VN Think I Need A Vent

As the oil heats does it expands enough to pressurize the case?

Daryl
MN
 
Uglydog said:
As the oil heats does it expands enough to pressurize the case?

Daryl
MN
Click to expand...
Daryl,

You are correct. Same principle in car/truck tires. Rule of thumb is you lose 1 psi for every 10 F you drop in temperature. Fill a tire to 35 psi at 70 F, it'll read about 30 psi at 20 F.

I used to work in the chassis group at our assembly plant building Cadillac CTS's. Our rear differentials had a vent on top so the diffs didn't pressurize and blow fluid out the pinion and/or axle seals. Kind of a funny (at least to me) side story. Our 2007 CTS had a lot of problems with pinion seal leaks. Go figure, the supplier (Sabo of Brazil) put the parting line of the seal right on the sealing surface. Their assembly line had workers wearing Optivisors and X-acto knifes cleaning off the flash. Get a little nick in the seal and our car would throw diff fluid all over the exhaust. We ended up changing suppliers to a seal supplier in China. The new company's name was "FN OK". Maybe just my crude sense of humor, but FN OK? At least the FN OK seals had the parting line on a non-sealing surface so it fixed the problem, but we still chuckle about the company name . . .

Bruce
 
OK, more info. The high speed sub head needs the spindle to be running in reverse. I have a tremendous amount of air bubbles in the oil, combined with the oil being flung straight up, oil is leaking out that cover. There is a gasket, but it is still letting oil by. I think I need to install a vent, then high tack the gasket.

Jason

BTW, don't run the machine with that cover off.
 
Jason Annen said:
OK, more info. The high speed sub head needs the spindle to be running in reverse. I have a tremendous amount of air bubbles in the oil, combined with the oil being flung straight up, oil is leaking out that cover. ...
Click to expand...
What oil are you using? Machine tool gear oil, like DTE Heavy Medium (not to be confused with the DTE number oils, which are hydraulic oils), have anti-foaming additives that should prevent that.

I don't think you need a vent. Pressure can escape around the control lever shafts. I think all you need new gasket and the right oil.
 
Non-detergent straight 30 weight, per the manual.
 
Jason,

I use DTE Heavy Medium in my 22L and recommend that you take Cal's advice. He is my go to guy for VN information. :)
I have a friend who has a few years old bench mill that was factory converted to CNC. They too recommend 30w non-detergent oil, but he had issues similar to yours. Manufacturer suggested he add a Lucas anti-foaming product to the oil. It worked and stopped the leak but when all is said and done, the next oil change will be to DTE Medium or Heavy-Medium.
 
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