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09-05-2014, 11:48 AM | #1 |
Member
Join Date: Jun 2013
Location: Texas/Wyoming
Posts: 35
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Spark Advance Linkage Length
I'm in the process of trying to find the root cause of my spark advance linkage not fitting properly. My linkage is factory standard of 17" inside-inside, or about 17-1/2" total length with the sliding sleeves. The distance from the inside-inside of the control rod arms on the steering column (down) and the distributor plate fully advanced in the distributor slot is 16-3/4" or about 1/4" shorter than the linkage. The linkage was "bowed to fit" before I started this process, as it was causing inconsiency is setting timing, etc. This is on a '29 roadster, with a 7 tooth steering column.
It appears my solutions are: 1.) find the root cause and fix it (preferred option), 2.) bend one of the control arms to fit, 3.) shorten the linkage by cutting and welding, 4.) leave it as is with a "bow" in the linkage. Has anyone else had this issue and found a root cause that's easy to fix? Or, is their a preferred option of the other ways to jimmy rig it (no offense jimmy)? I'm leaning towards option 2 if I can't find the root cause. I have checked to see if there is any misalignment of the engine to the frame, but all seems to be well with the motor mounts & rubbers (albeit they're old). I've also checked to see if there is any way to rotate the steering column, but all appears to be rigid. Thanks in advance if anyone has any guidance or preferred solutions to this problem. |
09-05-2014, 12:26 PM | #2 |
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Join Date: May 2010
Location: Waterloo, IL
Posts: 81
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Re: Spark Advance Linkage Length
If your car has a 2-tooth steering sector, you rotate the steering column so that the spark rod has proper movement from full retard to full advance at the distributor.
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Doug in Waterloo |
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09-05-2014, 12:44 PM | #3 |
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Join Date: Nov 2013
Location: Northern Bucks Co. Pa
Posts: 632
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Re: Spark Advance Linkage Length
As DDW says, Rotate the tube/sleeve of your steering column. Loosen the clamp at the bottom of the column and twist it in the desired direction. It's kinda like the last thing you think of doing, but that's the cure.
Terry |
09-05-2014, 02:14 PM | #4 |
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Join Date: May 2013
Location: E Tn.
Posts: 169
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Re: Spark Advance Linkage Length
Bergy stated "This is on a '29 roadster, with a 7 tooth steering column", so steering column is a NO GO.
I have a '28 roadster with the same problem and the only solution I have found so far is your option 4 - bend a bow in the linkage. With the bent linkage I was able to obtain the correct movement for both no advance to full advance. J |
09-05-2014, 03:21 PM | #5 |
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Join Date: May 2010
Location: San Diego,Ca
Posts: 1,377
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Re: Spark Advance Linkage Length
Hello Bergy,
I would go with your #2 method, in fact the service bulletins on page 480 say to do this as long as the distributor body has the correct movement 20* degrees between retard and advance, and the rod is the correct length, (some repops are not correctly made) It took just a little bending to fit correctly when I did mine. Regards Brian.
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Nothing can be made foolproof, ---- fools are ingenious bastards. Last edited by Brian T; 09-05-2014 at 03:39 PM. |
09-13-2014, 11:10 PM | #6 |
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Join Date: Jun 2013
Location: Texas/Wyoming
Posts: 35
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Re: Spark Advance Linkage Length
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09-14-2014, 07:32 AM | #7 |
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Join Date: May 2010
Location: Southbridge, Ma.
Posts: 1,614
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Re: Spark Advance Linkage Length
I think the control rod is too long. I've noticed that on most of the Model A's I've had. I end up by bowing the rod slightly, on one I must have rotated the column 10 degrees so I wouldn't have to bend the rod but it looked odd from the drivers seat so I just bent the rod.
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09-14-2014, 11:22 PM | #8 |
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Join Date: Dec 2012
Location: San Francisco, CA
Posts: 169
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Re: Spark Advance Linkage Length
I was just having this same problem today. It turns out, I had been looking at that brass piece among the parts I got when I bought my first roadster two years ago. I kept wondering what on earth it was for. I just put it to use and am happy as a lark!
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