Oil Experts

Had posted some about my engine temp being too high and got a lot of good advice as usual on our forum. Did a lot of things to cool it down and it worked though still wondering about the higher op temp aside from the hepped up things done that impact cooling. Anyway, had been running 20/50 high zinc oil (solid lifters) as that was the only high Z oil I could get at the stores. The oil psi was always real high so prompted me to ordere 10/30 high Z. I found a dramatic reduction in motor temp. Reading some on this evidently experts say running a lighter weight oil dissipates engine heat better due to faster oil flow. And additives today generate a stringy effect as the oil heats up to cling to lubricate the internals. I had thought the heavier oils would have less breakdown in viscosity; but not so much versed on the affects of engine heat. Anyone having experience with this, curious to hear your thoughts. Thanks.

Yes it is true. Thiner oil cools better and lubricates better. And you saw the evidence on your car. Good to hear an actual result of this.

I reasearched it when my friend built a new bracket race engine last year and these were the findings. Oil viscosity should be based on actual bearing clearances in your particular engine. Joe Gibbs website is good at explaining about engine heat and laps in a circle track car and weight of oil to use.

They went on to say that you buy an oil made for the flat tappet cam, do not use additives in off the shelf oil for late model cars. It has too much detergent and it doesn’t let the zinc additives work like they say on the bottle.

Im sorry that this will offend folks who do it that way. Don’t get mad or hurt, just read and learn. Just know it will work better when you get oil made for flat tappet cams. Just because a 20 year old article says to add zddp doesn’t mean we stay the course for our whole lifetime. The shelf oil has changed since then.

I dunno about thinner oil running cooler.
I wound up doing so to get my indicated oil pressure down.
Makes sense, though - the engine would be working less hard against the resistance of the heavier oil,
I guess.
Wound up with 10W30 Valvoline ZR1 since it's available locally (high zinc).

R413 said:

...They went on to say that you buy an oil made for the flat tappet cam, do not use additives in off the shelf oil for late model cars. It has too much detergent and it doesn’t let the zinc additives work like they say on the bottle.

Im sorry that this will offend folks who do it that way. Don’t get mad or hurt, just read and learn. Just know it will work better when you get oil made for flat tappet cams. Just because a 20 year old article says to add zip doesn’t mean we stay the course for our whole lifetime. 5e shelf oil has changed since then.

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I totally agree. As you said lots of folks have just used the additive in regular oil and been okay but oil manufactured with the goodies already in it, is always better...

My motor is bored .60 so obviously lost a bit of metal and one guy had mentioned that requires better cooling ability so with my ills of excessive heat installed a 7 blade fan, shroud, top seal on rad, reduced the ratio of anti-freeze, and added water wetter. It definitely helped; but never thought of the oil. There had been discussion in posts about the possible cons with coolant running so fast through the rad like minus a thermo and high flow pump that the coolant is in and out of the rad before cooling can happen. Well, the faster flow of oil makes sense far as I can ponder and so far seemed to really effect the temp. That was a one hour ride on a 70 degree day...maybe will know more when it's a lot hotter...lol.