I am replacing the vacuum advance can on my '67 427 (points and ballast resistor), with the Duke recommended "2 inch rule" NAPA unit. In looking at the distributor, I am wondering if the two screws that hold the old can on, on either end of the pull lever in the advance plate, can be removed without removing anything else. And if not, (it looks tricky with only partial access to the heads getting it back on might be hard) how do I get full access to the screws without messing everything up, like the points gap, etc. Is there a way of removing the plate the points are on without having to redo the gap, etc.? I can't see which screws hold it down except the ones on the points. I am just trying to do it without too many follow-up things to reset. Thanks.
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Big Tanks In the High Mountains of New Mexico -
Re: Replacing Vacuum Advance Canister, help needed
Hi Mike,
You can wedge a screw driver against the plate and distributor body and rotate the cam plate forward to give you clearance to get at screws. Also , if you take off rotor , remove springs on weights and turn shaft for clearance.
It is the vac can that is giving you the resistance. New cans can be off a bit on the amount of advance they give, I had to put a nylon collar on the can shaft to limit the amount of advance, it was rated at 15 degrees but pulled in 19 .
Some other can give their opinions if there is a more correct way .
Jack -
Re: Replacing Vacuum Advance Canister, help needed
Jack,
Thats the way it's done in my book.
Michael,
It may not feel right but Jack hit it on the head, you may have to put suction on the can which can be done by mouth and a vacume line.
DOMComment
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Re: Replacing Vacuum Advance Canister, help needed
Thanks guys, you just saved me maybe a day or more of messing around, you're the best and so is this board
Big Tanks In the High Mountains of New MexicoComment
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Re: Replacing Vacuum Advance Canister, help needed
I trust by what you say you are trying to do this with the distributor in place in the engine. This can be done ok, but it is much easier with it out with regards to making sure you don't loose the screws or damage the ground wire, etc. Also, that's a good time to check over the rest of the distributor when it is out. If you choose to use vacuum to pull the plate forward, get yourself a Mityvac pump as it will hold the pull whereas by mouth it's not easy. You might want to use a magnetic screwdriver too as loosing a screw can be fun, either in the distributor or down behind the engine.
Stu FoxComment
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Re: Replacing Vacuum Advance Canister, help needed
Stu,
That makes it easier but sometimes you have to use whats available and that's what we use the most
In my case it kept me from cursing while I was trying to get the screws started
DOMComment
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Re: Replacing Vacuum Advance Canister, help needed
Right, thanks, and yes I am doing this with the distributor in the engine. I try not to mess with too many things at once if I can help it. I now have it done and she runs fine, just like before, but now I am hoping I get more advance pulled at lower vacuum. My old unit was marked MS 201 15. I think that is a Delco unit that pulls max 15 degrees advance but not til above 13 inches or so I think. It was a very rusty and corroded unit (but no deducts last flight judging), and I doubt it was working well or maybe at all. I now have the VAC hooked full time from the center carb, not ported, and the new B26 unit should pull max at around 9 inches vacuum. I'll take it out for some test runs soon to see. Thanks for all the help.
Big Tanks In the High Mountains of New MexicoComment
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Re: Replacing Vacuum Advance Canister, help needed
L-71 with the OE camshaft should pull about 14" @ 900 idling in neutral.
The B26 VAC spec is approx. 0 @ 6", 16 @ 12".
The ...201 15 is about 0 @ 8", 15 @ 15.5"
After installing a B26 and converting to full time advance, one should accomplish the idle speed/mixture adjustment with a target idle speed of 900.
DukeComment
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Re: Replacing Vacuum Advance Canister, help needed
Thanks for those specs Duke, my L71 is pulling 14" at 900, and the new VAC is making a noticeable difference at idle and low speed stop and go driving at 95 degrees ambient temps. Looks like the final piece of the puzzle to get her done and functioning well. Thanks again for all the help on the other items too.Big Tanks In the High Mountains of New MexicoComment
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