balance problem

[mats carlsson]

Whats the meaning of this?
To balance whats already balanced with the balance tube?

[tyler carlson]

A little different! Never noticed something like that before. Is it possible these are different maker supplied manifold castings? Even different motors-normal vs. super? Inquiring minds want to know!

[Norm Miller]

Mats,

The pipe between balances the carbs and reduces pulsing.

The slot in the casting balances the ports.

Just a little upgrade as they went along.

Norm

[C J Murray]

There is not much talk about the single barrel equipped cars. I have a '57 Speedster with the Super single barrel Solexes and I have learned some things the hard way. The reason for the attempts to balance things out between carbs is that each carb is feeding a pair of cylinders that are 180* out of phase. Because of this there are strange pulses that are both positive and negative(reversion) almost at the same time, 180* apart then 540* gap, repeat, repeat, repeat. This condition is corrected by the use of two barrel carbs where each cylinder stands on it's own with reversion occurring only every 720*. The net result of the single barrel carbs is that the car idles like it has a long duration cam and this can not be corrected. Road & Track made a big deal about how smooth the new '58 Zenith test car was compared to the previous year.

There is a trick to making the single barrel cars to idle much better than most of them run. Before setting the carb balance, take the car for a very long drive. Very long, not around the block or just running in the driveway while you organize your tools. The horizontal carb linkage is the culprit. Our engines grow in width considerably when hot and the linkage does not. This is why Porsche made the linkage change that is less effected by the engine expansion. Balance the carbs at idle and 2500rpm with the engine hot hot hot. The car will run well but still idle lumpy. If you set the balance on a luke warm engine it will run very lumpy when fully warm and do so even above idle. Let the car cool down to room temp and inspect the distance between the idle speed screws and the carbs. One will be touching the carb and the other will be 1/8" or so air gap to the carb. Out of sync! Until the engine gets real hot and then all is good. These cars idle poorly until hot and that's just the way it is.

[Wes Bender]

Damn, CJ. Where were you when I was trying to get my early A tuned properly in 1962?
Now I know what the problem was.....

Thanks,
Wes

[C J Murray]

Damn, CJ. Where were you when I was trying to get my early A tuned properly in 1962?
Now I know what the problem was.....

Thanks,
Wes

I was 10. I was in the back of my Dad's '60 Normal coupe while he and my mother chain smoked in the front. It's amazing that I have lived long enough to learn this stuff!

I hope it helps because I hear a lot of guys compain about how the pre '58 cars run.

[Norm Miller]

Cliff,

You mentioned your 57 is a super. Thus it has the #*^@%$ 40's on it , right.?
The 32's were a much easier carb. to deal with and I don't remember many issues.

Norm

[Larry Wilson]

zzzzzzzzzzzzzz

[Norm Miller]

Larry,

No argument! They were "super" strong! Very nice looking engine.
I think racing is a controlled enviroment whereas back in 58/59 cars driven around the city summer and winter by owners with no idea whatever about routine maintenence whose last car was a 390cu V/8 did have problems keeping the prrr in the exhaust.

Regards,
Norm
Left PCA 1961
REG member #3294

PS: I really think it was the cold pink Beru plugs at fault. Mucho fouling.

[C J Murray]

I like the oddness and correctness of these carbs and they run well above idle when tuned propperly. They can not and do not idle nearly as good as ANY single barrel per cylinder carb set-up. This is why high performance engines with sporty cams almost always have one barrel per cylinder. There is a point a bit above idle that the odd pulses of the siamese manifolds no longer has such a great effect and the car is pretty smooth. I have never tuned a single barrel Normal but those engines have very mild camshafts and very small venturis so they should idle much better than a Super.