Return-Path: Received: from [216.52.245.18] (HELO ispwestemail1.mdeinc.com) by logan.com (CommuniGate Pro SMTP 4.2b1) with ESMTP id 3154958 for flyrotary@lancaironline.net; Fri, 09 Apr 2004 15:04:11 -0400 Received: from ispwest.com (unverified [216.52.245.25]) by ispwestemail1.mdeinc.com (Vircom SMTPRS 3.1.293.1) with ESMTP id for ; Fri, 9 Apr 2004 12:04:04 -0700 Message-ID: X-EM-APIVersion: 2, 0, 1, 0 X-Priority: 3 (Normal) From: "Bill Schertz" To: flyrotary@lancaironline.net Subject: cooling problem Date: Fri, 9 Apr 2004 12:04:04 -0700 MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_84815C5ABAF209EF376268C8" ------=_NextPart_84815C5ABAF209EF376268C8 Content-type: text/html; charset=US-ASCII Content-Transfer-Encoding: quoted-printable

Dave,

In getting to see the sketches, I am more convinced than ever that your=20= problem was air in the system=2E Consider the following scenario=2E

1=2E you fill the system=2E air is bound to be trapped at the inlet of = the=20 radiator=2E

2=2E You make some low rpm runs=2E Assuming you had enough water to hav= e the=20 pump primed, you got some circulation, but at a low rpm, the flow is low eno= ugh=20 that it cannot flush all the air out of the radiator inlet=2E The water will= flow=20 down some of the tubes, and others will have no flow, being blocked by the a= ir=20 bubble=2E (Uneven temperature distribution on the radiator) Encouraged= by=20 the fact that it seems to be working you then go to:

3=2E Higher rpm=2E This increases (momentarily) the flow rate through t= he=20 radiator, which then sweeps a slug of air up to the pump=2E The pump loses p= rime,=20 and shuts off totally=2E You now overheat=2E

Until you get all the air out of the Radiator inlet, you cannot get the=20= pump to keep pumping=2E Could you add a petcock vent on the high end of the = rad --=20 pressurize the system with coolant and get all the air out?

Your proposed modification should work better, but you still could get = a=20 slug of air from the rad unless you get it hydraulically solid=2E The vent l= ine=20 will remove small amounts of air as the engine runs, but you still have to w= atch=20 out for the 'big slug' of air when transitioning from idle to high rpm=2E

Bill Schertz
KIS Cruiser # 4045

------=_NextPart_84815C5ABAF209EF376268C8 Content-type: text/plain; charset=US-ASCII Content-Transfer-Encoding: quoted-printable Dave, In getting to see the sketches, I am more convinced than ever that you= r problem was air in the system=2E Consider the following scenario=2E 1=2E you fill t= he system=2E air is bound to be trapped at the inlet of the radiator=2E 2=2E You make som= e low rpm runs=2E Assuming you had enough water to have the pump primed, you got some = circulation, but at a low rpm, the flow is low enough that it cannot flush all the air ou= t of the radiator inlet=2E The water will flow down some of the tubes, and others= will have no flow, being blocked by the air bubble=2E (Uneven temperature distrib= ution on the radiator) Encouraged by the fact that it seems to be working you the= n go to: 3=2E Higher rpm=2E This increases (momentarily) the flow rate through th= e radiator, which then sweeps a slug of air up to the pump=2E The pump loses prime, and = shuts off totally=2E You now overheat=2E Until you get all the air out of the Rad= iator inlet, you cannot get the pump to keep pumping=2E Could you add a petcock vent on t= he high end of the rad -- pressurize the system with coolant and get all the air out= ? Your proposed modification should work better, but you still could get a slug of = air from the rad unless you get it hydraulically solid=2E The vent line will rem= ove small amounts of air as the engine runs, but you still have to watch out for the '= big slug' of air when transitioning from idle to high rpm=2E =20 Bill Schertz KIS Cruiser # 4045=20 ------=_NextPart_84815C5ABAF209EF376268C8--