M758

Now the issue on oil vicosity for a 944 or 951 on the track is different that other cars.

The reason is the the tendancy for the #2 to spin. Oil temps can get high in a 944 motor on the track. So you need a high at temp viscosity. This means a 50 number alough you might be ok with a 40. I would NEVER track a 30wt oil in a 944. I have seen it done and shortly after seen the rod berings spun.

For the 944 motor on the track start up wear is not the driving factor. The driving factor is high load, high RPM, high temp film strength. The #2 bearing spins not so much from start up wear although it is a contributor. It spins from a localized loss of film strength to support rod loads. Once rod to crank contact occurs the bearing spins and seconds later it can seize and blow up the motor.

The key to do all you can to prevent ANY metal to metal contact durign operation. There are many ways to reduce that risk, but one key factor is oil quality when hot. Bearing don't spin at idle, they spin on the track at full load 15+ into a session. This when the oil is the hottest and working the hardest.

Syntheics are better to stand up to the abuse, but I feel the weight is the most critical factor. The heavier that oil the better it can stand up to temp. When it come oil performance at given oil viscosity sure the synthetics are better.

I used to run Mobil 1 15w50, but found that even with formulation from 4 years ago it would lose more pressure when hot than AMSOIL series 2000 Racing 20w50. To me that reduction in hot pressure at full throttle was a sign its viscosity was decreasing thus giving it less film strength at the rod journal.

Since then I run the AMSOIL as extra protecion. BTW... oil temps in my 944 NA race motor can be 260F in the bottom of the pan. This in racing conditions with air temps over 95-105F and using an external turbo oil cooler.

hacker-pschorr

The motorcycle guys will neer use synthetic oil - this has been well known for years:

Subject: Beware synthetic oil

Beware of synthetic oil, it can do terrible things to you and your beloved motorcycle. It will not only leak out of your engine faster than you can put it in, but it will also cause your oil filter to clog and implode, dumping debris and dirt into your lubrication system. It also will make every part of your bike permanently slippery because of its linear molecular chain dispersion action. Then it will leak onto your kickstand causing it to retract automatically, dropping your bike on the ground! But that's not all...

Synthetic oil will round off your gears and spin your bearings. It will also splatter onto your seat causing your girlfriend to fall off in the apex of a turn and she'll never ride with you again. Synthetic oil coats your sight window and your timing window with a whitish pro-emulsification additive that is both non-removable and highly corrosive. Synthetic oil will completely leak onto the ground overnight and your dog will drink it and die.

Synthetic oil will wear out your tires and make your battery leak. It will give you the desperate need to urinate after you put your full leathers on and then jam your zippers shut. It will contaminate your gasoline causing your bike to stall on railroad tracks and accelerate uncontrollably near police cars. It will make it rain during rallies and on weekends. It will lubricate four timing belts causing them to jump teeth and break your valves to bits. Synthetic oil chemically weakens desmodromic valves and causes the clearances to change every six miles. Then it melts the black soles of your riding boots night before you walk across your new carpeting.

While riding past groups of attractive women it will cause both of your handlebar grips to slip off at the same time so you smash your windscreen with the bridge of your nose. It also causes your swingarm to crack, your studs to break, and your rotors to warp, and then it voids your warranty by changing your odometer reading to 55,555. It also dries out your wetclutch and wets your dryclutch. It makes your clutch slave cylinder seal fail in the heaviest traffic on the hottest day of the year while putting an angry wasp in your helmet for good measure.

Synthetic oil hides your 13mm socket and puts superglue on your earplugs. Synthetic oil will scratch your faceshield and make your gloves shrink two sizes night before trackday. Synthetic oil stole your neutral and sold it to the Chinese for $1.25. Synthetic oil will make you grow a tail.

Potomac-Greg

I'll take your word for it. All I know is my "glug-glug" test. When I poured 15W50 synthetic this weekend (40 degrees) it ran like milk, and when I poured 20W50 dino, it was like pancake syrup (I could measure it with a ruler, and cut it with scissors!).

Thanks for the wisdom on oil temps and how the #2 bearing spins. When I think of the three things that could ruin my marriage, #1 is a clutch job, #2 is a spun bearing and #3 is marital infidelity. That's in order of probability.

Veloce Raptor

The motorcycle "guys" wear leather pants, too.

Nuff said.

hacker-pschorr

If you actually read the entire post you would have seen it was satire making fun of the anti-synthetic crowd.

Veloce Raptor

I know, I know. Just adding extra crispy sarcasm.

hacker-pschorr

Wrong smiley then!!!

DWalker

This is one of the better oil articles I have found : http://ferrarichat.com/forum/faq.php...tor_oil_basics

But is a bit dated and doesnt take into account the need for ZDDP. If you think that the pushrod guys are the only ones affected by the lack of ZDDP you are sorely mistaken. Even in my EVO 8 with DOHC/roller rockers you can actually feel and hear the difference in the valvetrain between an oil high in ZDDP and one thats low in ZDDP. You can still use your mobil1 or whatever and simply add in ZDDP from Torco or whomever you choose to buy it from.
Currently I use Redline, Eneos, and Torco pretty much exclusively and carry them in the shop and on my online store, but they can all be had pretty easily from various sources, it just takes a bit of looking.
I no longer use Mobil1, although I did use them exclusively for many years. Once they started changing formulations I began seeing higher component wear and increased engine failures related to lubrication leading me (and others) to switch to other oils.

bgiere

What we are all concerned with is not settled by "thick" or "thin" oil debates...One of the specs that can help decide is an oils HTHS or shear rating. Some 10w40 oils (like Redline) have a higher HTHS than most 20w50's. I have run too many oils to remember and tested with used oil analysis for years. I have no affiliation with Redline Oil. I have never seen a better UOA in my race cars than 10w40 Redline.

I am trying the new holy grail, Brad Penn, in the 944 cup right now...we'll see how she looks after a few drains.