UK Formula

Hello all, I hope you're all well. I'm in the process of a complete restoration of a 1994 Formula f303. The original engines being completely shot we have recently shipped 2 540s from the USA to the UK. The engines are "guestimated" to be around 600hp each and should push her along nicely. So, I'm after some advice. The engines have water crossover kits with bypass fitted and I can see that the systems ran water dumps in the boat they came out of however I don't have the original thru-hull fittings. Is there a particular size of water dump fitting required? I'm guessing they dont just release pressure but are also maintaining a level of pressure too. We don't have water pressure guages but I could retro fit for during testing if need be. If more info is needed please feel free to ask. Anyway, all help and advice much appreciated. All the best,

GPM

I'm not sure about your application, usually the water goes through the oil cooler, engine and out through the exhaust. Pictures may help

Griff

Diagram of Crossover with bypass https://www.cpperformance.com/instru...asscooling.pdf

Personally, I would just ditch the crossovers and install water recirc pumps with 140* Tstats

Either way, I would install permanent water psi gauges. Do you have oil temp gauges?? or do the engines have oil thermostats??

BTW, you cannot post pics until you have 10 posts on OSO.

UK Formula

Thanks for the replies. I only have a video of the engines running in the boat and now a collection of parts on the floor ( engines were stripped to long block and shipped) i can see that the water passes through powersteering/engine oil cooler upto crossover manifold where flow splits to block and upto centre feed of thermostat housing (then splits either side to the Stainless Marine exhausts). Between the crossover manifold and thermostat housing there is a Tee off to the side that goes straight to the water dumps high on the transom. Thermostats appear to have 3 holes drilled into them too. I hope that explains it? Difficult without pictures, sorry.

Engines don't appear to have oil thermostats, though I could fit them.

thanks 👍

Griff

Leave the holes in the Tstat. They allow some water flow for more consistent temps.
The T'd off hose probably had a pressure relief valve to control the flow to the thru hull water dump. https://www.cpperformance.com/c-121-...ef-valves.aspx

UK Formula

Thanks all. I've checked and the thermostats are 140° and will use them with the holes drilled in and the Tee is 3/4 so will buy 3/4 dumps either with preset valve or 3/4 thruhulls and an adjustable valve. Gonna have to install water pressure guages to check correct setup and from previous replies and more research on OSO seems it would be silly not to have oil temp guages too. My blocks are Gen V HO and only have one drilling above the filter housing which is currently used for oil pressure and alarm switch. It seems there are several views on oil temp sender location being either oil pan or before cooler. I was assuming there would be a fitting out there already to replace the sump plug with a 1/8npt to 1/2-20 plug and fit sender into there but can't seem to find one. Anyone know of one? (Will drill and tap if not) or other option is to drill and tap filter housing or if anyone knows of one, an inline fitting with mercruiser flared pipe threads? Thanks again

UK Formula

Sorry, one last question! 🙈 I've just replaced the guages to Livorsi, they offer 2 water pressure guages, 0-30psi and 0-60psi, anyone know what the likely water pressure will be? Cheers all. 👍

Griff

You want water pressure to ideally be around 20psi at WOT so get a 0-30 gauge

UK Formula

Thanks Griff, I'll get it all ordered! Soon be summer! 👍 all the best, Anthony