View Full Version : Bubbling head oil

11-17-2006, 07:04 PM
Please take a look at this picture and let me know if this is excessive foaming. This was taken with the mill running at 1800 (stock motor) after 30 mins. After turning the mill off the oil level levels out at just a little over half of the sight gauge and the bubbles are gone ater just a few minutes. I am using Mobil iso68 med heavy (or whatever Aaron recommends for 1800 operation). Should I go to the next lighter oil? I plan to do mostly Al and some steel. Thanks


11-17-2006, 08:07 PM
I suspect that as long as some moving object is above the oil level....it will always draw in air and create the foaming.....what is the recommended oil level?

11-17-2006, 09:14 PM
I am not sure what the recommended level for the IH mill is (the instructions are barely in English) but the other machines in the shop with oil sight gauges recommend filling up to the one-half sight level. I used to have the level above the sight gauge and that had just as much foaming AND oil came out the vent on the head.

11-18-2006, 02:18 PM
Wildcat, that's about what mine looks like.

You probably are going to want to get the faster motor anyway if you cut a lot of aluminum. Run it like this for a while longer, then drain it and go to the lighter oil when you upgrade your motor.

With all the pix of people's gearboxes, I am really tempted to convert to a belt drive, maybe even 2:1 so I can run 6000 rpm for aluminum when I swap motors. It doesn't look to me like it would be that hard to do. No oil at all in that case!



NC Cams
11-18-2006, 09:26 PM
Oil areation is something that should be avoided - after all, air doesn't lube very well.

HOWEVER, when you use a simple dipping/slinger type of splash lubrication, you're relying of violent oil agitation of the oil by the gear teeth to distribute oil throughout the gear box. A non-pressurized, splash lube system utilized by a machine designer to cut cost is virtually impossible NOT to incur oil aereation.

When the machine designer makes what seems to have been a poor compromise, you can try some things to get around the aereation he's built in.

Get a MSDS and/or a lube certification spec for your particular brand and viscosity of oil. Call the tech dept of that lube maker and ask for their opinion and follow their suggestions. Some gearbox oils have anti-foaming suppressants - when the gearbox is acting like a mix master, however, total de-foaming ain't gonna happen.

If your particular grade of oil is CLOSE in viscosity and/or specs to Dexron III, a switch to Dexron might help the situation.


It is proven gear box oil the is used in splash fed manual boxes that transmit way more power under more severe operation than what you'll be seeing.

It has anti-foaming and other anti-friction and anti-wear agents. It also has seal lubes and conditioners and anti-rust addititves and corrosion inhibitors that simple spindle oils DON"T have. It is PROVEN & APPROVED gearbox lube for Excello mills - hardly a light duty item.

We have a spindle that used "spindle oil" (factory recommended viscosity and brand) and had repeated problems with the ball bearings in it (lite viscosity spindle oil was primarily chosen for the bored babbit lined bearing used for the 50mm spindle shaft).

We came to learn that the spindle oil was basically just highly filtered oil with minimal if any additives of any kind - hardly the optimum for protection according to a lubrication engineering colleague.

His suggestion: Dexron III.

Even though the Dexron had a higher viscosity and ran a bit warmer (more viscous drag), it actually worked BETTER (you could see better grinding finishes) than the OEM spec'd "spindle oil".

In spite of the "it won't work" admonition by the machine's tech dept, it has worked far better than the OEM stuff.

In the process of dealing with this issue, we learned that some of the machine tool industry is still relying on 50 year old ideas regarding oils and oiling methods. During the same time frame however, the auto industry has learned a lot about lubes, methods and additives.

In our case, Dexron III has proven to be cheaper to use, easier to get and demonstrated far superior performance over the factory recommended fare.

BTW, some gearboxes have collection troughs that collect the flung off oil and channel it to the bearings or other critical areas. An oil that self de-areates will recompose itself in the collection trough well enough to lube the critical areas in the needed fashion.

If that is the case, I wouldn't worry about your sump aereation situation.

11-19-2006, 09:11 PM
Yup, mine foams like a rabid dog as well.
I and others swear by Redline Heavy Shockproof for the transmissions and final drives of BMW motorcycles.
I have to assume the gears, seals and shift dogs in there are somewhat higher tolerance/precision than the gear head on this mill so I'll be changing over to that as soon as I get a few hours on the head.
Made the bike shift superbly and I mean AS SOON as I changed it out.:cheers:

11-19-2006, 10:36 PM
I use Mobil DTE light in my mill, it foams up the same way, nevers comes out the vent.
If you have the gear box apart you will see it's not all splash lubricated. I would say all but the top gears are totally submerged in the oil, and the top gears are partially submerged.

12-20-2006, 05:45 PM
I agree with NC CAMS , has anyone tried dexron in there's yet ?

12-20-2006, 05:55 PM
Keyteem - I switched to Dexron III after replacing the motor with a faster motor. The head temperature is a little higher (now around 185 F after a couple of hours - see thread in the IH forum), there is still a little foaming... and after running for a couple of hours there is a puddle on top of the head (coming out the vent). Is it better? Well, I have to believe the expert (NC Cams). Sure is easier to come by and smells better than the Mobil lube. The head is quieter but that could may have more to do with replacing the motor or popping the head open during the replacement. I use a lot of small tools so mainly run at 3600 RPM.

12-20-2006, 09:40 PM
Thanks wildcat, i am gonna switch over to the dexron too.
you say the head is a little quieter now too, and your using the higher speed motor? runner440 was kinda saying he thought his was a little quieter too,
he is using a higher speed motor also.
i wonder if it's the motor thats making a lot of the noise?
you would think it would get louder with higher speeds,,,
anyhow i am gonna try the dextron3/5 and see how the foaming is compared
to the mobil.
thanks again

12-20-2006, 11:12 PM
Keyteem - It could be the motor... I ran both motors before putting them on the head and both were very quite. Another contributing factor to the noise reduction could be from having pulled the top off the head to see if there might be a reason the head was popping out of gear. Or perhaps I am not as sensitive to higher pitch noise as lower pitch noise :)