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Allis B Compression

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H

History Guy

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I checked the compression on my Allis B and cylinders 1 and 2 are about 40 PSI while cylinders 3 and 4 are 25 psi. Should I put new rings in or do an overhaul?

Thanks
Aaron
 
You need to be 90 or above. I would think your best bet would be a complete overhaul. To be sure you would have to open it up and take measurments. A few years back I bought a tractor that the fellow had put in an engine kit (sleeves and pistons) The engne was very low on compression. When I pulled the head I found that he did not grind the valve seats. He had put in new valves but the seats were pitted and would not seal. The valve guides were also over size and needed to be replaced.
If you were lucky you would find the same and would only need to grind the valves and seats. The only way you will know is to take it apart, measure and inspect all parts.
 
More info would help. How long has it been sitting with out being run?? etc. etc. It could be as simple as stuck rings and or valves set wrong. I have one engine here that when I started working on it it was locked up. I got if free but still had low compression so I then filled the cylinders with more ATF and let it sit a few days longer. Compression came up to around 90psi in all cylinders and it run well now
Hobby farm
 
It was just running not more than 2 weeks ago. Now I can't get her started so I have been troubleshooting. I have hot blue spark now but hardly any compression. I will check the valves. That is a good idea.
 
If it was running a couple weeks ago I would check for stuck valves. ATF in the cylinder will never hurt either way and also can help the valves if you have a hand crank and can turn the engine with the plugs in. What that will do is maybe find any stuck valves because you will see it in the carb or exhaust
Hobby farm
 
Automatic transmission fluid =ATF. You could also have a couple push rods off the rockers and that will cause low compression and a no start problem
 
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