Avoiding a hot running engine...
Posted: Mon Feb 09, 2015 5:44 am
I would like to write a few words down here about water cooling issues and what to do about it because I think it will be a great help for a lot of people...
I would like to recommend everybody who have a big bore kit installed on the PCX to use a NGK CR9E spark plug to have a better, cooler running engine and to avoid detonation to start with.
- Now about the cooling system, the name of the enemy from a water cooling system is “air”.
As soon as air bubbles come in to your water cooling system, or when the pressure is gone it’s game over with the cooling capacity from your water cooling system.
If you are faced with a hot running engine, then I really would like to recommend you to install a open loop thermostat instead of the stock thermostat (item with number 4 on the picture below) which opens stock only with pressure when your engine is already in the higher temperature range.
Keep in mind that as long as that valve don't open in the thermostat you are in a bypass closed loop, not open loop and you'r not using water that comes from your radiator, only water from your cylinder and head.
That water is pumping around in a small circuit until slowly the pressure gets higher and the small piston inside the thermostat opens, and is closing the bypass to allow water from the radiator to be pumped around.
If you are in open loop all the time you will not experience engine warming up problems because there is still a small diameter hose (Nr. 8 from the picture below) attached on your water pump that brings hot water from your cylinder and head back to your water pump. If you would eliminate that hose, then you would start to get warming up problems and your bike would feel the first 2km's like it needs choke.
If you are in open loop all the time it's a lot easier to get all the air out of your cooling system as well and to check the level from your coolant in your system.
If you had removed your radiator to install a big bore kit and you install the radiator again, then fill it up until the top and start your engine.
You will see small air bubbles coming out of the water and you want to get rid of all air bubbles in your cooling system, so let the engine run stationary until you see no air bubbles anymore in your circulating water.
If your water becomes too hot it will be pushed upwards.
If this happens while you try to get rid of the air bubbles, close the engine and start the engine again after a few minutes to continue to see if there are more air bubbles coming out of the water.
If you have no air bubbles anymore, then fill the radiator up entirely to the top so that you can’t trap air inside your radiator.
Air can enter in many ways in to your water cooling system.
The first way is a leaking/blowing cylinder head gasket because like this your piston is pushing air out of the combustion chamber in to your water circulation system.
Be aware that your radiator cap must be strong enough, original it’s 0.9 bar we recommend at least 1.3 bar with 1.6 or 1.8 bar as maximum.
At the moment your radiator cap opens, the pressure go’s away from your water cooling system and this will suddenly bring the boiling point from your coolant to a serious lower degree which means that your coolant will start to boil even more! You will start to produce a lot of steam, so water is disappearing from your cooling system and without water in your cooling system its game over with the cooling function/capacity from your entire cooling system. At that point your engine has no chance anymore to cool down and the only thing your engine can do at that moment is running hot and even running hotter.
Filling water up in the water tank is no solution, the engine needs to cool down and you need to fill your radiator up again until the top.
If you fill the water in your tank, then this water never gets in your cooler like it should be.
Be also sure that the closing surface inside your water cooler is perfectly flat!
With the surface we mean the surface area from the water cooler where the sealing rubber from your radiator cap will push on.
If that surface isn’t perfectly flat you can expect cooling problems because it will be possible to leak at that point so with a leak the pressure will be lower which will bring the boiling point lower and your coolant will start to boil premature.
The points I write down here are based on our personal experience and knowledge at Yuminashi so I it might be useful to you.
If you don't understand why a higher number bar radiator cap is useful, then you can click this link to read the explanation about this http://www.yuminashi.eu/high-pressure-radiator-cap-1-1/
Greetings,
Reggy
I would like to recommend everybody who have a big bore kit installed on the PCX to use a NGK CR9E spark plug to have a better, cooler running engine and to avoid detonation to start with.
- Now about the cooling system, the name of the enemy from a water cooling system is “air”.
As soon as air bubbles come in to your water cooling system, or when the pressure is gone it’s game over with the cooling capacity from your water cooling system.
If you are faced with a hot running engine, then I really would like to recommend you to install a open loop thermostat instead of the stock thermostat (item with number 4 on the picture below) which opens stock only with pressure when your engine is already in the higher temperature range.
Keep in mind that as long as that valve don't open in the thermostat you are in a bypass closed loop, not open loop and you'r not using water that comes from your radiator, only water from your cylinder and head.
That water is pumping around in a small circuit until slowly the pressure gets higher and the small piston inside the thermostat opens, and is closing the bypass to allow water from the radiator to be pumped around.
If you are in open loop all the time you will not experience engine warming up problems because there is still a small diameter hose (Nr. 8 from the picture below) attached on your water pump that brings hot water from your cylinder and head back to your water pump. If you would eliminate that hose, then you would start to get warming up problems and your bike would feel the first 2km's like it needs choke.
If you are in open loop all the time it's a lot easier to get all the air out of your cooling system as well and to check the level from your coolant in your system.
If you had removed your radiator to install a big bore kit and you install the radiator again, then fill it up until the top and start your engine.
You will see small air bubbles coming out of the water and you want to get rid of all air bubbles in your cooling system, so let the engine run stationary until you see no air bubbles anymore in your circulating water.
If your water becomes too hot it will be pushed upwards.
If this happens while you try to get rid of the air bubbles, close the engine and start the engine again after a few minutes to continue to see if there are more air bubbles coming out of the water.
If you have no air bubbles anymore, then fill the radiator up entirely to the top so that you can’t trap air inside your radiator.
Air can enter in many ways in to your water cooling system.
The first way is a leaking/blowing cylinder head gasket because like this your piston is pushing air out of the combustion chamber in to your water circulation system.
Be aware that your radiator cap must be strong enough, original it’s 0.9 bar we recommend at least 1.3 bar with 1.6 or 1.8 bar as maximum.
At the moment your radiator cap opens, the pressure go’s away from your water cooling system and this will suddenly bring the boiling point from your coolant to a serious lower degree which means that your coolant will start to boil even more! You will start to produce a lot of steam, so water is disappearing from your cooling system and without water in your cooling system its game over with the cooling function/capacity from your entire cooling system. At that point your engine has no chance anymore to cool down and the only thing your engine can do at that moment is running hot and even running hotter.
Filling water up in the water tank is no solution, the engine needs to cool down and you need to fill your radiator up again until the top.
If you fill the water in your tank, then this water never gets in your cooler like it should be.
Be also sure that the closing surface inside your water cooler is perfectly flat!
With the surface we mean the surface area from the water cooler where the sealing rubber from your radiator cap will push on.
If that surface isn’t perfectly flat you can expect cooling problems because it will be possible to leak at that point so with a leak the pressure will be lower which will bring the boiling point lower and your coolant will start to boil premature.
The points I write down here are based on our personal experience and knowledge at Yuminashi so I it might be useful to you.
If you don't understand why a higher number bar radiator cap is useful, then you can click this link to read the explanation about this http://www.yuminashi.eu/high-pressure-radiator-cap-1-1/
Greetings,
Reggy
