Flexi hoses capped?

[starsailor]

Hi guys! Daft question of the day! The flexi hoses that run from tinware to heat exchangers are missing and vents (?) capped on my engine. Do I need flexi hoses, are caps ok, could run without either?

Cheers

 

[bluenose]

yea it's normal to cap them if you have no heat exchangers. I believe someone did some tests and the caps are better if they have about a 10mm hole in the center of them.

Also you should block up the holes in the tin ware with covers where the flexi hoses should go to stop hotness coming through

 

[starsailor]

Nice one, thank you.

 

[mike202]

I would have thought you may get over heating problems doing this.

The way I understand it is that the fan blows cool air drawn in through the crescent air vents over the oil cooler and the warm air then leaves the fan shroud through the two exits on either side and out (usually) into the HX.

If the two holes are capped then there is no where for the warm/hot air to go, and means the engine compartment will get full of warm air, leading to poorer oil cooling. :msn4:

 

[Tofufi]

I would have thought you may get over heating problems doing this.

The way I understand it is that the fan blows cool air drawn in through the crescent air vents over the oil cooler and the warm air then leaves the fan shroud through the two exits on either side and out (usually) into the HX.

I can't speak for Singleport engines, but twinport engines like the one photographed have a vent at the back for the hot air that has been through the oil cooler.

 

[rlepecha]

I would have thought you may get over heating problems doing this.

The way I understand it is that the fan blows cool air drawn in through the crescent air vents over the oil cooler and the warm air then leaves the fan shroud through the two exits on either side and out (usually) into the HX.

If the two holes are capped then there is no where for the warm/hot air to go, and means the engine compartment will get full of warm air, leading to poorer oil cooling. :msn4:

Warm air from the cooler is dumped near the gearbox from the doghouse. The air from the front two ports is cool(fresh) air from the fan, the heat for inside the bus is absorbed from the heat exchangers.

As previously mentioned, a full seal on the caps is not recommended.. This causes a back pressure back into the fan housing and affects flow from the fan to the cylinders. That's what I remember reading!

 

[slow-lane-Matt]

I would have thought you may get over heating problems doing this.

The way I understand it is that the fan blows cool air drawn in through the crescent air vents over the oil cooler and the warm air then leaves the fan shroud through the two exits on either side and out (usually) into the HX.

If the two holes are capped then there is no where for the warm/hot air to go, and means the engine compartment will get full of warm air, leading to poorer oil cooling. :msn4:

Warm air from the cooler is dumped near the gearbox from the doghouse. The air from the front two ports is cool(fresh) air from the fan, the heat for inside the bus is absorbed from the heat exchangers.

As previously mentioned, a full seal on the caps is not recommended.. This causes a back pressure back into the fan housing and affects flow from the fan to the cylinders. That's what I remember reading!

....this makes sense, because if you have the HX flaps shut (ie turning off cab hot air) the HX part of the air circuit is a cul-de-sac, so can't be essential for engine cooling or the engine
would get hotter when you turn heating off.

...having positive pressure in the engine compartment makes sense too, keeps hot/dirty air out - but how is this achieved when the pipes are connected - unavoidable natural leakage ?

 

[mike202]

I would have thought you may get over heating problems doing this.

The way I understand it is that the fan blows cool air drawn in through the crescent air vents over the oil cooler and the warm air then leaves the fan shroud through the two exits on either side and out (usually) into the HX.

If the two holes are capped then there is no where for the warm/hot air to go, and means the engine compartment will get full of warm air, leading to poorer oil cooling. :msn4:

Warm air from the cooler is dumped near the gearbox from the doghouse. The air from the front two ports is cool(fresh) air from the fan, the heat for inside the bus is absorbed from the heat exchangers.

As previously mentioned, a full seal on the caps is not recommended.. This causes a back pressure back into the fan housing and affects flow from the fan to the cylinders. That's what I remember reading!

I learn something new every day! :lol: I didn't know about the doghouse cooler exit point. So maybe it's ok then.

 

[matt-me]

wouldn't it force more air from the fan housing through the flaps onto the cylinder heads? so not a bad thing?

 

[Tofufi]

....this makes sense, because if you have the HX flaps shut (ie turning off cab hot air) the HX part of the air circuit is a cul-de-sac, so can't be essential for engine cooling or the engine
would get hotter when you turn heating off.

...having positive pressure in the engine compartment makes sense too, keeps hot/dirty air out - but how is this achieved when the pipes are connected - unavoidable natural leakage ?

The flaps in the heat exchangers don't make them into a cul-de-sac. The heat exchangers vent to under the gearbox/engine area when you turn the flaps in them off...

 

[rlepecha]

....this makes sense, because if you have the HX flaps shut (ie turning off cab hot air) the HX part of the air circuit is a cul-de-sac, so can't be essential for engine cooling or the engine
would get hotter when you turn heating off.

...having positive pressure in the engine compartment makes sense too, keeps hot/dirty air out - but how is this achieved when the pipes are connected - unavoidable natural leakage ?

The flaps in the heat exchangers don't make them into a cul-de-sac. The heat exchangers vent to under the gearbox/engine area when you turn the flaps in them off...

Exactly this.

A fully blocked hole results in a dead end where dead air sits and this dead air affects flow to the heads. I can't remember exactly why, it was a while since I looked.