Evan Fischer Cats: Seeking Install Advice

PhillyJake

TJ Enthusiast
Joined
Sep 22, 2020
Messages
106
Location
Philadelphia
Need a little installation help on my Evan Fischer mini-cat replacement for ‘04 rubicon. There were no installation instructions in the box, I can't find them online, and the OEM bolts and captive retainers (see pics below: retainers in black) that hold the cat flange to the manifold are entirely different than the nuts, bolts, springs, and round things (maybe crush gaskets? do I need those?)

First question: How do I attach the new cats to the OEM manifold with the bolts, nuts, springs, and gaskets? I'm assuming the spring goes over the bolt, which then passes up through the new flange then the factory manifold flange, and is closed by the nut. However...

Next Question: How in the fresh hell do I compress the spring enough to get the bolt all the way through both flange holes so the nut grabs? It’s a stiff spring that absolutely can not be manually compressed - I've tried zip ties, but that's no good. Thinkin those captive retainers might be the right move, but the head of the bolt slips right through the hole in the new flange...maybe I could stack some washers?

Hpefully this makes sense and maybe the pictures clear some things up...thanks in advance!

298283739_10160356750648899_1494612100836312621_n.jpg


298333364_10160356750568899_7796146207498239567_n.jpg
 
Need a little installation help on my Evan Fischer mini-cat replacement for ‘04 rubicon. There were no installation instructions in the box, I can't find them online, and the OEM bolts and captive retainers (see pics below: retainers in black) that hold the cat flange to the manifold are entirely different than the nuts, bolts, springs, and round things (maybe crush gaskets? do I need those?)

First question: How do I attach the new cats to the OEM manifold with the bolts, nuts, springs, and gaskets? I'm assuming the spring goes over the bolt, which then passes up through the new flange then the factory manifold flange, and is closed by the nut. However...

Next Question: How in the fresh hell do I compress the spring enough to get the bolt all the way through both flange holes so the nut grabs? It’s a stiff spring that absolutely can not be manually compressed - I've tried zip ties, but that's no good. Thinkin those captive retainers might be the right move, but the head of the bolt slips right through the hole in the new flange...maybe I could stack some washers?

Hpefully this makes sense and maybe the pictures clear some things up...thanks in advance!

View attachment 350218

View attachment 350219

Just taking a stab at this.
On my 06, I remember the spring bolts being at the tail end of the pipe near the big cat. The black bolts are for the exhaust to manifold. Looking at your pics, it looks like the plated bolt threads are not long enough to go thru the flange and into the manifold nut, plus, the flare on the plated bolt will interfere with that seating. ( or Possibly it's a newer design to try and keep the bolts from coming loose ?.....making a pain in the ass job a bigger pain)

My guess, you were sent an extra set of spring bolts, when you only need two ? If the donuts came off your old setup, yes you need them, and maybe consider a new set of exhaust flange to manifold bolts and nuts. Using the old ones tend to work loose after a short time......at least that was the case with mine.
Later tonight I'll climb under mine and see if I have the spring bolts at the back end.

Edit: I just climbed under and I don't have the spring bolts on any of the exhaust, I looked at the Evans add, and it shows 4 spring bolts for the manifold... It says 04-06, maybe there was a change in the 04 year ? Sorry this wasn't much help.
Ray
 
Last edited:
Just taking a stab at this.
On my 06, I remember the spring bolts being at the tail end of the pipe near the big cat. The black bolts are for the exhaust to manifold. Looking at your pics, it looks like the plated bolt threads are not long enough to go thru the flange and into the manifold nut, plus, the flare on the plated bolt will interfere with that seating. ( or Possibly it's a newer design to try and keep the bolts from coming loose ?.....making a pain in the ass job a bigger pain)

My guess, you were sent an extra set of spring bolts, when you only need two ? If the donuts came off your old setup, yes you need them, and maybe consider a new set of exhaust flange to manifold bolts and nuts. Using the old ones tend to work loose after a short time......at least that was the case with mine.
Later tonight I'll climb under mine and see if I have the spring bolts at the back end.

Edit: I just climbed under and I don't have the spring bolts on any of the exhaust, I looked at the Evans add, and it shows 4 spring bolts for the manifold... It says 04-06, maybe there was a change in the 04 year ? Sorry this wasn't much help.
Ray

I finally got that cats on, but only after I ditched the springs + bolts. I couldn't reasonably compress the springs, insert the bolts, and thread the nut...it just wouldn't work. I went to Ace Hardware, purchased some captive retainer u-nuts and bolts and slapped them on. Worked like a charm, and didn't bend the exhaust or the manifold flange, which is what I was worried about.

No more CEL!