9n compression numbers and what to do?

First of all I have been scouring the threads on compression tests and trying to figure out what I need to do for my old tractor. Lots of data and information but hard to piece it together. I have a 9n that was running fairly well but then started to miss and has no power, it was on the weak side to begin with. Figuring it was time for new points, condenser, plugs and spark Wires, I change all of these with no change in the performance. So I did a compression test and had these numbers. Dry #1 - 65, #2- 97, #3 - 87, #4 -95
wet was 75, 102, 115, 103

My question, is this indicating a valve problem on Number one and does Number 3 look like ring problems? if so what does it entail to get it fixed? Thanks for any and all help ahead of time!
 
Could be as simple as valves needing adjusting or needing ground. Also broken valve spring. But could also be rings.
 
(quoted from post at 10:06:43 08/12/19) First of all I have been scouring the threads on compression tests and trying to figure out what I need to do for my old tractor. Lots of data and information but hard to piece it together. I have a 9n that was running fairly well but then started to miss and has no power, it was on the weak side to begin with. Figuring it was time for new points, condenser, plugs and spark Wires, I change all of these with no change in the performance. So I did a compression test and had these numbers. Dry #1 - 65, #2- 97, #3 - 87, #4 -95
wet was 75, 102, 115, 103

My question, is this indicating a valve problem on Number one and does Number 3 look like ring problems? if so what does it entail to get it fixed? Thanks for any and all help ahead of time!
You have what looks like blowby on the rings and at least one bad valve. I would expect to see signs of the blowby coming from the crankcase breather. The valve repair is the one that will give you more heartburn. It requires a seat cutter and an experienced operator. The blowby can be fixed by installing a $175 piston and liner kit.

TOH
 

A cylinder leakage test will locate the leakage... My bet you have valve sealing issues...

#1 cylinder will ware faster than the others because it runs cooler than the rest its getting the cooled coolant all the time blasted aging the front of #1 cylinder wall.

Anyways a compression test is used to lead you in the next test needed to find leakage if its below acceptably levels...

The latest greatest is a Pressure Waveform analysis....

https://www.picoauto.com/library/training/pressure-school-part-2-a-running-diagnosis
 
(quoted from post at 15:06:43 08/12/19) First of all I have been scouring the threads on compression tests and trying to figure out what I need to do for my old tractor. Lots of data and information but hard to piece it together. I have a 9n that was running fairly well but then started to miss and has no power, it was on the weak side to begin with. Figuring it was time for new points, condenser, plugs and spark Wires, I change all of these with no change in the performance. So I did a compression test and had these numbers. Dry #1 - 65, #2- 97, #3 - 87, #4 -95
wet was 75, 102, 115, 103

My question, is this indicating a valve problem on Number one and does Number 3 look like ring problems? if so what does it entail to get it fixed? Thanks for any and all help ahead of time!

Thanks for the quick responses!

So it seems the only thing to really do is start tearing it down to see what needs to be corrected. Can one rebuild the engine without removing the block? If so does one need special tools to get it done or is it easier to just remove the block and take it to a machinist?
 
I'd say do a leakdown test then a wallet weigh. You have to decide how much you want to put into a 9N as a complete engine rebuild will get pricey.
 
Update on the Compression and tests. After looking at it I opened the inspection panel to view the Valves and assembly. Two exhaust valves had lost the keepers that hold the valves in place. the keepers were worn and deformed some I believe. I then went ahead and removed the head to remove the valves and inspect them for damage. I could see evidence that the valves had been hitting the top of the head. The valves are the non adjustable kind so I removed all of the valves for inspection. After reading some, it sounds like I should replace the valves with newer adjustable assemblies. My plan is to take the block to a machinist and have him check it out to make sure the seats are in good condition and then replace all the valves with the newer adjustable valve assemblies. My new question is now about the rotating exhaust valves? Is this something I should get or since my keepers were the same for all the valves originally,don't worry about this?
 
Thain Cashmore,No you don't really need exhaust valve rotates unless you plan on using 40-60 hours a week.You need to get all new valves ,springs with retainers and locks and adjustable lifters.It would be best to tell the machine shop what you want and have them get the parts,talk it over with them.If you have more cash (pun) Have the shop rebuild it for you,sieves,pistons,rings bearings,oil pump.Ask about their experience on rebuilding Ford N engines and oil pumps.Weather you have them do the entire engine or just the valves,sleeves and oil pump (oil pumps have to rebuilt correctly and with the correct with (thickness) gears) and you do the rest good luck with it.
 

The valve keepers and retainers are different and can not be interchanged.

If you are not schooled on setting up the free rotating set up use the non rotating set up... You will need the valves, retainers and keepers that go with the type of valve you are using. About the only thing that will interchange is the springs I would recommend a new set of spings either way you go.. BTW 9N springs are longer so beware when you order them...


search in modern view

Hobo.NC,,, key word "Rotat'n" in 9n,2n,8n, forums

procedure is in the I & T FO-4 manual

More rotat'N talk





https://forums.yesterdaystractors.com/viewtopic.php?t=380581&highlight=rotatn

Ford tractors are the only engine I have worked on that use this style of assy... Rotating valves is not uncommon but the way the set them up is to me...
 
(quoted from post at 07:44:16 09/23/19) Thain Cashmore,No you don't really need exhaust valve rotates unless you plan on using 40-60 hours a week.You need to get all new valves ,springs with retainers and locks and adjustable lifters.It would be best to tell the machine shop what you want and have them get the parts,talk it over with them.If you have more cash (pun) Have the shop rebuild it for you,sieves,pistons,rings bearings,oil pump.Ask about their experience on rebuilding Ford N engines and oil pumps.Weather you have them do the entire engine or just the valves,sleeves and oil pump (oil pumps have to rebuilt correctly and with the correct with (thickness) gears) and you do the rest good luck with it.

Thanks So Much! This is what I needed and somewhat along the same lines of my thinking. You and the others have cleared my plan of action. This is one of the best forums, thanks to all of you!.
 
(quoted from post at 07:44:16 09/23/19) Thain Cashmore,No you don't really need exhaust valve rotates unless you plan on using 40-60 hours a week.You need to get all new valves ,springs with retainers and locks and adjustable lifters.It would be best to tell the machine shop what you want and have them get the parts,talk it over with them.If you have more cash (pun) Have the shop rebuild it for you,sieves,pistons,rings bearings,oil pump.Ask about their experience on rebuilding Ford N engines and oil pumps.Weather you have them do the entire engine or just the valves,sleeves and oil pump (oil pumps have to rebuilt correctly and with the correct with (thickness) gears) and you do the rest good luck with it.

Thanks So Much! This is what I needed and somewhat along the same lines of my thinking. You and the others have cleared my plan of action. This is one of the best forums, thanks to all of you!.
 

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