COMPRESSION

[dwbelcher]

CHECKED THE COMPRESSION ON MY 48 8N AND RESULTS ARE AS FOLLOWS:
1 130
2 140
3 135
4 95

DO I NEED TO WORRY ABOUT #4. WHAT SHOULD COMPRESSION BE ON EACH CYLINDER.
THANKS FOR ALL THE HELP ON THIS TRACTOR. I AM IN THE PROCESS OF RESTORING IT.

 

[jtwat]

Yea, number 4 is low. As a rule of thumb, compression should be within 10% of each cylinder.

 

[Bob]

Have you been using and WORKING the tractor?

If so, something is going on with #4 that likely needs attention.

If it has been sitting unused, and just now you got it running and have been toying around with it, the compression numbers aren't as meaningful, IMHO.

 

[dwbelcher]

(quoted from post at 17:13:01 09/06/15) Have you been using and WORKING the tractor?

If so, something is going on with #4 that likely needs attention.

If it has been sitting unused, and just now you got it running and have been toying around with it, the compression numbers aren't as meaningful, IMHO.

ITS BEEN SITTING 7 YEARS IN A BARN. I GOT IT HOME A COUPLE OF WEEKS AGO AND STARTING WORKING ON IT. IT HAS NOT BEEN STARTED, JUST CHECKED THE COMPRESSION TODAY.

 

[Hobo,NC]

I wonder how did you get those high numbers on 1-2-3....
I don't believer them... Try another compression tester...

#4 may still be a issue but 130/140 on a N taint gonna happen...

 

[old]

Have you had something like ATF in the cylinders before you started spinning the engine over much if any. You may have sticking rings or a sticking valve on the #4 cylinder.

 

[dwbelcher]

(quoted from post at 19:04:05 09/06/15) Have you had something like ATF in the cylinders before you started spinning the engine over much if any. You may have sticking rings or a sticking valve on the #4 cylinder.

WHEN I FIRST GOT THE TRACTOR A COUPLE OF WEEKS AGO, I PUT ATF IN EACH CYLINDER AND OIL IN EACH CYLINDER TO MAKE SURE IT WAS LUBICATED BEFORE I TURNED THE ENGINE OVER.

 

[dwbelcher]

(quoted from post at 18:22:16 09/06/15)
I wonder how did you get those high numbers on 1-2-3....
I don't believer them... Try another compression tester...

#4 may still be a issue but 130/140 on a N taint gonna happen...

I THOUGHT THE NUMBERS WERE HIGH TOO. I WILL RECHECK TODAY. THANKS

 

[Hobo,NC]

Maybe you got allot of excessive oil in the cylinders something would have to take up space to achieve those numbers :wink:

A leak down test would be in order especially on #4...
I would not get my drawers all in a wad over those high #s they can still be used...

Compression numbers should be with end 10% of each other so #4 is still a issue...

Lets go one step farther for those that are shocked that #4 should be investigated...

https://en.wikipedia.org/wiki/Leak-down_tester

http://www.gregsengine.com/cylinder-leakdown-testing.html

The shocking part
How do we arrive at 90psi being the minimal speck and yours is above that and could be a issue. #4 may not be a issue and something is taking up space in the cylinder on 1-2-3. I would do a cylinder leakage test on #4 either way...

If normal good compression for a N engine is 110/120 and anything under 20% of that is considered below spec 20% of 110/120 is 22 to 24 leaving you with 88 to 96 as a threshold...

It will be interesting to see what you fine out.... I would not go dig'N into it till I had some direction on were I were headed...
1-2-3 are not leaking so why are those #'s so high...

 

[old]

Ok then on #4 may have a valve that is sticking. I picked up an 8N years ago that had a loader and part of a Sherman back hoe on it and had a valve problem on one cylinder

 

[Dune Country]

Hasn't been started?
If it were me I would fire it up and work it for a couple of hours, "might" just fix itself ,has been known to work