Oil coomming from vent

[Vern Houseman]

Ok guys heres my prob ? everytime we run our ashalt car we have a serious prob with oil comming out of crank case vent, we ran at wall turkey durby this weekend and besides our other probs on the track this oil prob was getting all over the right side of car causen car to get loose, anyone have any ideas ? we do have  a catch can .

[knoxracing]

How much oil are running in the car? How old is the motor? How is your catch can plumbed and where is it located?

[Vern Houseman]

motor was built this summer ,while we where at a shootout in charlott this prob began as  we got faster,running oil level between 1/4 and 1/2 in glass when motor is off. the catch can is mounted right above the vent in front of the carbs with a drain line going into the oil fill hole have run it without the drain setup and still have same prob ?

[Gimpster]

 Some heavy engine oils do not have polymeres formulated in the oil. I used to have a 1250 with the same issue on dryslick 3/8 mile tracks where there is a lot of decell time. Even after rebuild it would blow oil out the breather in the same situations.  the oil has to have an anti foaming agent (poly) in it. First I cut a brillo pad and stuffed part of it into the breather hose where it slips  over the breather nipple. that knocked it down but we were still a lot of oil in the catch can. I switched to Honda GN4 motorcycle oil ( with poly in it for gear case foaming) and that helped too. Eventually I ran a breather hose from the engine, along the inside of the driveshaft tunnel to a catch can which I located from a built bracket adapted to where the fuel cell mounting hold down plate stud is at (up high). Problem was solved. The engine never did blow any oil for the life of the engine after that.
 I blamed the issue on oil foaming in the gear case from molecular break down while compressed between the gear teeth and oil pooling in the gearcase side of the engine from g-forces of the corner. Motor is mounted sideways as apposed to in th ebike it was designed for. I must warn you that if you switch to a good quality motorcycle oil that your engine may have a tendency to smoke for a while. These engine oils are high in detergent and will clean the scum cooked onto the bottom of pistons left by what I call dirty oils (havoline, valvoline, castroil etc...) and may cause the engine to smoke as it cleans the scum internally. Eventually that problem will clear up.  Anyway, my theory on topic is that you have a foaming issue going on with your oil in the gearcase because it is not draining back into the pan quick enough in a foamed state.

----- Gimpster -----

[Vern Houseman]

thanks Gimpster will look into that we are running amsoil 20/50 motor cycle oil too

[Gimpster]

 There is still something I am overlooking in that situation then. I laid out the post above kind of to inform newbies of some of the simple fixxes. The info hasn't been posted in a while. Figuered you knew most of that and had it covered, Vern. I run the Amsoil also since I am a dealer for it, without the issue in all 3 of my 1200's with no special breather modifications other than a smal K&N filter on the end of the hose to keep dust out of the engine. Ran that breather system I mentioned on the 1250 that we did have issue with.  Almost makes me question the overhaul they did or if a ring or two didn't seat during mineral oil break in ? Hope it isn't a cracked head or sleeve issue.... Do a leakdown test on the cylinders to nail any of those issues

Later

----- Gimpster -----

[VMS Motorsports]

thanks Gimpster will look into that we are running amsoil 20/50 motor cycle oil too

I agree, not an issue with the oil itself.
So if I read correctly (sorry, tired), your can drains directly into the fill hole. Do you have a picture of your set-up?
Correct me if Im wrong, but wouldnt there be pressure from inside the engine forcing the oil from draining back, thus pushing it out the breather filter on your catch can?

[Vern Houseman]

Your right , kinda but I was thinking that there is preasure from both hoses but under cuation it would drain back in ? and last nite at wall the turkey durby was plenty of cuastions ?The next thing im going to try is moviing the tank as hi as I can onto the firewall ? the only prob now is the car wont be run till next year if there is another million dollar race or special race. as fare as  something cracked ?we checked what we could and everything came up ok.kinda wish windage trays where legal. maybe that would be the ticket Jason runs this car as hard as it will take it so I have to come up with something ?

[thunder938]

You can NOT run "vent" lines from BOTH the vent and a fitting on the oil fill. Both are PSI and WILL pump oil.  Now if you are not using the rear oil pan port on the left side of the pan as a return.  This is a NON PSI port and is used by alot as a overflow return.  If you can not use that port you can use a catch / over flow can, I have scene a old bottle used.  You should not get that much oil, unless it is over filed.  Now when you are on pavement the oil sees more Gs that push the oil out the vent

[Vern Houseman]

thanks Dave

[thunder938]

NP..

[VMS Motorsports]

You can NOT run "vent" lines from BOTH the vent and a fitting on the oil fill. Both are PSI and WILL pump oil.  Now if you are not using the rear oil pan port on the left side of the pan as a return.  This is a NON PSI port and is used by alot as a overflow return.  If you can not use that port you can use a catch / over flow can, I have scene a old bottle used.  You should not get that much oil, unless it is over filed.  Now when you are on pavement the oil sees more Gs that push the oil out the vent

Thanks for confirming...I thought that was the case

[Vern Houseman]

your prob right about vent lines. I just tryed it this past race. it was only hooked up to just the vent before this weekend with a petcock on the bottom of the vent can and still had alot of oil blowing out. we have the texas style filter system on the car where we use bother oil pan ports, so I cant use the back one to vent the can.could i make another connection in front of pan where some people hook up the temp sending unite ?

[thunder938]

I also used both ports and 2 coolers.  So, I took the petcock out of the vent can and ran a hose to a old oil bottle and tiewrapped to the cooler and frame.  Drilled a hole in the bottle cap and put the hose into it.  I would get maybe a few ounces over a year in the bottle over a season, bt no oil on the body or tires.  Also when I change the oil I use a painters bucket that had markings on it . this way I put the same amount in that came out.  This helps with over filling the car and then having the motor push it out on high speed tracks

[knoxracing]

Whoa whoa whoa! The method you have for the can is fine, if you understand why this is being done.  The car I am currently racing is plumbed EXACTLY that way, although the type and size of can will make some difference. Make sure the vent line is plumbed into the bottom of the can and the line from the fill is to the side port of the can, this serves two purposes. 1)The vent will push oil into the bottom of the can under high rpm's, under lowere rpm's it will go back into the motor through the same line it came out of and the oil will not stay in the can robbing you of oil. 2)The oil fill port vented into the can will allow ALOT of heat from the motor to vent out of the can through the can breather. I plumbed ALOT of car back into the oil pan, I will not do this ANY more. The pan is full of oil. this port goes into the bottom of the side of the pan, oil cannot go back into the pans because the pan is full, and it can push some oil up that line. Now back to the problem, USLC HAD issues with the sleeves they were using and the result was loss of hp and blow by. Contact John Hagan At USLC and let him know your semi-fresh motor is down on power and pushing oil, they will work with you and get you back to what you paid for. They have changed to a different sleeve, the hp is better and problems like your are fewer.
Dennis Knox
Buckeye Legends
330-310-9212