MIKE H

I have a question related to preheating the cooling water to my 540 c.i. carbed motor dynoed at 650+ hp. I run my boat up in Canada where the water at times is very cold. I presently have the water enter through an IMCO external pickup, goes through a regular water valve so that I can controll flow and some amount of presure spikes before entering my sea strainer, power strearing and oil cooler, then to a Magnaflow-Cam driven water pump which then enters the engine block. At the exit from the engine I have a pair of valves that I use to regulate block presure before entering my IMCO Powerflow plus manifolds and riser system. I am having some problem with obtaining much engine temp, about 120 running hard none at low speed. What I was concidering doing was preheating the water in the manifolds first. My concern is when I tried this before I had a great deal of condensation on the outside of the manifolds and found that I had some moisture forming on the inside of the manifolds at low rpm's. Can this hurt the engine. Am I beter off just to restrict the flow prior to the water pump untill it reaches a higher engine temp. I can increase the presure by closing the exit valves on the top of the engine to keep presure at the desired 18 - 20 pounds. I have an oil thermostate that keeps my oil at 190 degrees. Any opinion appreciated.

Geo 100

Mike, I run pre heated water as you were discribing.
Through hull/shut-off valve/1"cam driven/ tee's at pump exit/through each exhaust/enters motor/no thermastat/exits
motor to exhaust.
I boat on the lower Colombia river so my water is a little warmer
but 125@idle 150cruise 170 WOT. I saw 180 once after 20 min @
5200-5600 cooled right down after slow down. 468 Pfaff motor
I think you are on the right track.
GEO

MIKE H

Thanks Geo for reply.
Sounds like your setup is very similar to mine. If I try to get that kind of temp out my motor the feed valve is practically closed without preheating water first.
Do you have any trouble with condensation in the manifolds? When I had this setup before there was a lot of water in the bottom of my manifolds at idle, the constant cool water turned the brass valve guides brittle which when they started to crack found there way into the engine eventually leading to a total grenade of one piston.