Okay. I'll bite.

If the noise is not piston slap, what is it? And why would the "correct" oil quiet it down?

 

Is the German formulation different?

We are talking automotive, not motorcycle oils, correct?

Please quantify the percentage HP increase you have observed.

Thanks.

 

Both the Motul and Mobil 1 I have used come in five gal drums from Europe. They are not motorcycle specific oils. It just seems that only motorcycle shops carry Motul though. Four to six percent increase in power. The Valvoline, Castrol, and Yamalube have all been purchased at local shops in Orange County CA.

 

He's saying that changing to a 5-20 from 5-30 mobile 1 has eliminated the knocking heard when starting a cold engine. Many have complained of this noise and wondered if it may be piston slap they are hearing.

 

I run mobil 1 in all my cars with increased oil change intervals. All except the Lightning which gets changed about every 2,000 miles. Lately I've found that wal-mart has been selling 5 qt containers of all the mobil 1 weights for $19.8x That's 20% cheaper than $4.99 a qt that I see everywhere else in town.

Rich

 

I was pretty clear on what he said. And simply saying it again does not answer my questions, which were unambiguously articulated:

1. "If the noise is not piston slap, what is it?"

2. "And why would the 'correct' oil quiet it down?"

 

Do you have any documentation on this? I don't see any way a change to this oil will increase power by that amount.

 

What? Why are you wasting the oil. I know the old saying that oil is cheap insurance, but 2,000 miles isn't even reasonable. You would be further ahead extending your intervals and doing oil analysis. It would cost less and tell you a lot more about what is going on inside your engine than just keep dumping fresh oil out.