Hot Rods flathead 2x2 tuning

My stock flathead Seems to be running to rich. how low can I jet a Stromberg?

 

Hello, which strombergs do you have on, ie..97s, 48s or 81s..What is the CI of your engine, headers, ignition????
Duane.

 

At your altitude, try .043 mains with # 69 powervalves - lean is mean, but I wouldn't go skinnier than .042's. Sometimes, lowering your floats helps a wee bit helps, too.

 

I love that roadster.
I'm having the same issues. Different climate down here, hotter I'm thinking. I just ordered up some .043s and .044 to see what happens. It's a 276 c.i. headers, cam, Offy heads, 2x2, dual point... by the way.

cheers, Gary

 

Ive got a stock 36 flathead running 2 97's, reds headers, stock ignition.

 

Uncle Max, is right, not to lean..
Duane.

 

That's TWICE now we agree on something!

 

Max, behave yourself, or your headed for a time out.

 

OK, that's it. I'm quitting carbs and starting a stamp collection. Maybe knitting?

 

An old trick for figuring out how much smaller jets you need is to insert a very fine wire in the jet, and see how it runs, when you get it running right, get jets that are smaller by the diameter of the wire. Saves buying a whole bunch of jets, although .001 steps are tough, wire that small , well........

 

I think knitting or sowing, again I agree with you..LOL..
Duane.

 

get jets that are smaller by the diameter of the wire

Way, way, way off.
Example: .057" jet runs better with .003" wire - that method calls for .057" - .003 = .054" jet. This will be much leaner than the original jet and wire.
Actual .057" jet area is .002552 square inches.
.003" wire removes .0000071 square inches.
New jet area is .002545 square inches.
Jet ID for that area is still .057" (actually, .0569") - too small a change to make with a stock jet.
The .054" jet called for is .002290 square inches, or 10% leaner.

Correct calculation:
(original jet^2 - wire^2)^.5
Using bigger sizes to exaggerate the difference and make the math easier:
original jet is .080", wire is .015" (method calls for .065" jet)
.080^2 - .015^2 = .0064 - .000225 = .006175
.006175^2 = .0786, use .079" as both cloest and safest.
The .065" jet called for would be .0466", or 66% leaner than the original.

How to do a safe 5% leaner change by wire:
((original jet size^2) × 5%)^.5
Example with .057" jet:
.057^2 = .003249, × 5% = .00016245, ^.5 = .0127": use .013" wire.

 

what size are stock mains? what are powervalves? I haven't found them listed for sale.

 

The Hot Rod Company sells them, plus lot of others..Stock jets are .045 and .043 depending on altitude. The power valve is at the bottom of the accelerator pump well, stock is .065 and .067 for the .043..
Have you taken you strombergs apart, bought a kit?????????
I think you need to do some research..
Duane.

 

Here I go again. . . Seeing as how you're fairly new at this, send me your carbs, I'll do all the work for & flow check 'em. No Charge. You pay 16 bucks for two pair of jets, 20 bucks for two powervalves & return postage. 24 hr turnaround. God Bless America.

 

Uncle Max is an angel. Sell him one of your deluxe jet wrenches while your at it.