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CA engine compression?

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Topic: CA engine compression?

Posted By: boggen
Subject: CA engine compression?
Date Posted: 05 Jun 2017 at 12:00am

can't find my manual, that i thought had compression listings in it.

front of engine

1 cylinder - dry 50PSI - wet 75 PSI

2 cylinder - dry 49PSI - wet 80 PSI

3 cylinder - dry 50PSI - wet 80 PSI

4 cylinder - dry 50PSI - wet 80 PSI

rear of engine

having some issues with engine and a knock sound, and wanting to know what it should be reading at if all was perfect.

Replies:

Posted By: DrAllis
Date Posted: 05 Jun 2017 at 7:27am

I'm guessing your dry compression should be just over 100 psi......100 to 120 is what my memory tells me.

Posted By: steve(ill)
Date Posted: 05 Jun 2017 at 7:32am

many of the small motors only had 6.5 - 7.0 to 1 compression ratio. ON the gauge you might measure 80- 100 psi. A lot of them running with 80 psi.... SEe if the compression goes back down to 50 after setting for an hour. If it does, you rings might be worn and loosing compression. It wont run much at all with 50 psi.

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Like them all, but love the "B"s.

Posted By: jaybmiller
Date Posted: 05 Jun 2017 at 7:38am

I was thinking compression ratio x 14.7= the cylinder compression.
say 6.5 ratio, x 14.7 is.... 95.55 ,so 95 PSI, more or less.

what is important is that all are close,say 5 psi, to each other.

when an engine gets 'tired', say 80 PSI, it won't pull like it used to.....

had a walkbehind tiller here, started great, put in dirt it died....only had 40# !

Jay

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3 D-14s,A-C forklift, B-112
Kubota BX23S lil' TOOT( The Other Orange Tractor)

Never burn your bridges, unless you can walk on water

Posted By: Dennis(IA)
Date Posted: 05 Jun 2017 at 8:13am

50 psi is on the border for starting. I had a tractor that had under 50 and it would not start. After oil in the cylinders it finally started and after running the compression came up. This tractor sat outside and had a stuck engine (3020 JD) and after I run it the compression came up so it would start and run. This was not my tractor, I was working on it and that is all he wanted done.

Posted By: Brian Jasper co. Ia
Date Posted: 05 Jun 2017 at 12:34pm

I installed a Valu-Bilt new engine in an 8N once. Wouldn't start, beating my head against it and decided to check compression and measured 75 psi. I shot some oil in the cyls and it jumped to 130 and then was willing to run. That engine must have set in the warehouse for a long time for all of the oil to drain off the pistons.

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"Any man who thinks he can be happy and prosperous by letting the government take care of him better take a closer look at the American Indian." Henry Ford