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Posted by: Joseph Mills Sep 5 2003, 04:40 PM

Am finally going to install my Mallory Unilite distributor (w/vacuum), and HYFIRE CD box.

I installed the lighter gray springs that alters the advance curve that is more suitable for the T4. As I understand it, the vacuum line will improve gas mileage a bit and run a little cooler also, while improving the smoothness of throttle response.

Here is my delimma:

The 44 IDFs I previously installed came with an extra hole tapped with about a M4 screw, which I assumed could be removed and fitted with a brass nipple and used for the vacuum line.

However, I have not been able to locate a small enough brass fitting (for the vacuum line) to fit into that small a hole in the carbs. I've checked hardware stores & FLAPS with zip results. Anyone know of a source for such a small size?

I am wondering if that small a size will even allow enough air to work?

An alternative I'm considering is just drilling a larger hole in the manifold itself and tap it for a larger fitting. Any reason why this wouldn't work?

Anyone have experience with this? Good idea? Bad idea?

Any advice mucho appreciated!

Posted by: Mockmaw Sep 6 2003, 01:12 AM

Uhh, my understanding is that you just remove the screw and slip your vacuum line over the brass extension.. that's how I've done it at least. Unfortunately, I don't have a shot of my carbs to show you what I'm talking about.

When you speak of a hole that's tapped... is it just hole in the side of your carb with a screw in it, or is the screw inserted into a small brass fitting that extends about 3/4" from the carb body?

Posted by: Joseph Mills Sep 6 2003, 07:26 AM

Yes, it is a hole in the side of the carb with a screw in it. It is listed in my Tomlinson weber manual as a "blanking" screw. It is immediately to the right of the idle mixture screw. To the left of the idle mixture screw is the air bypass screw.

My carbs do not have a brass fitting that extends 3/4". This blanking screw is about 4mm, or 3/16" - just doesn't seem like there is much room there for an air passage.

I'm beginning to think that this "blanking" screw location is not intended for a vacuum line?

If I drill and tap a hole in the manifold, any idea as to the size it should be?

Thanks.

Posted by: Tom Perso Sep 6 2003, 08:47 AM

I think you have an old set of 44's. They did not have vac. fittings.

The question is, I think you need vaccum *above* the throttle plates - I need to do some research to find out what works the best.

The new 44 IDF's with vac. connections have a small hole that is just above the throttle plates in the carb body.

Lemmi find out.

Tom