What compression is within spec on a Farmall Cub?

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mike758
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What compression is within spec on a Farmall Cub?

Postby mike758 » Mon Apr 25, 2016 1:15 pm

I have a 1953 Cub which I recently got, and it runs and drives pretty well. However, when it is warm, it burns oil, and there is oil on the plugs which shows it. On the original plugs, there were spacers on the plugs which are to my understanding to prevent oil fouling. Anyway, I performed a compression test with the engine warm and all the plugs out. The results were pretty even, being 80, 70, 70, 70. However, I can't find any reference ANYWHERE, telling what the "ok" compression range is.

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RaymondDurban
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Re: What compression is within spec on a Farmall Cub?

Postby RaymondDurban » Mon Apr 25, 2016 3:10 pm

Fresh engine from a rebuild should have 120-130 psi. Decent engine will have 90-100 psi. When you start getting down in the 70's, you start burning oil and having a hard time starting.

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Re: What compression is within spec on a Farmall Cub?

Postby Eugene » Mon Apr 25, 2016 4:05 pm

I used my Cub for about 1 year with 70 psi compression, until I got around to overhauling the engine. Worked OK, mowed and plowed the garden.

You might try some Seafoam in the engine oil and gasoline. This might free up any stuck piston rings, MIGHT.

Edit: Agree with Stan's figures,
I have an excuse. CRS.


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