Roadrunner 45

iTrader: (1)

Need some help guys.

On the mini, the radiator will be lower than the steam tube that comes from the heads. So I bought an air sep tank to mount higher than the rest of the cooling system (see pic), but no one seems to know exactly how to plumb the thing for an LS1 so it works correctly. The instructions are vague and for a conventional SBC water pump and cooling system.

The tank has a 1/4" npt bung on top (instructions say to add a bung to the top of the radiator and plumb this to the top of the radiator), and a 1/2" NPT bung on the bottom (instructions say to route this to the inlet of the water pump).

My original plan was to plumb from the 1/2" NPT bung on the tank to the front heater core tube on the water pump (that would normally come from the heater core) and plug the rear tube on the water pump (normally to the heater core). Then connect the steam tube from the heads to the 1/4" NPT fitting on top of the surge tank. The thing that bothers me about doing this is that I wonder if the surge tank would get sucked dry as there is a 1/2" outlet that is always "active" to the water pump and only a 1/4" inlet to the tank.

Any ideas or pics of a setup already out there?

67pete

OK, so let's stop and think of the exact purpose of the steam vent hose...It's to release the pressure, if any, from the high point of the engine, the heads, right! So if we have a higher point in the stock set up, in this case the radiator, we have a place for the pressure to go to. Remembering that the top of the radiator is the "low" pressure side of water. So why can't we route the steam vent line higher than the head and then back down to the radiator tank / hose even though it maybe lower then the head? Does this make sense?

Roadrunner 45

iTrader: (1)

because air will always revert to the highest point- in your example- back to the "high" point on the steam line. However, I've seen pics that would at least partially support your point- I believe it was on a trailblazer SS where the steam tube went to the heater core outlet/waterpump inlet- I know many on here have done a similar deal- tapping the water pump and routing the steam line to the tapped fitting (which is on the inlet side of the pump- so it's being "sucked"). The purge tank works on basically the same principal bout would allow the air to actually escape when the rad. cap on the tank vented, instead of being sucked back into the engine, or being trapped in a high point on the steam line.

By the way, I guess I'm thinking of this wrong, but I've read before what you noted about the "low" pressure side of the radiator. Water is non-compressable, so pressure is pressure right? If there's 18psi in the cooling system in the top of the radiator, it's 18 psi at the bottom of the radiator. Just something I don't get the "high" and "low" pressure side of the radior deal.

67pete

Actually by 'low' I mean the suction side of the water pump. Like when you open your radiator cap to add fluid while the engine is running. If you have steam, ie. very hot water, you have pressure, which should be more then the 'low' pressure of the water being sucked back into the engine, thus sucking the steam out of the heads to be replced, hopefully, by water.