High RPM oil loss

[Mavrick]

My 1999 Fontaine 550 Is using lots of oil on a 1000 mile trip. I was wandering since it has a 4:88 rear and 70 to 75 mph is burnin on the rpm if it is sucking it all out the blow by. It has no leaks just slightly damp intercooler conections. She just turned 50,000 miles and never smokes ever. Ive used Amsoil from day one any ideas

[adfields]

What is your RPM's at 70-75 mph? With that low gearing you could be on to something. May be worth wile to get a Gear Vender's OD unit for double OD and get your RPM's down just for fuel mileage. 1500 RPM is way more fuel efficient then even 1900 is and sounds like you would be running it over 2500 all the time.

[Mavrick]

75 mph is about 2700 to 2900 i will double check in the am.

[adfields]

That is up there. Is their a reason you need 3.88's in it? I'm not even sure how tall you can go in a F550. I think it will have a Dana 110 under it but it could be a Sterling 10.50" I guess. It will be big what ever it is.

[2whlfreak]

I have the same problem, with no signs of leakage, except a little in the intercooler. But my truck is a 99 f250 7.3 with 3.73 gear and 95k on the odometer.

[adfields]

There is a post some place on hear about injector O-rings and/or bad injectors cosing oil disappearing without a sign, it's a good read for you. But Mavrick's post asks about high RPM. It's possible that the crank case vent can allow oil in the intake at the turbo inlet over the left valve cover and burn it as fuel without smoke as well. It's worth checking it out for sure. Pull the inlet off the turbo and look at the crankcase vent, some oil is normal but not much. If your air filter is clogged the motor can pull a good vacuum in the inlet and then if your crankcase vent allows excessive flow past it you could get quite a lot of oil at high RPM.

I will look for that post in the AM and link it hear.