Flathead CO level at idle.
 

Hi, Can anyone tell me the correct Carbon Monoxide level at idle to expect on an 8BA flathead running a holley 94 carb. I have set her up using a colourtune, idle speed and timing are spot on but I am running about 6% CO at idle on a hot engine, which I am thinking is a little high. :giveup

Crikey thats getting a bit techo isn't it?! Any oil burning or air leaks in the exhaust will upset any readings. 6% is a little on the high side but if its happy there i wouldn't be concerned. About 3% to 4% would be pretty good but old engines, low compression, bad combustion chamber etc. Just wind mixture screws in till it goes off song, then out till same & set screws in middle of that.

Only old-truck guys could say this...
 

.... Just wind mixture screws in till it goes off song, then out till same & set screws in middle of that......

"Till it goes off song"

(amazingly accurate use of the language)

Hell that's what I was thinkin. I like that. If there are no flies around it's about spot on.

1949 was not a high point in the history of designing fuel-efficient and low-emission engines. I don't have any original specs for the emissions as I don't think they originally bothered to record them.

If your engine is running smoothly without blowing smoke, you can try to reduce it a little by turning the idle screw to the leanest point, or even replacing the jets with a smaller size, but you might have to just face the fact that these engines pollute a bit.

Emissions aint they great!
 

Due to the fact our respective governments are dreaming up new ways of taxing us, including hitting us for carbon emissions, you want to be doing your fair share of emitting to get your money's worth.

Turn the thing till it gets rich!! Aim for CO of 40-50%. Heck we only use 20% of the oxygen in a breath!

... Hanno, here's a double posting

greetings
Eagle Eye Chris ;)

Thanks Four Eyes! :D

Threads now merged.

H.

There have been some emissions testing on Antique Cars
 

Hi All

I do remember that there has been some recent emissions testing done on antique cars in the US with in the last few years which included a Ford Model A and I think some Ford V8s. I'll do some searching and see if I can find the test results.

As to fuel air testing I know that there was equipment back in the early 50s because my father had a test unit which he used to tune up high performance big block Lincoln flat head V8s. Family had a 49 Lincoln running a 337 bored to 350 flat head. Engine was rated at 150 HP by the time he finished playing it was producing 150 HP+ delivered to the ground at the rear wheels. So all the testing was for power not necessarily clean air.

Cheers Phil

Exactly. When gas was 20 cents a gallon who cared if the car only got 10 MPG. A friend of mine owns a 49 Meteor with a Holley 94 carb that is stock except for being stroked from 239 to 255 cubic inches. Next time I see him I will ask what his fuel economy is.

Paul

We have emission testing in this province, even for vintage vehicles. When I took my Dodge M152 (flathead Chrysler 6 cylinder) through the first time it failed. I didn't really expect it to pass but I wanted a baseline. After a valve cleaning and new head gasket it passed with about 30% of the maximum allowable emissions.

The idle test results were 314 out of 972 ppm for hydrocarbons and 2.26% for CO with a maximum allowed of 4.90%. NOx was never measured.

thanks guys.
 

Hi, Thanks Guys for the replies, here In the UK, I understand there is an upper limit of 4.5% CO for this vintage of vehicle, however as a track laying vehicle and because of its age there is no requirement to pass an MOT. I will tweek those mixture screws in a little and aim for about 4.0% CO in air keeping it 'on song'.

Many thanks Kevin.