Tuning a Holley

[rossk]

Hi all,

Need some advice please with reference to tuning my Holley street avenger carb. I've looked through the books, but sometimes its easier to ask someone who has been there a done it.

My eventual plan is to take it to At Speed to get it tuned on a rolling road. But in the interim I just want to get it running reasonably well.

So far I've set the timing at 10 degrees advance and have set the rpm at approx. 750-800 (I have a hughes whiplash cam) I started with the idle mixture at 2 full turns out and have with the aid of a vacuum gauge slowly turned them inwards. I've also set the float level so you can just see the fuel at the bottom of the window.

I'm practically turning the idle mixture screws all the way in, and that reads just in the green on the vacuum gauge, and it's reacting well on the throttle but it's blowing a fair bit of black smoke out the back and smells very much of petrol.

On the plus side when I take it down the road it is rapid and reacts the best it ever has.

Not sure whether to accept it as it is and live with the smoke? or does anyone have any tips?

thanks

Ross

[Pete]

In my opinion you need to warn the engine up and set the timing at 34 degrees full advance (Vacuum advance off / plugged), then see what timing you have at idle. Then you set the carb to suit.

[rossk]

Thanks Pete, I can try that. Just happy to be able to drive it at the moment, been off the road for too long!

[Pete]

Stick with it, the engine should be at full advance at around 3000 rpm...

[Blue]

Yes sort out the timing first, you will almost certainly need more than 10 initial. Find out what it wants then limit the total to 34 and then move on to the carb.

[rossk]

Thanks both, I shall persevere

[John]

As Pete and Jon have said get the timing sorted out before fiddling with the carb. One of the most common problems is having to much mechanical advance built in to the distributor. Ive always found my cars have run best with around 20 degrees initial and a total of 34 to 36 degrees which means a good ball park would be 15 degrees mechanical. The only thing with this is you will have to determine whether your distributor is adjustable and then get someone to do it unless you have a go yourself.

[Blue]

Not hard at all to limit the dizzy, just work out by trial and error what the initial needs to be then you know how many degrees to limit the advance by, get one of these plates, remove and strip the dizzy and drop it in, jobs a sausage..

https://www.ebay.com/itm/Mopar-Distribu ... SwQJhUdOgX

[rossk]

Hi all, I’m running it with a crane distributor, coil and ignition system, not sure if that makes a difference at all?

[Blue]

Hmm, I know nothing about that set up, probably totally different.