I invested in a small hand vacuum pump/brake bleeder. Just so I'm certain....if the advance is functional, I should be able to move the distributor with it, right? It doesnt move.
Is there anything specific year to year with these vac advance units? The parts listings seem to be by a group of years but they all basically look the same.
Reading old threads, it looks like maybe car and truck advance are different? Have a 1962 engine in a 1951 truck but no clue where the distributor came from.
The different part-numbers/years for 216/235/261 vacuum advance units might their angle from the block. The angle was different with different engine mounts (I think) - car and truck.
The distributor must move when vacuum is applied to the vacuum advance. If it doesn't either the distributor is tight in the block(O ring used on housing is one example of a problem), or the advance diagram has a hole in it.
There were a number of vacuum advance units produced by Chevrolet through the years. An obvious difference was the mounting angle of some to clear the side mounts(passenger car only). There were also different advance rate for different applications(controlled by the internal spring rate).
The existing steel line is male flare at the advance connection and a female compression fitting at the connection to carb. (Carb port has a male to male in it)
No, they had the clearest photo I could find (and a good price).
I usually buy from ClassicParts.com or Jim Carter or Chevs of the 40s (in that order, after checking total cost, including shipping). All are listed here in Links.
What's the shipping cost? A line that size and shape is going to require some pretty creative packaging. Jerry
"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt! There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway Love your enemies and drive 'em nuts!
Spent 20 minutes with the Napa guy today searching for a vac advance. They use actual books to help you find parts, but we still struck out.
Got to thinking there might be one on a couple spare engines in the shed "out back." What looks like a raccoon turd in the attached pic is an actual, functioning vacuum advance as verified by my handy new vacuum pump.
All I have to do now is make it look less like a raccoon turd. Beats spending $40+ for one of questionable origin on eBay.
It is absolutely amazing to me how many of these ancient vacuum advance units are still good. I haven't run into a bad original one yet. I have heard about complaints with the reproduction ones not lasting.
1952 5-window - return to "as built" condition | 1950 3100 with a 235 and a T-5 transmission
How about a strong solution or warm water and Dawn dishwashing liquid? If it takes crude oil off baby ducks without killing them, a greasy vacuum advance shouldn't be much of a problem. Ditto for Tide or one of the other heavy duty laundry detergents! Jerry
"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt! There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway Love your enemies and drive 'em nuts!
Vacuum advance units aren't rocket science- - - - -why couldn't a more available item like one for a small block Chevy V8 be adapted to the stovebolt linkage? I'll bet I could spend an hour or two with a drill press, a hacksaw, and a few sheet metal screws and bring some of those dead ones back to life! I believe the stroke could even be made adjustable to fine tune the total degrees of advance in the process! Jerry
"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt! There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway Love your enemies and drive 'em nuts!
Hey JW, I too have a 1962 Chevrolet 235ci motor, on my 1948 Truck (btw my Chassis is a '51). Here are a couple pictures. The distributor moves (counter-clockwise) about 1/5th of a turn, under acceleration.
I put a new Vacuum on it that I purchased from Bowtiebits.com (1947-55 Vacuum Advance Part Number: AD-475-MECV-945) and the tubing came from InlineTube.com (part CTV4702) The distributor is an original '48 setup, however, I put a Pertronix 1168LSN6 ignitor into it, which get's rid of the points setup. Still uses a rotor, but it's 2x as better spark I hear. The engine is configured with a 6V setup (6V coil, 6V starter, 6V Battery, a 139 tooth Flywheel and the 6Volt Pertronix Ignitor in the distributor.)
The carburetor is a Carter YF. The Vacuum line that attaches to the Carb, has a straight line with a brass BB that goes over the tube, but inside the nut (like a plumbing fitting). Everything works just fine with the setup. I tested the Vacuum pressure with a gauge that hooks up to the fitting on the outside of your Intake Manifold, just below the Carb. The gauge reads in mercury pressure or inches per Hg. Shop manual says the vacuum should be between 17-21 in/Hg I believe.
I did a quick clean/check/regrease on my distributor this past week and discovered that the vacuum advance is inop; I guess I'll be looking for a new or working one as well.
Anyone who is willing to send me one of those non-working advance units would make it a lot easier for me to develop a possible modification to make use of a more readily available vacuum chamber. I don't necessarily need the clamp assembly that attaches to the distributor housing, just the advance chamber itself. PM me for a mailing address. Thanks! Jerry
"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt! There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway Love your enemies and drive 'em nuts!
Thanks! I believe it's possible to adapt a less expensive, more available vacuum chamber to the stovebolt advance bracket with a small piece of angle iron and a couple of sheet metal screws or pop rivets. GM used the same advance unit on virtually all their V8's for many years, so that would be a good candidate. Jerry
"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt! There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway Love your enemies and drive 'em nuts!
