04-10-2020, 03:54 AM | #1 |
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Join Date: Jul 2013
Location: La Porte, IN
Posts: 143
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Cam spring
Does anyone know the correct length of an original cam spring? The replacement spring I got from Snyders I think is too short.
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04-10-2020, 07:34 AM | #2 |
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Join Date: Jul 2010
Location: Cow Hampshire
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Re: Cam spring
I have just examined two I could access from engines "apart."
One of these measures 1-3/16. This one I don't give a lot of credence to since it came from a timing cover where the plunger was "stuck" in place flush with the boss which contains it. The cam was obviously free to move forward and back and had worn the plunger boss. The spring itself seems somehow "thin" and weak. The other measures 1-1/2. This one I put to "more original" of the two. Fully functional albeit worn engine when removed. No evidence of modification and the spring seems somehow more "stout." This one I would re-use after wire-brushing. Hope this helps. I see at least one new spring in my Model A future. Joe K
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04-10-2020, 09:35 AM | #3 |
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Join Date: May 2010
Location: Portland OR
Posts: 6,340
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Re: Cam spring
Even if the spring is shorter, under compression it could still have the same force of the original if the diameter of the wire used to make it was larger.
If the spring for example needed to be compressed to say 1 inch, a spring with larger diameter wire would need to be compressed less to get the same working force as a spring that was made of smaller diameter wire. Example; If spring A with larger diameter wire is 1-1/4 inches long and when compress to working length of 1" has a force of 15 LBS (numbers are examples for illustration only, not real) and spring B with smaller diameter wire is 1-1/2 inches long and when compressed to 1" has the same LBS force. Both springs would work in the case of the plunger springs because the working length changes very little. As springs are compressed the force increases, that is why valve springs have two working numbers, closed and open given in most cases given in pounds force.
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04-16-2020, 11:15 PM | #4 |
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Join Date: Dec 2014
Location: Shawnee, Ok
Posts: 3,471
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Re: Cam spring
My computer is messing up so I can't post pictures, so, let me say...
Just changed out on original spring and plunger, plungers looks the same so no issue there, but the springs are way different, original is thinner wire but much longer, new one is thicker wire and much shorter but more stout. After fitting the old against the new on the engine I noticed that the compression felt more or less the same until the cover started tightening against the engine, the new short one felt much stronger and better to do the job. I went with the new short spring.
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04-17-2020, 07:02 AM | #5 |
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Location: Cow Hampshire
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Re: Cam spring
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Doc would take on a component inspired (usually) by some anomaly found at a Flea Market - and usually ending up for an afternoon at the Benson Archives and would tell you everything you needed to know. But alas, Doc passed in 2016. Certainly missed. https://www.wietingfuneralhome.com/o...kalinka-dvm/s/ Joe K
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