TRWright

I have almost 4k miles on my rebuild and I am about to change the oil. I used plain old dino oil as recommended to me. I just picked up some Mobil 1 15W-50.

Is 4k miles enough to switch over to synthetic oil?

How many miles does it typically take for the piston rings to seat?

Is Mobil 1 15W-50 a good choice?

Please edumacate me!

Ski

This is just MHO. Since the merger of Exxon and Mobil, I have not been pleased with Mobil 1 after about a year after the merger. I reference the track car. Fresh rebuild, great compression, great leakdown numbers. Jim installed a catch can from LR in the car and started watching it. Well, DE weekends were producing 3/4 cup, there were some temp changes in there as well, so we also got some water. There were a couple of cars out of Dallas that were experiencing some lifter wear and lifter failure. Oil? Maybe, can't say for sure but the rumor mill was already starting.

We switched, on advice, to Valvoline 20/50 racing oil and haven't looked back. I run it in the street car, track car, Jim runs it in his 2.8 and will run it in his wifes 930. I talked to a PCA club racer the other day and he too had dropped Mobil 1 in favor of Castrol 20/50.

I drained the cars catch can after Hallett - there was barely two teaspoons in the catch can and Jim reported the same thing after a weekend at TWS. I was getting a tiny amount of smoke if I went to full 6k rpm and on boost in fourth, shift to fifth; not anymore - none. I feel confident that I will be able to report the same evidence in the catch can after the upcoming DE in Memphis and Jim and I will both be driving the car, same as Hallett.

My $$, I'd run Valvoline 20/50 racing and change it as you normally would. I've been very impressed with it so far.

Skip Wolfe

I agree with Ski, also switched from Mobil 1 and noticed a drop in consumtion on the track. I switched to Amsoil 20-50 racing oil and have been quite happy. The more poeple I talk to the more I hear about the Mobil 1 thinning out to much on the track. The Amsoil is just a tad bit more expensize and is tougher to get but worth the peace of mind.

EJ

I use the new 60W amsoil racing in the summer and then the 20/50 racing in the winter. All their products are great.
Eric

mroberts

Where do you get the Valvoline RAcing oil ?

ehall

ask special tool for his oil link. he runs agip 20/60 and swears by it.

Tom M'Guinn

Add me to the list of those no longer using Mobil 1. In my case, I just couldn't keep it from leaking out my old motor. I switched to dino and haven't dropped a drip since.

TurboTommy

Well, here's what I got told:
Mobil 1 does have the reputation of being a bit thinner; but that doesn't mean it's a bad thing.
After properly broken in, a fresh engine has good tight tolerances. Lower viscosity synthetics do a good job of lubricating these tight tolerances.
Just because thicker/dino oils burn less, leak less, and less turns up in a catch can, doesn't mean they lubricate better!

Take this for what you will.

Evan70

There have been quite a few people that have done thorough research, and Mobil1 just doesn't stack up that well anymore. Yes, it's better than your standard conventional oil, but nowhere near as good as several other synthetics (Valvoline, Redline, Amsoil). I personally have switched from Mobil1 to Valvoline synthetic on all my cars.

TRWright

Thanks for the replies.

When is the engine broken-in enough to switch to synthetic?

Evan70

PS, here's a great link to the "motor oil bible". Plan on spending an hour or two to really get the most out of it.
http://www.zag.si/~jank/public/bmw/oil_bible.pdf

Ski

go for it Ted, you've got plenty of time on that engine to do what you want.

z3bra

Here's what I was thinking about running, motorcycle shops sell a castrol 20w-50 synthetic for 4 cycle motorcycles. It's expressly designed for high temperatures like a motorcycle engine can see. It retails for around $6 or $7 a quart. It has the API certifications and all that but it seems like it was a letter or two behind the current SJ or so that car oil is up to. It certainly ought to hold up well in a turbo car I think. If not there's always Redline.

Eyal 951

Mobil isn't a performance oil anymore, German Castrol is going to be the way to go for me I think.
~Eyal

RKD in OKC

Very interesting.

When I had my 88 Turbo S Six years ago, everyone that ran Mobile 1 in a 944 Turbo experienced leaks. I ran 15w40 Pennzoil Long Life with no problems. When I asked my mechanic about using Mobile 1 or Redline he said it was just a matter of how much money I wanted to pour down the drain.

Here is his description...

The main reason you have to change your oil is because of the water that gets in it. And that is also the main job of an oil filter, to catch water. For every gallon of gas that is burned it creates 3 gallons of water. The high heat of running oil thru the turbo helps the oil to attract and retain water. Because of this the oil should be changed every 3000 miles. If you are going to change your oil every 3000 miles, then it doesn't really matter what oil you run, synthetic or dino.

His recommendation changed when I got my 928 GT. That same mechanic said that the tolerances and clearances of the 928 engine was designed for Mobile 1 synthetic and anything else would cause problems. When I asked about the 3000 mile thing, he said the 928's oil was not exposed to the high temperatures of the turbo.

Also the Pennzoil Long Life was formerly called GT Racing oil and was the recommended racing oil of the day when our cars were designed.