Another likely fail on emissions - Vauxhall 1800 8v on twin webers

[Martin Moxon]

In today for MOT and a couple of other bits. Fortunately mechanic is a good guy who runs an emissions test before doing MOT to find my emissions were way too high - it's not been running too great recently.

 

He's hung on to it to try to sort it (I wouldn't be able to use it this weekend anyway) and needs the following

 

Vx 1800, 8 valve on twin weber DCOE 40's - basic settings after strip down for mixture screws

 

I'll have a look on the tech section on here for webers but being somewhat on the side of technical numptys might miss something so would appreciate being pointed in the right direction or just given the answer.

 

Martin Moxon

Not the Cricketer

[chris perry 1]

Hello,

 

My 2002 1600 8V VX failed its MOT on emissions a few weeks ago. It was reading CO = 4.5, HC = 1400.

 

This week i went to Aldon Automotive in Stourbridge who have a rolling road and set my Webers up for me. What a difference!

 

We also re jetted at the same time.

 

As caterham supplied:

 

Main = 115

Air Corrector = 195

Choke = 30

Idle = 50F6

Air Valve = 4.5

Emulsion Tube = F7

 

Now:

 

Main = 120

Air Corrector = 170

Choke = 30

Idle 50F6

Air Valve = 4.5

Emulsion Tube = F16

 

The 50F6 idle jet as caterham supplied is rich. We tried a 45F9 but it was too week. Aldon adjusted the 50F6 idle jet screws and achieved CO = 3.0, HC = 0 which will pass the MOT emissions test. So it can be done.

 

On the rolling road it made 101 bhp @ 5200 rpm and 120 lb ft torque @ 3250 rpm. (120 thats the same as an 1800 K series!)

 

You could try balancing the carbs and check the air through each choke is the same with an air flow metre. Also clean the air filters with the K&N cleaner kit. It really is very small adjustments on the idle mixture screws that make all the difference.

 

I can recommend taking it to a rolling road to have them set up professionally, my car runs considerabley better than it did before.

 

Hope this helps!

 

Chris Perry

 

Edited by - chris perry on 2 May 2009 11:51:13