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pablovent Samba Member
Joined: July 14, 2010 Posts: 900 Location: Chile
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Posted: Sat Feb 24, 2018 7:55 am Post subject: What is the correct way to decrease the CO? |
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Hello ;
I am running the first miles with my Westy 1978 engine code CJ type4 2.0, dual 32-34 pdsit completely rebuilt (stock cam, stock CR, stock carbs) all seals and hose perfect .... In the first emission control the numbers were:
-Idle: HC 145 ppm - CO 6.34
-2.500 rpms: HC 152 ppm - CO 6.56
This numbers show aparently a fuel mixture too rich.....Before the emission control the carburetors were tuned without a machine (best idle run), and the timing with strobo light 5º BTDC iddle - 30º BTDC max at 3200 rpms.
For decrease the CO numbers and carburetors tune up work, will be necessary to reduce the jets size?.
Thanks...
Last edited by pablovent on Sun Feb 25, 2018 4:43 am; edited 3 times in total |
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williamM Samba Member
Joined: August 07, 2008 Posts: 4333 Location: southwest Arizona
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Posted: Sat Feb 24, 2018 8:03 am Post subject: Re: stock type4 2.0 carbureted emmision control failled |
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before doing much, I would go over the settings on you linkage,run the timing back a few degrees, get the motor broke in a bit and make sure your chokes are completely opening.
My fiat wouldn't come down on CO so we finally ended up dropping a cat into the exhaust- never did find out what was wrong. _________________ some days I get up and just sit and think. Some days I just sit.
opinion untempered by fact is ignorance.
Don't step in any! |
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pablovent Samba Member
Joined: July 14, 2010 Posts: 900 Location: Chile
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Posted: Sat Feb 24, 2018 8:20 am Post subject: Re: stock type4 2.0 carbureted emmision control failled |
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williamM wrote: |
before doing much, I would go over the settings on you linkage,run the timing back a few degrees, get the motor broke in a bit and make sure your chokes are completely opening.
My fiat wouldn't come down on CO so we finally ended up dropping a cat into the exhaust- never did find out what was wrong. |
Yes, linkage setting fine, dual carbs sync with empi tool and chokes 100% open....engine run hot to 210º oil temps. |
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williamM Samba Member
Joined: August 07, 2008 Posts: 4333 Location: southwest Arizona
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Posted: Sat Feb 24, 2018 8:26 am Post subject: Re: stock type4 2.0 carbureted emmision control failled |
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any spec's on what the carbs are now- got pics of your set up. _________________ some days I get up and just sit and think. Some days I just sit.
opinion untempered by fact is ignorance.
Don't step in any! |
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pablovent Samba Member
Joined: July 14, 2010 Posts: 900 Location: Chile
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Posted: Sat Feb 24, 2018 8:31 am Post subject: Re: stock type4 2.0 carbureted emmision control failled |
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55 idles, 140 mains, stock airs 155, 93 RON fuel....Sparks plugs looks very clean white and light brown....stock central air cleaner, stock style muffler, unfortunately I can not use a wideband because the exhaust system. |
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williamM Samba Member
Joined: August 07, 2008 Posts: 4333 Location: southwest Arizona
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Posted: Sat Feb 24, 2018 8:45 am Post subject: Re: stock type4 2.0 carbureted emmision control failled |
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It will be a while but I have a few of those, so can see what hey actually ran, there maybe a section in the "Technical" section here, or in the "without guesswork" books - probably from 73, as a 2.0 in USA T-4 motor had FI system. _________________ some days I get up and just sit and think. Some days I just sit.
opinion untempered by fact is ignorance.
Don't step in any! |
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pablovent Samba Member
Joined: July 14, 2010 Posts: 900 Location: Chile
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Posted: Sat Feb 24, 2018 10:10 am Post subject: Re: stock type4 2.0 carbureted emmision control failled |
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Yes...this is the problem, my CJ type4 engine code not sale in USA with carbs.....stock jetting info 52,5 idles, 135 mains, 155 airs....
MY engine run really fine...the HC numbers are too small maybe will increase this numbers when decrease the CO...Just only I look for other similar tune up experiences! |
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Abscate Samba Member
Joined: October 05, 2014 Posts: 22648 Location: NYC/Upstate/ROW
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Posted: Sat Feb 24, 2018 3:57 pm Post subject: Re: What is the correct way to lower the CO? |
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Failing to salute in front of the Corporal... _________________ .ssS! |
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raygreenwood Samba Member
Joined: November 24, 2008 Posts: 21513 Location: Oklahoma City
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Posted: Sat Feb 24, 2018 4:35 pm Post subject: Re: What is the correct way to lower the CO? |
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If this is a brand new engine.....do not worry about CO and fine tuning yet. Synch the carbs and make sure its neither excessively rich or lean.
Yes....the cam and lifters break in in 20-30 minutes.....but I have found the rings can take upwards to a few thousand miles of running to REALLY get sealed. Ray |
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Tram Samba Socialist
Joined: May 02, 2003 Posts: 22711 Location: Still Feelin' the Bern- Once you've felt it you can't un- feel it.
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Posted: Sat Feb 24, 2018 4:40 pm Post subject: Re: stock type4 2.0 carbureted emmision control failled |
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pablovent wrote: |
Yes...this is the problem, my CJ type4 engine code not sale in USA with carbs.....stock jetting info 52,5 idles, 135 mains, 155 airs....
MY engine run really fine...the HC numbers are too small maybe will increase this numbers when decrease the CO...Just only I look for other similar tune up experiences! |
Yes, you are running into the common problem that a lot of people in the USA who have to have their classic cars checked have... modern emissions standards vs. cars that were built before they were mandated. It's ridiculous.
First thing I would suggest is to research and call around to see if there is a way your car can be exempted since it's all original stock configurations, in good repair, but still cannot pass emissions.
The problem you will have is that once you get your engine to where it will pass emissions, the changes you will make will very likely cause the engine to run poorly, too lean, and too hot.
If you change jets to pass emissions, you'll likely want to change them back once you get certification. _________________ Немає виправдання для війни! Я з Україною.
Bryan67 wrote: |
Just my hands. And a little lube. No tools. |
To best contact me, please use the EMAIL function in my profile |
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kevineo Samba Member
Joined: May 09, 2011 Posts: 49
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Posted: Sat Feb 24, 2018 4:50 pm Post subject: Re: What is the correct way to lower the CO? |
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Drop yours, install a buddies motor that passes. Re-install yours and break it in properly. Unfortunately skirting the law is the sane move. Do not, Do not try to get exempted! When your denied you will be flagged for life. |
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pablovent Samba Member
Joined: July 14, 2010 Posts: 900 Location: Chile
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Posted: Sat Feb 24, 2018 5:16 pm Post subject: Re: What is the correct way to lower the CO? |
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My preference is the best air/fuel mixture for the first miles after rebuilt work...the emission control was only for this reason.....just I want not run too lean and not run too reach....Now is summer in my country and run too hot is very risky for a heavy bus.....thanks |
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scubaseas Samba Member
Joined: May 24, 2013 Posts: 442 Location: ME & Texas, in a Bus or on a boat somewhere
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Posted: Sat Feb 24, 2018 6:05 pm Post subject: Re: What is the correct way to lower the CO? |
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Quote: |
For decrease the CO numbers and carburetors tune up work, will be necessary to reduce the jets size?. |
Probably not. Retard timing 5* to 0*TDC/25*BTDC @ 3200 . it should drop about 2 off the CO. If this is a new motor you need to drive it at least 10? hours at highway speeds before testing.
You may be too lean. Your HC numbers are low and your CO is high so it may be running lean at idle. Back out the idle mixture screw 1/4 turn and see if the CO drops.
You really need a wide band mixture tool/machine to tell you if your jets are the right size and if you may be running too hot. A Cylinder Head Temperature gauge would also be a good idea.
What number do you have to reach to pass? _________________ Al
08/1970 T2a Westphalia owned since 1980
ASE Master certification. 50 years pushing a wrench
Retired |
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scubaseas Samba Member
Joined: May 24, 2013 Posts: 442 Location: ME & Texas, in a Bus or on a boat somewhere
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SGKent Samba Member
Joined: October 30, 2007 Posts: 41031 Location: Citrus Heights CA (Near Sacramento)
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Posted: Sat Feb 24, 2018 8:27 pm Post subject: Re: What is the correct way to lower the CO? |
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does Chili have smog tests on cars that old? _________________ “Most people don’t know what they’re doing, and a lot of them are really good at it.” - George Carlin |
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pablovent Samba Member
Joined: July 14, 2010 Posts: 900 Location: Chile
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Posted: Sun Feb 25, 2018 5:00 am Post subject: Re: What is the correct way to lower the CO? |
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[quote="scubaseas"]
Quote: |
What number do you have to reach to pass? |
SGKent wrote: |
does Chili have smog tests on cars that old? |
Thank you....In my country for old cars (old classic & carbureted up to´93) the emission control requirement must be done every 4 months and is measured in idle, 2500 rpms and 2500 rpms with a roller machine ..... The max numbers are only two: 800 HC and 4.5 CO%.
In my city (Santiago - 1.800 feet elevation)) unfortunately in winter times we have high pollution levels, so the old cars use in winter is restricted only to weekends.
But I just want the best and happy engine health, in the past I reheated my old engine (melted piston), also I had problems with high temperatures and valve seats dropped, so I want to stay in the safe zone timings and air / fuel ratio.
Best.
Last edited by pablovent on Sun Feb 25, 2018 5:32 am; edited 2 times in total |
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pablovent Samba Member
Joined: July 14, 2010 Posts: 900 Location: Chile
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Posted: Sun Feb 25, 2018 5:21 am Post subject: Re: What is the correct way to lower the CO? |
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Thanks for the additional info!! |
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scubaseas Samba Member
Joined: May 24, 2013 Posts: 442 Location: ME & Texas, in a Bus or on a boat somewhere
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Posted: Sun Feb 25, 2018 6:37 am Post subject: Re: What is the correct way to decrease the CO? |
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Quote: |
Thanks for the additional info!! |
De nada. más para usted
http://www.ratwell.com/technical/VDOGauges.html#cht
If you have melted a piston and dropped valve seats you definitely need to check your jetting and cooling system. And get a CHT to monitor things so it doesn't happen again.
https://www.thesamba.com/vw/forum/viewtopic.php?t=293837 _________________ Al
08/1970 T2a Westphalia owned since 1980
ASE Master certification. 50 years pushing a wrench
Retired |
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Wildthings Samba Member
Joined: March 13, 2005 Posts: 50338
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Posted: Sun Feb 25, 2018 9:27 am Post subject: Re: What is the correct way to decrease the CO? |
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I think you will have a hard time getting the HC dialed in until you get the engine broken in. I would try retarding the timing by a few degrees as that is very easy to do and is very readily reversible.
Assuming you have the carbs synched well:
-your idle mixture is controlled by the idle jet and the idle screw.
-low throttle opening mixtures are controlled primarily by the idle jet
and
-larger throttle openings mixtures are controlled by the main jets. |
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SGKent Samba Member
Joined: October 30, 2007 Posts: 41031 Location: Citrus Heights CA (Near Sacramento)
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Posted: Sun Feb 25, 2018 11:13 am Post subject: Re: What is the correct way to decrease the CO? |
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turn the idle mixture screw out on each carb just until the engine runs smoothly then slowly turn each one in until the RPM begins to drop quickly, then turn it back out 1/8th turn. Then sync the carbs and test again. If the engine hesitates when you step on the gas, open the idle mixture screws a 1/8 turn more. Set your timing so it is at 30 - 31 degrees before TDC at 3500 - 3800 RPM with any hoses off the distributor then put them back . See how that tests. If the CO is still too high turn the idle mixture screw in 1/16th turn at a time and try again. Make sure that ALL vacuum leaks are found and fixed before you start this. _________________ “Most people don’t know what they’re doing, and a lot of them are really good at it.” - George Carlin |
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