Alternative Vacuum Source?

[Tmac897]

When I was rebuilding the engine of my S3, I had to replace the head. I wasn't remotely thinking about headlight operation at that stage of the rebuild, and so I did not drill out a port on the intake manifold to fit a connection to the vaccum system. Drilling a hole in the head at this point gives me the willies - I can see the metal filings complete with evil grins happily marching into cylinder 1.

My question is would the airbox itself be a reliable source of vacuum? Other unintended consequences?

[h20hamelan]

I believe there are 12v electric pumps

[Tmac897]

I believe there are 12v electric pumps

Yes, and there are 12v electric actuators. Not my question, though. The airbox connection, if viable, presents a much simpler solution.

[h20hamelan]

sure, until you have low vacuum while running which is I believe why folk use electric motors to actuate the pods.

while pumps may be actuators, actuators may be pumps. I don't think either statement is true.

[steve lyle]

I wouldn’t think there is much, if any, vacuum upstream of the throttle plates.

[quaybook]

Maybe remove front carb, put a grease covered rag with an extractor string attached to it down the port beyond where you are going to drill to block the port, then a second grease covered rag behind the point where you are going to drill. Drill out the port, remove the outer rag carefully hopefully with all the swarf, clean up inner end of drilling, then very carefully remove the inner rag. Maybe?

Vernon

[alanr]

You could of course fit an electric headlight conversion.
Or fit a strong vacuum pump like one of these. Seems very overkill to me though.
https://www.carbuilder.com/uk/electric-vacuum-pump

Realistically though I don't think you have any option but drill the manifold if you want vacuum.
As others have suggested, plenty of grease both inside and outside the manifold to catch the drill swarf and take a deep breath and drill/tap the manifold seems the easiest solution to me. It would be done in minutes.

Alan.

[rgh0]

Maybe remove front carb, put a grease covered rag with an extractor string attached to it down the port beyond where you are going to drill to block the port, then a second grease covered rag behind the point where you are going to drill. Drill out the port, remove the outer rag carefully hopefully with all the swarf, clean up inner end of drilling, then very carefully remove the inner rag. Maybe?

Vernon

I did this on a head that I also fitted before realising the vacuum connction had not been drilled and tapped. No problems with extracting all the metal filings. Turn the engine until the inlet valve is closed on No1 cylinder and you can always vacuum out any metal that mat get past the plugs in the inlet.

cheers
Rohan

[Tmac897]

Maybe remove front carb, put a grease covered rag with an extractor string attached to it down the port beyond where you are going to drill to block the port, then a second grease covered rag behind the point where you are going to drill. Drill out the port, remove the outer rag carefully hopefully with all the swarf, clean up inner end of drilling, then very carefully remove the inner rag. Maybe?

Vernon

I did this on a head that I also fitted before realising the vacuum connction had not been drilled and tapped. No problems with extracting all the metal filings. Turn the engine until the inlet valve is closed on No1 cylinder and you can always vacuum out any metal that mat get past the plugs in the inlet.

cheers
Rohan

Thank you for the suggestions. Sounds doable.

[The Veg]

I say this tongue-in-cheek of course, but if you wanted to get REALLY crazy you could acquire the vacuum-pump from a Turbo Esprit, which is rather compact and driven by a V-belt. Having a pressurised intake manifold, those cars needed a vacuum-pump to operate the brake servo. And when I had a Turbo Esprit some years ago, that pump was a right pain in the arse to loosen and remove its belt, which was the outer-most of THREE V-belts on the engine and the pump was so far down that it had to be dealt with from below the car, and it required a modified hex-key to loosen a bolt behind its pulley, in a difficult place to reach. If I still had that car I'd yank it off and GIVE you that damn pump!

[rjaxe]

My plus 2 has two vacuum connections on the intake one for the lights the other for the brake servo are you missing this one as well?

[shynsy]

I believe that you can buy an alternator which has a vacuum pump integrated into the housing.
Tim

[Tmac897]

My plus 2 has two vacuum connections on the intake one for the lights the other for the brake servo are you missing this one as well?

I have an S3 SE, but no servo fitted. Perhaps the original owner removed it, or it was a "delete" option on the SE?

[Tmac897]

I say this tongue-in-cheek of course, but if you wanted to get REALLY crazy you could acquire the vacuum-pump from a Turbo Esprit, which is rather compact and driven by a V-belt. Having a pressurised intake manifold, those cars needed a vacuum-pump to operate the brake servo. And when I had a Turbo Esprit some years ago, that pump was a right pain in the arse to loosen and remove its belt, which was the outer-most of THREE V-belts on the engine and the pump was so far down that it had to be dealt with from below the car, and it required a modified hex-key to loosen a bolt behind its pulley, in a difficult place to reach. If I still had that car I'd yank it off and GIVE you that damn pump!

Probably beyond my fabrication skills anyway

[Tmac897]

I believe that you can buy an alternator which has a vacuum pump integrated into the housing.
Tim

Thanks, Tim. Sounds like a reasonable option. Does it require a change to negative ground to install an alternator?