It was not a typo. They both have a viscosity of "10" at 227 degrees. They are like a 30 when at room temperature. The oil needs to flow as quickly and easily as possible, and yet not break down when hot. This article explains it in more detail: http://www.bobistheoilguy.com/motor-oil-101/
I've read Oil 101 and you need to do so again(I'm a regular over on BITOG)... The 10 viscosity(cSt that I posted above) equals the average 30W at 212F, not at room temp where it will be more like 50 or in the range of a 80 or 90 weight oil if there were such a product... A 25W-70 is the thickest oil I've seen... Here's something that's easy to understand... http://www.upmpg.com/tech_articles/motoroil_viscosity/
Agree on frequent oil changes for break-in and for the life of the engine. To me, oil to engine is pennies to dollar - I'd rather pay for the oil many times over vice paying for a new motor...
Pony, I would have to agree with that statement. I have absolutely no problem paying for oil changes, I just don't want to waste money on the wrong oil per-se. I do have a high volume pump installed on it and my idling oil psi is around 45-50 and jumps to 60 psi when i hit about 3500. Not sure how much it would change with a load on the engine though. I suppose I'll change down to about 10W-30 then when I go to change it. I'll buy some Valvoline then. I do have about .0015 (give or take a .0001) bearing clearances all around, and I believe that to be close to stock. So I'll give lighter oil a try. I'm not sure about the idea to go against Cam Research, but if they probably planned it for a higher performance application then I'll try 10W-30 and add the zinc additive to see if that helps. Does that sound about right?
I`ve built over 100 engs. & what I do is run straight 30w hd oil for the first 500 miles,driving normally,then change the oil to whatever you are going to run,and have at it.Believe it or not,the rings seat in the first 15 min.,and all the older engs are designed to run at 180deg,get a good aluminum radiator and keep your temp. there and the eng. will last a long time.Also,when you get your machine work done,have stellite exhaust seats installed in your heads or the seats won`t last very long because they no longer put lead in gasoline anymore.I love Mobil 1 synthetic oil,have had great luck w/it at the track and in street cars.
You must build really good engines. I've never heard any modern engine builder recommend straight 30 for break-in. It's too thick at start-up and has no anti-foaming detergents. I broke mine in with 5w-30, and most builders and books recommend using the same viscosity oil for break-in as what is going to be used regularly.
I just had a very nice talk with the VP or R&D at Royal Purple a week or so ago.................we were talking about rearend oil and auto trans fluid. We also got into a discussion on the type and viscosity of oil I should use in my race motor. In a lot of drag motors I have used 15/50 and he told me I was probably giving away anywhere to .010 to .030 seconds because the viscosity of the oil and it cooling down during rounds or never getting hot enough to really work. He did say that I should be using 10/40, and this is what my engine builder suggested and did use on the dyno pulls to break it in and set the initial tune. He said that the only time 20/50 was needed was in NASCAR engines and Road Race motors where the motor/oil will maintain the highest temp for a long time. After our conversation he sent this email..........................and I quote " ", Good morning John, If you are still using this 408 inch small block Ford engine in a dedicated drag race only application a 20W-50 oil is not likely going to be needed as it there is very little opportunity to put heat into the oil and it is extremely thick and is simply going to eat up a bunch of horsepower without actually providing any additional protection. If you were road racing without an effective engine oil cooler, a 20W-50 may then be appropriate. Choosing the right viscosity: The viscosity of a Royal Purple ultra film strength oil you chose to run, should mostly depend on how much heat gets introduced into the oil with your specific usage and where that heated and thinned oil puts your oil pressure when it is at that temperature. Try to make arrangements if you can, to get the engine fully warmed and then make two or three back to back wide open throttle drag passes at minimum to get your oil very hot, and then take a look at your oil pressure at several different RPM points.(typically 3,4,5 and 6 thousand rpm) If you are running significantly more than 10 psi of oil pressure per 1,000 RPM (tested when the oil is as hot as it is likely to ever get), you might look at this as being a bit like throwing away or wasting valuable horsepower due to excessive pumping and parasitic loses. On street/strip cars running a “too thick” oil can also contribute to higher operating temperatures, since over all oil flow is reduced with a thicker oil less heat is able to be removed. In strictly drag race applications too thick also leads to less consistency due to more and faster thickening between rounds which can be very unpredictable without keeping a close eye on oil temperature with an accurate oil temperature gauge. This unpredictable thickening makes selecting an appropriate dial in very difficult. When using a Royal Purple ultra high film strength oil like XPR or HPS, you technically really only need between 6 to 8 psi of oil pressure per 1,000 RPM when the oil is at its hottest point. Check it at several RPM points typically 3,4,5 and 6 thousand rpm. Idle oil pressure readings are not going to be meaningful or very helpful, also checking at very high rpm is also not terribly meaningful either because above a certain point most pumps will hit the pressure relief valve setting and the psi will plateau. At high rpm continuing to build pressure is not typically needed because a hydrodynamic wedge of oil is created by the rotation of the crank shaft, so the pumped in high pressure oil cushion is basically replaced by this oil wedge. As long as sufficient flow remains and oil is delivered appropriately and consistently. Many motorsport enthusiasts and professional engine builders can be kind of old school and many still think that thicker oil and higher oil pressure always equal better protection, yet that is simply not the case. Better protection is best achieved through superior chemistry, which in the case of Royal Purple XPR racing and HPS oils results in significantly higher film strength and better wear protection and this allows for safe optimization of oil pressures to more efficient levels as lighter oils do allow you to make more power than heavier oils. Since all oils thin when heated and thicken when cooled, starting out with thicker oil is legitimately needed when the oil temperatures are expected to become extremely high on a regular basis which can result in lower than desired oil pressure. For example on endurance, road racing, or air cooled road racing engines. Low oil pressure is less common in drag race applications but it can result from very high levels of fuel dilution, or if your internal crank shaft bearing clearances are modified and opened up significantly. For your 408 inch small block Ford in a dedicated drag race only application we recommend one of the following: Engine: Royal Purple XPR 5W-20 (part #01011, quart bottle) Royal Purple XPR 5W-30 (part #01021, quart bottle) Royal Purple XPR 10W-40 (part #01041, quart bottle) XPR Racing: http://royalpurpleconsumer.com/product-categories/automotive/#!xpr-racing-oil Oil filter: Royal Purple extended life synthetic oil filter part #30-8A; RP Oil Filter: http://royalpurpleconsumer.com/product-categories/automotive/#!royal-purple-oil-filters Auto Trans: Royal Purple Racing ATF (part #11569, quart bottle); Racing ATF: http://royalpurpleconsumer.com/product-categories/racing/#!racing-atf-automatic-transmission-fluid Differential: Royal Purple Max Gear 75W-90 (part #01300, quart bottle); Max Gear: http://royalpurpleconsumer.com/product-categories/automotive/#!max-gear For a street/strip application: Engine: Royal Purple HPS 5W-30 (part #31530, quart bottle) Royal Purple HPS 10W-30 (part #31130, quart bottle) Royal Purple HPS 10W-40 (part #31140, quart bottle) HPS: http://royalpurpleconsumer.com/product-categories/automotive/#!hps-motor-oil One thing I forgot to mention is that oil under high pressure can and does wear the metal on the crankshaft journal, I have seen this happen on more than one race motor......the reason a lot of race builders use close to standard oil pressure and not usually use a high volume pump unless the clearances are pretty big. One reason the new cars use 5/20 or 5/30 are that the clearances are really tight, not like we run in our street or race motors.
I agree about the too thick at startup(though would likely be fine above 50F), but a 30W HD oil is detergent so won't have foaming issues...
"a dedicated drag race only application we recommend." 10W-40 "a street/strip application:" 10W-40 sounds to me like he sells oil...
Same as my engine builder recommended..............along with the Rusty Renteria, the dyno operator at Dinan. Just a question; why are you running 20/50 in your motor?
