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Re: Catalytic Converters
Posted by: Marco_a_p ()
Date: January 08, 2021 04:09PM

Keep in mind that modern fules are not the same as they were in the "good ole days" Fuel is more volatile and evaporates more rapidly then back in the day.
Hence why modern cars have a "Closed" fuel system. Pressurized by evaporating fuel etc.

A 2nd Gen Monza Wagon, a 2nd Gen GB 8door, a 2nd Gen (61's were 1st Gen) R/s and a 62nd Gen Turbo coupe..

Hanging out with the scorpions, king snakes, road runners, coyotes and quails In the southern desert of the silver state
Mesquite NV 89024

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Re: Catalytic Converters
Posted by: CoCoCo ()
Date: January 08, 2021 04:32PM

I was able to buy a couple of Magnaflow cats a couple of years ago from one of the local O'Reilley's with no trouble.
A friend's brother works there, but I don't think that had anything to do with the availability since they were either in stock, or were delivered to the store within a day.


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Re: Catalytic Converters
Posted by: Brizo ()
Date: January 09, 2021 08:34AM

KenHenry Wrote:
> I put Flowmaster catalytic converters on my 1951 Ford flathead V8, mostly to quell passenger complaints as these engines engine need a fairly rich idle (~12.5:1) even with EFI added and sealing of the passenger compartment is poor. I have a WB02 mounted and cruise and light acceleration are fairly lean.
> They worked great for a few thousand miles over 2 months but now the exhaust stink is back and as bad as ever. I don't think they are plugged - just not functional.
> One limitation: they were mounted 4 or 5 ft down the exhaust system due to space limitations and may not have run hot enough to live a long life! Maybe one would last longer closer to the manifolds but hard to know. These are fairly inexpensive cats as well which may be a factor.

Does your '51 Ford still have the open crankcase vent pipe? If so, the passengers may be smelling blow-by vapers coming through holes in the firewall. Excess fuel pressure may cause hot soak flooding leading to vapor leaking into the car also. ?

Dan Brizendine, Circle City Corvairs
'64 8 door Greenbrier, stroked 184 ci.140 PG. "In beautiful Wanamaker Indiana...with one stop light and 5 pizza shops"

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Re: Catalytic Converters
Posted by: KenHenry ()
Date: January 09, 2021 09:21AM

Fuel percolation after shutting down was always an issue, and one of the reasons I converted it to EFI (Megasquirt with Ducati fuel injectors). I also set up a PCV system for it so I think the remaining smell is mostly unburnt hydrocarbons due to the rich idle. The idle gets choppy when I try to lean out the idle, wonder whether it would work better with port injection...

7EEF1CBF-000C-450E-ACE2-6B30A94A98D5 by kenhenry_06268, on Flickr

Ken Henry, Rochester, NY USA
1965 Corvair Corsa
140 hp, 4 speed

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Re: Catalytic Converters
Posted by: alphasud ()
Date: January 09, 2021 09:40AM

Combustion chamber design is the reason you can’t run lean. I think in your case a good old fashioned thermal reactor to do with the HC is all you could do. I know on the air cooled VW’s if you leaned the idle below 3% CO the HC’s would start climbing from the misfires.

David North Idaho
1965 Corsa Turbo converted to 140
1971 Super Beetle with 2.5L Subaru engine
1965 Corsa mid engine project
1973 Mercedes 280 project

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Re: Catalytic Converters
Posted by: wittsend ()
Date: January 09, 2021 02:50PM

Quotes by cschneider53
"...but my tolerance for the smell of unburned fuel is a lot different than it was 20 years ago."

"I figured this would pair well with a set of cats to make it bearable for my wife to have the Vair in the garage. I can roll it out to start but can't roll it in after shut off because of the slope of the driveway."

As I've re-read all of this it seems like the main complaint is "unburned fuel" and it comes after he enters the garage. I mean even if he has to "power" into the garage how many seconds is the engine running to do so.., two seconds (and likely with the exhaust pointing out the door)? The cost of EFI and CATS seems rather pricy for the few seconds the Corvair drives in the garage to eliminate an odor - if it even would. Is CATs in this case like putting a tourniquet around the neck for a nose bleed?

A few have mentioned evaporating fuel and I'm inclined that is (at least the greater part of) the real problem. Whether from a fuel leak, evaporating fuel in the float bowls (most likely), fuel tank venting etc. A hot oil (leak or otherwise) can also contribute "vapors," especially in the absence of a PCV system.

Perhaps a greater analysis by the poster and more information would help to reasonably solve the problem.

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Re: Catalytic Converters
Posted by: didget69 ()
Date: January 11, 2021 06:23PM

Most muffler shops in my area that are 'quality' shops can install an aftermarket cat, even with thin washcoat, that will last their 24 month / 24k mile warranty period.

I was the recent 'recipient' of a cat hack-attack,on a Honda Element (top 10 candidate for a cat-ectomy...) and local shop replaced cat with aftermarket for $300 installed with 24/24 warranty - and I'm fine with that. They've always stood behind their work, and guarantee no emission/exhaust related codes for warranty duration. Local garages trust their Cat work to this one shop... and have for over 20 years.

bryan in NC

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