360 Pre Cat Check

I would just get rid of the pre cats do not ever worry about again , and not mention your car will sound a heck of allot better. I replaced my with Fabspeed headers cost around 2800.00 BUT !! if I had to do it over again I would have taken my stock headers cut them open and knock that crap pre cats out and re weld back together IMHO

 

Here is a link that has a ex ray on the 360 headers with the precats this should be help for you to see where they are located

 

Just pulled my 01 modena headers off, and yes you can clearly see the pre-cats. Mine were in tact.... but white power everywhere.
I have a/m headers going in soon.

We used to just use a long steel rod to knock cat's out of stock pipes.... appears to be suitable access in these headers.
I can take a pic if you like. Have them sitting in a box in my shop.

Pc of mind pulling those out. I'm sure that white powder (IF it is getting in the cylinders) is NOT good for ring seal, and cyl lubrication.

Terrible design IMHO for such a flag-ship auto...... terrible I tell ya!

 

I for one am not convinced that this Fabspeed fellow is a qualified radiologist. With this patient at minimum he should have ordered a CAT scan.

I'll show myself out.

 

bass - nice job sir.

 

I don't think punching or pulling the cat out would be a nice or easy job. Hacking in through the heat shields to get them out is pretty ugly too. With the heat shields peeled off the answer would be to chop the cat section off and weld on a decent collector and spot weld the heat shields back on. That would be my mode of attack.

 

I’ll post up a pic, you have good access to the cat to just punch it out.

just looked at my oem headers. Lmk if you want the pic.

 

i used a huge drill on my 360's pre-cat. it will not budge!

so , i cut the header to do that , then I weld it back.

I don't understand why people want to use aftermarket headers coz they usually cause heat issue and melt things and cost a LOT of wrap them. And it looks bad too.

 

Once you start punching/pulling, you will have to get 100% of the cat out. Every last bit including whatever holds it in there.

 

24000- if my factory precats were already coming apart I would have just whacked them out. But since they are intact better to save original parts if I ever sell.

Amazing the high prices used factory headers bring!

 

here you go..... looks like good access for the hammer and rod method as used for the past 30 years by cat decommissioners world wide.

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Photo show what appears to be a Metal Matrix Catalytic Element. What component fails? The metal webbing erodes?
My understanding, Ferrari learned their lesson on the 355. The ceramic matrix were notorious for breaking down causing cylinder damage.

 

From May 15 2014 post—/

“caught it before any damage to engine, the loose precat sounded like popcorn when cold, then normal when hot,

got lucky on this, now have new headers with no pre cats, runs great.

The pre cat appears to be a metallic honeycomb as opposed to ceramic. Its very durable but it seems to be a press fit into the collector of the stock header and can become loose like mine did, seems like chance of reversion into engine head is low on a 360, but still glad I caught it.”

 

My cat was not loose, but I had the white powder. I’ll keep the stock headers cats w the car upon sale if new owner wants it.

 

I had a long talk about this topic with Fonzie at J. Scuderia in New Jersey last night. He said that the cat components can be removed from the header without cutting it but... the result is that the space left by the cat causes a power loss due to turbulence and less back pressure in the mid range RPM's and recommended against it. He also said that the typical failure mode is from misfires, where unburned fuel gets into the exhaust, explodes when it reaches the cat and that pressure wave destroys the delicate matrix of metal and ceramic. As the cat falls apart, the little pieces get tossed around in the header and get into the engine, potentially destroying it.

The good news, at least from his opinion, is that the damage can be detected before it wrecks the engine. If your engine misfires and a new sound is detected like "pennies in a jar", stop the engine, pull the O2 sensor and scope the cats. The damage should be obvious. At that point, the car shouldn't be started and a header replacement, along with a careful inspection of the engine should be done. Waiting for a flashing CEL is like shooting your car in the head, literally. It's already cratered. Pulling the spark plugs is a good start. If they look normal, the engine is probably ok. If they look sandblasted, it's toast and is going to require a teardown and a lot of expensive parts.

He said that the problem can start from a bad injector. A good practice would be to check the spray pattern of the injectors and check for leakage at regular intervals. Another cause of misfires is when the car starts, the master ECU is awake from the immobilizer but the slave ECU doesn't wake up right away. If you start the engine and it runs rough, turn it off and restart. The slave ECU should be awake at that point and the car should run smoothly. He said that misfires from the slave ECU can be avoided by turning the ignition on, defeating the immobilizer, then turning it off (without starting), then back on again. The second time the ignition is turned on, both ECU's are awake.

Fonzie recommended replacing the headers if there is any doubt that the cats aren't in perfect shape.

<opinion>I think a lot of this issue can be avoided by being "one with the car". Listen to the engine. If any new sounds or a change in sound is detected, figure out why before going on that long, spirited drive.</opinion>

 

If there is really "lots of warning" before the pre-cats fail, then either the pre-cats weren't actually the root cause of whatever failed on my car, or I'm an idiot.

Unfortunately we can't yet rule out the possibility of either.

 

Interesting about the space left by the cat causing turbulence etc. I have challenge car headers on my 430 and they are simply stock manifolds without cats and have the space or cavity where the cat would normally be. Certainly no loss of power, I would say the opposite but would need back to back dyno runs to prove that. If my headers ever come off again I might chop the cat cavities off and make nice merge collectors to go on there which I'm sure would be an improvement.