catch can does ?
06-09-06, 05:02 PM
#1
Full Member
Thread Starter
Join Date: May 2006
Location: Toronto, Canada
Posts: 137
Likes: 0
Received 0 Likes
on
0 Posts
catch can does ?
what does a catch can do? does it help to reduce the oil smell coming from my exhaust? got rebuild engine, turbo fairly new, and Steve to tune.
06-09-06, 08:06 PM
#2
RX-7 Bad Ass
iTrader: (55)
Maybe, maybe not.
Most cars have a PCV setup - positive crankcase ventilation. The oil pan gives off fumes, and by federal emissions standards any fume coming from a car must be burnt by the engine then scrubbed by the catalytic converter. On the FD, there are 2 nipples on the oil fill neck that plumb into the intake - this sucks any fumes out of the oil system into the engine to be burned.
Now, you can't just cap the nipples up. The crankcase (which is a misnomer on a rotary - really just the oil pan and oil system) needs to breathe. The oil expands and contracts with temperature, as does the air at the top of the oil pan and the oil neck. If you cap it off, the pressure has to go somewhere, which is usually into the motor or turbos, resulting in smoking.
Anyhow, while the system is all fine and dandy, you do end up sucking some oil into the engine's intake. This coats the inside of the intercooler, inside of the pipes, etc. and is not super good for performance. Simple catch cans just go in between the hose from the oil neck to the intake - any excess oil goes into the catch can, and the air and vapor goes into the engine. You just empty the can out on oil changes - done.
That said, it's worth first off converting your car to the '95 PCV system. There's a large tannish grey and black check valve going from the oil fill neck to the intake. '95s eliminated that system - remove the check valve and hoses and cap both ends up. The other nipple goes to the primary turbo intake, which is usually fine, but you can plumb a catch can in there if necessary.
But, before tackling all that, take your oil cap off the car and drive around. If you're still getting smoke, it's not a PCV issue - it's very likely one or both of your turbos are heading south. Not a big deal, as good used turbos are reasonably priced, although it's a bit of work to swap out. If you aren't getting smoke with the oil cap off, it's something with your PCV system.
There's your long post by me - welcome to the forum
. Read up on this stuff and learn. Get you a shop manual and study the system too to learn more.
Dale
Most cars have a PCV setup - positive crankcase ventilation. The oil pan gives off fumes, and by federal emissions standards any fume coming from a car must be burnt by the engine then scrubbed by the catalytic converter. On the FD, there are 2 nipples on the oil fill neck that plumb into the intake - this sucks any fumes out of the oil system into the engine to be burned.
Now, you can't just cap the nipples up. The crankcase (which is a misnomer on a rotary - really just the oil pan and oil system) needs to breathe. The oil expands and contracts with temperature, as does the air at the top of the oil pan and the oil neck. If you cap it off, the pressure has to go somewhere, which is usually into the motor or turbos, resulting in smoking.
Anyhow, while the system is all fine and dandy, you do end up sucking some oil into the engine's intake. This coats the inside of the intercooler, inside of the pipes, etc. and is not super good for performance. Simple catch cans just go in between the hose from the oil neck to the intake - any excess oil goes into the catch can, and the air and vapor goes into the engine. You just empty the can out on oil changes - done.
That said, it's worth first off converting your car to the '95 PCV system. There's a large tannish grey and black check valve going from the oil fill neck to the intake. '95s eliminated that system - remove the check valve and hoses and cap both ends up. The other nipple goes to the primary turbo intake, which is usually fine, but you can plumb a catch can in there if necessary.
But, before tackling all that, take your oil cap off the car and drive around. If you're still getting smoke, it's not a PCV issue - it's very likely one or both of your turbos are heading south. Not a big deal, as good used turbos are reasonably priced, although it's a bit of work to swap out. If you aren't getting smoke with the oil cap off, it's something with your PCV system.
There's your long post by me - welcome to the forum
. Read up on this stuff and learn. Get you a shop manual and study the system too to learn more.Dale
Thread
Thread Starter
Forum
Replies
Last Post
