Thread: best vacuum port on a Series 1?

Hi

This has been discussed on the UK series 1 forum. The only thing to do is drill and tap a hole in the inlet manifold.

Some types of engines seem to respond to the vacuum gauge method of tuning better than others do , don't know why this is so.

Tuning for me , is rather a hit & miss process on these series 1 engines , I noticed my engine kicking back on start up so I retarded the distributor a few degrees til the kick back stopped , it seems to be running fine !

If drilling the manifold, from memory the manifold has a water jacket to prevent icing, and you really don't want to drill into this!

Originally Posted by JDNSW

If drilling the manifold, from memory the manifold has a water jacket to prevent icing, and you really don't want to drill into this!

The water jacket inside the inlet manifold surrounds the carby base, it is nowhere near the two outer inlet ports

Yes - if drilling a vacuum port, just make sure you know what you are drilling into.

rsz_inlet_manifold.jpg There is a convenient threaded hole already in my Manifold on the firewall side of the inlet and nowhere near the jacketed area ardour the carbs. I assume it is there as a mount for something that my 1953 80" does not have. This seems the most method as I can just drill through the centre, and use the existing thread for a plug and for a vacuum take off.

Any reasons why not?

thanks
Jeff

I'd be wary about that - I think it is a place for something to bolt on to, and I am not sure a hole drilled into it would go into the manifold itself - that bit on the end could be solid; I can't think of any good reason why it would be hollow!

Originally Posted by JDNSW

I'd be wary about that - I think it is a place for something to bolt on to, and I am not sure a hole drilled into it would go into the manifold itself - that bit on the end could be solid; I can't think of any good reason why it would be hollow!

The bracket for the hand throtle cable bolts to that hole

It's quite save to drill and tap..W.