Oil catch can for Crankcase ventilation tubes?

[53guy]

I have been following this post and I have a few questions for you all. Does it make any noticable performance gains by adding a catch can? I clean my TB about once every few months or every time I hit the mud and I've noticed the oil in my intake runners that I cannot clean out. Does an accumulation of oil in a catch can indicate a failing motor or just the rings?

 

[Dr. Dyno]

Dr. Dyno ... thanks for the response. Love your website, and it's great to read your knowledgeable posts.

Do you think the catch can is worth it? I mean ... if it only catches a tiny amount of oil in 6 months, what's the benefit? CW said he needs to drain his every few months.

What might explain the difference between your jeep and CW's? Could that indicate your motor isn't misting much oil under the valve cover? Or could it indicate the catch can isn't catching all of the oil? Maybe your motor is newer with less blowby? Whaddaya think?

Thanks.
I do think the catch can is worth having even though mine is hardly catching anything. My motor IS relatively new (23k mile old 4.6 stroker) and since oil consumption is negligible (5000 miles since last oil change and it's used less than 1/2 a quart), I've obviously got good piston ring seal.
The filtering medium inside my catch can may not be trapping all the oil though. I used Scotch Brite scouring pads and I've since learnt that sponge is a better filtering medium, so I'll probably change mine to sponge and see how well it works.

 

[CW]

I have been following this post and I have a few questions for you all. Does it make any noticable performance gains by adding a catch can? I clean my TB about once every few months or every time I hit the mud and I've noticed the oil in my intake runners that I cannot clean out. Does an accumulation of oil in a catch can indicate a failing motor or just the rings?

There are a lot of issues that cause blow by on high mileage engines, pulling the valve cover off and cleaning the internal valves will help. The catch can does help keep the intake cleaner. Seafoam will help clean your intake runners and compustion chambers out if you want to clean them without taking the manifolds off.

See here for info on blowby.
http://www.off-road.com/jeep/cherokee/xjtech/engine/40ltr/blowby.htm
and here
http://www.off-road.com/jeep/cherokee/98/04_apr/valvecover/cover.html

 

[montanaman]

I used Scotch Brite scouring pads and I've since learnt that sponge is a better filtering medium, so I'll probably change mine to sponge and see how well it works.

Just regular kitchen sponge? Or maybe those big loose-foam sponges for washing vehicles.

Also ... I noticed in your pics that you seem to have a 1/2" hose coming off your intake man. to the catch can. Do you have a 1/2" outlet off the manifold there? On my '91, there is a skinny little plastic tube coming from the rear valve cover grommet to the Intake manifold. Looks like a 1/4" or 3/8" outlet from the manifold.

What do you think? Anybody else have this problem? I might have to install a 1/2" pipe on one side of the can and a 3/8 barb on the other, or something like that.

 

[Dr. Dyno]

Just regular kitchen sponge? Or maybe those big loose-foam sponges for washing vehicles.

Also ... I noticed in your pics that you seem to have a 1/2" hose coming off your intake man. to the catch can. Do you have a 1/2" outlet off the manifold there? On my '91, there is a skinny little plastic tube coming from the rear valve cover grommet to the Intake manifold. Looks like a 1/4" or 3/8" outlet from the manifold.

What do you think? Anybody else have this problem? I might have to install a 1/2" pipe on one side of the can and a 3/8 barb on the other, or something like that.

Yeah, I meant just regular kitchen sponge. Just cut the green scouring portion off and use the rest.
I used 5/8" heater hose to link the valve cover grommet to the catch can, and the same size hose halfway from catch can to manifold. The other half is a piece of smaller diameter rubber hose that fits snugly over the nipple on the manifold at one end and slides snugly inside the length of heater hose at the other. I sealed off the joint with black RTV silicone. The fittings on the catch can are short lengths of 1/2" copper pipe.