Oil Mist Blowing through Dipstick Tube

[shotgunslade]

Please pardon this repost from the Ultralite Yahoo Group, but I haven't had any response over there. Was wondering if anyone here had any similar experiences with Honda (or other) engines. At this point, I'm going to get a compression test for the engine. Trick is to find someone who will work on it.

 

I did my first track day with the new XR7 and ran into a very very serious

problem that ended my day after 2 laps. Yesterday at Lime Rock was a crappy day.

About 40 DegF and misting rain. Not an auspicous beginning for the track career

of my XR7. I was finishing the warm up lap, taking it easy. Only took it up to

about 6000-6500 rpm on the main straight. At the end of the straight is a

decreasing radius turn called the Big Bend. Another car came out of pit lane

about 25 yds in front of me and to my right, throwing up a little spray. My

windshield turned opaque white. So here I am at about 90 mph approaching a

decreasing radius turn with no visibility whatsoever. Locked in deep in the

seat with 5 pt belts, I couldn't even squirm around to look over or around the

windshield. The only way I could tell if I was still on the track was to look

directly to the side to see the sidelines on the paving. I had to drive the

entire lap back to pit in this way. Even going slowly, it was extremely

difficult to know where to go, and I'm sure the people behind me were cursing.

Needless to say, it isn't an experience I want to redo any time soon.

 

Back in the pits, the problem was revealed. The hood back of the dipstick

opening and the windshield were covered with a thin film of oil. I can only

assume that the dipstick tube is blowing a fine mist of oil that is being

deposited on these surfaces. It doesn't happen much at idle but must be pretty

intense at higher rpms. It coated the entire windshield in a single lap. It is

not something you can see when it is happening, but the results are pretty

apparent, especially when the windshield gets wet.

 

I have installed a breather with catch tank, supplied by Brian when I first

noticed that there was some oil on the hood, but it is attached to a port on the

valve cover, because that is the only obvious connection point, Obviously, this

didn't fix a problem, which is that the crankcase must be at positive pressure

dependent on rpm, and is blowing the oil mist from the crankcse up and out the

dipstick tube.

 

Backyard mechanic wisdom says that if your dipstick is popping up, you probably

need a ring job. Hopefully this isn't the case for this 2005-2006 S2000 engine.

 

Anyone else seem anything like this or have any insights as to what is going on

or how to fix it. Obviously, I'm not taking it on the track until I'm confident

it's fixed. Given my problems with OBDII emission compliance in NJ, the car is

parked until I can diagnose and fix this problem.

[Dave W]

Check and see if you have oil in the catch can. The breather or hose may be plugged or restricted so the pressure is not vented to the can. A lot of breathers have baffles or strainers that can get plugged up, not allowing the pressure to vent correctly. You could also add a 2nd vent. If you had big problem with the engine, you would have been using oil and you could see the smoke from the exhaust.

 

Dave W

[WestTexasS2K]

I have an Ultralite and havent had this issue before. You might have a faulty PCV valve. What is the catch can attached to? Do you have catch can on the PCV valve line or the vent on the front of the valve cover? The hose at the front of the valve cover should be recirclulated back to the intake usually right behind the air filter. If your dipstick is blowing out then the engine is getting pressurized.

 

One problem that I have experienced before and I know a few others have as well. Usually during auto X but it has happened to me on the track before. When you have the engine above 8k and you get out of the gas and make a very hard right hand turn. You can suck some oil into the intake past the PCV valve and it will smoke like a mosquito machine and lose alot of power it will clear up after a few min.

 

The cause of this problem is the engine really pumps large amounts of oil to the head and cams to engage the VTEC system. When you get of the throttle suddenly all that oil about 1.5 qts is still up there. Combine that with a high G load during a turn and a big vaccum shift it can suck up enough oil to make you worry. A catch can on the PCV valve line will solve this issue. Some of the newer valve covers have a better shield built in them that reduces this problem.