like standard hydraulic stuff. I'm going to hit up bond fluid air here in town before I order. They will probably have slot of that same stuff
cheaper.

If not, I will order that stuff.

I can't fathom a need for a sea strainer in my boat.. I always run in freshwater lakes, and typically stay away from areas you would pick something up. Been running boats with no strainers for 20 years on the same lakes.. Why start now

Tom

[Tborisch]

Hey Carl, were are you going to get the thru hull fitting from?

Tom

[Carl C]

Hey Carl, were are you going to get the thru hull fitting from?
Tom

A stainless steel one is also coming from CP Performance.

[Tborisch]

So, better to put the relief valve before or after the raw water pump?

I'm thinking before.... right?

Tom

[Carl C]

So, better to put the relief valve before or after the raw water pump?
I'm thinking before.... right?
Tom

Yes, between the sea strainer and raw water pump. I got mine done today. I now have a solid SS raw water pump . The rear through-hull is the water dump. I decided on this location after a lot of discussion about it.

[thehow33]

I like the location....looks uniform. and less hose in the bilge if you were thinking about putting it on the other side port side. And i'm jealous of that awesome water pump

[MOP]

Carl hate to say it but all the info I found over the last couple of years says valves after the oil cooler, the reasoning is when the valves open they increase flow through cooler when your engine needs it most have not seen. I was going down the same road, had the fittings made up to go into the intake hose just after my strainer that would dump the excess onto the top of my drive. I explained it to a couple of folks that I know that race they told me I was nuts and to ditch the idea and go after the oil cooler, so no my drive will get a little warmer water.

Phil

[Carl C]

Carl hate to say it but all the info I found over the last couple of years says valves after the oil cooler, the reasoning is when the valves open they increase flow through cooler when your engine needs it most have not seen. I was going down the same road, had the fittings made up to go into the intake hose just after my strainer that would dump the excess onto the top of my drive. I explained it to a couple of folks that I know that race they told me I was nuts and to ditch the idea and go after the oil cooler, so no my drive will get a little warmer water.
Phil

As usual opinions will vary but this guy races: http://seriousoffshore.com/forums/sh...71&postcount=3

[Cuda]

Opinions are like buttholes: Everybody has one, and they all stink.

[MOP]

As usual opinions will vary but this guy races: http://seriousoffshore.com/forums/sh...71&postcount=3

Carl you are F/W like I am you are also loosing flow to your exchanger!
http://www.offshoreonly.com/forums/g...ock-lower.html Read #2
http://www.offshoreonly.com/forums/g...ve-496-ho.html Read #3
http://www.offshoreonly.com/forums/g...-valves-4.html Read #31 It is not an opinion just simple logic, reducing flow to items that have critical need at speed does not make sense. I know quite a few put relief valves at the strainer but if you read the posts they are raw cooled, closed needs the flow. At high speed is where your engine develops the highest temps, that is when it needs maximum flow the most.

[Tborisch]

So, what hose number here are you saying to install the relief valve on? 11?

http://www.boats.net/parts/search/Me...tem/parts.html



Thanks.
Tom

[Carl C]

Carl you are F/W like I am you are also loosing flow to your exchanger!

I'm not limiting flow; Only excess pressure. I did not add any restrictions to flow.