Re: "Kill the cat"

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After reading all of the letters in this forum about gutting the "cat", I thought I was ready to give it a try on my '96 4w/d std cab with 55k miles. I soaked all of the clamps overnight with Liquid Wrench and began at 8:00 AM. After loosening all of the clamps, I began trying to remove the cat. Ha! After two hours of hammering, twisting and cussing,(my neighbors used to like me) I was no closer to getting the cat loose than I was when I started. It would not move forward, backward or twist. I finally discovered that all of the female pipes had slots in them, and all of the male pipes had tabs welded to them which slid into the slots. Of course these little items are on top of the pipes and not visible. You have to start dis-assembly from the tailpipe forward. This is when I discovered that Godzilla at the factory had crimped the muffler/tailpipe joint with the clamp. In order to remove the muffler and tailpipe as a unit, I jury-rigged hangers out of rope, then unbolted the real hangers from the frame. After much pulling on the tailpipe from the back bumper, the muffler seperated from the rear of the cat. I was on my way. Gutting the cat was relatively easy. Getting everything back together by myself was not. Of course by now it's 4:00 pm, my 60 year old body has been lying on the damp concrete for many hours, my neighbors wont talk to me, and my driveway is covered with soot and broken ceramic. I would suggest checking for these slots and tabs berore starting any of this work and if present, have someone there to help with the pushing and pulling. By the way, the results were well worth the effort. There is a definite increase in power, especially in the higher gears. (5 spd transmission)

 

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Amen, brother! I'm STILL sore in places I didn't know I had! Had the same problems you did, and have the busted knuckles to prove it!
I got around separating the tailpipe from the muffler by attaching a come-a-long to the muffler, and cranking it back. I was then able to slide the cat off. Geez, what pain!

Ok, soapbox time: Flame if you wish! For the past 20 years I've owned nothing but Japanese vehicles. I know, "We taught 'em everything they know!". #ad
Every one I've owned has had FLANGED EXHAUSTS! Remove two rusty bolts, and the exhaust just falls off. Why doesn't Detroit do that?? And while I'm up here, the Japs I've owned had had DRAINPLUGS on the DIFFS!! Hello, DC?? Are you listening? There are still folks out here who like to service their own vehicle!

Ok, whew, I'm better now, thanks! #ad


I do love my Cummins. It's by far the best truck I've ever owned.

Mr. Gilchrist, we'll have to link up sometime! I live south of town, but commute in every day.

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'96 Regular Cab, 113. 5K, SLT 2WD auto 3. 54, Vista topper, Pillar-mounted Autometer Boost/Pyro, transmission temp and oil pressure guages under dash, starwheel spun

 

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Nothing an air chissel coundn't solve. Heating the pipe helps some too.

 

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I forgot to mention all the skin left under the truck and the scorched fingers from heating the pipes. Chiseling was not an option because I didn't want to buy new parts, much less a bigger compressor and air tools. My mechanicing is strictly the shade-tree type. But it's FUN???

 

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An air chisel and Sawzal made the job easier for me. I did find it necessary to flair the connecting flanges a bit with the chisel, as well as cut some relief on the pipe (Godzilla assembled my muffler system also). However, don't be fooled though - as this is a fairly contancerous job. I then sharpend a 2'length of 3/4" conduit to act as a chisel to open the kitty.

I installed a 4" straight pipe with 45 degree elbow to replace the other pipe. This was not too difficult either and I was lucky to get a 10' piece of 4" aluminzed pipe from a local muffler shop for only $50. The more difficult part for me was finally getting the hangers welded back on. After posting on the board I was directed to us E6011. I discover 1/8 rod required too much heat and would burn thru the pipe. 3/32" E6011 rod with 90amps on my buzz box worked like a charm.

The truck has a very pleasent muffled big rig sound. I would say to the adventureist to lose the muffler.

The properly breathing kitty helped my EGT's eminsley.

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1995 4X4 std cab 12 valve, original owner, 100k miles, 14cm turbo, 4" straight exhaust - gutted kitty, EGT and Boost guage, #5 torque, 215 injectors, (370's and delivery valves on the way) AFC spring kit, Pscotty airfilter, Dunrite TC and Red Butt Engineering Torqueflite TransButtyy shift kit, 3. 54 rear, 17. 5" American Racing aluminum wheels, Mickey Thompson MTX's, Rancho's RS9000's, Helwig anti-sway, Starcraft camper and assundry dodad's. Only thing faster than a 12 valve is my Ducati 4 valve

[This message has been edited by A-bomb (edited 11-08-2000). ]

 

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I did mine the way you did, A. G. This was before the shop, before air power, and before Oxy-Acetylene torch days. It took time... ... A gorilla assembled my system and left a socket on one of the clamps because the nut stripped and I guess the assembly line just kept on truckin. Two exhaust systems later, I'm running a 6" system and I WILL NEVER TAKE OFF A STOCK SYSTEM TO ONLY RE-INSTALL IT EVER AGAIN! Whew! I feel much better now!


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Chris Timochko
1997 5sp 4X4, HX40, BD 4" Brake, Marine Compression, Custom Tuned Injection Pump, 370B Injection Nozzles, Delivery Valves, Governor & AFC Spring Kit, Psychotty Air, Water Injection, NOS Diesel Kit, 6" Chrome Exhaust System, No Smoke Valet Switch, McLeod Dual Disc Clutch, Mag-Hytec Rear Cover, Cummins Chrome Kit, Optima Red Tops, Hadley Bully Horns, Hurst Line Loc, Goodyear Wrangler AT/S 305/70/16s. Test mule for Auto Wurks Diesel race program

 

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After spending 3 hours under my 3500,with air chisels,cutoff tools,pry bars and comealongs I bought out the oxy/acetylene,it took 5 minutes then. A sawzall will work fine if you don't plan on reuseing anything. I've done four other trucks since that first one by heating the ends red,all 5 minute removals. If your time is worth anything at all go rent,borrow, buy an O/A set or take it to a welder,it's really the only painess way to do it.