The cam selection was a web 119 0n a 105 degree lobe center, overlap is not a concern, as the vacuum signal is promoted by the static compression ratio...
some days engines run cleaner than other, barometric pressure and temperature makle a huge diffference even on the same day..
------------------
Jake Raby
Raby's Aircooled Technology
www.aircooledtechnology.com
I failed emissions!
-
Marc
- Moderator
- Posts: 23741
- Joined: Thu May 23, 2002 12:01 am
I failed emissions!
I think you'll find that a 108° lobe center will run cleaner at idle than a 105° with any grind - overlap is directly tied to HC emissions, regardless of the CR or vacuum.
I've sniffed the same engine with a Web 121 on 108 and on 105 (just out of curiosity, it was a race engine and didn't need to pass emissions) and the 105 was much dirtier.
I've sniffed the same engine with a Web 121 on 108 and on 105 (just out of curiosity, it was a race engine and didn't need to pass emissions) and the 105 was much dirtier.
-
Bruce2
- Posts: 7094
- Joined: Sat Oct 13, 2001 1:01 am
I failed emissions!
The problem is not the cam. If Jake says he used a WEB 119, that only has 240 deg of duration @ .050". Even if it was a WEB 110 at 256 deg, it should be able to be made to pass. I used an Engle W125 (262 deg) in a 2110 with 48 IDAs a few years ago and passed even tougher numbers than thinger has to deal with.
Thinger's problem is probably several things. First, I think he has the idle mixture set too rich. It should be leaned out to around 2-2.5%CO. This will bring down all the numbers at idle and driving. But there's a limit to how low you can go. Too far and the mixture gets too lean for the ignition to fire it, causing HC to skyrocket.
What's your idle timing (and total) set to? If too much advance, the HC goes up.
Beware of setting your idle speed too high. Where I live, they have sensors near the dynos that pick up the electric field generated by your ignition, and divide by the number of cyls to get idle speed. The sensors are fixed to the wall, so people think they don't test for idle speed anymore, until they fail. Maybe bump it up to 1000 rpm.
The tire diameter suggestion is good. Some places will shift into 3rd gear if the Rs exceed 3k in 2nd. If they are doing that, ask if you are allowed to request they stay in 2nd. Otherwise, taller tires will do it.
Thinger's problem is probably several things. First, I think he has the idle mixture set too rich. It should be leaned out to around 2-2.5%CO. This will bring down all the numbers at idle and driving. But there's a limit to how low you can go. Too far and the mixture gets too lean for the ignition to fire it, causing HC to skyrocket.
What's your idle timing (and total) set to? If too much advance, the HC goes up.
Beware of setting your idle speed too high. Where I live, they have sensors near the dynos that pick up the electric field generated by your ignition, and divide by the number of cyls to get idle speed. The sensors are fixed to the wall, so people think they don't test for idle speed anymore, until they fail. Maybe bump it up to 1000 rpm.
The tire diameter suggestion is good. Some places will shift into 3rd gear if the Rs exceed 3k in 2nd. If they are doing that, ask if you are allowed to request they stay in 2nd. Otherwise, taller tires will do it.
-
MASSIVE TYPE IV
- Posts: 20132
- Joined: Fri Jul 07, 2000 12:01 am
I failed emissions!
I have full confidence the problem is the carbs....
------------------
Jake Raby
Raby's Aircooled Technology
www.aircooledtechnology.com
------------------
Jake Raby
Raby's Aircooled Technology
www.aircooledtechnology.com
-
Paul Kipta
- Posts: 71
- Joined: Mon Apr 15, 2002 1:01 am
I failed emissions!
I was concerned about passing, I have one of Jakes engines. With a Web 119 cam. I did get the Amoco gas and ran it hard. Passed in all catagories, well under the allowable limits, in fact I ran only 25% of the allowable limits. I'm running Webbers, and spent some time with them prior to taking the test.
Spend time with the carbs.
Spend time with the carbs.
-
thinger
- Posts: 123
- Joined: Mon May 20, 2002 12:01 am
I failed emissions!
I guess I could try putting the 55 idle jets back in. I think I've got the 60's in there now. The problem was that last time I put them in, the car went so lean I was afraid I was going to burn up the motor.
I'll probably take it in latter this week.
I'll probably take it in latter this week.
-
Bruce2
- Posts: 7094
- Joined: Sat Oct 13, 2001 1:01 am
I failed emissions!
The CO you scored on the dyno tells you the effect of the idle jet. Since your driving CO is on the high side, going smaller on the idle jet is the right thing to do.
Although the main jet is not tested by the smog guys, I think the supplied main jet in Kadrons is too big. I swapped out the 130s in favour of 122.5s at sea level. At your elevation you should be able to go at least to a 127.5 without any danger of being lean. A 127.5 can be found in some 34 PICT stock carbs.
Here's some basics:
The idle CO is the result of where you have the idle mixture screws.
The driving CO is the effect of the idle jet (since the test is at around 25mph in 2nd, you aren't on the main cct yet)
The HC is what your engine does with the mixture fed to it.
[This message has been edited by Bruce2 (edited 07-22-2002).]
Although the main jet is not tested by the smog guys, I think the supplied main jet in Kadrons is too big. I swapped out the 130s in favour of 122.5s at sea level. At your elevation you should be able to go at least to a 127.5 without any danger of being lean. A 127.5 can be found in some 34 PICT stock carbs.
Here's some basics:
The idle CO is the result of where you have the idle mixture screws.
The driving CO is the effect of the idle jet (since the test is at around 25mph in 2nd, you aren't on the main cct yet)
The HC is what your engine does with the mixture fed to it.
[This message has been edited by Bruce2 (edited 07-22-2002).]