302 tuning

[ENTDOC]

I soldered the idle jet to the holder so that worked ok. I now have; 37mm chokes, 150 mains, 55 idle jets, 200 air correctors and F7 E tubes, 16 degrees advance. It starts and runs very well, idles good with little or no black smoke(60 idle jets smoked a good bit) but under load I get a good bit of hesitation and backfire, popping. I have the idle circuit out 1 turn, they are balanced . Any thoughts? Sounds lean

[PatBuckley]

Not that this is the cause, but what cam are you running?

[ENTDOC]

I have no idea Pat. The motor was built by Performance Engineering, but not for me. I do not get much reversion, so I think the cam is ok in that regard (not too much overlap)

[68gt500]

Sounds lean to me.

When are you getting the pops - accelerating lightly or heavy ? At what RPM ?

If on light accel - I´d check for the correct emulsion tubes or even the 3rd progression hole

If on heavy accel, probably too little pump shop - use a smaller bypass.

The one tool that made my whole Weber tuning much much easier was the addition of an Innovate Wide Band O2 Gauge - no more guessing if rich or lean.

[Clois Harlan]

Send Dean Lampe a PM he has recently gone through all this and may be able to help. I do know that as Pat said your cam has a lot to do with the webers performance. Not to much duration (maybe around 235-250 @ .50).

Clois Harlan

[ENTDOC]

I went to 155 mains, 55 idle and 205 air correctors and dropped down to 10 degrees advance(it was hard to turn over at a higher advance) and it is running much better, but still a nagging stutter at 2300 or so(very typical) I am going to order some F5 E tubes and see how it goes. I have them balanced well and it idles very good with no smoke. I also changed to new plugs, as anyone should when adjusting webers. They tend to foul quickly since most of the time we start off very rich.

[Gaz64]

Can I ask at what rpm your horsepower peak occurs at?
And also how hard you can rev the engine with 37mm chokes?