Hydrocarbons and engine temp?
Thread Starter
Racer
Joined: Sep 2005
Posts: 260
Likes: 0
From: Wheaton Illinois
Hydrocarbons and engine temp?
I just failed the emisions test on my 76 L-82. My hydrocarbons were 1450 and they need to be 700. I just put a new exhaust on the car a month ago (before my emisions test). I put a true 2 1/2" dual system with dual cats.
When I bought the car last year the engine temp was running 210 or more so I replaced the thermostat with a 160 deg. That didn't really help the car run cooler so I installed a DeWitt aluminum radiator. The new rad work great but I never replaced the thermostat. The car ran a pretty consistant 160 deg all summer.
Finally to my question. What tempurature thermostat should I run to get the most complete combustion/ lowest hydrocarbons?
Thanks
When I bought the car last year the engine temp was running 210 or more so I replaced the thermostat with a 160 deg. That didn't really help the car run cooler so I installed a DeWitt aluminum radiator. The new rad work great but I never replaced the thermostat. The car ran a pretty consistant 160 deg all summer.
Finally to my question. What tempurature thermostat should I run to get the most complete combustion/ lowest hydrocarbons?
Thanks
Thread Starter
Racer
Joined: Sep 2005
Posts: 260
Likes: 0
From: Wheaton Illinois
Originally Posted by rihwoods
Also...do a fresh oil change and get those cats good and hot by running on the highway just before test...
Good luck..
Rich
Good luck..
Rich
Drifting
Joined: Jul 2002
Posts: 1,943
Likes: 1
From: Rosemount MN
Originally Posted by rihwoods
Also...do a fresh oil change and get those cats good and hot by running on the highway just before test...
Good luck..
Rich
Good luck..
Rich
Le Mans Master
Joined: Apr 2004
Posts: 7,106
Likes: 38
From: Newark DE
a 160º t-stat is too low!!
the factory t-stat was a 195º and the reason was that the higher temps reduced emissions by helping to burn off excess vapors.
to pass emissions you should replace it with another 195º r-stat. A 1800º may or may not be enough to get you thru the testing.
i'd reinstall a 195º t-stat to pass your emissions. Afterwards you can either leave it in or replace it again with a 180º t-stat if you prefer.
In either case there is no reason at all to ever run a 160º t-stat in the car. That temp is too low and can help to form sludge in the oil by not having a high enough operating temp to burn off condensation that can formand that condensation gets into the oil forming sludge.
Get rid of the 160º t-stat, change your oil, and install a 195º t-stat to pass emiisions.
After you pass leave the 195º or replace it with a 180º - your choice but realize that there is NOTHING wrong with operating temps in the 195º-210º range as that was where the car was actually designed to operate.
the factory t-stat was a 195º and the reason was that the higher temps reduced emissions by helping to burn off excess vapors.
to pass emissions you should replace it with another 195º r-stat. A 1800º may or may not be enough to get you thru the testing.
i'd reinstall a 195º t-stat to pass your emissions. Afterwards you can either leave it in or replace it again with a 180º t-stat if you prefer.
In either case there is no reason at all to ever run a 160º t-stat in the car. That temp is too low and can help to form sludge in the oil by not having a high enough operating temp to burn off condensation that can formand that condensation gets into the oil forming sludge.
Get rid of the 160º t-stat, change your oil, and install a 195º t-stat to pass emiisions.
After you pass leave the 195º or replace it with a 180º - your choice but realize that there is NOTHING wrong with operating temps in the 195º-210º range as that was where the car was actually designed to operate.
Thread Starter
Racer
Joined: Sep 2005
Posts: 260
Likes: 0
From: Wheaton Illinois
I passed my emmisions test yesterday. I got the hydrocarbons to 474 a 1000 drop. I changed the thermostate to a 195 deg as sugested. I also changed spark plugs, set timing back to factory specs, adjusted carb and got the centrifical advance to work again.
Thanks for your help.
Thanks for your help.
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Le Mans Master
Joined: Apr 2004
Posts: 7,106
Likes: 38
From: Newark DE
congrats on passing emissions! 
I don't know about your state but where I live there is a "rolling" emiisions requirement. The car only has to pass emissions level for the year it was produced so for esample my '78 only has to pass what the requirements were in '78. my '65 doesn't have to pass any requirements at all!
Kinda interesting to find that passing emissions was easy once you reverted that car back to basically the factory stock condition with the correct t-stat, factory timing specs, etc.
Yep, the factory knew what it was going and it did the things they did for a reason......... on the mid to late 70's cars with all the early emissions stuff they did the factory may have sucked all the power out of the cars but they did know how to get them past the federal requirements
I don't know about your state but where I live there is a "rolling" emiisions requirement. The car only has to pass emissions level for the year it was produced so for esample my '78 only has to pass what the requirements were in '78. my '65 doesn't have to pass any requirements at all!
Kinda interesting to find that passing emissions was easy once you reverted that car back to basically the factory stock condition with the correct t-stat, factory timing specs, etc.
Yep, the factory knew what it was going and it did the things they did for a reason......... on the mid to late 70's cars with all the early emissions stuff they did the factory may have sucked all the power out of the cars but they did know how to get them past the federal requirements
Team Owner
Joined: Oct 2004
Posts: 23,831
Likes: 10
From: Springfield MO
St. Jude Donor '07
Originally Posted by BarryK
I don't know about your state but where I live there is a "rolling" emiisions requirement. The car only has to pass emissions level for the year it was produced so for esample my '78 only has to pass what the requirements were in '78. my '65 doesn't have to pass any requirements at all!
Le Mans Master
Joined: Apr 2004
Posts: 7,106
Likes: 38
From: Newark DE
Batman
generally I believe that is true, but I mentioned "my state" because although I may be incorrect on this I think that some states are slightly different and after 25 years may not require emissions testing at all? Don't some states say say after 25 years that a vehicle is exempt from emiisions tests? Like I said, I may be wrong on that.
generally I believe that is true, but I mentioned "my state" because although I may be incorrect on this I think that some states are slightly different and after 25 years may not require emissions testing at all? Don't some states say say after 25 years that a vehicle is exempt from emiisions tests? Like I said, I may be wrong on that.
Racer
Joined: Mar 2006
Posts: 366
Likes: 1
From: Houston Texas
You are right Barryk.
In Texas, not all counties even have emissions testing. For those that do, 25 years+ are exempt. You only have to have the 'original' emissions equipment to pass. Some of the counties do have roving 'sniffers' and can issue a ticket if you are over the limits, but you don't have to pass as part of the annual inspection.
In Texas, not all counties even have emissions testing. For those that do, 25 years+ are exempt. You only have to have the 'original' emissions equipment to pass. Some of the counties do have roving 'sniffers' and can issue a ticket if you are over the limits, but you don't have to pass as part of the annual inspection.
Team Owner
Joined: Oct 2004
Posts: 23,831
Likes: 10
From: Springfield MO
St. Jude Donor '07
Originally Posted by BarryK
Batman
generally I believe that is true, but I mentioned "my state" because although I may be incorrect on this I think that some states are slightly different and after 25 years may not require emissions testing at all? Don't some states say say after 25 years that a vehicle is exempt from emiisions tests? Like I said, I may be wrong on that.
generally I believe that is true, but I mentioned "my state" because although I may be incorrect on this I think that some states are slightly different and after 25 years may not require emissions testing at all? Don't some states say say after 25 years that a vehicle is exempt from emiisions tests? Like I said, I may be wrong on that.
Safety Car
Joined: Dec 2004
Posts: 4,071
Likes: 0
From: San Diego CA
They only require testing in areas that are prone to bad air quality. If the air quality results fluctuate a ton all the time they generally don't require smog testing because it's just added burden on the state and it doesn't make any difference. If the air quality is constantly not so good they will require smog testing because they need it. States will generally exempt cars 25+ years and older because few people drive cars that old and most that actually have them are secondary/collector cars that aren't gross polluters.
Also, areas that have a low population density are generally exempt from smog. In California, if you live 50+ miles from the nearest DMV you are not required to have your car tested for emissions every other year. In Arizona, if you live outside of metro Tucson or Phoenix you can request exemption and if you live outside Pima and whatever county Phoenix is in, you are exempt.
Also, areas that have a low population density are generally exempt from smog. In California, if you live 50+ miles from the nearest DMV you are not required to have your car tested for emissions every other year. In Arizona, if you live outside of metro Tucson or Phoenix you can request exemption and if you live outside Pima and whatever county Phoenix is in, you are exempt.
Drifting
Joined: Sep 2004
Posts: 1,532
Likes: 4
From: Fairview Heights Illinois, near Saint Louis MO, STL C3 Shark
glad you passed your emissions test. I bet the winning factors were these:
1) Higher water temp
2) factory timing specs
My guess is that for performance you have advanced the timing some (or a whole lot). By retarding it back to factory specs, it causes a hotter exhaust gas in the manifolds and exhaust to aid in burning those HCs
I've got my 76 registered as a antique vehicle so I'm exempt from the Saint Louis Metro area emissions testing.
1) Higher water temp
2) factory timing specs
My guess is that for performance you have advanced the timing some (or a whole lot). By retarding it back to factory specs, it causes a hotter exhaust gas in the manifolds and exhaust to aid in burning those HCs
I've got my 76 registered as a antique vehicle so I'm exempt from the Saint Louis Metro area emissions testing.
Team Owner
Joined: Oct 2004
Posts: 23,831
Likes: 10
From: Springfield MO
St. Jude Donor '07
Originally Posted by ruby76
I've got my 76 registered as a antique vehicle so I'm exempt from the Saint Louis Metro area emissions testing.
Thread Starter
Racer
Joined: Sep 2005
Posts: 260
Likes: 0
From: Wheaton Illinois
Originally Posted by ruby76
glad you passed your emissions test. I bet the winning factors were these:
1) Higher water temp
2) factory timing specs
My guess is that for performance you have advanced the timing some (or a whole lot). By retarding it back to factory specs, it causes a hotter exhaust gas in the manifolds and exhaust to aid in burning those HCs
1) Higher water temp
2) factory timing specs
My guess is that for performance you have advanced the timing some (or a whole lot). By retarding it back to factory specs, it causes a hotter exhaust gas in the manifolds and exhaust to aid in burning those HCs
Since the car was not all that quick before I think I will run these settings for a while. I might even get my gas mileage into double digits.