overfilled is overhyped

[TFB1]

Originally Posted By: TFB1
Originally Posted By: turtlevette
[

Understood. Its a tradeoff. Aeration vs having enough to avoid uncovering the pickup.

I thought you're a big time hot rodder. You haven't seen all these guys overfilling for the road course?


I think Doug is more into real race cars, over filling sounds like some of my SCCA freinds...

How'd this get to race cars that SHOULD have engineered system to take advantage of extra capacity... What about the the newer PASSENGER vehicles that under side is blocked buy a cover... You really think extra or a little low makes a difference???
Turtle, you never did give a straight answer to my question...

 

[Doug Hillary]

Hi,

Originally Posted By: Peter_M


The 928 engine featured has a conventional wet sump unlike most 911's. However the 928 engines suffered from occasional big end failures on No.2 and 3 cylinders when raced.

Be interesting to hear Doug's thoughts.


Peter the 928 engine came in a number of variations after its introduction. I Posted my views as you are aware on various Porsche Forums over a decade or so ago

Like you found many persons with vested interests pushed their ideas and products - and made money from them. I had/have no such interests

IMO many most 928 bearing failures were probably due to cavitation caused by lubricant starvation in very tight turns/heavy braking (perhaps) when tracking - or simply low lubricant level - see later. Those engines fitted with an Accusump never suffered such failures when tracking as far as I know

Some vehicles did suffer from high oil consumption (another Technical discussion - but not again for me) - this caused some serious "low on lubricant" problems of course. None were problem of the lubricant - simply engine use and application

IMO the final versions of the 928 (S4 and GT) have marvellous cooling and lubrication systems. I have done a lot of field testing personally and via other Owners that led me to that conclusion

One issue was allegedly low OP at idle on the normal 10W-40 lubricant of the time. Some repairers pedalled their idea such as 25W-60> to solve the issues - most went to 20W-50 viscosities rather than simply fixing the sensor/etc. problems!

At the same time Porsche commenced the first FF with a synthetic lubricant - Shell's XMO 5W-40 - that should tell you something

I always ran 5w-40 in mine - initially Shell Helix Ultra and latterly Delvac 1 5W-40! This viscosity was confirmed on my odd visits to the Factory or to the Nurburgring and I convinced many Owners to do the same - after all it was a Porsche Zuffenhausen call!

Oil consumption with my two 928s was virtually zero and my S4 did many many high speed trips between here and Brisbane - some with the ambient hovering around 40C>

I truely miss my S4 - it was a great car

 

[Peter_M]

Thanks Doug!

 

[SteveSRT8]

Originally Posted By: turtlevette
Originally Posted By: SteveSRT8
Good ole Turtle, he's a real sport. He knows it all and can snark with the best of them. Insulting members and misinforming are his primary modes.

Enjoy!


In Feb there was a thread where you say you have been overfilling for 40 years. But since this is really a social site rather than technical, it's much better not to mention that and just beat the ole black sheep.


Once again you distort what I said to fit your model. I was referring to specific platforms. Notably the two corvettes I raced for ages, and I have also mentioned UNDERFILLING at the drag strip. Too bad you didn't get that part.

You have an awful lot of other folks who are asking you questions here.

I am not...

 

[fpracha]

Hello,

Originally Posted By: Doug Hillary

Originally Posted By: Peter_M
The 928 engine featured has a conventional wet sump unlike most 911's. However the 928 engines suffered from occasional big end failures on No.2 and 3 cylinders when raced.
Be interesting to hear Doug's thoughts.

IMO many most 928 bearing failures were probably due to cavitation caused by lubricant starvation in very tight turns/heavy braking (perhaps) when tracking - or simply low lubricant level - see later. Those engines fitted with an Accusump never suffered such failures when tracking as far as I know

I always ran 5w-40 in mine - initially Shell Helix Ultra and latterly Delvac 1 5W-40! This viscosity was confirmed on my odd visits to the Factory or to the Nurburgring and I convinced many Owners to do the same - after all it was a Porsche Zuffenhausen call!

Doug,

Thanks for the opinion here from your extensive experience.

Would you say that these cavitation problems can be solved better with the 0w-50 grade synthetics as apposed to the 5w-40 that were earlier available?

 

[Doug Hillary]

Hello,

Originally Posted By: fpracha


Would you say that these cavitation problems can be solved better with the 0w-50 grade synthetics as apposed to the 5w-40 that were earlier available?


Changes in lubricant formulation may help a little and the increased HTHS viscosity (SAE40 over SAE50) is certainly another factor - however this situation (starvation-cavitation) is a really a mechanical/lubrication issue and not a lubricant issue

Any lubricant changes will only perhaps delay the inevitable

 

[Snoman002]

Interesting discussion on oil and racing. In response to overfilling the Corvette, I have heard this as wel. The justification was because at the end of the straight a large portion of the oil is pumped into the heads, and a long hard corner would cause starvation.

On the other hand, many of the L76's get a strong oil smell for a few days or weeks after an oil change. The rumor is because 'full' actually puts oil in contact with the crank and yo u get a lot of oil whipped up. I run mine half a quart low because of this (its a 9 quart sump, 1/2 low isn't going to hurt it).

 

[TFB1]

Originally Posted By: Snoman002
On the other hand, many of the L76's get a strong oil smell for a few days or weeks after an oil change. The rumor is because 'full' actually puts oil in contact with the crank and yo u get a lot of oil whipped up. I run mine half a quart low because of this (its a 9 quart sump, 1/2 low isn't going to hurt it).

That's no doubt bogus info, whipping the oil is bad - extremely so... No chance I'll believe GM can't figure out the correct amount of oil in the pan for normal driving...

 

[Snoman002]

Originally Posted By: TFB1
Originally Posted By: Snoman002
On the other hand, many of the L76's get a strong oil smell for a few days or weeks after an oil change. The rumor is because 'full' actually puts oil in contact with the crank and yo u get a lot of oil whipped up. I run mine half a quart low because of this (its a 9 quart sump, 1/2 low isn't going to hurt it).

That's no doubt bogus info, whipping the oil is bad - extremely so... No chance I'll believe GM can't figure out the correct amount of oil in the pan for normal driving...


[censored], Suzuki did it on my SV1000. Fill it to the full mark and watch the bubbles form on the sight glass. Windage is not extreemly bad, oils are designed to handle some agitation, they have to be as the pump itself is whipping that [censored] all to [censored]. Plus, the whipped oil is on top of the oil in the pan, not the bottom where the pump is. As long as there is sufficient time for the bubbles to come out of the oil before its picked up it doesn't matter how much it was agitated, and with a 9 quart sump that can be quite a while (relatively speaking). As far as normal driving goes, maybe it's fine at speed, just touching at idle.

 

[Peter_M]

Originally Posted By: Snoman002
...On the other hand, many of the L76's get a strong oil smell for a few days or weeks after an oil change. The rumor is because 'full' actually puts oil in contact with the crank and yo u get a lot of oil whipped up. I run mine half a quart low because of this (its a 9 quart sump, 1/2 low isn't going to hurt it).


I suspect the reality is that the mechanic are just like you and me and sometimes spill a little oil over side of the motor when refilling......