I think the motors and oil are running a little too cold for their own good (motors 120-130, oil 160-180). Am looking for opinions on which would be best, going to closed cooling or installing oil thermostats. I think both would cost about the same (around $500-600 per engine). Motors are 454's, about 450 HP.

Recommendations ?

-Greg

Are you running t-stats ? 120*-130* You should be running atleast 150*-160*. If you can increase engine temps with t-stats this will help increase oil temps. T-stats are cheap start there.

It's a direct flow system with no recirculating pump. Raw water pump runs to the two oil coolers. Each oil cooler outlet feeds to one block inlet. Outlet on the intake splits it again into each header.

The old Gil manifolds I had setup so the water went from the oil coolers to the mainfiolds to the blocks then to the tailpipes (preheat style). The new headers aren't setup for preheat (manufactureres recommendation, as with the very long collectors the water lines leaving the headers would have to run from the transom all the way forward again to the engine inlets, something like 6 feet).

-Greg

The only way you are going to control the engine temp is to install a thermostat housing of some kind. You may want to install an engine recirc pump with a stock type thermostat housing. As HOTBEEK said -- as you increase the engine temp. the oil temp will come up. You want the engine temp to be no hotter than 160 to 170 degrees on an open system. And the oil temp should always be above 212 deg.

. . . and if you run in salt water, which in Annapolis you probably do, you really don't want to get the water temp much above 150 with a raw-water cooling system. As the water temp goes up, salt and other minerals tend to precipitate out of the water and on the cooling passages which, as you very well know, will corrode out you engine block, heads, intake and the like. Yes, higher water temps will allow the engine to run more efficiently than lower temps, but in order to go higher without corrosion damage, you should go to a closed cooling system.

Thanks for the reply's. I may take a look at a closed system, if not guess I'll look the way of an oil thermostat system.

-Greg

Do you have any kind of restrictor in the thermostat housing? You can buy them in various sizes to restrict some of the water flow. I would be more concerned about the oil temp. Get it at least to 200+ degress to get the water condensation out. An oil thermostat wouldn't be a bad idea. There was a posting in the General Discussion with pics of an automotive style oil thermostat that was considerably cheaper the marine ones. The oil thermostat/remote iol filter mount is kind of pricey and not really necessary in my opinion.
If you do go to a closed system, make sure it has the capacity to cool the manifolds if they're aluminum. And make sure the manifolds can be plumbed for FWC. A friend of mine bought a system that was intended to cool the manifolds, but he had Imcos. No easy way to plumb the exiting water due to internal passages.
Gary
Gary

Gary -

If I went with a closed system the exhaust would still have to be raw water cooled, as there is no return from the headers, it dumps into the exhaust inside just at the transom.

I've seen a simple oil thermostat, but even that gets complicated by the time you add all the extra hoses (my current system is plumbed to go to the coolers then the filters).

-Greg

What is the manufacture of the headers and crossover system?

You should be able to run a thermastat with holes in it or go to a restrictor plate of various sized openings.

You're not allowing the engine to warm the water before passing it through the system.

Bob

Bob,

Headers are Lightning. It isn't really a crossover, as the outlet of the oil coolers (Merc bellhousing mounted duals) just run to elbows at the block water inlets (CP Performance inlet plates).

-Greg