HS8 question.

[genneton4]

Hello. I wondered if I could ask a question about an XK120 here for the E type oracles. ?

I have an E type going very well but am currently tinkering with the XK120.

I have fitted 2" HS8 carbs and I am disappointed with the low down torque (ie off the line power) they have delivered. They are quite a bit better higher up the rev range but I really wanted to improve the off the line power.

It is a 3.4 with an SE head (not C type), both inlet ports reamed to 2". The engine was rebuilt 1000 miles ago. I have trumpets with foam covers. The needles are standard XJ6 BAW. Powerspark ignition.

Is there any way I can dig myself out of this hole. ? Maybe retard the ignition a tad ? Different needles ?

Any wisdoms gratefully received.

Keith

[mgcjag]

Hi Keith...JagLovers has a very good XK forum.. Steve https://forums.jag-lovers.com/c/xk/28

[abowie]

Is there any way I can dig myself out of this hole. ? Maybe retard the ignition a tad ? Different needles ?

There's not really an easy subjective answer to this.

I fitted a 4.2 engine to my Mk2 with the same double HS8 XJ6 setup that you have.

I then had the car tuned on a rolling road dyno. I think that this would be your best option too.

[genneton4]

Just for closure.

Fitted a 123 ignition on curve 4 - all is well.

I think the Powerspark dizzy I had fitted (from Ebay) has a faulty vacuum.

[Simonpfhc]

As a matter of interest Keith, which 123 have you fitted - the standard GB one or the XK one?

Glad you have it all sorted.

[genneton4]

I have the GB one.

[Simonpfhc]

Appreciated Keith, thanks.