I have just stripped, cleaned and rebuilt my HD8 carburetors using the SU overhaul kit from SNG. All went well and I followed a number of You Tube videos as tutorials.
I am very happy with the build and all jets are centered very nicely.
Now all the components are fully assembled, I cannot find any advice on where to initially set the jet, idle and volume screws before I fit the manifold to the car.
Any advice on initial ‘cold’ setting for all things that adjust would be appreciated.
Hi Philip…do you have a service manual…there is a section detailing exactly this information…(details are also in the printed booklet that should come with the rebuild kit)…I followed it and the car fired up and ran really well straight away… Steve
Set the needle height by sliding a 2 thou feeler gauge into the groove on the needle and then tightening the locking screw so that it is just lightly pinched between the groove and the piston body.
Set all 3 jets 60 thou below the bridge with a vernier caliper.
Fully close the slow idle screws and then undo 2 1/2 turns.
Set the fast idle screws so that with the choke fully off you can just pass a 2 thou feeler gauge.
Make sure you have all 3 butterflies completely closed with the links done up.
It is important to set the link arms so that they all have the same amount of freeplay in them before they actuate when you push the throttle. This is why they are in 2 parts rather than just being rigid.
Hi Steve
I have a Haynes manual…is that the one you mean or something else?
Hi Philip…I was refering to the Jaguar service manual…however its also in Haynes…SU carb adjustment and tuning page 89 in mine…however adowie above has detailed it for you…Steve
Here’s a couple of refs from my archive when I rebuilt last year
How to tune SU Carburetors.pdf (523.1 KB)
Ray Livingston’s SU Carb Adjustment _ 1969 Jaguar E-Type Restoration.pdf (170.0 KB)
Tuning Your S.U.pdf (132.8 KB)
Link to Bentley Manual Section:
https://drive.google.com/open?id=17phdzQPQHR4ST-stG5s3q_8BMVO-hI91
Neat, I’ve never seen these with polished bowls and bodies. Lotsa bling there.
I think you have the gist of the settings already. Note that they’re very high and rich so start backing off slowly once it’s running and stabilized being sure to keep them all even and balanced with a flow meter.
As described, the three spindles must start moving in unison and the wobble joints that screw onto them should hang down and have some free play before they firm up and move the spindles.
There are also instructions starting on page 65 of the Operator’s Manual that came with the car.
When I installed the adjustable jets for the Strombergs, I called Joe Curto for tips. He suggested I listen to the exhaust (as also discussed in the Operator’s Manual) to determine if the mixture is right. That technique applies to both SU and Stromberg carbs with the adjustable jets.
Thanks all for the responses…I now know what I have to do. Jag-lovers comes up trumps again !!
