Corolla; engine stumbles and wont rev up on anything over ~20% throttle
02-09-2009, 05:54 AM
#81
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Re: Corolla; engine stumbles and wont rev up on anything over ~20% throttle
That's why you let the ------- thing warm up.
I have severe doubts that "back pressure" from a thermostat does anything substantial to the performance of the cooling system.
I have severe doubts that "back pressure" from a thermostat does anything substantial to the performance of the cooling system.
02-09-2009, 06:25 AM
#82
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Re: Corolla; engine stumbles and wont rev up on anything over ~20% throttle
have you ever run no t stat? it never warms up. i even drilled 1 hole on the outer edge of a t stat once for more cooling and it never let the motor hit temp
02-09-2009, 11:19 AM
#83
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Re: Corolla; engine stumbles and wont rev up on anything over ~20% throttle
Originally Posted by t_cel_t
when coolent is coming in cold all the time the oil breaks down into a form that likes to gel, this was a problem on a few toyotas from the 80's
02-09-2009, 12:19 PM
#84
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Re: Corolla; engine stumbles and wont rev up on anything over ~20% throttle
Originally Posted by wafflesincars
Explain.
Even if you have an engine where water would flow evenly through the engine without the thermostat, running it cooler will cause problems. Engines are tolleranced to run at a certain temperature and load. Change either and working clearances change.
02-09-2009, 12:31 PM
#85
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Re: Corolla; engine stumbles and wont rev up on anything over ~20% throttle
Originally Posted by Joseph Davis
This is why 7M, among others, have ---- oil pressure at idle.
It's also why my ---- ran for 4 months with 0 oil pressure.
02-09-2009, 01:35 PM
#86
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Re: Corolla; engine stumbles and wont rev up on anything over ~20% throttle
My old 89' camry held 3 PSI at idle. Spec was 7 I think. It never knocked though and ran well, but we ran 10w40 in it all the time after seeing it held 3 PSI when warm. :1
02-10-2009, 08:27 PM
#87
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Re: Corolla; engine stumbles and wont rev up on anything over ~20% throttle
Originally Posted by patsmx5
Water pump has an inlet and outlet. High pressure side and low pressure side, relatively speaking. Change in pressure is what causes flow to occur. No delta P, no flow. A lof of engines are designed to use a thermostat and it being a restriction cause water to flow through certain subsystems. IE, if you have a water cooled turbo, it takes water from after the pump and sends it to the turbo, then it returns to the inlet of the pump. The larger the delta P, the more flow cools your turbo. Some engines rely on this for cooling the engine itself, like a mazda BP where if you remove the thermostat, water no longer flows through the 4th cylinder. Similar designs are found throughout many I4 and I6 engines.
Even if you have an engine where water would flow evenly through the engine without the thermostat, running it cooler will cause problems. Engines are tolleranced to run at a certain temperature and load. Change either and working clearances change.
Even if you have an engine where water would flow evenly through the engine without the thermostat, running it cooler will cause problems. Engines are tolleranced to run at a certain temperature and load. Change either and working clearances change.
I was just wondering if you had anything empirical to back that up, I just have a hard time believing that a sealed incompressible fluid system wouldn't flow better in all areas with less restriction; a system will always flow in the path of least resistance but that is also neglecting convection. The only thing that comes to mind is the dwell time of the fluid affection operating temperature.
Jw.
02-10-2009, 08:56 PM
#88
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Re: Corolla; engine stumbles and wont rev up on anything over ~20% throttle
Originally Posted by wafflesincars
I know how a water pump works, and how engines are designed to run at operating temperature.
I was just wondering if you had anything empirical to back that up, I just have a hard time believing that a sealed incompressible fluid system wouldn't flow better in all areas with less restriction; a system will always flow in the path of least resistance but that is also neglecting convection. The only thing that comes to mind is the dwell time of the fluid affection operating temperature.
Jw.
I was just wondering if you had anything empirical to back that up, I just have a hard time believing that a sealed incompressible fluid system wouldn't flow better in all areas with less restriction; a system will always flow in the path of least resistance but that is also neglecting convection. The only thing that comes to mind is the dwell time of the fluid affection operating temperature.
Jw.
Empirical evidence of my own, little. Mazda BP's I noted have a poor cooling design where changes in pressure affects the cooling of the rear most cylinder. On this engine, coolant exits at the rear of the head, goes through the heater core, and then returns to the water pump inlet. This flow is what keeps the rear cylinder cool. As the engine is put under load and the thermostat opens more and more, the pressure difference drops, reducing flow across the rear cylinder. Many many many people have ruined a BP and it's always the #4 cylinder. Rerouting the cooling system to correct the aforementioned coolant route fixes this. Some older diesel Isuzu engines are also designed this way and will overheat and blow a head gasket if you run them without a thermostat.
02-10-2009, 09:15 PM
#89
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Re: Corolla; engine stumbles and wont rev up on anything over ~20% throttle
I think I'm still not following you completely here.
So the coolant comes out of the engine into the bottom of the radiator, up through the radiator, through the thermostat housing where it T's into the head, through the heater core and then back into the inlet stream? Positive side?
It just sounds odd because fluid doesn't compress enough to have a pressure differential that would affect the flow like that, and with increased flow the venturi effect would be higher if it's sucking it back into the inlet stream, but I don't know why it would.
I just want to know what's what before I go put the thermostat back in my civic, or my uncle's 240 that's been running without one for twenty some-odd years.
So the coolant comes out of the engine into the bottom of the radiator, up through the radiator, through the thermostat housing where it T's into the head, through the heater core and then back into the inlet stream? Positive side?
It just sounds odd because fluid doesn't compress enough to have a pressure differential that would affect the flow like that, and with increased flow the venturi effect would be higher if it's sucking it back into the inlet stream, but I don't know why it would.
I just want to know what's what before I go put the thermostat back in my civic, or my uncle's 240 that's been running without one for twenty some-odd years.
02-10-2009, 09:28 PM
#90
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Re: Corolla; engine stumbles and wont rev up on anything over ~20% throttle
This shows the miata factory routing, 323 BP GTR Routing, Miata "reroute", and some dipshit named hyper that didn't have a clue how to do a reroute.
Again, not all engines are designed to need the thermostat for even flow through the engine. But our engines and a few others I know of do. Regardless, why would you run without a thermostat in the first place?
Again, not all engines are designed to need the thermostat for even flow through the engine. But our engines and a few others I know of do. Regardless, why would you run without a thermostat in the first place?
