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Timing by Tappets from #6 Cylinder


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Two questions:

 

1) Vibration Damper Pully Timing Marks (TDC)

Did the CXXs have a band on top of the damper pully that had the timing marks? The shop manual picture and text indicate there is a band on top of the damper pully that has the marks on it, but if mine  had one originally, the band is long gone. I don't see it in the parts book either? Anybody have it? 

 

2) Timing from Rear Cylinder using Tappets

 

 

The shop manual indicates that proper timing is set by measuring when the rear intake tappet just makes contact with the valve stem. These should correspond with the timing marks on the sprockets.  According to the manual then, we should be all timing off #6 (last piston nearest the firewall), and not the first cylinder #1 (nearest the fan). That would also shed light on some of the discussions about timing in other threads where being 180 degrees off, might really be opposite, and we should be timing when it's the rear cylinder. 

 

It's probably six of one, and half a dozen of the other, and all relative as long as it's consistent, but it seems to me that the timing marks would be off if the factory did it from the last cylinder, and conventionally we were doing it from the first cylinder (and generally using #1 for the timing light).

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Edited by wagoneer
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Timing in the seciton of the manual you posted refers to valve timing, not spark timing.  The test seems to be a double check that the chain, sprockets, cam and crank are installed in the proper relationship, and it can also expose chain or sprocket wear..  Cyl 6 is used since it is the one that has the access hole to determine TDC. 

 

 

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I always use number 6 sparkplug with my 12volts sears timing light. I just reverse the leads to be representative of the 6v positive ground and not negative ground.

 

My timing mark on my dampener is approx. 2 degrees before TDC and I can get the car adjusted to that marking.

 

Rich Hartung

 

Desoto1939@aol.com

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For Entertainment only.

From Model T days there was a tool maker who discovered how badly Henry Ford's cams were off. Now the "adjustment" for Ford tappets was done when you did a valve job. When you ground the seats you also ground the stem of the valve to get the right clearance. The theory was that the seats wore with the valves and the tappets equally. KR Wilson realized that Ford valve action really wasn't timed right and that changing the tappet clearance could make a big difference in the performance of a Model T. So they made a simple tool which "timed" the valve based on the piston position. You turned the crank until you felt the tool move then you ground the valve stem til the valve was just seated regardless of the clearance. The tool corrected the inaccuracy of the cam/gear set/timing by changing the clearance. Making sure the valve didn't open too soon and loose cylinder pressure.

They say it worked.

Model Ts had so many things that made noise I suppose loud tappets were never a worry.

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I agree with ken combs.  This section is all about valve timing and not ignition timing.  Even the specs themselves give a pretty wide tolerance on intake valve opening timing.  You really need to be able to determine the exact TDC location on the pulley.  Even if the pulley is marked, they can be off several degrees from the factory and should be checked for accuracy using the TDC of the piston at some point, preferable during your rebuild process.

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