Jump to content

Needle bushing?


PeaTear
 Share

Recommended Posts

I'm not sure if that's the proper name for it but the dirty brass barrel in the picture. Should it have that ridge on it. Looks to me like someone has overtightened the grub screw but both needles are like this. 

20180525_134242.thumb.jpg.9d1691136690c5058a063acaae33ed67.jpg

Link to comment
Share on other sites

1 hour ago, PeaTear said:

I'm not sure if that's the proper name for it but the dirty brass barrel in the picture. Should it have that ridge on it. Looks to me like someone has overtightened the grub screw but both needles are like this. 

20180525_134242.thumb.jpg.9d1691136690c5058a063acaae33ed67.jpg

That dirty brass barrel is the needle guide. The 'pip' you're referring to in association with the spring biases the needle up against one side of the jet. Should be marked with a line or V on the visible face.

This type allows you to set the bias towards the throttle butterfly or away from it. Later types had a locater for the grub scew so could only be fitted one way round.

David

Link to comment
Share on other sites

1 hour ago, PeaTear said:

on a side note. From what I can determine the standard needle is aan but the ones in my carbs are aaq. Why would someone have changed these?

Probably should ask which car we're talking about,but..

The AAN needle was the standard needle for MK4 Spitfire. According to the MOSS catalogue recommendations  https://www.moss-europe.co.uk/media/pdf/SPI001.pdf page A17 the AAQ is the richer needle recommendion for a 1500 when you've fitted both K&N filters and a tubular exhaust.

I think mintylamb is still down, but if you like to compare http://mk1-performance-conversions.co.uk/technical_carb.htm has a nice spreadsheet, but you'll need LibreOffice installed.

If AAN is your standard needle I think AAQ would be a bit rich for a MK4 but OK if for a 1500 with different exhaust and air filters.

David

 

Link to comment
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
 Share

×
×
  • Create New...