• Hey Guest!
    British Car Forum has been supporting enthusiasts for over 25 years by providing a great place to share our love for British cars. You can support our efforts by upgrading your membership for less than the dues of most car clubs. There are some perks with a member upgrade!
    **Upgrade Now**
    (PS: Upgraded members don't see this banner, nor will you see the Google ads that appear on the site.)

carb piston spring

Share this page

tahoe healey

tahoe healey

Yoda
Offline
Moss lists red and green piston springs for the HD8 carbs. There is no color to the present springs. How do I know which is right? How do I know if they need replacing. I've been suspicious that the carbs are acting different but not much.
Thanks for the help.
 
See the attached pic.
A crude but effective spring checker.
A transparent box just larger than the spring OD.
Calibrated weights to compress the spring. Someone with an accurate scale can calibrate the test weights or you can just stack quarters to suit.

The pic shows a red spring that is somewhat under it's original rating. ie, 2 5/8" at 3.8 oz. Where it should be 2 5/8" at 4.5 oz.

The absolute spring weight is not so important as having the springs matched. The tension can be increased by slightly stretching the low one until they match.

SU carb piston spring specs

Code-----------------Force Oz.------------At Length

Blue---------------------2.5----------------------2 5/8"
Red----------------------4.5----------------------2 5/8"
Black/Green-------------5.25---------------------2 1/2"
Yellow----------------- 8.0----------------------2 3/4"
Green---------------------12-----------------------3"
Red/Green--------------11.25--------------------3 7/8"
Brown-------------------14------------------------3"
White--------------------18------------------------3 5/8"
Red/Yellow-------------24------------------------1 3/16"
Red/White--------------41------------------------3 7/8"
Blue/Black--------------4.5------------------------3 7/8"
Blue/Red----------------18------------------------3 7/8"

The aluminum weights are 2.0 & 3.0 oz
The steel weight is 5.0 oz
A quarter dollar weighs .20 oz
A nickel weighs .17 oz

Austin - Healey factory springs:
100-4 = 2 x H4 carb yellow
100-4 = LeMans 2 x H6 red
100-6 Early = 2 x H4 red
100-6 late = 2 x HD6 yellow
Bn7, BT7 = 2 x HD6 red
BN7, BT7 = 3 x HS4 red
BJ7 = 2 x HS6 red
BJ8 = 2 x HD8 red/green
D
 

Attachments

  • 256596-SUSpringChecker.jpg
    256596-SUSpringChecker.jpg
    143.1 KB · Views: 160
th, did mine yesterday, had joe curto redo my throttle shafts i also had the same question,call him,i bought two new
springs my old ones are rusty. joe curto-(717)-762-7878, nice guy!tell him i sent ya! heck let ya go in the back and see the dancing girls and listen to the "jazz" - :"keoke:" will tell ya! /ubbthreads/images/graemlins/yesnod.gif
 
/ubbthreads/images/graemlins/savewave.gif

Dancing Girls! and Throttle Shafts at! Joe Curto's??. Prolly meant to go to Joe's but stopped off sum place else and got the "shop's" /ubbthreads/images/graemlins/confused.gif---Keoke- /ubbthreads/images/graemlins/cowboy.gif
 
Back
Top