BB1980
NAXJA Forum User
- Location
- Seneca, SC
So, we all know the story.... Filter on right was driven for a couple of months, the one to the left of it was driven for 3-4 weeks on and off.
I had the stock tube on the rear valve cover to intake connection, and a large heater hose running from the front valvecover connection to the airbox since the original hard plastic line had broken on the front.
While fooling around at work (Advance Auto Parts) I took off the brass nipple that screws into the intake and brought it in.
I found the thread of the intake manifold and then found that we sold an adapter from that thread (1/4" NPT) to 5/16th brake/fuel line. It was $1.50. Next I got a 40" piece of 5/16ths metal line for $5. I also found that we can order the plastic emissions harness that is on the Renix engines for around $21 per half, so $42 for both sides. I didn't have to replace these necessarily, but I had had to splice rubber hose between broken plastic ones and had a large heater hose running from the valve cover over to the airbox.
Adapter:
Brake/Fuel line. BL-540 at Advance is 5/16 line, 40" long.
It also helps if you already have a line bender or can do it without crimping the line accidently:
Here is a comparison of the rear connection vs the brakeline and the front brass nipple vs the new adapter:
SO, the process is simple. Remove the old rear tube. Remove the brass nipple from the intake manifold. Thread in the new adapter to the intake. Start bending your metal line to run from the intake to the rear valve cover connection. You will wind up cutting off around 6" of line at the rear and removing the flare nut from that end. I then started the flare nut into the adapter on the intake manifold. Before completely tightening the flare nut, push the rear of the metal line into the valve cover grommet. It is a tight fit, and you will feel it go in a short distance and then stop. If you keep pushing harder, you will feel it go through another part of the grommet and then feel it start into the valve cover. Pull it back out just a little so that it is still engaged into the bottom piece of the grommet. Then you can full tighten the flare nut on the front end.
This is the finished product with my old heater hose line from the airbox to the front of the valve cover. This should've worked fine for most people, but I knew a lot of my vacuum lines were all old and broken and spliced and some were possibly hooked up wrong:
Here are the two halves of the harness I purchased through work for $42 total:
And here is the final installed harness. I did have some vacuum lines ran incorrectly. When I bought the jeep, all the lines were in the rear hatch along with the valve cover, injectors, and fuel rail. So, I had to wing it hooking them up trying to do it off of a vacuum line diagram I found online.
The much larger rear connection should keep from clogging with crap and allow the proper direction of flow from the airbox into the valvecover and then into the intake manifold to be burned. In the terrible event that it does get clogged, it can be removed, cleaned and reinstalled without worry of breaking a small plastic pipe like before. I have installed another new air filter and will monitor it every week and post up results. I drove the jeep shortly afterward and it seems to run and accelerate just fine with the larger line potentially making the A/F mixture run lean. In the end, if you only need to replace the rear line to prevent blowby, you can do it for less than $8.00 at your local parts store.