mobythevan Posted February 19, 2004 Share Posted February 19, 2004 Since everyone is modifying their cooling system on swaps and I have set up a few I was wondering what pressure do you run with sbc? Caps are made at 7lbs, 13lbs, 16lbs and other values. What is the advantage of running 7lbs vs 16lbs or vice versa Higher pressure will raise the boiling point of the coolant, what other factors are involved? Quote Link to comment Share on other sites More sharing options...
Kevin Shasteen Posted February 20, 2004 Share Posted February 20, 2004 As you stated the coolant system is under pressure, why even put it under pressure to begin with? The reason is to alter the boiling point of water/coolant. For each pound# your coolant is put under pressure you will have successfully altered the boiling point by 3* (* means Degrees). Another point of interest about coolant systems and pressure is that for every gain of 1000ft in elevation you will loose 1# of pressure: which means if someone were to go from Sea Level up to your neck of woods in Colorado they will loose 6# of pressure: and a high probability that they will experience overheating. Different elevations and levels of performance require different pressure ratings. Kevin, (Yea,Still an Inliner) Quote Link to comment Share on other sites More sharing options...
mobythevan Posted February 20, 2004 Author Share Posted February 20, 2004 ok thanks, sounds like I will run a higher pressure cap up here then. Quote Link to comment Share on other sites More sharing options...
johnc Posted February 20, 2004 Share Posted February 20, 2004 Another reason to run high pressures is to reduce the chance of localized boiling in the head. Sometimes you'll get hot spots that create small steam pockets. A higher overall system pressure will reduce the chance of the steam pockets forming. Quote Link to comment Share on other sites More sharing options...
grumpyvette Posted February 20, 2004 Share Posted February 20, 2004 the guys covered that before I saw you posted this, just a couple things to add oil flow, not coolant does the first heat transfer from the critical bearings,rings,rockers,springs,ETC. oil flow must remain constant and under enought pressure to always provide a film between the moving metal parts, a high capacity oil pan in the 7qt-9qt range and windage control system for the oil helps a great deal with engine cooling. I have repeatedly said that your oil temp should keep above 215° to allow moisture to burnout of the oil and that your coolant temp should stay in the 180-220 range SMOKEY YUNICK, in several places in several books, refers to extensive dyno testing he did for General Motors, where they consistently found, that both engine wear and hp production benefited when the oil temp stayed above 215° but below 240°, and the coolant temperature stayed between 180 and 220, degrees, or as SMOKEY said, trying keep your oil hot, but your coolant, about 20 to 30° lower in temperature but the coolant should never be below 180°, and should not exceed 220°, while temperature should never below the below 215°, and 235 to 240 is about ideal, mineral base oils tend to start breaking down over 240°, synthetic oils can easily handle temperatures up in the 270 degree range in for extended periods, but they performed best in their lubrication in cleaning function went down in the 240 range I normally buy oil pans from these guys as they are good quality for the money http://www.parts123.com/PartFrame.asp?ZTM=cadefjgb&GHOME=www.midwestmotorsportsinc.com&TITLE=Midwest_Motorsport i don,t usually have alot of money to waste so I normally buy this #KEV 1090 oil pan for $100 and weld a sump extension forward with this kit they sell for $26 # MWM 15900 and add a windage screen #MIL 32250 for $80,so for about $220-$245 you can have a baffled 9.5 qt oil pan with windage screen http://www.moroso.com/catalog/categorydisplay.asp?catcode=11330 while I tend to build or modify my personal oil pans MOROSO has a good product, in several versions, which I can recommend if your buying one! you will need to carefully measure clearances for the cross member,suspension,headers,starter,oil filter, ground clearance, ETC. before ordering , or modifying an oil pan restricting coolant flow speeds to help cooling is a MYTH,started when guys found that removing the thermostat could cause overheating on some cars, the thermostat did not restrict the flow significantly but it did tend to prevent the waterpump from cavitateing and failing to efficiently move coolant. large tube aluminum radiators tend to cool very effectively mounting an electric push fan infront of your radiator can significantly help lower temps water wetter additive can disolve some types of paper thermostat gaskets a 17lb radiator cap is about as high a pressure rating as you can use on a standard cooling system air flowing over the outter surface of a road racing style, 8qt or larger extended sump oil pan removes a good amount of heat from the engine, tall valve covers can also act to radiate heat from the oil running over the inner surfaces header coatings can also help reduce under hood temps naca ducts or side vents that allow efficient removal of air flow behind the radiator can help cooling A lower rated 160f thermostat will not make the car run cooler. It only allows the coolant to begin circulating at a lower temperature thru the block and radiator. The main controlling factor in engine temperature is radiator size/effeciency/ coolant volume and flow rates and your ability to move massive amounts of air thru the heat exchanger (radiator). That is the most important single process in how the engine gets rid of excess heat YES YOU SHOULD RUN A THERMOSTAT, about 180F-190F prefered on most high performance cars FACTORS THAT IMPEDE COOLING EFFICIENCY 1 - Coolant does not pass through radiator freely. Over time, chemical reactions can cause corrosion buildup in the radiator tubes and can restrict the flow of coolant through the radiator. Also, debris can accumulate at the tube openings (similar to a strainer) and the resulting blockage can restrict flow. The result is that the heat is not transferred from the coolant to the fins and overheating will likely occur. 2 - Air flow is restricted through the radiator and heat cannot be dispersed into the air. If trash or bugs clog the fins on the radiator, then the air flow cannot pass over the fins and the heat is not dispersed into the air. The buildup of heat can cause overheating. 3 - Deterioration. Over time, the metal fins oxidize and deteriorate. Road salt and salty air from coastal areas contribute to speeding up the oxidation process of radiator fins. http://www.jcwhitney.com/productnoitem.jhtml?CATID=5131&BQ=jcw2 RADIATOR CORROSION INHIBITOR Prevents overheated radiators caused by rust, scale and corrosion. Save money on needless flushing, repairs, anti-freeze changes, special additives! Zinc anode slips in radiator filler neck and neutralizes rust/corrosion-causing chemicals. Lasts for years. NOTE: Not for radiators with plastic tanks. http://www.pjhbrands.com/vht/coppergasketcement.htm http://www.radcapproducts.com/order.html" http://www.radcapproducts.com/order.html if you don,t read the links youll miss most of the info! http://www.radiatorbarn.com/ http://www.streetrodstuff.com/Products/157/ http://www.streetrodstuff.com/Articles/Cooling/More_Cooling_Suggestions/ http://www.streetrodstuff.com/Articles/Cooling/Cooling_Suggestions/ http://www.prenhall.com/autoweb/chekchart/classch5.pdf Quote Link to comment Share on other sites More sharing options...
mobythevan Posted February 20, 2004 Author Share Posted February 20, 2004 Excellent, just what I was looking for. I can never find the good articles when I search the web. I particulary like the link http://www.streetrodstuff.com/Articles/Cooling/Cooling_Suggestions/ from your post. Out of those 10 things I was doing at least 4 wrong in my old van and it always overheated. I won't make the same mistake again in the truck I am working on right now. Thanks Grumpy and everyone else that replied Quote Link to comment Share on other sites More sharing options...
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