| Author | Message | ||
     benzjagbe Unregistered guest Posted From: 71.210.169.164 |
I took my 79 Shadow to my local exhaust shop today to repair an exhaust leak. The guys showed me the right catalytic converter was rattling inside. I could NOT hear it inside the car. The car ran perfectly. I spent $220.00 to have it replaced. Thereafter, I really see/hear no difference in the running of the car. Should I have just left it alone? My car does not have to be inspected in my state. Thanks! Richard (Message approved by david_gore) | ||
| David Gore Moderator Username: david_gore Post Number: 3860 Registered: 04-2003 |
I suggest you did the right thing by replacing the converter purely on safety grounds. The converters get very hot during operation and if the internal elements are not securely fixed in position, it may be possible external "hot spots" may be created which could be a catalyst for setting fire to nearby flammable items and subsequent destruction of the car and injury to occupants. A "nuisance" item for sure but still potentially dangerous in the right conditions. | ||
| Patrick Ryan Grand Master Username: patrick_r Post Number: 2296 Registered: 04-2016 |
David is spot on Richard. Most people think about theses cats as black magic items, but they will surely bite you on the bum if not replaced when needed. As David mentions hot spots and fires, but they can rattle around long enough to get to the exact size to wedge its self in the outlet, then this is like someone in the old days of jamming a potato up your tail pipe. This is a “fail to proceed” moment just waiting to happen. | ||
| Richard Greene Frequent User Username: benzjag Post Number: 227 Registered: 12-2012 |
THANKS David and Patrick! I feel good now as I did not think about the possible hazard! Appreciate your input! You learn something new every day! HAPPY NEW YEAR to you and all the list! Richard | ||
| David Gore Moderator Username: david_gore Post Number: 3861 Registered: 04-2003 |
Thanks Patrick, I was hoping you would be able to provide more information given your experience. Personally, I am only aware of one instance where a car fire was attributed to a hot catalytic converter and this involved a country car being driven through high grass which was caught up under the car and started smouldering before it caught fire. The situation was made worse by the fact they didn't carry a fire extinguisher in the car which is essential for country driving IMHO. | ||
| Patrick Ryan Grand Master Username: patrick_r Post Number: 2297 Registered: 04-2016 |
You’re right David, any older car should carry at least one, or even 2 x1kg fire extinguishers. These cars, even though insured, are irreplaceable. It would be heartbreaking just helplessly standing by watching it burn. The worst thing with some aftermarket (non genuine replacement part) replacement cats, is they do not have any heat shielding & insulation which really reduce the direct contact & radiated heat which can cause these fires. The next issue is that some people want to modify their exhaust for one reason or another, and they forget to then relocate the floor mounted heat shields that are either bolted or spot welded to the underside of the floor directly above the cat, with an air gap that stops excessive heat from contacting the underside of the floor. Of course directly above that floor is insulation and carpets that can be affected by this heat radiating directly on the steel floor below. Some of these can reach and even exceed an internal operating temp of 800 degrees C. The monolith will actually glow during operation, but of course this is all hidden from view. But older cats, that get blocked can get even hotter and the ceramic core or monolith will start to crack, get hot spots and sections can actually start to melt, and then they start to break up, then blocking the outlet. | ||
| Patrick Ryan Grand Master Username: patrick_r Post Number: 2298 Registered: 04-2016 |
Gents, A couple of interesting images. A normal cat after being used.  One after excessive heat and then failure & blockage  | ||
| Robert J. Sprauer Frequent User Username: wraithman Post Number: 667 Registered: 11-2017 |
The single cats are 3 elements, one is a attenuator element. The single cat costs a whopping $4k. Many cats can be rebuilt if you have the know how. Have done many including my 1980 SWII California with a single cat. I use heat barrier above the cat and on the floorpan under the carpet padding. You may be very surprised when you see the floorpan, as some are rusted thru from the heat and trapped moisture. | ||
| Patrick Ryan Grand Master Username: patrick_r Post Number: 2299 Registered: 04-2016 |
Great points Robert. I have seen a few rebuilt as well, as far as I know, they have worked out ok, Quite amazing there are not more fires caused by these. Yes I have seen some shocking floors above cats. | ||
| Richard Greene Frequent User Username: benzjag Post Number: 228 Registered: 12-2012 |
Patrick....You jogged my memory when you mentioned the outlet could get clogged. I remember last spring, I heard a "bang" under the car. After that, the car ran hotter than normal. I bet it was the converter breaking up inside and blocking the outlet! I drove the car a few more times thereafter, and the temp gauge returned to normal. Evidently, a piece of the converter fell back away from the outlet! I thought my question was originally stupid, but now maybe NOT! Richard | ||
| Patrick Ryan Grand Master Username: patrick_r Post Number: 2300 Registered: 04-2016 |
No stupid questions here Richard, all these older cars can do things weird from time to time. It very well could be mate, only one way to find out. |
