1947 Ford 2N Engine side covers

[Ed S.]

I don't remember a fuel smell... a compression test should tell you pretty quick about the valves.

 

[Dwd14329]

I don't remember a fuel smell... a compression test should tell you pretty quick about the valves.

My results for compression test is as follows: firing order 1423

#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.

 

[Factotum]

Here's a question. Which would be the most likely to happen on an operated/ running engine? Would the valve guides get sticky from contaminated or old oil or from dirty or old gas? My logic would say it would be more likely from old oil and sludge causing sticking in the guides. In which case the spraying of carb cleaner or what not directly on the springs and guides would clean them up.
I had good compression cold. My tractor had the famous putt-puff at idle, which became worse when warmed after a few minutes of running. I found the valve clearances were next to nothing (like .005") and I figure as the engine warmed, the clearance went even less possibly even none. This, in my theory, caused the exhaust valves to leak during the compression stroke and cause the leaking unburned gas to be ignited by the next cylinders' exhaust fire. Adjusting the valve clearance cured 95% of the problem for me. Now, I'm not saying this is your problem.
Let's keep this as easy as possible. You should be able to diagnose sticking valves with a compression test. Adding oil for the second part of the compression test would not show an increase in pressure, pointing to leaking valves or head gasket.

 

[Ed S.]

Number two is low compared to the rest and might bear investigation. Are those dry or wet readings? Forgive me is this is stuff you know, but wet means you squirt a teaspoon of engine oil into the cylinder before running the test (and should be done after your initial "dry" test). Also, did you run the test with all plugs removed, and did you let the engine spin over until the pressure stopped rising (on a fully-charged battery)?

I'll add this, just because I've chased the wild goose a few times myself: don't discount that you might actually still have an electrical problem, even though you've chased that a bit. There's an old saying that "90% of fuel problems are electrical." If your symptoms are a regular miss, as if one cylinder is not firing, as opposed to intermittent, irregular missing, then by all means keep checking for sticking valves. Something irregular would lead me back to electrical, however.

I'm afraid you're just going to have to put in the elbow grease to keep running tests on your end until you get it sorted. I recently had a problem with a year-old CC garden tractor that the dealer wasn't able to fix. Spent a solid two days testing out every component and connection, and it turned out to be a bad main ground to the engine block.

Good luck with it!

 

[Dwd14329]

Number two is low compared to the rest and might bear investigation. Are those dry or wet readings? Forgive me is this is stuff you know, but wet means you squirt a teaspoon of engine oil into the cylinder before running the test (and should be done after your initial "dry" test). Also, did you run the test with all plugs removed, and did you let the engine spin over until the pressure stopped rising (on a fully-charged battery)?

I'll add this, just because I've chased the wild goose a few times myself: don't discount that you might actually still have an electrical problem, even though you've chased that a bit. There's an old saying that "90% of fuel problems are electrical." If your symptoms are a regular miss, as if one cylinder is not firing, as opposed to intermittent, irregular missing, then by all means keep checking for sticking valves. Something irregular would lead me back to electrical, however.

I'm afraid you're just going to have to put in the elbow grease to keep running tests on your end until you get it sorted. I recently had a problem with a year-old CC garden tractor that the dealer wasn't able to fix. Spent a solid two days testing out every component and connection, and it turned out to be a bad main ground to the engine block.

Good luck with it!

Hey Ed, thanks for the questions because I am not a mechanic and this is the first compression test I have conducted. I did this based on a YouTube training video I watched for 2N tractors. I removed plugs, initial dry test results with battery charged. I turned over the engine until the pressure stopped rising. About 4 complete turns. I will say, without removing the hood, it was difficult to thread the compression hose and I was only able to finger tighten the hose to each cylinder. What would be your recommendation My issue has been consistent missfiring after start up as if running on 3 cylinders. This started happening after cold weather set in but it happened suddenly. I was starting the tractor nearly every other day to make sure it was ready for snow removal and the missfire gradually got worse to the point it missfires consistently. That led me to believe i had a distributer issue. The wiring does appear to be old and I may have to replace the harness. I'm going to attempt to fire it up tomorrow after I re-assemble tomorrow and see if I can see arking in the dark. Are the compression readings bad enough to where I would consistently get missfiring? It is extremely damp outside so I'm choosing to wait for tomorrow.

I will also make sure I have a good ground. That's the only thing I did not check. It would make sense why I have a weak spark. Thanks again, Ed.

 

[Ed S.]

Hey Ed, thanks for the questions because I am not a mechanic and this is the first compression test I have conducted. I did this based on a YouTube training video I watched for 2N tractors. I removed plugs, initial dry test results with battery charged. I turned over the engine until the pressure stopped rising. About 4 complete turns. I will say, without removing the hood, it was difficult to thread the compression hose and I was only able to finger tighten the hose to each cylinder. What would be your recommendation My issue has been consistent missfiring after start up as if running on 3 cylinders. This started happening after cold weather set in but it happened suddenly. I was starting the tractor nearly every other day to make sure it was ready for snow removal and the missfire gradually got worse to the point it missfires consistently. That led me to believe i had a distributer issue. The wiring does appear to be old and I may have to replace the harness. I'm going to attempt to fire it up tomorrow after I re-assemble tomorrow and see if I can see arking in the dark. Are the compression readings bad enough to where I would consistently get missfiring? It is extremely damp outside so I'm choosing to wait for tomorrow.

Run a wet compression test (cold) and report back... your numbers aren't horrible for an older rebuild, but the 10+ lb. difference on #2 is a bit much. A valve that's really sticking bad, however, will result in 0 (zero) psi (or close to it), since it's not sealing at all.

Honestly, while there's no guarantee I'm right, your symptom description sounds more like an electrical issue to me. When my valves were sticking, the tractor was very hard to start, and I'd sometimes have to recharge the battery for another go if I couldn't get it running.

If your wiring is old (both plug and harness), I'd plan on an afternoon replacing both - they're not expensive (and sold here on YT). I have a new harness for mine sitting in the shop, actually - it's been 15 years since I rebuilt it, and it's getting crusty in places. I replaced plugs and sparky wires a few years ago...

Front-mount distributors can be finicky, and it's sometimes taken me several off/on cycles to get the pigtail lined up right, or not have an internal wire grounding itself out… always pull the whole thing and do your internal work on the kitchen table where you have good light and can get to everything good.

Make sure all wiring connections throughout your whole wiring harness are "clean, bright and tight."

One connection that's often overlooked is the mating surface between your starter and the engine block - that needs to be clean and bright, too - it's a major electrical pathway. If you haven't had your starter off yet, you'll learn about holding your tongue "just right" to get the bendix to clear the flywheel as you remove the starter (do NOT accidentally activate the bendix while it's out!! it's a bear to get it to retract if you do!).

Hope that helps...

 

[Dwd14329]

Run a wet compression test (cold) and report back... your numbers aren't horrible for an older rebuild, but the 10+ lb. difference on #2 is a bit much. A valve that's really sticking bad, however, will result in 0 (zero) psi (or close to it), since it's not sealing at all.

Honestly, while there's no guarantee I'm right, your symptom description sounds more like an electrical issue to me. When my valves were sticking, the tractor was very hard to start, and I'd sometimes have to recharge the battery for another go if I couldn't get it running.

If your wiring is old (both plug and harness), I'd plan on an afternoon replacing both - they're not expensive (and sold here on YT). I have a new harness for mine sitting in the shop, actually - it's been 15 years since I rebuilt it, and it's getting crusty in places. I replaced plugs and sparky wires a few years ago...

Front-mount distributors can be finicky, and it's sometimes taken me several off/on cycles to get the pigtail lined up right, or not have an internal wire grounding itself out… always pull the whole thing and do your internal work on the kitchen table where you have good light and can get to everything good.

Make sure all wiring connections throughout your whole wiring harness are "clean, bright and tight."

One connection that's often overlooked is the mating surface between your starter and the engine block - that needs to be clean and bright, too - it's a major electrical pathway. If you haven't had your starter off yet, you'll learn about holding your tongue "just right" to get the bendix to clear the flywheel as you remove the starter (do NOT accidentally activate the bendix while it's out!! it's a bear to get it to retract if you do!).

Hope that helps...

Hey Ed, I'm going to run the wet test, will that improve numbers and what oil should I use? Should I put it straight down into plug hole? Although I think you are absolutely correct, I would like to verify my compression. I may have looked something over on my electrical end. It always possible. I appreciate your patience and taking the time to help out. I will run the test tomorrow and definitely would like to get back to you with your opinion. I'm charging my battery over night. Oh, I would never ask for guarantees, I know how this works. Thanks

 

[Ed S.]

Hey Ed, I'm going to run the wet test, will that improve numbers and what oil should I use? Should I put it straight down into plug hole? Although I think you are absolutely correct, I would like to verify my compression. I may have looked something over on my electrical end. It always possible. I appreciate your patience and taking the time to help out. I will run the test tomorrow and definitely would like to get back to you with your opinion. I'm charging my battery over night. Oh, I would never ask for guarantees, I know how this works. Thanks

Just a teaspoon or so of engine oil (SAE 30, same as you run in the engine), down the sparkie hole. You should see all your numbers go up a bit since that helps seal the valves better. If #2 comes up more in line with the others (±5psi), that might point to minor sticking on that cylinder. Couldn't hurt to add a few ounces of ATF to a full tank of gas, either.

Will look for updated numbers when you post 'em!

 

[Jim.ME]

Just a teaspoon or so of engine oil (SAE 30, same as you run in the engine), down the sparkie hole. You should see all your numbers go up a bit since that helps seal the valves better. If #2 comes up more in line with the others (±5psi), that might point to minor sticking on that cylinder. Couldn't hurt to add a few ounces of ATF to a full tank of gas, either.

Will look for updated numbers when you post 'em!

Oil is generally added to cylinders to help seal the rings during compression test after the original "dry" test. If the compression comes up after adding oil it is generally an indicator the rings are weak. If the compression doesn't come up with oil added it generally is more indicative of a weak sealing valve(s). At least that is what I was taught and has been my experience. YMMV

 

[wore out]

Just a teaspoon or so of engine oil (SAE 30, same as you run in the engine), down the sparkie hole. You should see all your numbers go up a bit since that helps seal the valves better. If #2 comes up more in line with the others (±5psi), that might point to minor sticking on that cylinder. Couldn't hurt to add a few ounces of ATF to a full tank of gas, either.

Will look for updated numbers when you post 'em!

"(Oil) helps to seal the valves better"

Adding oil to the cylinders typically affects the "ring seal" much more than the valves, and an increase in compression is usually attributed to the rings sealing better.

 

[Ed S.]

Y'all are correct - my aging memory pulled up the wrong file card!

 

[Dwd14329]

Y'all are correct - my aging memory pulled up the wrong file card!

No, it's not you Ed. It's my inexperience. On my previous post, I've been troubleshooting misfire from the beginning. You were dead on! After confirming that I don't have a sticking valve, I need to backtrack to electrical/ignition system. I'm not to the point of troubleshooting compression. I feel bad and hope I haven't misled anybody.

 

[Jim.ME]

No, it's not you Ed. It's my inexperience. On my previous post, I've been troubleshooting misfire from the beginning. You were dead on! After confirming that I don't have a sticking valve, I need to backtrack to electrical/ignition system. I'm not to the point of troubleshooting compression. I feel bad and hope I haven't misled anybody.

We all get mixed up at times and I wasn't trying to down Ed's response, just trying to be sure you look at the compression results the right way. A common rule of thumb with compression numbers is that a 10% or less spread between the high and low cylinder pressures is ok. Yours is slightly over but should still run ok. The engine cranking a bit slower during a cylinder's test or turning over a time or two more or less could affect the pressure. If you did #1 cylinder first, you could always recheck it after doing the other three to see if it gives a lower pressure due to a bit slower cranking speed because the battery has lost some charge. I often keep my large charger on a battery when testing to keep the battery up the best I can.

 

[wore out]

We all get mixed up at times and I wasn't trying to down Ed's response, just trying to be sure you look at the compression results the right way. A common rule of thumb with compression numbers is that a 10% or less spread between the high and low cylinder pressures is ok. Yours is slightly over but should still run ok. The engine cranking a bit slower during a cylinder's test or turning over a time or two more or less could affect the pressure. If you did #1 cylinder first, you could always recheck it after doing the other three to see if it gives a lower pressure due to a bit slower cranking speed because the battery has lost some charge. I often keep my large charger on a battery when testing to keep the battery up the best I can.

I absolutely agree with you, Jim! Sometimes a little correction is needed and it shouldn't be taken as a ''dig'' against the other person. Someone may find this thread in the archives years from now and corrections as needed will make it more valuable to someone looking at it down the road.

 

[wore out]

No, it's not you Ed. It's my inexperience. On my previous post, I've been troubleshooting misfire from the beginning. You were dead on! After confirming that I don't have a sticking valve, I need to backtrack to electrical/ignition system. I'm not to the point of troubleshooting compression. I feel bad and hope I haven't misled anybody.

"After confirming that I don't have a sticking valve"

Although I DOUBT you have a sticking valve while it's running the compression test you did doesn't ABSOLUTELY rule that out.

Just something to keep in mind as you go forward.

 

[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.