TheSamba.com :: View topic

Mon Mar 11, 2024 6:37 am

My 356 engine consists of a 912 crankcase with "C" heads and crankshaft.

Bearing in mind that it would be rather expensive to switch to different carburetors, do you think I'll get reasonable performance from the Zeniths?

Tue Mar 12, 2024 6:02 pm

Yes, I have the same setup on my C coupe and years ago I asked Vic Skirmants if he could build me a set of Solex's and after a discussion he convinced me to get a set of Zeniths since sub 6k RPM the performance was virtually equal to Solex's.

They perform great and stay in tune, I rebuilt them over this winter after 17 years and 60,000 miles and I am sure they will be good to go once again for another 17 years.

Tue Mar 12, 2024 7:26 pm

I realize off topic, but not really. I put ONE Zenith 32ndix on a 350 Chevy in a 1 ton Grumman Kurbmaster. WE are beekeepers, and need the ability to pull from an idle off road, and handle off camber..

Roland

Wed Mar 13, 2024 5:04 am

William Crowell wrote: My 356 engine consists of a 912 crankcase with "C" heads and crankshaft.

What cam do you have in it? The cam and carbs need to be matched. If you have a 912 cam you won't be happy with Zenith carbs.

I have a similar combination in my Speedster. I have a 912 case, crank, rods, and heads with a "C" cam and Zeniths, and AA 86mm P&Cs. I had autocrossed it with a full on 912 engine and wasn't happy so built this engine with autocross and normal street use in mind. I am VERY happy with it. I have full confidence that it will safely rev to 6000 if I need to and still have great performance in the low end where I drive it 99% of the time.

Wed Mar 13, 2024 6:03 am

LOL, I don't know what cam is in it, and since it is a good runner I don't want to split the crankcase to find out. You're right, wdfifteen, performance at lower RPMs is always the issue.

Wed Mar 13, 2024 7:02 am

Since you are dealing with an unknown quantity cam-wise, I would go with Zeniths. Zeniths paired with a 912 cam is not ideal, but it's a better combination than Solexes and a C or Super cam.

Thu Mar 14, 2024 12:21 pm

If you take off the front timing cover you can see if it has a stamping on the cam face ....or you can take off 1/2 head and #2 cylinder and rotate the engine and see if there is a stamping inbetween the lobes on the camshaft.....you don't really have to split the whole engine apart ....

Sat Mar 23, 2024 5:54 am

I went through the file on my B-model and found that I bought a "C" cam from Johnson Pacific Porsche-Audi of Oakland in 1978. Lukes and Shorman in Albany, CA rebuilt the engine at that time. It was my main driver and I drove the heck out of it and wore that engine out after many years. Now it's got a rebuild on it from the late Frank Lettini of Frank's Foreign Auto Repair in Sacramento that has a few miles on it, but seems to run well. So I still have that "C" cam from 1978, and from what you guys say it should run fairly well with the Zeniths.

Mon Mar 25, 2024 6:36 am

Yes, with that cam it will run better with Zeniths than with the Solexes.

Tue Mar 26, 2024 11:14 pm

Using Zenith carbs with your 356 engine setup (912 crankcase, "C" heads and crankshaft) can provide good performance, ensuring reliability and longevity for your engine.

Thu Oct 31, 2024 11:13 pm

I realize you are talking about Zeniths from a 356C model. Keep in mind, Zeniths were used on 60 HP normals and 75HP Supers. I SUSPECT they have different size venturis.
I'm quite certain the P40II Solexes from 912\s have 32mm Venturis and that's really too big to get stump puller low end driveability.
Your 356C carbs should be just fine.