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350Q HELP

david253

New member
"ok so i have been doing alot

"ok so i have been doing alot of research on this motor.
i originally had a 283 flywheel forward motor.
i bought a 350 flywheel forward block/heads ect.
the motor is now complete and im down to just installing the cooling system.
it has a heat exchanger the runs on the 4 port sherwood pump. as well as another jabsco pump to cycle raw water.
any ideas on how the flow diagram might be for this. i included pictures of my current state of the build.


284283.jpg
"
 
"Can't tell from the photo

"Can't tell from the photo if this is a "normal" cooling system or one with the pressure relief valves (CC's Thermocon-Develvo).... also is the heat exchanger sized for "full FWC" or "partial", i.e., the manifolds are not FWC.
."
 
"i believe its a partial syste

"i believe its a partial system, however when i tore apart the original 283, it had freshwater in the manifolds, and one side it had raw water.
on the end caps of the manifold it has the pressure valves. that is where im confused the most at because on thoes valves, its on the side that would dump overboard. it also had the cooling that came out of the heads and went into the exhaust manifold (fwc) the 350 does not have that. http://s89.photobucket.com/albums/k238/victimap/?action=view&current=Picture014. jpg]
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"Unless someone has one handy

"Unless someone has one handy they can share, suggest you go to:
http://www.marineengine.com/manuals/chriscraft/

It appears as if they have the manual for a 350Q which is sort of what you have, for sale.
I have the owner's manual for a FLV283 which shows the flow for a raw water cooled 283 with pressure valves, but don't think that will be all that much help. On second thought, it may. I'm emailing you directly the pages from that circa 1969 manual which shows how their cooling system with raw wqater cooling works. Than may give you some insight.

BTW..If your old engine had "fresh water" and I assume you mean antifreeze mixed coolant in one manifold, and raw in the other, it has obviously had the benefit of someone's "creative" repair/modifications, to say the least."
 
"yes the heat exchanger was fr

"yes the heat exchanger was from the 283.
and by freshwater your right i do mean antifreeze mixed coolant.
on the manifolds its got 3 different spots for water to flow, 2 had coolant the other had raw water (on each manifold) i do agree that it was someones creative modifications, but has me pretty confused."
 
"RE: "heat exchanger was f

"RE: "heat exchanger was from the 283. "

mmmmm... It may not be big enough. The 283 output was in the 185 HP region. A 350 w/4bbl likely to pump out 275+ HP depending on cam, etc.

The 283 may have been a "full FWC" system. Full FWC engines need some way to dump raw water out thru the "elbows". On newer engines, there is a fitting on the elbow for this and a blocking gasket is used at the juncture of the manifold and the elbow to keep the systems isolated, HOWEVER, it is entirely possible that the flow of raw water out the elbows is via a port into the manifolds and then out the end of the manifolds and into the elbows. "
 
"i called the number on the he

"i called the number on the heat exchanger, they said it should work.
i have the raw water side figured out now.
from the sea-through the pump to heat exchanger, out the exchanger to the front of the manifold down one side with a bypass on the adapter.
freshwater i think ive figured it all out except where the coolant exits the block. that part i havent figured out where it exits the block at yet."
 
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