Performance Boats Forum banner
1 - 11 of 11 Posts

·
Registered
Joined
·
17 Posts
Discussion Starter · #1 ·
What is behind this cover? Is it sealing off the timing chain and then open holes in the block to circulate the water in the engine? Does the water pressure only come from the jet pump?

Thanks,
Mike
Motor vehicle Blue Hood Light Automotive design
 

·
Registered
Joined
·
179 Posts
It's not really sealing off the timing set, as the timing cover does that.
It's an adapter plate to eleminate the automotive water circulating pump, and to plumb cold water from the jet pump into the front of the engine.

Just FYI, you should never limit the flow out of the engine. Limit flow at the pump into the engine to desired running temps. Limiting flow out of the engine can (WILL) over pressure the cooling system, and push out head gaskets and intake gaskets.

Just my $0.02

Dan'l
 

·
Registered
Joined
·
17 Posts
Discussion Starter · #3 ·
It's not really sealing off the timing set, as the timing cover does that.
It's an adapter plate to eleminate the automotive water circulating pump, and to plumb cold water from the jet pump into the front of the engine.

Just FYI, you should never limit the flow out of the engine. Limit flow at the pump into the engine to desired running temps. Limiting flow out of the engine can (WILL) over pressure the cooling system, and push out head gaskets and intake gaskets.

Just my $0.02

Dan'l
Thanks for the reply - So there is a timing cover behind that plate. Good. The kid I bought it from said it would run cold all the time so he said someone recommended to put valves on the lines to regulate it. I have been reading up on it but sometimes people can be confusing. Do you recommend putting a pressure relief valve on the intake hose and set it at 20psi - Then have both outlets on the thermo housing dump overboard? Then take plug out of manifold next to housing and feed the headers?
Mike
 

·
Registered
Joined
·
179 Posts
50 degrees.
You want 50 degree rise from ambient lake temp.
Pressure relief valves have a common failure, sand.
I'd avoid the pressure relief valve, in favor of a gate valve. Less moving parts. Less (like zero) failure rate.
Adjust gate valve to desired running temp. My BBC/ headers runs 120 ish at cruise, 130ish WFO. 140/150 in the no wake zone.
I run a valve for the headers at the drivers' seat, and adjust as necessary.
One 5/8ths hose overboard handles the engine cooling. Super simple and reliable. I may have 5-7 lbs of pressure in the cooling system, and that's guessing. You don't want 20+ psi, Olds engines, originally in 70s cars, maybe had a 15 lb radiator cap. Probably less. There's a reason for this. Don't over think it. Cold on a jet single pass system is normal. But having too much pressure, especially on an Olds, is a disaster in the making.

Jet boat performance has a diagram for water routing on their website.

Hope this helps.

Dan'l
 

·
Registered
Joined
·
17 Posts
Discussion Starter · #6 ·
Thanks again for your insight. In the picture is my intake valve. Replaced ball with a gate valve. Remove the ball valve on the overboard dump line. Install a pressure gauge on the intake manifold to see what pressure I'm running in the motor. Keep the ball valve on the line feeding the headers? It does have the tee fitting and looks like it has the blue orifice fittings on each feed line to the headers. I did notice in the diagram that they have a gate value on the dump line? Thanks again Mike
 

Attachments

·
Registered
Joined
·
179 Posts
Sounds good, especially the pressure gauge.
Mine has a valve by the drivers'seat, so I don't have a gate valve on the overboard water line.
JBP's diagram and explanation makes sense. Without a drivers' seat valve, I'd do like the diagram.

Dan'l
 

·
Registered
Joined
·
17 Posts
Discussion Starter · #10 ·
After thinking about what you said. You have a control valve next to you to control engine temp on the fly. You are controlling the overboard water flow. Set the incoming water pressure to 5 to7 psi and leave it there. As you need more or less heat on the motor control it with the value. If you have a picture of your valve set up that would be awesome. All makes sense now. Kiss - keep it simple.
 

·
Registered
Joined
·
179 Posts
I guess I was a bit vague.
I have a quarter inch line running to the drivers' seat (and back) for header water control.
I don't actually change engine temp on the fly, but can easily increase or decrease flow while on the beach. I've rarely done that.

Dan'l
 
1 - 11 of 11 Posts
Top