Jump to content


Photo
- - - - -

Pollution Test Hc Count


  • Please log in to reply
12 replies to this topic

#1 dotmatrix

dotmatrix

    Mini Mad

  • Members
  • PipPipPipPip
  • 288 posts
  • Location: Vejle

Posted 08 March 2019 - 09:33 AM

What is the normal HC count for a healthy a-series with a correctly timed md266 cam?

#2 ACDodd

ACDodd

    Up Into Fourth

  • Mini Docs
  • PipPipPipPipPipPipPipPipPip
  • 2,214 posts

Posted 08 March 2019 - 01:16 PM

About 500 to 600hc's

Ac

#3 dotmatrix

dotmatrix

    Mini Mad

  • Members
  • PipPipPipPip
  • 288 posts
  • Location: Vejle

Posted 09 March 2019 - 12:46 AM

About 500 to 600hc's

Ac


Great. Thanks. Mine was 1600 with low co so i suspect Worn chain and oil rings.

#4 KernowCooper

KernowCooper

    Sparkie

  • Mini Docs
  • PipPipPipPipPipPipPipPipPipPip
  • 7,815 posts
  • Name: Dave
  • Location: The South West
  • Local Club: Kernow Mini Club

Posted 09 March 2019 - 08:34 PM

Low CO will cause high Hc  reading, do a engine tune and then re test is what I'd do first


Edited by KernowCooper, 09 March 2019 - 08:34 PM.


#5 ACDodd

ACDodd

    Up Into Fourth

  • Mini Docs
  • PipPipPipPipPipPipPipPipPip
  • 2,214 posts

Posted 10 March 2019 - 08:39 AM

Also too much vacuum advance at idle will cause this. It's not uncommon to reduce the HC count by half, by removing and plugging the carb vacuum line to the dizzy. The long term solution in this case is a ported vac take off mod for your carb.

Ac

#6 unburntfuelinthemorning

unburntfuelinthemorning

    One Carb Or Two?

  • TMF+ Member
  • PipPipPipPipPipPipPip
  • 1,239 posts
  • Location: Bedfordshire

Posted 10 March 2019 - 03:59 PM

Also too much vacuum advance at idle will cause this. It's not uncommon to reduce the HC count by half, by removing and plugging the carb vacuum line to the dizzy. The long term solution in this case is a ported vac take off mod for your carb.

Ac

Why is it later SUs seem to have a vacuum take off which gives manifold vacuum so loads of advance at idle speed? 



#7 ACDodd

ACDodd

    Up Into Fourth

  • Mini Docs
  • PipPipPipPipPipPipPipPipPip
  • 2,214 posts

Posted 10 March 2019 - 04:59 PM

I think it's to do with retarded mechanical advance with the high compression ratios employed in factory engines.

Ac

#8 dotmatrix

dotmatrix

    Mini Mad

  • Members
  • PipPipPipPip
  • 288 posts
  • Location: Vejle

Posted 10 March 2019 - 05:40 PM

Low CO will cause high Hc reading, do a engine tune and then re test is what I'd do first


HC count did not change within Range i adjusted the co

#9 dotmatrix

dotmatrix

    Mini Mad

  • Members
  • PipPipPipPip
  • 288 posts
  • Location: Vejle

Posted 10 March 2019 - 05:42 PM

Also too much vacuum advance at idle will cause this. It's not uncommon to reduce the HC count by half, by removing and plugging the carb vacuum line to the dizzy. The long term solution in this case is a ported vac take off mod for your carb.

Ac


In what way should the vac takeoff be ported? Havent heard og This before

#10 unburntfuelinthemorning

unburntfuelinthemorning

    One Carb Or Two?

  • TMF+ Member
  • PipPipPipPipPipPipPip
  • 1,239 posts
  • Location: Bedfordshire

Posted 10 March 2019 - 06:18 PM

In what way should the vac takeoff be ported? Havent heard og This before

It should be as shown here:

 

https://www.britishv...ted-vacuum.html



#11 unburntfuelinthemorning

unburntfuelinthemorning

    One Carb Or Two?

  • TMF+ Member
  • PipPipPipPipPipPipPip
  • 1,239 posts
  • Location: Bedfordshire

Posted 10 March 2019 - 06:23 PM

This might help too:  http://www.theminifo...dvance-fitting/



#12 KernowCooper

KernowCooper

    Sparkie

  • Mini Docs
  • PipPipPipPipPipPipPipPipPipPip
  • 7,815 posts
  • Name: Dave
  • Location: The South West
  • Local Club: Kernow Mini Club

Posted 11 March 2019 - 10:14 PM

 

Low CO will cause high Hc reading, do a engine tune and then re test is what I'd do first


HC count did not change within Range i adjusted the co

 

This is after a run through the engine tune ? what happens when you take the revs up to 2000rpm



#13 dotmatrix

dotmatrix

    Mini Mad

  • Members
  • PipPipPipPip
  • 288 posts
  • Location: Vejle

Posted 12 March 2019 - 10:47 PM

 

 

Low CO will cause high Hc reading, do a engine tune and then re test is what I'd do first


HC count did not change within Range i adjusted the co

 

This is after a run through the engine tune ? what happens when you take the revs up to 2000rpm

 

 

this adjustment of the co value was after a long drive and then I pulled straight into the place where I measured the co. I didn't take the engine up in rpm as I only wanted to adjust the idle co. when that is right the whole rev range is usually right as it has previously been had the needle done on a dyno, but the mixture goes out of tune and the way the engine have been driving lately lead me to believe that it was running too rich again, but it wasn't. but the hc count did seem high (although I dont have a reference for this number because I never looked at it before) which is why I asked the question about causes for high hc count.






0 user(s) are reading this topic

0 members, 0 guests, 0 anonymous users

Mini Spares