Compression test results

[Dwd14329]

My results for compression test is as follows: firing order 1423
1947 Ford 2N

#1 cylinder 94 psi
#2 cylinder 81 psi
#3 cylinder 89 psi
#4 cylinder 83 psi

Can you or any mechanic see any red flags with these results? Please advise.

 

[Brown David]

I'd say they are low. Will probably run but performance will be low and most likely oil consumption will be a factor.

 

[Dwd14329]

I'd say they are low. Will probably run but performance will be low and most likely oil consumption will be a factor.

Do you know what the norm is?

 

[HFJ]

dude, i'm starting to think u stole my tractor. 125 is freshly rebuilt. 90 (what i have) is approaching marginal. my tractor smoked a lot from both ends and new rings and pistons cured that, but i didn't touch the valves and ended up with slightly better compression than yours. it's serviceable, but ALL i do is pull a 5 foot finish mower with it.

 

[Dwd14329]

dude, i'm starting to think u stole my tractor. 125 is freshly rebuilt. 90 (what i have) is approaching marginal. my tractor smoked a lot from both ends and new rings and pistons cured that, but i didn't touch the valves and ended up with slightly better compression than yours. it's serviceable, but ALL i do is pull a 5 foot finish mower with it.

Understood!

 

[Brown David]

Do you know what the norm is?

Pretty much what HFJ said.

 

[Dwd14329]

dude, i'm starting to think u stole my tractor. 125 is freshly rebuilt. 90 (what i have) is approaching marginal. my tractor smoked a lot from both ends and new rings and pistons cured that, but i didn't touch the valves and ended up with slightly better compression than yours. it's serviceable, but ALL i do is pull a 5 foot finish mower with it.

Oh, you can have the tractor as long as I get back what I paid for it. Lol

 

[wore out]

My results for compression test is as follows: firing order 1423
1947 Ford 2N

#1 cylinder 94 psi
#2 cylinder 81 psi
#3 cylinder 89 psi
#4 cylinder 83 psi

Can you or any mechanic see any red flags with these results? Please advise.

Did you have the throttle wide open while doing the tests, and are you sure there's no restriction in the air intake system?

Add a little motor oil to each cylinder and repeat the test. If the numbers are better that would point to leaking piston rings, if there's little change that would point to valves that aren't sealing.

You could also do a leakdown test to pinpoint exactly what's going on.

 

[Dwd14329]

Not sure how to do a leak down test but I'll work on the wet test first and move on from their. What am I looking for with a wet test wore out?

 

[Factotum]

This is why you do the whole test as one test. I replied in the other thread. You have to compare your dry and wet to guide you in what direction to take next. Wet worn out isn't really a thing. You get a set of numbers dry and where they go wet says what to do next.

 

[wore out]

Not sure how to do a leak down test but I'll work on the wet test first and move on from their. What am I looking for with a wet test wore out?

As I wrote: "If the numbers are better (after oil is added) that would point to leaking piston rings, if there's little change that would point to valves that aren't sealing.").

https://www.alldata.com/sites/default/files/file-attachments/cylinder_leak-down_testing_011019.pdf

Link above is cylinder leakdown test info.

 

[Dwd14329]

This is why you do the whole test as one test. I replied in the other thread. You have to compare your dry and wet to guide you in what direction to take next. Wet worn out isn't really a thing. You get a set of numbers dry and where they go wet says what to do next.

I understand! It's not likely that I will be able to do a leak down test sense the test calls for warming up the engine prior. I'll have to back track and find out why it's not firing smoothly. From what I understand, my initial dry readings aren't bad enough to cause the misfiring I'm having, is it? If I had a stuck valve, compression would be very low on one cylinder, correct? That's why i need to back track. I will definitely have to address the low compression at some point but getting a good spark should be my first priority, Shouldn't it? I've been accused of jumping all over the board and I agree. Inexperience habit Would you agree that I need to backtrack and troubleshoot a better spark? My initial problem was that I wasn't getting a solid blue spark on any plug to enable good combustion at the cylinders. I call it missfiring but it's sputtering and runs rough. That lead me to checking compression for a sticking valve. Why? Recommendations! I should have explained this at the beginning. I have 2 or 3 topics on this issue. The reason for compression test post was to get advise or direction on my next step. Which would be back to ignition circuit and start over on troubleshooting sense i dont have a sticking valve? Or is there reason to believe the compression readings i have could cause the sputtering and running rough? I feel bad about this. I can see how you would think I'm troubleshooting compression. My apologies gentlemen.

 

[Factotum]

From what I've read about your problem, it seems to be that you are getting a popping exhaust, it runs ok at first but then gets bad. You have ok spark, you've checked the electrical pretty well. You've rebuilt or at least cleaned the carb a few times now, so let's say that isn't the problem for the misfiring or stumble or popping. Unless I'm incorrect with my knowledge of your problem, I think the compression test would be next. This tells you whether it's rings or valves/ head gasket. You only know now that you have a lowish compression with just the dry test. You don't know if it's all valves or all rings or a mixture of both. If the tractor was blowing blue smoke when running that is pretty good evidence of an oil ring problem. If your compression test reveals no problem with the rings (no real increase with oil added), then you have good evidence that it is a valve / head gasket problem. Check the clearance to see if you have too little, which would cause a misfire or popping at least at idle. You can also check for sticking valves and if you have adjustable lifters with the valve covers off. You are in a bit of a tough spot though. Having a 2n, you might not have adjustable lifters unless someone put them in there at a prior rebuild. That will make things rather difficult. The head needs to be pulled off and valves removed and adjusted by grinding. Trying to diagnose and repair with the loader in the way isn't easy. I wish you luck, you've had enough difficulties already.

 

[Dwd14329]

From what I've read about your problem, it seems to be that you are getting a popping exhaust, it runs ok at first but then gets bad. You have ok spark, you've checked the electrical pretty well. You've rebuilt or at least cleaned the carb a few times now, so let's say that isn't the problem for the misfiring or stumble or popping. Unless I'm incorrect with my knowledge of your problem, I think the compression test would be next. This tells you whether it's rings or valves/ head gasket. You only know now that you have a lowish compression with just the dry test. You don't know if it's all valves or all rings or a mixture of both. If the tractor was blowing blue smoke when running that is pretty good evidence of an oil ring problem. If your compression test reveals no problem with the rings (no real increase with oil added), then you have good evidence that it is a valve / head gasket problem. Check the clearance to see if you have too little, which would cause a misfire or popping at least at idle. You can also check for sticking valves and if you have adjustable lifters with the valve covers off. You are in a bit of a tough spot though. Having a 2n, you might not have adjustable lifters unless someone put them in there at a prior rebuild. That will make things rather difficult. The head needs to be pulled off and valves removed and adjusted by grinding. Trying to diagnose and repair with the loader in the way isn't easy. I wish you luck, you've had enough difficulties already.

Thank you Factotum. I truly believe, if we could post videos on this site, you guys could diagnose just by sound, 90 % of the time. Inexperienced guys like me don't have a clue how to describe something we have little knowledge. I can say my terminology is horrible when it comes to engine mechanics. I know basically how an engine functions and most of the part names but engine troubleshooting is a definite weakness. If you have a furnace or AC not working, 99 % of the time I could walk a customer through the repair over the phone. It's all about education and experience. I'm probably the most inexperienced on YT. I'll try to back off and figure this out but thanks again. I had a guy walk me thru a hydraulic control valve replacement on my dearborn 19-23 and its never worked better, so I've kinda become dependant on YT.

 

[BradCNY]

My results for compression test is as follows: firing order 1423
1947 Ford 2N

#1 cylinder 94 psi
#2 cylinder 81 psi
#3 cylinder 89 psi
#4 cylinder 83 psi

Can you or any mechanic see any red flags with these results? Please advise.

Is that a misprint on firing order, shouldn't it be 1243

 

[BradCNY]

Is your firing order correct, 1243

 

[Dwd14329]

Yes folks, it's a misprint. I should have proof read it. Par for the course with me.

Is your firing order correct, 1243

 

[Abbby]

My results for compression test is as follows: firing order 1423
1947 Ford 2N

#1 cylinder 94 psi
#2 cylinder 81 psi
#3 cylinder 89 psi
#4 cylinder 83 psi

Can you or any mechanic see any red flags with these results? Please advise.

It if starts and runs good then leave it alone.

 

[Dwd14329]

After the dry test results, I went ahead and purchased a new quality coil and put the distributer back on. Unbelievably, the tractor Fired up, runs like a charm. This is the 3rd coil I've gone through. 1st one I thought was bad due to low spark so I replaced it with a cheap coil from Amazon. I read alot of threads saying just because the coils ohm out ok doesn't mean its a good coil. Bought my 3rd one all ag states parts. After all the trouble shooting and help I got from you guys, taking up your time, it ended up being a coil. Spark is blue on all cylinders now. I will eventually trouble shoot the low compression but not until fall, after snow season. Thank you for all your help.

 

[stevieb49829]

Unless I missed it, nobody mentioned timing. Is it timed correctly? Especially when you say you "put the distributer back on". Do you know how to adjust the timing? steve