Okay, so I 'm at it again...

I'm new to the whole offshore scene and I feel the need to learn as much as I can before I spend money on things and wind up with the wrong parts. (like my rect port inlet manifold for my oval port heads!)

I'm trying to figure out the best way to keep my engine cool and why.

I notice most people seem to run a bypass and a circulation pump to push water from the drive pick-up through the engine then out via the exhaust or a variation on that theme. Some other people seem to be running a standard marine water pump instead of the bypass and then there are those running cam-driven water pumps like on most v-drives.

Which is the best option for a Gen VI 454 running around 500hp in a Stinger 222? Why? What bits do I need?

My Sanger v-drive runs a cam driven Neovane from the pick-up on the cav plate and that seems to do the job just fine for almost any hp in any v-drive set up I've seen. So why the different set-ups for offshore? (I'm not taking the piss, I really don't know!)

I have a Jabsco raw-water pump from a previous project I want to use but I don't know what's best.

Does anyone have a flow diagram for a 454 with a bypass and wet exhaust?

Sorry if this question has been asked a million times before, I tried searching but all I could find was a 350 diagram and lengthy arguments about thermostats...

Anyway, any help would be greatly appreciated!

PS: Anyone want a Performer RPM Air-Gap for a BBC? (rectangle port of course!)

The Mercruiser-style block-mount pump, drawing water from a transom pickup and through a sea strainer is the best, most reliable, most efficient way of sooling your engine. Running a bypass with a thermostat gives you the reliability and the temperature control you need.

The cam mount pumps are way too hard on timing chains, they introduce funky cam harmonics that can cost you horsepower both on the valvetrain side and with spark scatter in the distributor, and lastly they don't pump enough water at idle and low RPM's.

I run a factory merc sea water pump, with a by-pass with a by pass to the therm housing a 140 merc stat w/4 holes drilled in it and works very well runs about 140

I asked a Merc rep once why do they all come with circulating pumps.

He said in most applications it provided better control of the temps throughout the engine.

Alright, so I need a sea-water pump (which I think my Jabsco is?) and a sea strainer along with a bypass hose. The t-stat housing or outlet housing; how many outputs does it need? 3, 4 or 5?
And are we saying not to use the water pick-up from the drive? where do I plumb that? back out?

Thanks again!

They definitely do that- and some engines suffer from premature wear on the front cylinders as a result of non-circulated raw-water cooling. But the downside is the circ pumps can and do fail, the additional hardware up front and the complexity and increased difficulty of servicing anything on the front of the engine- bobbing in water.

Does your 222 have an Alpha or Bravo drive??? If you have the original Alpha then the sea water pump is in the drive and you need to keep the recirc pump mounted on the block in place....if you go with a Block mounted pump like the bravos have, then the bast thing you can do for an Alpha is keep the stock pump in the drive and re-route the water back out the transom and use it as a shower to cool the drive off...then install a thru-hull pickup to feed the engine...
If you have a Bravo drive then you allready have an external sea-water pump inplace...you can get rid of the stock water recirc pump and install the water cross over if you want....

Aha! I have a Bravo 1 Drive. (probably should mentioned that earlier)

So that means I don't need a water pump on the front of the engine, just one on a bracket off to one side down low to push the water around the engine and out again or do I not need one at all on the motor, just the bypass???

Thanks to everyone for your answers so far!

PS: what are you running in your 222 Wally?

I can never get photo links to work!

Since you have the bravo then yes you have a sea-water pump mounted on a bracket off to the side of the motor..You do need to keep that regardless..and yes you could remove the recirc pump thats mounted on the front of the motor. But unless you have high HP application, your not going to notice any benefit of putting on a bypass...unless you want it for just looks...Or if you are having overheating problems then a bypass may help...but i would first find out what the problem is thats causing overheating to begin with....

As for my stinger....thats still up in the air.....i had a 5.7 LT1 engine i was going to "marinize" but the custom closed cooling system i would have to build would have ended up costing me more then the entire boat!! So now i'm back to searching for a good SBC....or BBC which ever one comes along first for cheapest!