Engine breather out of breath
02-16-2006, 10:26 AM
#1
Instructor
Thread Starter
Join Date: Jun 2001
Location: Africa
Posts: 178
Likes: 0
Received 0 Likes
on
0 Posts
Engine breather out of breath
I have a 964 3.8 engine in my racecar. Last year it ran super - no problems.
The oiltank sits in the front compartment. In 2005 we ran a pipe from the engine breather all the way to the front tank. From the tank we had a pipe into a small overflow tank in the front (fitted with a filter). Everytyhing worked fine.
This year we reconfigured the breather and fitted a 2 liter breather tank in the rear wheel fender. From the breather on the engine we run a pipe upwards before running through the 'sidewall' and into the tank in the fender. The tank is fitted with a small air-filter.
When driving normally (even using high revs) the tank is empty.
Today (first day out in the new car) we ran 10/10 on the track and the breather pushed out ALOT of oil - say 3 liters+ after a few laps... Why?
Needless to say the tank overflowed - rather messy affair.
Help. Tom
The oiltank sits in the front compartment. In 2005 we ran a pipe from the engine breather all the way to the front tank. From the tank we had a pipe into a small overflow tank in the front (fitted with a filter). Everytyhing worked fine.
This year we reconfigured the breather and fitted a 2 liter breather tank in the rear wheel fender. From the breather on the engine we run a pipe upwards before running through the 'sidewall' and into the tank in the fender. The tank is fitted with a small air-filter.
When driving normally (even using high revs) the tank is empty.
Today (first day out in the new car) we ran 10/10 on the track and the breather pushed out ALOT of oil - say 3 liters+ after a few laps... Why?
Needless to say the tank overflowed - rather messy affair.
Help. Tom
02-17-2006, 06:01 AM
#3
Instructor
Thread Starter
Join Date: Jun 2001
Location: Africa
Posts: 178
Likes: 0
Received 0 Likes
on
0 Posts
Steve,
Only thing leaking here is my bank account... They say one shouldn't change something that's already working fine.
Checked compression and leak down - all fine. We ran a hose from the breather to the tank in front this morning and ran the car. Even at repeated revs to 6k not a drop of oil, eventhough one can easily feel the air (breathing) when revving the engine.
Could it be because of the cornering and braking forces that the car 'coughs' oil through the breather? The car is a braking/handling car (as opposed to power car!) and runs 13" slicks, 2050lbs and GT3 brakes, ie. some significant G's.
Just thinking out loud...
We have no oiltank whatsoever in the rear - so oil must travel for/aft, maybe the scavenge pump is struggling? Total system holds about 14 liters of oil. One large cooler/filter in nose. No thermostat.
Tom
Only thing leaking here is my bank account... They say one shouldn't change something that's already working fine.
Checked compression and leak down - all fine. We ran a hose from the breather to the tank in front this morning and ran the car. Even at repeated revs to 6k not a drop of oil, eventhough one can easily feel the air (breathing) when revving the engine.
Could it be because of the cornering and braking forces that the car 'coughs' oil through the breather? The car is a braking/handling car (as opposed to power car!) and runs 13" slicks, 2050lbs and GT3 brakes, ie. some significant G's.
Just thinking out loud...
We have no oiltank whatsoever in the rear - so oil must travel for/aft, maybe the scavenge pump is struggling? Total system holds about 14 liters of oil. One large cooler/filter in nose. No thermostat.
Tom
02-17-2006, 10:25 PM
#4
Probaby the same reason why the factory routed the crankcase breather into the tank first before venting into the intake - same as your previous method when you vented to the front oil tank first. There's a lot of oil and air coming out of the crankcase breather.
Why did you change to a catch can direct from the crankcase - to save weight?
Sherwood
Why did you change to a catch can direct from the crankcase - to save weight?
Sherwood
02-20-2006, 01:09 AM
#5
Instructor
Thread Starter
Join Date: Jun 2001
Location: Africa
Posts: 178
Likes: 0
Received 0 Likes
on
0 Posts
Sherwood, Yep - the oil line from the breather to the tank was full of oil when we stripped the car and we were hopping to save a few lbs...
Due to routing of the pipe it has to run from the engine downwards and then upwards again before the tank - this creates a gooseneck and the pipe will always have oil in.
Well, back to basics.
Cheers, Tom
Due to routing of the pipe it has to run from the engine downwards and then upwards again before the tank - this creates a gooseneck and the pipe will always have oil in.
Well, back to basics.
Cheers, Tom
