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Should I cut the center out of the Thermostat???

Southern Airboat Gallery Archives

old 0-290
bang stick
MVC-002S
100_11771
1969 or 70
almost done
G

Grem62483

Member
I have a 350 chevy direct drive so I am only running around 1300-1700 RPMS. My temp rises to around 160-170 before the thermostat opens. Now I haven't run it yet in the mid 90s that we get here in LA in the summer. I plan on going frogging in the summer and I am concerned about running her hot while idling around the marsh. I did call a local boat builder and he told me to cut the guts out of the thermostat but don't remove it, so there is still some water restriction. So my question is Am I ok running at 160 degrees? My motor does take some time warming up and I dont want to take the center of the thermostat out and make this warm up time even longer. I was told that its not good to run the first ten minutes with the temp between 100 -110. Anyway I just want this to be right, so any advice will be greatly appreciated.



[/quote] Its either gonna go or its gonna blow! :wink:
 
Removing the center of the thermostat will take the motor longer to warm up. be sure to reinstall the outer ring to restrict the water flow.
the goo thing is that you will never have to worry about a sticking thermostat causing the motor to over heat.
we have two boat with SBC and no center in the thremostat. both run good.
 
I believe 160-170 is a good temp range, the trick is to have
enough radiator to cool the hot coolant before the engine sends
it another load of hot coolant. for running at speed ,air flow over
the radiator core should be sufficient , but for a lot of idling around
like frogging ( NOT TO OFFEND ANY OF YOU SUPER FROGGERS)
that frog on a plane, get an electric cooling fan for the radiator
you can wire it through a thermal switch, or a toggle switch and
just keep an eye on the temp.
 
but for a lot of idling around
like frogging ( NOT TO OFFEND ANY OF YOU SUPER FROGGERS)
that frog on a plane
Click to expand...

gigging frogs at an idle :shock:

ain't that akin to shooting turkeys off the roost?

or ducks on the water?
 
Grem62483":2yqokfov said:
Should I cut the center out of the Thermostat???
Click to expand...

Maybe off the SBC but not off a 500 or 472 caddy. They have a special thermostat that has a little plug at the bottom so when it opens, it plugs the internal bypass.

Without it, water follows the path of least resistance, and will go thru the bypass instead of the radiator!

You can only cut the guts out of the thermostat on a caddy if you manually plug the internal bypass hole - about a 7/8" hole directly under the thermostat housing. But leave a small hole for air to escape. Plug it with a freeze plug or JBweld.

(Thanks Stan) :)

matt.
 
i would think that you should adjust your prop to get at least 2800, maybe even 3000 before you do anything else then get the motor temp adjusted, but i think those temps are not bad just make sure there are no abstructions between the rad. and the prop and you should be good
 
OK , I'm not a expert here but if it was me I would leave it like it is if you running 170 I would change it if you hitting say 200. It would be a nice 20 dollar investment if you would in stall a high water temp warning sensor. They come so you can install it with a warning light . I have both low oil pressure and high temp with warning light and buzzer. Oil is set at 10psi and water is 200F.
 
goldhunter_2":20eg9oyi said:
I believe he said his is a Chevy
Click to expand...

wow you are observant! :roll:
What is your point?

Chevy is mentioned in my reply, and added more info about another GM motor.
 
moodfood":2ux8orfp said:
goldhunter_2":2ux8orfp said:
I believe he said his is a Chevy
Click to expand...

wow you are observant! :roll:
What is your point?

Chevy is mentioned in my reply, and added more info about another GM motor.
Click to expand...

Don't get touchy :roll:

My point ,since you asked , was that he asked specifically about a Chevy 350 and sometimes the fact gets lost that you where talking about a different engine (caddy witch was not mentioned) when people come back to skim through all the post
 
yeah, but the title of the topic is.... what?
Should I cut the center out of the Thermostat???

Touchy? ok.
Are you feeling nit-picky?
Glad we have you to clarify every post I make for those who can't read.
 
moodfood":1ibbi7a8 said:
yeah, but the title of the topic is.... what?
Should I cut the center out of the Thermostat???

Touchy? ok.
Are you feeling nit-picky?
Glad we have you to clarify every post I make for those who can't read.
Click to expand...

I'll Pm ya
 
Remove the guts, you will hit 200 deg. + if you are running in the marshes of La. I run a Ronnie's boat and the guts are out of mine. It takes a little while to warm up in the winter but it helps in the summer for sure. Just my opinion..........

You may want to add a little water wetter also it helps in the high temps of summer.
 
I agree. None of my engines come with a functional thermostat that run in the heat, and if a thermostat is nescessary, I drill holes around the outside so they'll burp easier, and at least get some form of flow if the thermostat screws up.

And also I don't wanna add to the confusion by discussing Caddys, but I think when a subject comes up, there are SO many readers in this forum that a lot of people who aren't directly related to the question still would like answers that apply to them. So I agree completely about the method for Caddys. It's the same deal with an LS motor. The W/P bypass is a dual function with the thermostat and if you wanna remove or gut it, you have to plug the bypass hole. And a freeze plug works best. A lot of people remove the thermostats on LS engines with success, but they have a very high flow W/P that can get away with it. But it really should be plugged cuz it probably cuts W/P efficiency by a good 30%. JMO

Felber
 
I have a dd 350 that has a 175 degree thermostat. What i did was drill 6 holes evenly spaced around the outer edge. The holes are 1/8th inch dia. this does not affect the operation of the thermostat. But it allows some water to flow if it sticks closed. I am also an idle frogger and the boat never rises above 180. I dont run a radiator fan either. 175-180 is the optimum temp range for older sbc. Above 190 195 is no good. hope this helps ya
 
First I think I have to re pitch the prop to about 9 or 10 degree's so that I can reach top RPMs. I did post a question about my prop and they did tell me that I should be between 2700-2800 RPMs and right now I am only topping out at 2200rpms. So I am going to take some of the pitch out and see what happens with the temp when I am running this thing a little faster. I was just going to leave the pitch at 12 to 13 degrees because I thought that if I reduce the pitch anymore that I am going to lose the little torque I use to run dry. But I guess that running higher RPMs will make up for that huh? The thing is that I dont have a gear ruduction ( its Direct Drive ). Basically what I am thinking is that the more pitch I have the more torque I will have but if I leave it alone I will lose the RPMs but still have the prop pitched enough to get me where I need to go. Maybe I am wrong but thats just me thinking. Like I said before this is my first boat and I dont know that much about them. The prop I am swinging is a 4 Blade Warp drive. I guess I will see what the temp does when I am running higher RPMs. Thanks for the reply. Bradley
 
Grem,

If you take pitch out you will get a little better fuel economy as well as push. It is not an issue of torque by loading it down your are not letting the engine make its peak numbers. You actually will gain torque by letting her run closer to where she likes to run and by taking extra load off the engine improve power numbers as well as engine longevity and fuel economy.
 
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