Costs:

£10 to £30 depending where you buy them from.

Considerations:

A fairly simple upgrade but you need to make sure that the spring kit will fit your carb’s throttle body. This is a Holley part.

What’s in the pack?

Bracket arm, spring ring, three lipped washers, three bolts, collar.

Two pairs of springs of varying strength, next to the original spring.

Choices:

The choices are from the combination of the springs and what you want to feel underfoot.

Background:

I decided to make a little upgrade to the car to help with a very minor issue that I decided to rectify. The modification also added a little blink under the hood and something else to clean while I’m at it.

The issue was that on the odd occasion when lifting my foot of the throttle and stopping the idle would be a little too high. This could be cured by tapping the gas pedal and it would settle down again. On investigation it appeared to be the throttle return springs on the standard throttle rod didn’t strong enough to return the carb throttle body to it’s correct closed position every single time.

For a stock set up there is a single spring to return the angled throttle rod. Not very safe if the spring breaks or stretches as it could leave an open throttle. So the simple fix is to fit a secondary larger spring around the outside of the smaller spring. Although this configuration was fine the throttle feel was very light under foot.

Process:

The first job was remove the old rod from the carb throttle body which was held in place by a lock nut. The two springs on the dog leg part of the old rod simply unhooked. This makes it easier to bolt the bracket in place, but you don’t have to remove the standard throttle rod if you don’t want to.

Depending on the combination of springs, it will determine the overall feel of the throttle. I decided that the stronger pair for a max return response would be my choice. There are two holes on the carb fitting ring (left picture), and two on the bracket. I made the mistake of putting the springs on the ring first.

This made life very difficult while trying to attach the pair of springs to the bracket as there wasn’t enough movement to allow the second spring to attach to the spring ring without tangling the other spring. So I had to remove one of the springs in order fit to the bracket first then onto the throttle ring.

The secret is to fit first spring to the ring as you normally would, then the second spring fitting needs to be twisted in reverse first to allow the open ring to untwist and end up where it should be. If you don’t the springs will tangle and be twisted once fully fitted. I won’t deny it, it took me a few attempts to get right, the air did turn the same colour as the car, very blue as the springs tangled up on the first couple of attempts. Fit the bracket and springs first.

Eventually I manged to connect both sections.

To fit the bracket it needs to locate over a corner stud with the bigger hole that holds the carb in place. If the stud was longer then a second nut would bolt the bracket down.

A second smaller bolt nearer to the front of the bracket that also holds the spring bracket in place and to stop the bracket twisting when the springs are under stress.

Note: As I have a 1″ phonetic spacer the bolt that bolts the carb down sits at the top end of the stud. That means I couldn’t bolt it down without changing out the stud. However, the top of the stud was protruding enough to act as a locating pin to stop any twisting.

To make sure the single bolt holes the bracket in place I fitted a large washer. The down side was that the washer was overhanging the bracket and snagging on the throttle body. This meant that I had to grind two edges flat to align with the carb body and then finish at the bracket’s edge. You can just about see odd shape in this picture. A smaller washer would have been fine I just wanted max hold.

With the bracket held firmly in place the tricky task of fitting the spring ring to the carb throttle body. In an ideal situation you could do with a third hand to do it easily.

Note: At his point I was going to replace my standard throttle rod with a polished billet version. With that in mind I had a rose joint to fit instead of fitting the original throttle rod back in place. You need to thread the screw through the rose joint, washer and the conical spring ring in that order.

If you are fitting the standard rod back in place refit as required.

Depending on the style of the carb’s throttle body you are given a selection of fittings to allow the spring ring to be bolted to the throttle body. The fittings you need will depend on where you fit the spring ring and into which opening on the throttle body itself.

In my case the billet throttle rod comes with a conical fitting for the larger opening of the throttle body. With the cone in place and the ring under tension to the bracket, you need a larger washer to stop the spring ring coming of the end. I didn’t use provided lock nut, but I still wanted to lock the bolts in place.

Nut number one labelled holds it all together, number two locks the two together.

The principle of fitting the spring ring in place is the same. It should move freely and not bind on anything. Notice the washer on the other side of the spring ring to make sure it doesn’t come of the throttle body.

That’s it.

I have shown how to fit the Billet Throttle Rod here.

With everything in place it should look something like this.

Time Taken:

Two hours with the washer redesign and and figuring out the spring process.

Results:

The throttle now snaps back into idle and the car instantly feels crisper under foot.

Conclusion:

An aesthetically pleasing look of chrome, along with a much more secure spring fitting. The throttle feels much more responsive. A slight lift of the foot will pull the throttle back. I will take a bit of getting used to to stop the jerky style of the on/off throttle. I just need to be delicate and not mash it. Unless i feel the need to 😉