Update: 46 A compression

[710ltd2002]

The compression tested out at 95/90/50/95. 1,050 rpms at full
throttle. I believe Ill overhaul this engine sooner rather than
later. Is it common to have only one cylinder read so low?
Should I expect to see some damage other than worn rings in
there? Dave

 

[wore out]

Unless you have already checked the head you could have a burnt or bent valve not seating tightly on the weak cylinder.

Or, if the valves are OK likely you will find broken or stuck rings, or possibly a burned piston and scored sleeve to cause that much leakage past the piston.

If you have access to a cylinder leakdown tester you can determine if the compression loss is past a valve(s) or the piston or possibly a combination of both.

 

[710ltd2002]

I havent taken it apart yet. I thought I would order the kit first and try to get the job done in a weekend. We will keep using it to mow in the meantime.

I forgot to mention that adding oil to the weak cylinder did NOT increase the compression. Thanks for your input. I plan to post photos of what I find. Dave

 

[fastfarmall]

Then it is a bad valve,Chances are, but also maybe a good time to put some Dome pistons in there!

 

[gene bender]

check the cycl that has 50 to see if the tappets are set correct rest of the readings are decent and no cause for alarm

 

[grandpa Love]

Pull valve cover off, may just need a little adjustment

 

[Mrfred54]

Maybe just needs a valve job. 90 to 95 compression is not to bad on the three cylinders. In fact a valve job will probably increase the compression a little on the three cyls. and bring the bad one up to par. If the cylinder walls look good and no deep scratches and good oil pressure don't believe I would overhaul at this time. Good luck!!!

 

[BarnyardEngineering]

I did a quick n dirty valve job on a 240 a few years ago. Made a world of difference and didn't cost a whole lot.

When I pulled the head one exhaust valve had a piece missing out of it so that cylinder was low.

Basically I cleaned up the valve seats with a valve seat cutter, bought all new intake and exhaust valves, lapped them in. Brought the compression up on that cylinder to the same as the other three, and the tractor ran great.

95PSI is nowhere near "overhaul" compression if you ask me.

 

[Gary Mitchell]

I second your opinion. I've had the same issue with the same remedy more than once, although I never lost any sleep
after replacing a bad valve with a good used one. ;-) gm

 

[710ltd2002]

I appreciate everyones input. I was leaning toward new pistons and sleeves because of the oil consumption. Its burning about a quart every four hours. Dave

 

[710ltd2002]

I wondered about flathead vs domed. Does it make a significant difference? I dont need much more power out of this engine, but I like the idea of fixing it up to be the best it can be. I also wondered if the domed pistons would cause more stress on the block or any other components. Dave

 

[710ltd2002]

Will a bad valve or rod cause the oil to get sucked up and
burned? Dave

 

[Lucid]

Ok, so Old hasn't replied to this yet? Try dumping in some automatic transmission oil in each cylinder and let sit. Then few days later, pull plugs back out and spin motor over to blow out excess fluid. Put plugs back in and fire it up. Run the snot out of it. Then redo compression checks. Worked for me and cost $5.

 

[old]

What me say something about ATF??

 

[fastfarmall]

It wont hurt the block at all, it will run like a sewing machine, i said Dome pistons but the right trem is power crater!!

 

[710ltd2002]

Ok thank you. This site offers both style pistons at close enough pricing.