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The mkiv Supra Owners Club

What oil for freshly built engine


johnd-mkiv

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Just about finished my 1000 mile run in after a full engine build, but unsure what's the best oil to use for my build! I have searched on here and read people saying all depends on spec of the engine, that and oils changing and upgrading all the time made me ask.

 

Fully forged high compression engine, 280 cams, raised rpm expected 800+

 

Thanks :)

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I would use a 10w60 in that engine

 

We use the Millers 10w60NT

 

Why? 60 grade oil is only any use if the car is going to be constantly at 6000rpm for extended periods. The thinner the oil the better it is for circulation and fuel economy under 'normal' conditions. The factory spec on a stock engine was SAE30 or SAE40. A few machined components don't mean you change the oil spec. Ferrari spec in a 40 weight oil and their engines are manufactured to very high and very tight tolerances. SAE 60 should be left exclusively for track days.

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Why? 60 grade oil is only any use if the car is going to be constantly at 6000rpm for extended periods. The thinner the oil the better it is for circulation and fuel economy under 'normal' conditions. The factory spec on a stock engine was SAE30 or SAE40. A few machined components don't mean you change the oil spec. Ferrari spec in a 40 weight oil and their engines are manufactured to very high and very tight tolerances. SAE 60 should be left exclusively for track days.

 

We see lower oil pressure on the 10w40 oil

 

Also this car is going to be used hard and tracked, will be revving high and 800hp+

 

I don't think he will worry about fuel consumption

Edited by Lee P (see edit history)
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I'm using millers 10w40 running in oil at the moment when warm at 3000rpm my gauge is reading 6 bar around 2-3 bar on idle at 1100rpm seems high to me but I can't find specs to what I should be seeing. What do you normally see pressure wise on a fresh build Lee?

I know it's all down to where the sensor is located and to go by mechanical gauge ideally!! Mine are apexi el series gauges with the sensor mounted on the oil filter relocate attached to the block

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Sounds high for running in oil, maybe slightly over reading

 

I'm using millers 10w40 running in oil at the moment when warm at 3000rpm my gauge is reading 6 bar around 2-3 bar on idle at 1100rpm seems high to me but I can't find specs to what I should be seeing. What do you normally see pressure wise on a fresh build Lee?

I know it's all down to where the sensor is located and to go by mechanical gauge ideally!! Mine are apexi el series gauges with the sensor mounted on the oil filter relocate attached to the block

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Iv been running the said 10w60 for years now and my car has all ways performed at its best and the owner before me used the same

 

 

SAE 60 is really for racing or it could be used in old slapper engines to reduce noise and oil consumption. The higher viscosity, roughly twice that of a 40 weight oil, just ensure a higher viscosity when operating at the endurance limits. Seeking out higher oil pressure is meaningless, the thicker the oil the higher the pressure because there is a higher resistance to oil flow which translates to lower oil flow. It may look good on the pressure gauge but may not look as good on the bearings.

 

Porsche and Ferrari do high revving engines that leave the factory on 40 weigh oils. The 40 weight oil will also give significantly better fuel consumption than a 60 weight oil. Now as Lee said Supra T or TT drivers don't tend to be too concerned with fuel and running costs but I can't see why you'd burn fuel just because you can? If the OP is looking for the best of both Worlds then a 50 weight oil would suffice. If the OP is just looking to thrash normal Supra style then a 40 weight oil will be good. If the OP is just going to be running the Le Mans 24hr then go for the 60 weight oil.

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