Question: Automatic Spark Advance on 1929 straight 6

[jps]

In the 1929 Detailed Specs booklet on page 33 there is a brief explanation of the Automatic Spark Advance mechanism.  All the booklet really says is that the mechanism is located in the distributor cup, and that it automatically advances or retards the spark at different driving speeds.  It cuts in at 11 mph and gradually advances the spark up to 15 - 19 degrees at 40 mph.  This is in addition to the manual advance that the driver can perform via the steering wheel adjustment.

 

Does anyone know how this works?  What is the actual thing that makes this happen?

 

John

[bradsan]

I suspect that it is a mechanical system using pivoting weights and springs and the principles of centripetal  (or centrifugal depending on your frame of reference) force. You will find it under the plate holding the points and condenser. That is what our 1925 Std has .

 

Brad

[Guest]

Here is an illustration of the distributor on a '27 Buick.  Less than half a second for Google to locate this.

[Bill - 29 Buick]

1 hour ago, Tinindian said:

Daily driver of a Series 6-30B assembled in Regina, Saskatchewan on June 6, 1930 and purchased new by my Grandfather.

 

Tinindian:

 

Where'd you get the Regina plant build info ?  I contacted GM Oshawa's Vintage Vehicle Services and they said they didn't have any info at all, from the Regina Plant.

 

Do you have any info for the 1929 Model year ?

 

Bill McLaughlin

1929 Silver Anniversary Buick Club

[Oregon Desert model 45]

This is an earlier distributor shaft which shows the 3 weights and the cam. Underneath are springs that pull the weights "in". As the motor speed increases, the weights begin to swing "out" and push against the arms at the base of the cam, which advances the cam.

[Peter R.]

The 1936 Delco-Remy Distributor Service Manual explains it as follows:

 

Edited June 17, 2020 by Peter R. (see edit history)

[Peter R.]

Keep in mind that the distributor runs half the crankshaft rpm. So crankshaft advance angle and speed will be twice the distributor advance angle and speed.

 

 

Edited June 16, 2020 by Peter R. (see edit history)

[edinmass]

Just a short note......many to most of the mechanical advance units are gummed up from oil and dirt, and often not functioning to full potential. In a perfect world you should set it up on a Sun distributor tester and check its operation. We usually recurve the advance set up on cars with newly rebuilt engines, and add in more timing and get it in quicker. Makes for a much better running and driving experience. We don't just change springs, we change weights, and total advance, along with tip in..........

[jps]

Thanks to all for the info.  That is exactly what I wanted to know.

 

John

[Guest]

On 6/15/2020 at 2:04 PM, Bill - 29 Buick said:

Where'd you get the Regina plant build info ?

I got the information for my car in 1962 from GM in Oshawa.  I believe the only products assembled in Regina were Chevrolet, Pontiac and Oldsmobile.

I am attaching pictures and files that I have.

e mail: gmhistorian@btinternet.com for queries on Canadian Chevrolet/GMC/Chev-based Pontiac, to 1958, and also Chev/Pontiac/Olds/Buick 1928-39 as I have the date books for the latter, and a database for the former!
I also have my draft book on the history of Regina Plant written over numerous years which may get published one day! I have the Regina serial numbers for all years, for all makes, and the opening and closing dates: roughly December 1928-mid-1931; February-August 1932; December 1937-June 1941. However when Regina re-opened for the second time in 1937 for 1938 MY, they used '8' as a plant code on the serial number after the Model Number, and Oshawa became '0'. 1935-1937 vehicles sold through (distributed through) the Western Zone Office in the Regina Plant had 'W' after the Model Number, although 1932-4 although sent to the Western Zone based in the closed Plant, they did not apparently indicate this on the build plate.

It appears that the Fisher bodies built in Oshawa were sent to Regina to be trimmed and then mated with a Chassis.

 

https://www.google.com/search?q=general+motors+assembly+plant+regina&rlz=1C1CHBF_enCA819CA819&oq=General+motors+regina&aqs=chrome.2.0l3.11391j1j8&sourceid=chrome&ie=UTF-8

https://www.insideottawavalley.com/news-story/4279964-regina-built-1940-pontiac-with-same-owner-35-years/

[FLYER15015]

15 hours ago, edinmass said:

Just a short note......many to most of the mechanical advance units are gummed up from oil and dirt, and often not functioning to full potential. In a perfect world you should set it up on a Sun distributor tester and check its operation. We usually recurve the advance set up on cars with newly rebuilt engines, and add in more timing and get it in quicker. Makes for a much better running and driving experience. We don't just change springs, we change weights, and total advance, along with tip in..........

Yup, an old hot rod trick was to add some weight to the cams, set it up on an old Sun machine and sharpen the curve.

 

Also on my'40 Buick LTD, I ditched the 3 balls that the points plate rides on and went to the 3 plastic sliders.

That and a new vacuum advance unit made a world of difference in drivability.

 

Mike in Colorado

 

  

[Bill - 29 Buick]

 

Tinindian:

 

Thanks for the Regina plant info ?  I was hoping some 29 Buicks were built there.

 

Bill McLaughlin

1929 Silver Anniversary Buick Club

[Guest]

You are very welcome Bill.  I have a friend with a '37 Olds and one with a 30 Chevrolet both built in Regina.  As a Funeral Director in Victoria I met a man who was making funeral arrangements for his Brother.  He asked about the Pontiac on the parking lot.  When I told him it was built in Regina on June 6, he said both he and his late brother would have worked on it.  After the service in which 4 family members rode to the Cemetery there was about another fifteen that wanted a ride a car that was built by their relative (Dad, Granddad and Uncle).