Catch Cans, Anyone Use Them?

[Blue88Comanche]

I was on the Jeepgarage.org forum last night when i came across a post about catch cans. So with the theory that it will collect blow by oil before it gets to the air intake and filter, I decided to make one for dad's MJ as it currently has it pretty bad. I know the best solution would be to fix the problem, but this is a good time for me to experiment and have a little fun.

 

does anyone use a catch can on their MJ?

 

Borrowed pic of basic catch can theory

 

[AMCJeepMJ]

I used this on my old 93 Accord when I put a short cold air intake on it; I'd get a bit of oil being drawn in. It only caught 1/4" of oil in the can every oil change (it was a modified small canning jar... real high tech, I know). Without the can, oil would be drawn into the engine or drain down into the cone filter and drip on the inner fender, so it served its purpose.

[Blue88Comanche]

dad's MJ has an oil soaked air filter, so doing this will help prevent that and give me a heads up if it starts acting up again after i fix the problem. good to hear first hand knowledge..

 

my current design is a mason Jar with 2 tubes in the lid and it sealed with black gasket around the tubes. i did not have a Comanche with me when i bought the tubes so it looks like i will end up getting some adapters to make it work, but it shouldn't be a big issue

[AMCJeepMJ]

One note about the a glass jar: be sure to secure it to something with at least zip ties- you don't want it clunking around the engine. Glass shrapnel and collected oil everywhere is not fun to clean up. After my first one broke from it not being well secured and exposure to heat [it was a slender olive-type jar], I went with a canning/mason jar... they're more durable, and the lid is easier in which to put holes.

 

Now, before anyone goes off about me putting a glass jar in the engine compartment, it was originally intended to be a temporary solution until something better was done... its just that the 'something better' never got around to happening. :doh:

[sinkrun]

Why not put the time into installing a newer style valve cover and be done?

[Blue88Comanche]

I have a new style cover I may put on it, but this is something simple that will help keep the system clean in the future should it ever start blowing oil again. its a free / cheap mod that's simple to do so why not? I was planning to fix the blow by issue anyway.

[Pete M]

I originally used a small juice bottle but the truck filled it up and started spitting out oil after only a few hours on the freeway. so I supersized it. :D

 

[cruiser54]

Just do this and be done with it:

 

 

Cruiser’s Valve Cover Mod

 

Most early and even later Renix 4.0s could be bothered by excessive oil in the air cleaner box. A fix from my old days as Service Manager at a Jeep dealership follows. Information was provided to me from a buddy at JeepTech during those days. I don’t believe it ever came out in a Technical Service Bulletin.

 

　

 

Remove the valve cover and turn it over. Next, remove the fluted tubes that are now facing you by removing three screws on each. Chop 1 inch off each of them. Then, about a half inch up from the area where you just sawed them off, drill a half inch hole in the tubes so the holes will face the rear of the valve cover. Clean and de-burr/sand all rough edges nicely, clean with solvent, and reinstall. Don’t be concerned about the chintzy gaskets that will probably crumble into oblivion when you remove the fluted tubes. They can go back together without gaskets.