Use of sump evacuation systems like this are illegal in Canada for all CASC
racing, and have been for years. The sump must be vented to a properly
sixed catch tank only. The point is that if the engine starts to pump oil
because of sump pressurization, the excess oil will go onto the track
through the exhaust and cause a hazard for other competitors. This is not
something that I would like to see, and I'm curious if any of the people
advocating this have thought of their fellow competitors at all!
When I scrutineer cars, I always check for catch tanks and I pull the
tickets of cars that don't have them. If I caught someone with a system
like this at a race that I was teching, the car would be on the trailer for
the weekend.
01:29 PM 11/10/96 -0500, you wrote:
>
>
>Hi Jack,
>
>Good use of an old trick, Drag racers have been using this method for years.
>For a V-8 the common method is to use 2 backfire valves, one per header
bank and
>vent each valve cover to it's respective header. sometimes a cover over
tube is
>also used between the valve covers breathers to equalize pressure. I know a
>couple of after-market company's ( Mr.. Gasket, Moroso, etc..) used to market
>complete kits, fittings, anti-backfire valves hoses etc.. all together.
>Hope this might help anyone else who is thinking about doing it.
>
>Just insure that there is also a source of clean ( filtered) air entering the
>crankcase other wise you will suck the oil right out of the engine! Don't
laugh
>I saw it happen one night at the old Fremont, California drag strip! Yes I do
>remember them!! lot of blue exhaust smoke! ( before it broke!)
>
> Steve
> 1963, Jaguar MKII 3.8,& 72 XJ-6 (I grew up!)
>
>______________________________ Reply Separator
_________________________________
>Subject: Re: A Series engine breathing
>Author: "Jack W. Drews" <vinttr4@FORBIN.COM> at SMTPLINK-clavin
>Date: 11/6/96 8:26 PM
>
>
>Here's an alternative means of venting the interior of the engine. I am
>using this on my TR4 vintage racer engine as are two others in my circle
>of friends. I make no claims for HP increase, etc since the only way
>we'd know is by dyno measurements.
>
>Basically the method is to vent it to the exhaust system. Weld a small
>diameter - in my case 3/8" - tube into the collector pipe of the header
>so it protrudes about halfway into the exhaust stream at at a 45 degree
>angle. The end of this tube inside the header should be cut off also at
>a 45 degree angle so that the opening is actually at a 90 degree angle
>to the exhaust flow. To the end of the tube sticking out of the header,
>braze a pipe fitting so you can screw onto it an anti-backfire valve
>from a Chevy available from NAPA, for example. Then run a rubber hose
>from a vent on the engine to the anti-backfire valve. On my engine, I
>used the vent in the rocker cover.
>
>In my area, circle track racers and tractor pullers use this technique.
>They claim better ring sealing due to the slight vacuum pulled on the
>engine interior due to the suction created by the flow of the exhaust
>gas. They caution us to use the anti-backfire valve so in case of
>backfire you don't blow the pan off, which has been done on Chevy V8's
>On my car it worked successfully, yielding an almost leak-free engine,
>no sign of performance deterioration, but no big boot in the pants
>increase either.
>
>I expect this approach to be rather controversial and will enjoy seeing
>the responses to this one.
>
>Jack W. Drews (A squealing tire is a happy tire - we Iowa guys know
>about that squealing stuff)
>
>
>
>
Brian Evans
Director, General Sales
UUNET Canada Inc.
20 Bay Street, Suite 1910
Toronto, ON, M5J 2N8
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