BEC cooling system.

[Colin 1985]

Hi,

I was looking for some advice, I have been having problems with the cooling system and before I put a new larger pump in, just wanted to check that I had the circuit correct, would appreciate advice from someone who has a BEC or is in the know.



The car is mid engined and front cooling. I have removed the thermostat which was causing a bit of a restriction.

[bonesX]

You'll have more joy posting that question on the locost builders forum. They have a dedicated BEC section

[Dave Dax builder]

Shouldn't the water enter the rad at the top and then back into the engine from the bottom?

[robcollingridge]

Surely it depends on the bike engine you are using? The system in my 2003 R1 engine is a combined oil/water cooling system and has balanced flows too. Because of this I left it alone and plumbed it in just like the bike installation, even using the R1 radiator. This is what I did:

http://www.robcollingridge.com/kitcar/design/cooli...

Has worked perfectly for the last four years :-)

Rob

[Colin 1985]

Dave Dax builder said:

Shouldn't the water enter the rad at the top and then back into the engine from the bottom?

Possibly(?), I will have a looking the morning if they are as described, the tubes are hidden in the body work and I might have miss-looked.

[Colin 1985]

robcollingridge said:

Surely it depends on the bike engine you are using? The system in my 2003 R1 engine is a combined oil/water cooling system and has balanced flows too. Because of this I left it alone and plumbed it in just like the bike installation, even using the R1 radiator. This is what I did:

http://www.robcollingridge.com/kitcar/design/cooli...

Has worked perfectly for the last four years :-)

Rob

I did actually read this earlier today, quite interesting...

The motor is a Hayabusa with dry sump so separate (I think). It ran well last year but I have been having a nightmare this year with it keep boiling its fluid seamanly at random, so was wondering if perhaps I should conect it up differently to optimize.

I'm using a small electric booster pump at the moment which worked well previously but despite replacing it with another (identical) pump I am having boiling problems. Going to replace with a much more powerful pump (which will also draw more watts).

Edited by Colin 1985 on Thursday 11th November 21:45

[singlecoil]

Colin 1985 said:

Going to replace with a much more powerful pump (which will also draw more watts).

Not sure that is going to help, unless there is something wrong with the current pump. If the water is being circulated through the radiator, and isn't being cooled enough to stop it boiling then I think you need to look elsewhere. Dave correctly points out that the water should enter at the top and return from the bottom, so you need to check that.

Have you done all the usual stuff, for instance, are the pipes clear, and not kinked, have you done a back flush, and most importantly, is the radiator getting hot? Is there good airflow through the radiator. Is the pressure cap the correct rating, have you tried a new one?

[Colin 1985]

singlecoil said:

Colin 1985 said:

Going to replace with a much more powerful pump (which will also draw more watts).

Not sure that is going to help, unless there is something wrong with the current pump. If the water is being circulated through the radiator, and isn't being cooled enough to stop it boiling then I think you need to look elsewhere. Dave correctly points out that the water should enter at the top and return from the bottom, so you need to check that.

Have you done all the usual stuff, for instance, are the pipes clear, and not kinked, have you done a back flush, and most importantly, is the radiator getting hot? Is there good airflow through the radiator. Is the pressure cap the correct rating, have you tried a new one?

Thanks for the reply, the problem doesn't seam to be that the system doesn't have the capacity to cool (worked fine last summer), I think perhaps there may be hot spots in the engine (for some reason?) which is causing boiling air to replace the water and stopping flow, I thought a faster flowing pump might fix this.

I have emptied and refilled the system a number of times and there didn't seam to be any blockages, but I will try with a bit more pressure maybe to clear anything that is in the engine (ie. maybe something loose that is only occasionally getting stuck). I don't think there is anything wrong with the cap, but since they are cheap I may as well get one anyway.
Also to free up flow I removed the thermostat and added a digital controller.

It just odd that it will work for a while, remain within normal operating temp. and then for no obvious reason over heat.

Edited by Colin 1985 on Thursday 11th November 22:19

[singlecoil]

Colin 1985 said:

singlecoil said:

Colin 1985 said:

Going to replace with a much more powerful pump (which will also draw more watts).

Not sure that is going to help, unless there is something wrong with the current pump. If the water is being circulated through the radiator, and isn't being cooled enough to stop it boiling then I think you need to look elsewhere. Dave correctly points out that the water should enter at the top and return from the bottom, so you need to check that.

Have you done all the usual stuff, for instance, are the pipes clear, and not kinked, have you done a back flush, and most importantly, is the radiator getting hot? Is there good airflow through the radiator. Is the pressure cap the correct rating, have you tried a new one?

Thanks for the reply, the problem doesn't seam to be that the system doesn't have the capacity to cool (worked fine last summer), I think perhaps there may be hot spots in the engine (for some reason?) which is causing boiling air to replace the water and stopping flow, I thought a faster flowing pump might fix this.

I have emptied and refilled the system a number of times and there didn't seam to be any blockages, but I will try with a bit more pressure maybe to clear anything that is in the engine (ie. maybe something loose that is only occasionally getting stuck). I don't think there is anything wrong with the cap, but since they are cheap I may as well get one anyway.
Also to free up flow I removed the thermostat and added a digital controller.

It just odd that it will work for a while, remain within normal operating temp. and then for no obvious reason over heat.

Edited by Colin 1985 on Thursday 11th November 22:19

Is the radiator getting hot? It's the single most important question.

[Colin 1985]

singlecoil said:

Is the radiator getting hot? It's the single most important question.

The radiator heats up as normal until the problem occurs, at which point the system doesn't seam to flow water and the radiator cools.

eg. Last week when I finished refilling the system after installing the digital controller (which I hoped would cure the problem by allowing the removal of the thermostat) I took it on a run and it all worked fine - pump okay, no loss of fluid, radiator warm as expected etc. so I assumed all was fine with the world.

A few days later, I thought I would have a bring your kit car to work day, on the way to work it boiled again (luckily I was virtually at work so shut off the engine and coasted). That night filled it up and it drove home fine. It didn't get particularly hot on the way to work at any point except when the 'problem' occurred so I assume it boiled a small quantity of water in the engine and the pump was unable to replace this with fresh water for an unknown reason (voodoo curse possibly?).

[mickrick]

Airlock?

[singlecoil]

One test for air in the pipes is to squeeze the pipe at the highest part of the run and see if you can hear air being forced down through the water.

Put up some pictures of the installation, maybe we can suggest something.

[Stubby Pete]

robcollingridge said:

Surely it depends on the bike engine you are using? The system in my 2003 R1 engine is a combined oil/water cooling system and has balanced flows too. Because of this I left it alone and plumbed it in just like the bike installation, even using the R1 radiator. This is what I did:



Has worked perfectly for the last four years :-)

Rob

+1
I have a slight issue when statioary though, considering a separate electric pump as the flow is a lot longer than when in the bike.

[mikeveal]

How about that overflow pipe....
If the system isn't able to pressurise then the water will boil at 100C, and it's probably designed to run at around 80 -> 90C. (My R1 fan doesn't kick in 'till the water hits 95C)

I've just posted in your other topic on replacing your bulbs with LED's. I had forgotten that many Busa BEC's use a electric water pump. Fitting a higher power water pump would be a bad idea if you are already overloading the generator!

[pilbeam_mp62]

Head gasket problem, which is pressurising the system ?

[Smart roadster]

If the system is set as shown then you need to move the feed from the resevoir to the suction side of the pump. As you have it the water will go to the resevoir rather than the engine as the resevoir will put up less resistance than the engine will.

[Colin 1985]

pilbeam_mp62 said:

Head gasket problem, which is pressurising the system ?

Oh god I hope not! Any relatively easy way to check? (ie. I'm not that tooled up) Could the head leak gas into the cooling system to replace the water and cause boiling?

Smart roadster said:

If the system is set as shown then you need to move the feed from the resevoir to the suction side of the pump. As you have it the water will go to the resevoir rather than the engine as the resevoir will put up less resistance than the engine will.

I did wonder about this, seem to remember reading it somewhere that this was to increase the pressure on the suction side of the pump, but was worried that if I did that the pump would suck all the water from the reservoir and not from the radiator and hence effectively remove the radiator from the system. Is this not the case?

[mickrick]

singlecoil said:

One test for air in the pipes is to squeeze the pipe at the highest part of the run and see if you can hear air being forced down through the water.

Put up some pictures of the installation, maybe we can suggest something.

Usualy the top pipe going to the rad. It should also get hot, as has alread been mentioned, the top rad hose should come from the engine.
Your drawing shows it the other way around.

[Colin 1985]

Some pictures, apologizes for the quality - taken on phone.

[Smart roadster]

The header tank (resevoir) should always go on the suction side of the pump. The resevoir is there to contain the expansion and contraction of the fluid with it heating and cooling. If you are pressurising the resevoir how is fluid supposed to get back in to the system? Also if you pressurise the resvoir you might be forcing fluid out of the pressure cap.