I am looking to hook up an vacuum advance on my Powerspark distributor. Can I hook into the manifold vacuum line from the vacuum canister?
Vacuum for distributors needs to come from either the manifold or from one of the carbs, it needs a fluctuating value, the vacuum canister is going to be a constant, not what you want.
Thanks Robin , superb answer.
It helps with my future direction regards
Ian
You are going to want to drill a small hole, say 1/16" in the bottom of the hole the arrow is pointing to on the front carb in the picture. Then tap the larger hold to accept a brass nipple. You attach the vacuum line to that nipple.
Thanks John,
Perfect! Just the comprehensive info I required. The pic is a big help.
Should be easy to perform?
No NEED to do so. You CAN connect the vacuum advance directly to manifold vacuum.
My V12 runs happily like this.
http://www.pclarkson.plus.com Mr Clarkson explains how to drill the port to give you the required vacuum from yr ZS carb…this is what I did. Also some ZS carbs on later ( mid 70s ) XJ12s had the ports already fully drilled.
How would you do this ?
Thanks Ian
T into the vacuum feed that goes off to the brakes BEFORE the 1-way valve - if you don’t want to modify the intake manifold. Otherwise, you could install a fitting underneath the intake manifold where it is not easily seen.
Thanks Phillip for your instructions . Much appreciated.Ian
What happens to the metal shavings that then go into yr intake n the cylinders?
They will be small enough that they will probably be burnt up in the cylinder. But most people will use some grease on the drill bit to help make the shavings stick so they will not fall inside. Or if you are still concerned, remove the carb.
Tom
I had the carb off of the car. When you drill virtually all of the swarf goes up the flutes, especially with aluminum. And if you were to have a shop vac sucking when you tap the hole it will suck up the waste from the threading. And, you don’t tap the complete depth of the hole, you only do it deep enough to secure the nipple in place.
I have to wonder if your Stromberg engine had a blank off for the advance. If so you might have to consider the centrifugal advance that would be excessive with a vacuum unit.
I have not used them but looks like this place will tap the port if you are not comfortable doing the job…https://www.britishvacuumunit.com/ported-vacuum.html.
David
68 E-type FHC
I looked at that link- great pics. my manifold has the indention but no holes- what size do I drill and where do I get the nipple? With just the two SZ carbs in the 1 1/2, not 3, anything to make engine “livelier”
is welcomed. Just want it running it’s best. Thx guys
Chris, so if I understand, you would like to add a vacuum advance mechanism to your 1969 S2, which did not come with one. My understanding is the vacuum advance device is used to provide better fuel economy. When one wants power (livelier?) the vacuum drops and the vacuum advance is not activated. I am not sure you should expect and more “livelier” by adding a vacuum advance.
Tom
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I drilled a 1/16" hole and bought a male thread brass nipple at the hardware store.
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It’s a ‘68 1 1/2 “Heinz 57” lol if that matters. Yes, I’ve heard the advance won’t affect performance just mileage
How do I “tap” the drilled hole? Is that to put threads in the hole so the nipple screws in or can I just try to screw the nipple in the 1/16 hole?