flyrotary@lancaironline.net Mailing List Archive

Guys,

We have two schools of thought going in this discussion and have had for some time..........One

opinion has the bottom of the expansion tank plumbed to the "Outlet" of the pump (as Tracy does &

others)..........The other has the bottom of the expansion tank plumbed to the "Inlet" of the pump

(as Al G., Mark S. & others do)..........I believe the inlet position came from the "Stewart Racing

Pump" site...........The rational being that this was the lowest pressure site of the cooling system and

would not subject the system pressure "Cap" (on the expansion tank) to both system and pumping

pressure

Yes; both ways work. If the ‘expansion tank’ is also where the pressure cap is; there are two advantages to connecting to the low pressure (inlet) side of the pump – slightly greater resistance to boiling and slightly greater resistance to pump cavitation; both due to the system pressure under high power being higher by the amount of the pressure drop around the loop.

Air bleed lines can be very small; like 3/16” aluminum, or equivalent; which will bleed air just fine, but flow a negligible amount of coolant; so bypass flow is not an issue.

Al G