Zeniths

Weissach911 · 12-13-2011, 08:38 AM

have decided to try to make some Zeniths work with a 3.0 litre engine and have started by making some 34mm dia chokes and work from there.

I have looked at several of the threads on this subject and found them very useful.

neilca · 12-13-2011, 01:52 PM

I am running 36mm chokes on a fairly stock 2.0. I would bet you could go a full 40mm with a 3.0l. Main jet would need to be about 200, I think. Nice looking chokes you made there.

Weissach911 · 05:28 AM

Quote:

Originally Posted by neilca

I am running 36mm chokes on a fairly stock 2.0. I would bet you could go a full 40mm with a 3.0l. Main jet would need to be about 200, I think. Nice looking chokes you made there.

Have you bored the body oversize? I would normally use a 36mm choke in a 45mm bore carb as I was always taught that the bore to choke ratio should be about 1.25

neilca · 12-14-2011, 04:32 AM

No, I looked into it and posted on this forum. Someone told me there are air passages that would be opened up if I tried to bore them. I simply opened the choke from 34mm to 36mm didn't need to increase the main jet I was already at 180.

As for the ratio I understand the theory behind it, I am not sure I agree in practice. As Chuck Reid has been quoted

"In theory, there is no difference between theory and practice; In practice there is."

Weissach911 · 12-14-2011, 11:16 PM

We are currently running a 1982 3.0SC on a pair of Weber 40IDAPs.

They have the standard idle air corrector bushes which I think are 140, 60 idle jets, 32mm chokes, F3 emulsion tubes, 135 main Jets and 180 ait correctors, pump jets and aux. venturies are stock.

The engine is standard apart form having 1.5" headers and a 2 in one out muffler.

It seems to run well, it idles nicely gives good progression and will rev to 7400 quite cleanly.

When I read this forum it seems that many people recommend 34mm chokes on a 3.0litre and I thought we would give this a try and see how they compared to Webers on the same motor.

mor-bla · 12-17-2011, 03:40 PM

Weissach911, Would you be interested in making another set of chokes? I have been trying to find larger chokes for the zenith and have been coming up empty.
Doug

Weissach911 · 12-18-2011, 01:31 AM

Quote:

Originally Posted by mor-bla

Weissach911, Would you be interested in making another set of chokes? I have been trying to find larger chokes for the zenith and have been coming up empty.
Doug

Doug, while we were at it we made 5 sets so we have plenty.

Send me a PM and I will respond.