The Stovebolt Site Forums The Shop Area Engine Shop Exhaust smells

I had the '37 out today running around in the sunshine, and the wife was noticing the exhaust smell. I have to admit, with the windows up it does smell a bit. Not rich fuel smell but just lots of normal exhaust stink!
Would a universal CATALYTIC CONVERTER get rid of some of the smell, or would add to it? I have the idle jets set for 14.7 air to fuel ratio, so the lean condition is adding to the smell. A converter should also help it be "green" since thats in now. Joe

I looked at your galary pictures (nice truck by the way) but I couldn't see where the exhaust exits. Aside from making sure there are no leaks underneath I would exit the pipes out the back or to the side behind the rear wheels. You don't want those nasty smells swirling around and coming back into the cab, expecially with mama in there. A cat would be about the last thing I'd put on my 'bolt but to each his own. My truck is already green anyway.

The pipe is under the rear fender and exits out the drivers side behind the rear tire. For one the doors don't seal 100% and two, its only when the wind is behind blowing the exhaust forward that you notice it. I don't mind cleaning up the exhaust emissions if I knew a converter would help.

if the pipe was on when the pic on your page was taken, then it doesn't come out far enough to avoid being blown up under the fender, needs to dump outside the trucks air flow .... the problem prolly would go away if the pipe came out behind the truck instead of at the side - I doubt a catylic converter would make much difference in emissions, and wouldn't change the smell problem - certainly not enough to be worth wasting more of the planets limited supply of platinum [over $800/ounce!] on a system not designed to make proper use of it

Bill

This has been a problem from time to time that comes threw my shop. Some muffler shops will install a pipe and not know what the outcome will be.

You say it is behind the tire. That area does not get the air flow that it may need. I can not see it in the pictures. Does the pipe come out past the side of the bed?

If not then my best guess would be that the fumes are collecting under the bed area and being pushed back under the cab and into the inside.

Big question. Did this do this before you parked it for the winter?

The smell may be that the fuel has jelled up and it will take a good run with fresh gas to clear that up.

It's always done it, I just lived with it. The pipe does need moved, I just haven't done it yet. I thought I might be able to help out the planet and solve the problem. I guess I need to read up on how the converters work, I never really thought much about them, plus order up some pipe.

Joe

ok, I will explain to you how they work. I would not recomend putting one on because it WILL reduce your Over all horse power.

What a Cad.converter does is. It will heat up and burn the unused fuel left over from the Comb. Chambers.
They get real hot. and they to can smell if not used right.

For example. At the Cadillac Dealer I had a guy come in. The car runs off reg. gas.

On the first two rounds we replaced them under warrenty. Then We had some very clear questions for him. What gas is he using?

Turned out he used prem.gas... well for a short story. we would no longer replace the converter. so, If you want to use one you will need one to match the type of gas you are using.

His car smelled like a roten egg.

To fix your probem. You can just pick up a longer pipe to add to your tail pipe on the tip.

You can find those at most auto stores. It may take you an hour but, it will save you the problems.

catalytic converters are pretty technical items, either "2 way" or "3 way" reacting, and designed for the particular application, which nowadays includes way different fuel delivery and monitoring, including feedback from the converter - in their intended applications they can reduce some noxious emissions, but I doubt adding any ol one to your modified engine would do more than plug it up ... just keep'er well tuned

Bill

Joe, are you sure the exhaust donut is not leaking and contributing making small problem even bigger?? Just a thought.

I dump mine just ahead of the rear axle and have never had a problem with smell.

Could it be blow-by gases from the engine itself?

The whole system is tight, its just the normal old tail pipe smell. After driving new cars all the time, the old carbureted one just stinks more. And like I said, its only when the wind is behind blowing the exhaust forward and setting still. Once I get going, the exhaust is blown away and all is well. I run the engine very lean, so thats not helping anything. Joe

I do run with a 160 thermostat, so it may be to cold. I think I will bump it up to a 180 and see if it helps burn off some of the emissions.

A cat converter would not work on an old truck like that. It would get too hot & the rotten egg smell would be worse then the exhaust oder. It would brobably be short lived also.

Somewhat related: The stovebolt sixes have they're own smell that is different from other engines I have had..My kitchen has a door that opens to the garage and some years ago I left it open while starting my truck and backing it out of the garage..the house stunk for almost a week..if it was a new car that smell would have been gone in 10 minutes..permeates clothes fabric..just nasty..I started a thread about it here:

https://www.stovebolt.com/ubbthreads/ubbthreads.php?ubb=showflat&Number=441543&fpart=1

Keith

Keith, That post is just what I'm talking about, just old exhaust! I push mine out of the garage some days before starting it just so the garage doesn't stink. Once I get home, I leave it out side till it cools, other wise the garage smells like fuel evaporating out of the intake. Joe

You are more likely getting the smell from the crankcase fumes. You could convert your road draft tube to a PCV system. There was a PCV available for Cab Over and Box Van engine applications that kept the cab from stinking up in city use. The first emissions laws in the country required PCV, for a good reason. It really works, and doesn't rob any horsepower.

Personally I love the way my truck smells. I can close my eyes and be a kid again around that odor.

And as far as "saving the planet" I doubt that if you fired up every old vehicle in the world they wouldn't produce as much CO2 as one of those coal fired power plants they're building in China at the rate of one a week!