Rotella T6; 8300mi 1990 Porsche 911

[porterdog]

This is Rotella T6 at 8300 miles in my 1990 Porsche Carrera 4. I did not change the oil or the filter. Porsche's rec is ~12k miles on synthetic oil, and as a) lots of my miles are highway, and b) I'm adding roughly 1 qt every 3000 miles (it's a leaker; many of this vintage are) my goal is 15k.

These are older engines with flat-tappet cam followers and are purported to need a high ZDDP oil. Looks good to me!

PS: Make up oil was 2.75L; Polaris it seems can't be bothered with fractional amounts.

 

[autodetailer]

what would you say is a high wear number for copper

 

[porterdog]

Don't really know, honestly. The lead is reasonable, so some of it may be coming from the oil cooler. This car has a *lot* of oil plumbing.

Unfortunately there's not a lot of comparable UOAs here.

 

[DB_Cooper]

I don't think the copper number is too high. Porsche used two very long copper oil lines to the front oil cooler (which has copper in it too) Part 4A and 5A in the parts diagram.

In operation there is a slow bleed of oil to the front cooler, by design, even if the oil cooler thermostat is closed and the engine oil is not warmed up.

I think that this would raise the copper numbers in the sample. No problems.

Nice report. I use Rotella T6 in my 1986 911 with confidence.

 

[porterdog]

Got any UOAs, DBC? Your 3.2 isn't too different than my 3.6 internally; airheads gotta stick together

 

[DB_Cooper]

Porterdog..sorry no UOAs. I change my oil about like you, near 10,000 miles. In 1985 Porsche recommended an oil and filter change every 15,000 miles on the 911s. I don't have the leaks and my engine uses about a quart every 3000/4000 miles..it is an air-cooled thing..most would not understand.

Most would not understand we can go a long way between oil changes because our engines hold about 12 quarts.

I use the Rotella T6 too..great stuff.

Nice report too..thanks for posting. I may join the club and do a UOA next oil change.

 

[electrolover]

That looks pretty dang good to me. I would stretch it to 15k

 

[stranger706]

Does look good...

My dad has a 94 c2. He uses gtx 20w50 at once a year change intervals, which comes out to 10,000 - 12,000 miles. He sticks with the thicker weight for track use and our mild climate down here.

I do know that the Rotella is very popular with the club members down here.

 

[A_Harman]

Phosphorous looks weak for RT6. Should be ~1150ppm.

 

[porterdog]

Does P get consumed? The virgin T6 analysis (~1 yr old) does show 1100ppm vs. my 928...

 

[DB_Cooper]

I don't think P is consumed..others may know for sure. Might want to check back with the oil analysis people too.