Loose vs. Tight tolerances

[T Bone]

I had read that the new S65 V8 and the S85 V10 were built with "loose tolerances".....anyone know what in high horsepower cars, engines are build with loose tolerances??

[Gearhead999s]

Originally Posted by T Bone

I had read that the new S65 V8 and the S85 V10 were built with "loose tolerances".....anyone know what in high horsepower cars, engines are build with loose tolerances??

Generally a "loose engine" would be be refering to a larger piston & ring clearances,which would cause higher oil consumption.This would make sense in a high RPM engine in order to reduce internal friction so as to produce more power.

[T Bone]

Originally Posted by Gearhead999s

Generally a "loose engine" would be be refering to a larger piston & ring clearances,which would cause higher oil consumption.This would make sense in a high RPM engine in order to reduce internal friction so as to produce more power.

Thanks....the next obviously question is when the engine ages, does it decrease in power at the same rate as a "tight" engine?

[Gearhead999s]

Originally Posted by T Bone

Thanks....the next obviously question is when the engine ages, does it decrease in power at the same rate as a "tight" engine?

It all depends on how hard it is used.The more high RPM cycles that an engine sees in its lifetime the more wear that will happen than an engine that sees shorter periods of high rpm.But then we could get into the whole thing about piston speeds on long stroke vs short stroke motors

[T Bone]

Originally Posted by Gearhead999s

It all depends on how hard it is used.The more high RPM cycles that an engine sees in its lifetime the more wear that will happen than an engine that sees shorter periods of high rpm.But then we could get into the whole thing about piston speeds on long stroke vs short stroke motors

Let's, I believe oversquare engines like the V10 and V8 (with lower relative torque / unit of displacement) wears alot better than high torque, long stroke motors....

Debate....

[Gearhead999s]

Originally Posted by T Bone

Let's, I believe oversquare engines like the V10 and V8 (with lower relative torque / unit of displacement) wears alot better than high torque, long stroke motors....

Debate....

That is true,but then there are other factors like valve train issues with high rotational speeds.