Having owned and maintained 2 different sets of 6 drives, I always went with Mercurys recommendation of using Torco MTF in the gearcases. While at the Miami Boat show ran into Bob Teague and got to discussing gear oils and such. He didnt have very kind things to say about Torco, and said he runs an Amsoil 10w40 MCF oil in his drives. Yes, I know he is sponsored by Amsoil. I have a lot of respect for Bob, and I doubt he would recommend something that is going to perform worst than Torco just because he is sponsored by them. Was wondering if anyone else has tried Amsoil in their dry sump 6's

He would be a fool to recommend anything other than his sponsor's product and from what I have seen and read he is anything but a fool. All it takes is 1 guy on a computer and goodbye sponsor !!!!

i ran the amsoil. also ran there synthetic race oil. switched back to Torco for the gear cases and Brad Penn for the engine. mostly cause of pricing, seocd found no performance gain either way. so if you change oil often, i couldn't justify the added cost - almost 50% more for Amsoil.

also the Torco is not a full synthetic compared to Amsoil. I've also noticed here in Florida with high humidity that 100% synthetic products seem to be adversely affected by the humidity.

i've also run Fina's gear oil meeting the same specs with no issues and costs less than half the torco.

Bob is telling you straight about amsoil.Vern Gilbert tore Bobs race drives apart since it had been on the 36 skater for 2 years with only amsoil in them.Vern told me he was shocked to see how good every thing looked.
I run amsoil in all my #6 drives.

I only run Amsoil! MCF 10w-40 . That stuff rocks, if you sign up online you get a discount on pricing and it's on your doorstep within 1-2 days!

No mineral oil will compare with amsoil synthetic, if your running #6 drives the price should not be a factor. They only hold 5-6 quarts. I run amsoil in everything and years ago was the only way my #3 big shafts would live running 1100 hp through them. Tear down inspections give the best feed back. As for as water any synthetic will separate faster than mineral oil.

We recommended Torco MTF to Merc for use on our drysump drives.

I have never tested amsoil for foaming (not good in a drysump drive) aereated oil is not good for lubrification. We only ran the torco on the dyno and in the raceboats. We run a drysump tank so it is easy to check the oil to see how it is doing.

A good rule of thumb is, synthetics are twice the cost half as good. We have had a lot of trouble with synthetic oils. They break apart from the base oil and the addatives leaving a chewing gum like muck behind to clog our pick up screen and spraybars.

With high hp not just 525's you might want to run a little heavier mineral oil. Breaking in the drives is a good idea also. Do not just go out there and leave it at part throttle or full throttle give it a break once and a while to cool down and burnish the gears in a little. Full throttle / cut throttle / full throttle etc.... 15 minutes.

pat W

other than having someone look at your gears, have you guys ever done or looked for tests other than Amsoil's touted ball bearing test.

i'm not anti-sythetic, just that sometimes just because it costs twice as much doesn't mean it's twice as good.

i use sythetics in some situtations where i have seen a difference, just can't justify the costs in some uses if there isn't proof its that much better?

Shifter, what do you recommend for a wet sump 6 drive?
I know, a little off topic,
Greg

All merc drives are wetsump or wetsump with a pressure pump. The coversions we make are drysump, scavenge and pressure pumps with a separate tank.

The bell ray works really well for pleasure boats. If you get water in it it will seperate and you can drain the water out and fix the problem. I have yet to see anything else do that.

pat W