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1980 crusader operating temp

"Ayuh,...

Freshwater coolin

"Ayuh,...

Freshwater cooling,..?? 180°....

Raw watercooling,..?? 160°...."
 
I have fresh water cooling.

I have fresh water cooling. Thanks. I think one motor has a 180 therm and one a 160.
 
ok my mechanic told me he repl

ok my mechanic told me he replaced a 140 thermistat with a 160......but the engine should still run at 180?
 
"Ayuh,...

The Higher the Te

"Ayuh,...

The Higher the Temps,... The More Effecient a gasoline motor is.....

The Reason raw water cooled motors are run So Cold, is to slow the mineral migration into the pores of the cast iron...
Salt Rot....."
 
"Actually, it's because th

"Actually, it's because the water in the block is not pressurized like in a closed cooling system. It will boil at idle after a hot run, when it drops to 1 psig or less, and steam doesn't cool worth a damn.

In a FWC system, the pressure stays about 7 or 8 psi all the time.

Jeff"
 
"I have 160 degree stats in my

"I have 160 degree stats in my boat now and It
will not go over 120 because our waters here in Seattle are so cold, salf or fresh.
That what I was told."
 
If the thermostat is working p

If the thermostat is working properly it cuts off water supply to the engine at low temperature which in turn results in the water being heated by the engine. If the engine is not heating to the temperature rating of the thermostat something is wrong or you are circulating water to some other device from the engine like a water heater. One way to check the thermostat is to place it in a pan of water on the cook stove with a thermometer in the water. Slowly increase the temperature of the water and see at what temperature the thermostat opens.

Chuck Hanson
 
Water is bypassing those t-sta

Water is bypassing those t-stats somehow. Better find out why and correct it. Cold motors produce acid that creates sludge and eats bearings.

Jeff
 
I am confused. So the 6 differ

I am confused. So the 6 different marine mechanics are wrong here in Seattle.
Is that what I am hearing on this subject?

Raw water temperature has nothing to do with how warn your engines gets?
I will have to differ on this being a HVAC Engineer.
If I want 72 degrees using hot water in a room with hot water that is 200 degrees I will need to have the refrigerant set at 128 degrees to off set the hot water to make the room 72.

If my stats on my boat are set at 160 and the raw water is coming in at 40 degrees
Then I would see a 120 degree motor. If I wanted a true 160 and the water is 40 then I should be using a 200 degree stat to maintain 160 degree engine temp.

I might be wrong but my math comes up with this.
 
"In a FWC (closed loop coo

"In a FWC (closed loop cooling system) the engines will get to any temp that is set by the thermostat. The coolant in the fresh water side of the cooling system will not circulate until the thermostat opens (at whatever temp the thermostat is to open). While the thermostat is closed, there is VERY little water circulating through the heat exchanger. Even if the raw water temperature was 32F, the engine coolant in the block will get to the thermostat temperature."
 
"hmmmm, no.(gastite)

"hmmmm, no.(gastite) The thermostat is a variable orifice flow restrictor with a temp. sensor built in. Very simply, it closes when below the set point, and opens when above the set point. It attempts to keep the coolant at a constant temperature at that point in the system; that is, at the thermostat housing. Engine temp control operates at the premise that when closed, the coolant becomes warmer. It's unlikely a chevy motor will operate with cold coolant with a closed thermostat at cruise power. Now, I will say that the oil could run cold, since the oil cooler is not thermostatically controlled and your oil cooler will be exposed to the cold raw water flow."
 
"I guess it depends on the eng

"I guess it depends on the engine or something because I just put
New 165 degree stats in and my engine and it will not get up to 160
It stays at 120, even sitting at the locks for 1 hour or so. I had a mechanic go
Thru everything last month and the flow of water is good, heat exchanger is good, oil cooler is new, I use 100% antifreeze, I had new raw water impellers put in last month, great flow
All 16 cylinders have great compression.

I have twin Crusader 1984 270hp each. Both have 1600 + hours on them. Maybe
I am just lucky and should just leave the engines alone ?

I just don’t understand then why I can’t get 160 degree."
 
a couple of questions: what t

a couple of questions: what temp are you seeing at cruise power (3200 rpm after 20 minutes or so)? How are you measuring the temp? Why 100% antifreeze? Seattle shouldn't require that kind of protection and 100% has relatively poor heat conductivity as well. My engines won't exceed 140 at idle with 85 degree raw water; I don't think the idle measurement is particularly meaningful.
 
"diver dave: At cruising speed

"diver dave: At cruising speed 110-120 at 3200-3300 rpm's and about the same at Idle speed. I am measuring by my brand new temp gauges, upper helm and lower helm.
100% antifreeze I was told would be good and not a problem."
 
"The specific heat of 100% ant

"The specific heat of 100% antifreeze is much less than water (restating what Dave said) = less heat transfer.

on the new gauges, did you have a dual station istallation before the new gauges went in? Have you ever checked the sender units?

Being a HVAC engineer, you should be able to get access to a thermocouple-based (or IR) temp measuring device. I'd suggest using this independent measurement, at the thermostat housing, as a check with the gauge readings. If you're good with the heat transfer equations, you should be able to estimate the steady-state temperature of the cooling systems (I do electrons and haven't been in a thermo class in decades)."
 
"exactly. There are no operat

"exactly. There are no operating conditions where 100% glycol is a good idea. It actually reduces boilover protection; Go to 50%. (unless you are using a pre-mix solution)..
Also, running two gages on a sender requires a dual station sender. If a single station sender is used, then readings will be low."
 
"Glycol has far less heat abso

"Glycol has far less heat absorbtion ability than water, so if you want to see it overheat....It also freezes at a higher temperature withou about 40 % water added.

Jeff"
 
"You guys got me to dig out so

"You guys got me to dig out some reference material.

Turns out the freezing point of antifreeze solution does rise for any mixture where the water is 33% or less.

Per the teleflex data sheets I have, a single temp gauge needs to see 240 ohms to 'read' 120 deg. When you run two gauges in parallel, the sendor needs to sink the same current from each gauge, so it needs to provide half its "single gauge" impedance. I took the few data points they provided and plotted them out. Pretty linear over the 'normal' operating temp range (<200F).

The conclusion is that if the engine has a single gauge sender and is hooked up to a dual gauge setup, when running @ 160F, both gauges will show you 120F.

Gastite: If you can get a thermometer (or functional equivalent) take a measurement at the thermostat outlet. there's a good chance the situation has been that way for a long time and you are the first one to be curious enough to ask the questions because it didn't sound quite right.

hope this helps"
 
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