Good Day!

I have searched and couldn't come up with an answer.

My charcoal canister is leaking oil out of the bottom. I believe I may have it hooked up incorrectly.

I removed all of the emmisions on the car, except the charcoal canister. I have one of the lines going from the oil fill tube (lower hole) to the charcoal canister. The other line I am not sure where it goes to be honest.

The car is an 87 NA with a S4 TII swap.

It has taken about 2,000 miles for this to develop. It seems that progressed to being a problem during a track day on this previous Monday.

The car does not smoke (unless I let it idle for a really long time).

Anybody have any ideas?

Thanks,

Rob

 

Connect up the purge system according to the schematic in the Haynes/FSM.

 

I now have the system hooked up as per the FSM. It is fine during normal driving. However, oil still comes out of the bottom of the charcoal canister during track events.

 

Might be time to replace it.

 

I do not understand what you want me to replace. THe charcoal canister has a hole in the bottom with a line coming off of it to empty any solids from the canister. THe problem is that during high load right hand turns, the oil in the pan rides up the fill tube and into the PCV system. This allows oil into the canister. Oil leaking out of the canister eventually ends up under the car and on the track (Very bad!).

Anybody have any suggestions on how to eliminate oil going to the canister?

When I do a track day, can I eliminate the PCV system? Just cap it off? What are the side effects?

Thanks!

 

I've never had that problem...

I just recently removed my canister. Took 10 minutes. I just capped off the lines. I've put 300 miles on the car this way and it seems just fine. No lung mustard. No leaks. It may just be my imagination, but my MPG seems to have gone up. I'm at 155 miles on 2/3 of a tank... I was getting between 20-23 with the canister on.

 

Or just install a catch tank. If you still have the cold start assist bottle run the drain tube into that.

 

A catch can is a poor band aid. It takes oil from the oil pan and effectively removes it from the system. On top of this, it will fill up 1 qt of oil in about 30 minutes on track!

I think I am going to have to add a pressure vent line on the passenger side of the engine.

 

I don't see a problem with running a catch tank. Lots of people do it. If your on the track so much just remove the canister...

 

Just block off the nipple at the bottom and have the second nipple at the top venting to atmosphere or running to the intake or whatever you have left of the purge system. You could also just run the line to a coke bottle or something, just for the track days to catch the oil.

 

After much research and talking with other persons at the track and on this board, it seems the problem is fairly common.

The main reason this happens is due to there being only a pressure release system on the drivers side of the motor. On any right hand corner, the oil sloshes to the drivers side and "blocks" the pressure release system. The "crankcase" pressure than pushes the oil into the pressure relief system. This oil will then travel to the charcoal canister, or if you have a catch can, to the catch can.

In this situation, it does not matter if you have the charcoal canister or a catch can, the oil will leave the oil pan and end up in a canister somewhere else. This is not good! The oil needs to stay in the engine!

The research I have done led me to a conclusion: Both sides of the engine needed vented to releave pressure.

I am tee'ing a pipe nipple off of the top of the turbo oil return line near the OMP. This should let the pressure out of the "crankcase" on those right hand turns. With the pressure releaved, the oil should not be "pushed" into the pressure relief system.

I will post my results after Oct 11th track day.

Thanks for all of the suggestions!


P.S. if you removed your charcoal canister, how do you vent the pressure inside the engine?

 

I've seen some catch-cans that do have a drain-back to the oil pan so you arent permanently removing oil from the crankcase, but your solution seems more complete, as long as you T the new line in to the existing one before the PCV

 

I'm making a recirculating catch can. I'll post pics when it's done.

At high boost pressures it's hard to avoid blowing oil.

 

Leave it to Mr. Cake to better the engineering of the RX-7 ...i can't wait to see what both you guys come up with. maybe together you guys will help all the people running boosted 7's on the forum solve a very big issue with the crankcase

 

Does the PCV not vent enough? Older cars did not even come with charcoal cans. All you need is a PCV or something similar.

 

i would like to see finished product of said recirc catch can