Dump The Mobil 1
Race Director
Joined: Oct 2002
Posts: 16,477
Likes: 26
From: Gone
CI 6-7-8-9-10 Veteran
St. Jude Donor '03
Originally Posted by cenzo
Had there been any ill effects of the Mobil1/GM collaboration it would be all over this forum by now.
Every engine builder I know of, including many forum tuners insist on using dino oil for proper ring wear-in on a fresh engine. After that initial 500 miles or so, yes, synthetics are the way to go.
If the manufacturer knew everything, perhaps they wouldn't have such a high rate of oil consumption issues to deal with. There's a clear connection, and it's too convincing to be considered "urban myth".
I'd like to see some of the more knowledgeable engine builders (Cartek, Andy, etc) chime in here.
Drifting
Joined: Sep 2004
Posts: 1,912
Likes: 33
From: S.D. CA
Originally Posted by TLewis4095
Man, what a discussion this has turned into! I have no idea what GM's break-in secrets are.....but we do motors and gears in our race cars all the time.
Motor: We first fill with a conventioanl 20w50 for 10-20 runs and then switch to Mobil 1 15w50 and cut the filter open to examine for wear signs.
Tranny: These are Dedenbaer case power-glides built to withstand 2000 plus HP and we fill with dex II, type F, or synthetic and don't worry about break-in. The only difference we see is in operating temp, syn is cooler by 5-10 degrees.
Rear gears:
We fill w/80w90 gear lube for first 20 or so runs and then change to synthetic. If we run syn right from the start the gears do NOT properly break-in and we end up with "hot spots" and premature failure. They definately last longer breaking in with regular gear lube.
The motors we use cost $14-19k each so we would not think of starting out w/synthetic, but we have used M1 for years after break-in and I am amazed at how they look after we tear-down for re-fresh each season. We also do new lifters/valve springs, no matter what they look like. We cannot risk a rod through the block and oil on the tires at 177 MPH.
As far as our C5 it has 106,000 miles of raced 2-3 times a week year round since new and still uses no oil and runs as strong as ever. We use the same 15w50 M1 in it and switched to 15w50 from 5w30 after 20k miles.
Motor: We first fill with a conventioanl 20w50 for 10-20 runs and then switch to Mobil 1 15w50 and cut the filter open to examine for wear signs.
Tranny: These are Dedenbaer case power-glides built to withstand 2000 plus HP and we fill with dex II, type F, or synthetic and don't worry about break-in. The only difference we see is in operating temp, syn is cooler by 5-10 degrees.
Rear gears:
We fill w/80w90 gear lube for first 20 or so runs and then change to synthetic. If we run syn right from the start the gears do NOT properly break-in and we end up with "hot spots" and premature failure. They definately last longer breaking in with regular gear lube.
The motors we use cost $14-19k each so we would not think of starting out w/synthetic, but we have used M1 for years after break-in and I am amazed at how they look after we tear-down for re-fresh each season. We also do new lifters/valve springs, no matter what they look like. We cannot risk a rod through the block and oil on the tires at 177 MPH.
As far as our C5 it has 106,000 miles of raced 2-3 times a week year round since new and still uses no oil and runs as strong as ever. We use the same 15w50 M1 in it and switched to 15w50 from 5w30 after 20k miles.
Instructor
Joined: Sep 2004
Posts: 184
Likes: 0
Seems we got a big disagreement here.
Let me ask this.
Surely breaking it in with dyno oil rather than synthetic oil for only the first 500 miles will do no significant harm right? No doubt you want synthetic over the life of the car, but having dyno oil for only the first 500 miles can't really do the engine much bad, can it?
Let me ask this.
Surely breaking it in with dyno oil rather than synthetic oil for only the first 500 miles will do no significant harm right? No doubt you want synthetic over the life of the car, but having dyno oil for only the first 500 miles can't really do the engine much bad, can it?
Le Mans Master
Joined: Aug 2001
Posts: 8,145
Likes: 1
From: Bradenton FLORIDA
Can't do it ANY bad! Current top brand Dino's are great protection, Syn is the best for high temp protection and long term wear protection. In fact a good dino I would leave in for 2,000 mile break in.
