X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Received: from imr-da04.mx.aol.com ([205.188.105.146] verified) by logan.com (CommuniGate Pro SMTP 5.3.9) with ESMTP id 4464891 for flyrotary@lancaironline.net; Mon, 13 Sep 2010 09:36:42 -0400 Received-SPF: pass receiver=logan.com; client-ip=205.188.105.146; envelope-from=Lehanover@aol.com Received: from imo-da01.mx.aol.com (imo-da01.mx.aol.com [205.188.169.199]) by imr-da04.mx.aol.com (8.14.1/8.14.1) with ESMTP id o8DDZthP012139 for ; Mon, 13 Sep 2010 09:35:55 -0400 Received: from Lehanover@aol.com by imo-da01.mx.aol.com (mail_out_v42.9.) id q.cd7.72f2a35b (43954) for ; Mon, 13 Sep 2010 09:35:46 -0400 (EDT) Received: from magic-d17.mail.aol.com (magic-d17.mail.aol.com [172.19.155.133]) by cia-dd01.mx.aol.com (v129.4) with ESMTP id MAILCIADD013-abb24c8e28b234c; Mon, 13 Sep 2010 09:35:46 -0400 From: Lehanover@aol.com Message-ID: <3916d.20d06bc.39bf82b2@aol.com> Date: Mon, 13 Sep 2010 09:35:46 EDT Subject: Re: [FlyRotary] Radiator cap - system pressure To: flyrotary@lancaironline.net MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="part1_3916d.20d06bc.39bf82b2_boundary" X-Mailer: 9.0 Security Edition for Windows sub 5378 X-AOL-IP: 173.88.9.178 X-Spam-Flag:NO X-AOL-SENDER: Lehanover@aol.com --part1_3916d.20d06bc.39bf82b2_boundary Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable Content-Language: en =20 In a message dated 9/13/2010 6:57:15 A.M. Eastern Daylight Time, =20 candtmallory@embarqmail.com writes: =20 Gents,=20 What pressure caps are you running with? What maximum should be used? = I=20 currently have a 16 lb cap, but have found ones up to 29 =E2=80=93 31 lbs= . I know=20 more pressure means more cooling, but is there a maximum limit before=20 hurting the engine?=20 Chris The radiator manufacturer will have a maximum number based on how stiff= =20 the flat sided tubes are. Too much pressure rounds those tubes and then = pulls=20 them loose from the fins when pressure is removed. Also the rounded tubes= =20 slow airflow through the radiator.=20 =20 Racing radiators tend to have higher pressure ratings than auto radiators= .=20 =20 Most racers run 16 to 22 pound caps. Higher pressure means higher boiling= =20 temp for the coolant. Also more stress on the connections. With a 2" hos= e=20 and 22 pounds you have just about 70 pounds trying to pull the hose off = of=20 the fitting. With silicone hose and safety wired clamps it would not be a= =20 factor. That does not include Chinese replica clamps. Just real American= made=20 name brand clamps. You can also use real aircraft quality clamps already= =20 drilled for safety wire.=20 =20 Many modern cars use no pressure cap. Just a sealing filler cap on a make= =20 up bottle. An air space above the coolant level provides a volume of air to compress= =20 to control the pressure. If the moron at the gas station fills that bottl= e=20 all the way up while reading the message on the bottle not to fill above= =20 this line, the end tank will blow off of the radiator just like on my wife's car. = =20 =20 The 22 pound cap is middle ground, a bit more insurance, not likely to=20 hurt the radiator.=20 =20 I use 22 pounds. Distilled water with 10% glycol and either Redline Water= =20 Wetter or 1/2 teaspoon full of dish washing detergent. It is gentle on th= e=20 hands. Never a problem since 1980. =20 Lynn E. Hanover=20 --part1_3916d.20d06bc.39bf82b2_boundary Content-Type: text/html; charset="UTF-8" Content-Transfer-Encoding: quoted-printable Content-Language: en =

In a message dated 9/13/2010 6:57:15 A.M. Eastern Daylight Time,=20 candtmallory@embarqmail.com writes:

Gents,

What pressure caps are you running with? What= maximum=20 should be used? I currently have a 16 lb cap, but have found ones= up to=20 29 =E2=80=93 31 lbs. I know more pressure means more cooling, but= is there a=20 maximum limit before hurting the engine?

Chris

The radiator manufacturer will have a maximum number based on= how=20 stiff the flat sided tubes are. Too much pressure rounds those tubes and= then=20 pulls them loose from the fins when pressure is removed. Also the rounded= tubes=20 slow airflow through the radiator.

Racing radiators tend to have higher pressure ratings than au= to=20 radiators.

Most racers run 16 to 22 pound caps. Higher pressure means hi= gher=20 boiling temp for the coolant. Also more stress on the connections.= With a=20 2" hose and 22 pounds you have just about 70 pounds trying to pull the hos= e off=20 of the fitting. With silicone hose and safety wired clamps it would not be= a=20 factor. That does not include Chinese replica clamps. Just real American= made=20 name brand clamps. You can also use real aircraft quality clamps already= drilled=20 for safety wire.

Many modern cars use no pressure cap. Just a sealing filler= cap on=20 a make up bottle.

An air space above the coolant level provides a volume of air= to=20 compress to control the pressure. If the moron at the gas station fil= ls=20 that bottle all the way up while reading the message on the bottle not to= fill=20 above this line,

the end tank will blow off of the radiator just like on= my=20 wife's car.

The 22 pound cap is middle ground, a bit more insurance, not= likely=20 to hurt the radiator.

I use 22 pounds. Distilled water with 10% glycol and either= Redline=20 Water Wetter or 1/2 teaspoon full of dish washing detergent. It is ge= ntle=20 on the hands. Never a problem since 1980.

Lynn E. Hanover

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