Breather setup when using catch can
Discussion
Hi guys
Looking for some advice please, when you run a catch can (in my case on the sigma 150 engine) what do you (or have caterham done) regarding the pcv?
It's my understanding that a pcv valve works on vacuum therefor once vented into a catch can the crank gas cannot escape as the valve won't open (as its not pulling a vacuum from the inlet manifold)
Say on a 140 or 150 with a catch can, have the internals of the Pcv been gutted? The top cam cover breather doesn't require a vacuum.
I'm getting a lot of blow by gas on the 150 engine, no oil spurting out just lots of gas from the can! I can only assume the PCv isn't letting gas by due to no vacuum which has now shagged my rings? I'm having the bottom end rebuilt this week and don't want a repeat issue.
Looking for some advice please, when you run a catch can (in my case on the sigma 150 engine) what do you (or have caterham done) regarding the pcv?
It's my understanding that a pcv valve works on vacuum therefor once vented into a catch can the crank gas cannot escape as the valve won't open (as its not pulling a vacuum from the inlet manifold)
Say on a 140 or 150 with a catch can, have the internals of the Pcv been gutted? The top cam cover breather doesn't require a vacuum.
I'm getting a lot of blow by gas on the 150 engine, no oil spurting out just lots of gas from the can! I can only assume the PCv isn't letting gas by due to no vacuum which has now shagged my rings? I'm having the bottom end rebuilt this week and don't want a repeat issue.
pilotprice said:
Hi guys
Looking for some advice please, when you run a catch can (in my case on the sigma 150 engine) what do you (or have caterham done) regarding the pcv?
It's my understanding that a pcv valve works on vacuum therefor once vented into a catch can the crank gas cannot escape as the valve won't open (as its not pulling a vacuum from the inlet manifold)
Say on a 140 or 150 with a catch can, have the internals of the Pcv been gutted? The top cam cover breather doesn't require a vacuum.
I'm getting a lot of blow by gas on the 150 engine, no oil spurting out just lots of gas from the can! I can only assume the PCv isn't letting gas by due to no vacuum which has now shagged my rings? I'm having the bottom end rebuilt this week and don't want a repeat issue.
I fitted the genuine Caterham catch tank to my new Twenty with the Sigma 135 engine.Looking for some advice please, when you run a catch can (in my case on the sigma 150 engine) what do you (or have caterham done) regarding the pcv?
It's my understanding that a pcv valve works on vacuum therefor once vented into a catch can the crank gas cannot escape as the valve won't open (as its not pulling a vacuum from the inlet manifold)
Say on a 140 or 150 with a catch can, have the internals of the Pcv been gutted? The top cam cover breather doesn't require a vacuum.
I'm getting a lot of blow by gas on the 150 engine, no oil spurting out just lots of gas from the can! I can only assume the PCv isn't letting gas by due to no vacuum which has now shagged my rings? I'm having the bottom end rebuilt this week and don't want a repeat issue.
It basically removes the connection between the PCV and the plenum.
The pipe from the PCV then goes to the catch tank, and the other breather from the cam cover also goes to the catch tank too.
The brass inlet on the throttle body is then just capped off. As is the plastic one on the plenum body.
This has worked well on my car, and has eliminated any blow back which made my car smoke on hard left hand corners.
I hope that helps, some pictures here to hopefully explain better.
Thanks for the reply,
I have the same setup, bar the inlet manifold being replaced by throttle bodies -
The thing I can work out is now you're (and mine) PCV valve on the short motor does no longer have a vacuum to draw gas/open the ball valve as it just vents into the can.
My rings have started to pass gas through and the PCV was unable (i assume) to vent this excess pressure which has caused blow by and oil consumption
I have the same setup, bar the inlet manifold being replaced by throttle bodies -
The thing I can work out is now you're (and mine) PCV valve on the short motor does no longer have a vacuum to draw gas/open the ball valve as it just vents into the can.
My rings have started to pass gas through and the PCV was unable (i assume) to vent this excess pressure which has caused blow by and oil consumption
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