Valvoline VR1 20w 50 vs Rotella 15w 40 ??

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May 25, 2009
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Im running a 1986 5.0 HO block with a mild flat tappet street cam... Its a fresh rebuild that I got last year ( it came with 5 qts rotella 15 40 for break in) said to use it for 500 miles then swap to whatever. Well finally got the motor in and 500 miles on it... needed to put some oil in it. So did my research seemed like VR1 20w 50 oil was the stuff of choice for guys running the flat tappet cams... Put in 4.5 qts in and ran it around to get it up to temp to see how it did... what I noticed was the oil pressure was nearly identical to the rotella oil... however the engine ran hot. with the rotella oil 190 or so was normal operating temp... with this stuff I pull in from the drive and im at 200 and rising steady. First thought was my electric fan didnt come on at 185 like normal... but on inspection it was blowing strong. I killed it and pushed it into the garage.. My question is would the change in oil being heavier not allow for proper oiling of the engine. I have read that people are using this oil in racing machines and new motors with equally tight clearances... should I invest in 10 30 vr1 ? of course I tossed around the options of moil 1 15w 50 ... and royal purple, brad penn, so on and so forth... but this vr1 is readily available at all stores with appealed to me. by the way this engine is in a 65 ford f100 that is being restored. any info would be greatly appreciated. Thanks, josh
 

65fordguy

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Another thought I had was to add stp or ZDDP additive to rotella to kick up the rotella... since it is pretty good oil.
 
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Oil viscosity doesn't affect engine temp to a large degree. You need a better radiator, higher flow water pump, better electric fans, etc, etc. Check the thermostat also - sometimes they stick or maybe their isn't one in there or maybe its a 192 or 205 thermostat. If that is the case, use a 180 thermostat.
 
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Why not just stick with the 15w40? Unless the engine has a lot of bearing clearance or runs very hot the 20w50 should not be needed. Don't worry about the additives, they aren't needed with your mild flat tappet camshaft. As for the operating temperature, what are you using for a radiator/fan setup? What was the ambient temperature when you were seeing the higher coolant temps?
 

65fordguy

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ok. its a brand new HD 3 or 4 row radiator... highflow waterpump (aluminum) fan is a 15 inch forget the numbers on it but they were good.... The thermostat is a 180 the thermostat that on the fan is 185 - it works. drove it around today again and driving the temp stayed low... stop and it creeps up to 200 or so. It was about mid 80s outside. I did notice however that my oil pressure did drop to just above 45 when I stopped... this was a new one. it almost never dropped below 50 or 55 with the rotella. running down the road it stayed pegged at little more than 60 which is what the rotella did as well. I do have a high flow melling performance oil pump... so not sure what the issue is... but the engine did seem to like the oil it ran fine maybe even smoother.... Again its a new rebuild built by a race engine builder he used alot of good stuff in the build. and it has tight clearances.... which has me wondering if the oil is just to thick for it. who knows. All I know is that the way he did the heads he used beefier parts and did alot of porting on it... the springs are a stock spring from another style of ford head that "better" its been over a year I cant remember all he did.. but Im going to give him a call tomorrow and see what he has to say about the whole oil thing.
 
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 Originally Posted By: occupant
I'm surprised a 20-50 made a V8 run hotter. You sure there isn't another problem lurking somewhere?
^^2nd
 

JT1

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Running at 200 degrees is not a problem if that is the hottest it gets sitting still, you have nothing to worry about it.
 
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The difference in idle oil pressure is probably due to the higher operating temperature you observed. A coolant temperature of 200F is nothing to worry about, especially with an ambient temperature of >80F. Lots of stock engines have the electric fans turn on at 210F for emissions reasons. I would run 15w40 without concern in that setup, but the smart thing to do is get the opinion of your engine builder.
 
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I'd stick with 15w40. You can mix VR1 10w30 with VR1 20w50 to get 15w40, but VR1 is only for 3000 mile max OCI, due to lower detergents. How about Valvoline Premium Blue 15w40? Either way, a little zddp boost (Redline Breakin Additive about 2 oz per crankcase) wouldn't hurt.
 

65fordguy

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my engine builder recommended straight 40 VR1 valvoline oil. said that is a common choice among alot of his builders in his network. SO> looks like im draining the 20 50 and pouring in the 40
 
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