Emissions

Tips and help requests for your cars mechanics. points gaps, timming settings all those sorts of things

Emissions

Postby HC Fairley » Wed Jun 05, 2019 9:32 am

On the topic of MOT's I had one yesterday. While the Viva did pass :hapbirthday3: , the hydrocarbons were very high :scared3:
I have a single Stromberg CD150 screwed fully in but can't seem to get the hydrocarbons down far enough. This has been a problem the last 3 times I have went to MOT. Can anyone provide any advice on how to get the hydrocarbons lowered ?
HC Fairley
GT Viva
GT Viva
 
Posts: 111
Joined: Sun Mar 01, 2015 3:19 pm
Location: Ballynahinch, Northern Ireland

Re: Emissions

Postby 1972nail » Wed Jun 05, 2019 11:02 am

The fuel in the carb is not the only producer of hydrocarbons the engine oil also contributes. An oil change just before the test may help. Temporary fixes include a few extra degrees on the timing may raise cylinder temperatures enough to burn some more and removing the air filter.
Editor of the VVOC Magazine ReVival

"When you have a Firenza like mine, who needs any Minis?" copyright David Maxwell 1979.
User avatar
1972nail
Old Nail
Old Nail
 
Posts: 3354
Joined: Sun Aug 07, 2011 4:16 pm
Location: Ballymoney Co Antrim - some say....the World's best place to live!

Re: Emissions

Postby HC Fairley » Wed Jun 05, 2019 2:28 pm

I'll look into that, didn't realise the oil played a part in it :jawcropyel:
HC Fairley
GT Viva
GT Viva
 
Posts: 111
Joined: Sun Mar 01, 2015 3:19 pm
Location: Ballynahinch, Northern Ireland

Re: Emissions

Postby droopsnoot » Wed Jun 05, 2019 6:24 pm

When I had excessive hydrocarbons on the Firenza, the tester suggested looking for air leaks in the inlet side.

I spent ages removing the carbs from the manifold, checking the O-rings, putting them back, balancing them, then as I was doing that last bit, I noticed the massive hole on the side of the servo pipe that wasn't visible from the front of the car.
My real name: Mike. My web site: http://www.firenza.net

My stuff for sale: http://www.firenza.net/forsale.shtml
droopsnoot
Old Nail
Old Nail
 
Posts: 2308
Joined: Mon Oct 31, 2005 2:08 pm
Location: Cheshire

Re: Emissions

Postby HC Fairley » Thu Jun 06, 2019 8:51 am

Sounds like a thorough inspection is required tonight then. The car runs good but this has been a recurring MOT problem the last 3 years. :wutend: :hissyfit:
HC Fairley
GT Viva
GT Viva
 
Posts: 111
Joined: Sun Mar 01, 2015 3:19 pm
Location: Ballynahinch, Northern Ireland

Re: Emissions

Postby 1972nail » Sun Jun 09, 2019 10:27 am

just had an idea when posting on another thread. Your air filter will probably be the long rectangular type with a vacuum controlled hot air flap. You'll need to check all the vacuum pipes in that system for leaks and tight connections. Any air leak in this system will cause a slightly weak mixture which will be harder to ignite and cause higher emissions.
Editor of the VVOC Magazine ReVival

"When you have a Firenza like mine, who needs any Minis?" copyright David Maxwell 1979.
User avatar
1972nail
Old Nail
Old Nail
 
Posts: 3354
Joined: Sun Aug 07, 2011 4:16 pm
Location: Ballymoney Co Antrim - some say....the World's best place to live!

Re: Emissions

Postby HC Fairley » Mon Jun 10, 2019 11:54 am

Yes it is the long rectangular type. I took a look at the pipes and don't see anything glaringly obvious but I will take a closer inspection within the next few days when I get a chance.
HC Fairley
GT Viva
GT Viva
 
Posts: 111
Joined: Sun Mar 01, 2015 3:19 pm
Location: Ballynahinch, Northern Ireland

Re: Emissions

Postby 1972nail » Mon Jun 10, 2019 12:47 pm

They also need to be connected up the correct way round. The one that connects the system to the carb is the most likely one to fail. I'll look out the info in the manual when I get time.
Editor of the VVOC Magazine ReVival

"When you have a Firenza like mine, who needs any Minis?" copyright David Maxwell 1979.
User avatar
1972nail
Old Nail
Old Nail
 
Posts: 3354
Joined: Sun Aug 07, 2011 4:16 pm
Location: Ballymoney Co Antrim - some say....the World's best place to live!


Return to Mechanical

Who is online

Users browsing this forum: No registered users and 1 guest