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Anyone have advice on passing emissions inspections

68ChargerAG

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Now that I have my car all together, I have to take it for safety and emissions checks before I can register and license it.

Here is Utah 1968 and newer cars have to be inspected. I knew I should have never moved here... :black_eye:

For the safety inspection everything has to work... even the windshield sprayer.

Not sure what will happen with the emissions part. Any suggestions for passing the first time would be greatly appreciated.

I jetted the carb for this altitude, have heard that maybe it needs to be leaned out another jet size or two... does that seem necessary?

Anyone else live in a state where you have to pass emissions on pre 1970 car?
 
Considering the difference in the gas now and then, I would suspect you won't have any trouble passing emissions
 
I have heard that using a methanol blended gasoline can help, but use it only for the test...

Hmmm... I may have heard that before too. Just a a few gallons of E85 added to a full tank of regular right? Probably worth a try, we used to have an E85 station right down the street, not sure if it is there anymore.
 
We have a gas company here that sells a blend at the pump. Contains 10% ethanol. They claim it reduces emissions as it introduces oxygen into the mix during combustion, thus reducing emissions...I am no expert here FYI, but I believe the dry nature of ethanol can harm your engine if it's not designed for it...I believe a shot in the tank on the way to the gas sniffer would be ok provided you top it up with your regular blend post inspection...
 
Yes, I agree, there are other things that must be done to the fuel tank, line, and carb to run ethynol on a regular basis. I have looked into that a little before when thinking about running higher compression or forced injection. But just once per year to pass inspections would be fine I am sure... if it helps.
 
Do they sniff test or just make sure the smog parts are there? Back when I had one that would not pass a sniff test, I ran it down to less than an eighth of a tank, put in 4 bottles of heat, gas line antifreeze and a gallon of gas. Drove it hard back down and it passed. E85 should do the same thing, good luck.
 
Just dump in a 600ml bottle of methyl hydrate to 1/4 tank of fuel run your test then fill your tank to thin it out after..The methyl hydrate helps to clean out the carbon in newer cars cat's but it does burn hotter and cleaner and gives a good reading, most of the time...We use it in the shop on cars that fail and almost always the failed car will pass.The # 1 thing to do is dump in the methyl hydrate run the car nice and hot on the hwy and then drive it rite to your appointment,don't shut it off and let it cool down.And #2 don't change from you normal octaine..the last thing you want to do is change the burn time of your fuel.
 
We have a gas company here that sells a blend at the pump. Contains 10% ethanol. They claim it reduces emissions as it introduces oxygen into the mix during combustion, thus reducing emissions...I am no expert here FYI, but I believe the dry nature of ethanol can harm your engine if it's not designed for it...I believe a shot in the tank on the way to the gas sniffer would be ok provided you top it up with your regular blend post inspection...

I recall reading a Chrysler factory TSB in the late 80's about methanol and ethanol in fuel. The factory engineers at that time were saying that the ethanol blended fuels (I think in the 10% range) were okay, but said to avoid anything with methanol as it caused corrosion in the fuel system with prolonged use. Most gas stations that use "oxygenated" fuel are selling the 10% ethanol blend. Methanol is also known as wood alcohol, and is the main ingredient of Heet fuel line antifreeze. Heet is okay to use occasionally, but the engineers didn't recommend long term exposure.
 
In CA we already have up to 8% ethanol and who knows what else, but I can tell you it's nothing like it was in the 80's. The ethanol, or oxygenate, is said to effectively lean the mixture compared to real gas, so in some cases a slight increase in idle feed restrictor size may be necessary to correct the mixture. Going too lean will cause a lean misfire, which will bring up the HC value.

If you have any kind of a hotter than stock mechanical cam (i.e. increased overlap) you can loosen the valve clearance to kill some overlap. High overlap will cause high HC as well. I did this trick on my 68 RR 383 with a .528" 284 DC cam and it passed with flying colors!

Other things you can do is retard the timing and readjust the carb to compensate. This usually makes a big difference in HC and CO. Of course you should have clean oil and sharp plugs and other tune up stuff in check first. Running the proper octane fuel for your compression ratio is also advised. Basically you want the fastest burning fuel you can barely get away with.
 
Ok, this all depends.

Just take it to the test as you have it and see what they say. Most states are required to give you a specific printout of what you failed if you fail. I am not sure how they can fail that old of a car but it will come down to one of three things:

HC: Hydrocarbon or unburned fuel.
CO: Carbon Monoxide usually due to a bad catalytic converter (which our cars don't have) caused by a cool mixture.
NOX: Nitrous Oxides caused by too lean a mixture or high combustion chamber temps.

IF you fail HC, rejet the carb to run as lean as possible. Also you may want to adjust timing to get it in. Also, put three bottles of ISO-HEAT in a half-full or less tank. The Isopropyl alcohol will cause the chamber to run hotter and will not be detected as a HC. If you had a catalytic converter it would also cause it to run super-hot and solve any CO problems too.

IF you fail CO. Make sure the engine is super-hot. Like run it hard on the freeway right before testing. Of course some ISOHEAT will not hurt this either.

If you fail NOX (highly unlikely since we do not have EGR valves) you may be in trouble. High combustion temps cause this and it is hard to correct without an EGR. IF you do, you need to do the OPPOSITE of what I said above. You want the engine cool as possible and you may want to retard the timing and make it run badly to pass.

Lastly, find the smallest inspection shop you can find. One setup and run by a single guy. Tell him what you got and whether he would pass it or not. You may not have to have those wipers working after all. hint hint.

Randy
 
Ok, this all depends.

Just take it to the test as you have it and see what they say. Most states are required to give you a specific printout of what you failed if you fail. I am not sure how they can fail that old of a car but it will come down to one of three things:

HC: Hydrocarbon or unburned fuel.
CO: Carbon Monoxide usually due to a bad catalytic converter (which our cars don't have) caused by a cool mixture.
NOX: Nitrous Oxides caused by too lean a mixture or high combustion chamber temps.

IF you fail HC, rejet the carb to run as lean as possible. Also you may want to adjust timing to get it in. Also, put three bottles of ISO-HEAT in a half-full or less tank. The Isopropyl alcohol will cause the chamber to run hotter and will not be detected as a HC. If you had a catalytic converter it would also cause it to run super-hot and solve any CO problems too.

IF you fail CO. Make sure the engine is super-hot. Like run it hard on the freeway right before testing. Of course some ISOHEAT will not hurt this either.

If you fail NOX (highly unlikely since we do not have EGR valves) you may be in trouble. High combustion temps cause this and it is hard to correct without an EGR. IF you do, you need to do the OPPOSITE of what I said above. You want the engine cool as possible and you may want to retard the timing and make it run badly to pass.

Lastly, find the smallest inspection shop you can find. One setup and run by a single guy. Tell him what you got and whether he would pass it or not. You may not have to have those wipers working after all. hint hint.

Randy


As it turns out... I did this over the weekend. I didn't do anything to it and took it in just to see where I stand. I passed CO and HC very well and was way over on NOX. Nice... :edgy:

Before the inspection I had jetted the carb for this altitude (based on chart from Holley manual). It is a 750cfm so slightly large for my 383 so I wanted to ensure it wasn't pumping too much gas. So I have gone back and put the bigger ones back in now.

The engine was also running very hot so I put a cooler t-stat in and now it runs right at the line where it should.

I have read that retarding the timing causes higher temps... and that advancing timing causes higher temps... so not sure exactly what to do there. I think there is much confusion between the temp of the burn and the temp of engine due to the effects of each of these. I'm still trying to determine exactly which is right for the temp of the burn and the resultant NOX emissions.

I was running 85 octane which does seem to be bad because I do hear pinging when I get into it... so adding octane boost and will only put higher octane in from now on.

Now that I have done all this, I am going to give it another try to see where I stand. I think adding fuel, raising the octane, cooling the engine, and resetting the timing should get me at least closer...

I did pass the safety part without issue. Everything works, so no reason not to.

Thanks everyone for all the great information, I am learning quite a bit as I go through this.
 
A Holley 750 is not exactly a smog carb so you might be better off with something that resembles the factory one. Do you have access to a 500 or 625 AFB? Or even an emissions oriented Holley?

HC is raw unburned fuel and usually caused by a misfiring cylinder or an extremely weak (lean) mixture as in a vacuum leak. You can get an HC reading over a can of gas but the CO will be zero because no combustion is taking place.

CO is strictly a mixture issue and occurs from the result of a combustion process. High CO = too rich. Extremely low CO accompanied by high HC = lean.

CO2 reading of 14.7% = proper combustion. This is a peak value and it falls off to either side when the mixture is rich or lean.

O2 reading for a proper mixture should be 2%. Too high O2 = lean. Too low = rich. Looking at O2 is a good way to tune a cat equipped vehicle.

NOx (oxides of nitrogen), as stated above, is the result of high combustion chamber temps (over 1400 deg F). EGR valves, low compression, retarded timing all play a roll in reducing NOx. I look at it as anything that makes your engine run efficiently and well produces NOx.

From your latest info it sounds to me that you need to get your engine in good tune before you attempt this test again. Run it at 180-190 deg F. Keep your advance curve fairly slow and the initial as late as possible. Make sure the jetting, float level, and power valve are correct (a lean engine will ping). Octane booster will only make the problem worse because the fuel burns too slow. Unless you have something like 11:1 CR you don't need octane booster. Find out why it's pinging.
 
You are right Meep... my timing was waaaay too early. One item I have been very confused about since I started the engine up is why I wasn't seeing the timing mark anywhere close to the timing flag with a timing light... but could get the engine to idle smoothly if I just adjusted it by "feel" as I used to do with a normal stock engine. I verified that it is correct at #1 piston TDC, but when the engine was running it would run very rough or almost dye if I tried to time it to the recommended 5 deg btdc.

After much reading I figured out that I should set it to about 13 deg btdc for the cam that I have, and that it is supposed to have a lope because of the cam. My lack of experience had me timing it by "feel" to where it ran best at idle... which was somewhere between 20 - 30 deg btdc. :head_smack:

I have it timed at 13 deg btdc now and it runs very nice... and guess what... no pinging.

Man... I sure wish I had one of you guys standing here helping me get this thing tuned. I am having to learn everything the hard way. :blush:

Thanks again for all of the input.
 
Wow emmisions test on a 1968 car in Utah? Crazy. How strict are they on that?
 
Since you passed everything but NOX, plug your vacuum advance line and go get re-tested. It should pass that way unless you have the timing extremely advanced.
 
It should pass that way unless you have the timing extremely advanced.

Which I did... I am thinking more and more that this was my problem. I am going to get retested in the next day or two now that I have corrected it. Thanks.
 
Wow emmisions test on a 1968 car in Utah? Crazy. How strict are they on that?

The limits are:

%CO < 4.42 I was good at 2.55
PPM HC < 391 I was good at 133
PPM NO < 2753 I failed at 4067

Not sure how strict that is compared to other states. But I do think it is crazy to test on a 1968 car.
 
You are right Meep... my timing was waaaay too early. One item I have been very confused about since I started the engine up is why I wasn't seeing the timing mark anywhere close to the timing flag with a timing light... but could get the engine to idle smoothly if I just adjusted it by "feel" as I used to do with a normal stock engine. I verified that it is correct at #1 piston TDC, but when the engine was running it would run very rough or almost dye if I tried to time it to the recommended 5 deg btdc.

After much reading I figured out that I should set it to about 13 deg btdc for the cam that I have, and that it is supposed to have a lope because of the cam. My lack of experience had me timing it by "feel" to where it ran best at idle... which was somewhere between 20 - 30 deg btdc. :head_smack:

I have it timed at 13 deg btdc now and it runs very nice... and guess what... no pinging.

Man... I sure wish I had one of you guys standing here helping me get this thing tuned. I am having to learn everything the hard way. :blush:

Thanks again for all of the input.


Nothing wrong with learning things the hard way. I still do it :grin: Glad you are on track to getting this test behind you.
 
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