New rings in old bore

root

Member
Anyone ever put new rings on old pistons and in a old bore? I honed the bores and check them. The worst was about 5 thou out at the bottom. They didn't have an deep scratches in them either. It's still a stock size so I am trying to talk myself into getting the head rebuilt and install new rings and button her back up.

I was actually kind of shocked at how good it looks inside with all the blow by it had. I was sure there was a cracked piston but all the hard parts are fine. Even the piston skirts look pretty good.
 

.005 taper is the max allowed but your not past it
You've already honed it so toss in a set of rings, rework the head and run it. Unless it sees hundreds of hours per year of everyday farm work it should last for several years.
 

That's kind of where I'm at. tilling the garden in the spring and mowing 7 acres during the summer are the bulk of what this tractor does.
 
Make sure that the rings are cast iron, and are not coated/plated or else they won't seat into the bore. The surface of the cylinder bore in the block get's harder over time due to the many heating, and cooling cycles. When you have a block bored oversize the hard surface of the bore is removed (just honing a old bore won't remove the hard surface) then you use a piston ring that is coated/plated. Hope that makes sense.
 
(quoted from post at 12:16:20 03/07/22) Make sure that the rings are cast iron, and are not coated/plated or else they won't seat into the bore. The surface of the cylinder bore in the block get's harder over time due to the many heating, and cooling cycles. When you have a block bored oversize the hard surface of the bore is removed (just honing a old bore won't remove the hard surface) then you use a piston ring that is coated/plated. Hope that makes sense.

"worst was about 5 thou out at the BOTTOM"

Does that not seem STRANGE to you?
 
(quoted from post at 14:16:20 03/07/22) Make sure that the rings are cast iron, and are not coated/plated or else they won't seat into the bore. The surface of the cylinder bore in the block get's harder over time due to the many heating, and cooling cycles. When you have a block bored oversize the hard surface of the bore is removed (just honing a old bore won't remove the hard surface) then you use a piston ring that is coated/plated. Hope that makes sense.

I never use a chrome rings, but have had good luck with moly coated rings no matter if on a fresh bore or a honed rering job
 



I am going with the ring set they sell per piston here. I don't see it noted as chrome or moly.
 
That does seem strange, but he likely meant the top. OR, he had the block upside down when he made the measurements. That's how I do it with my cylinder wall sled gauge.
 
Taper is the ring killer any time the top of the cylinder is larger than bottom by more than.005 the ring like is shortened.
 
Do it. The top 1/2 or so of the cylinder will be unworn. If this ridge is not removed the new top
ring will hit the ridge on the underside of the ridge, and break. Even if it doesn't break it will
be very noisy. Use a ridge reamer on it to assure success.
reamer
 

Im starting to second guess myself. I did measure again and yes I had the top and bottom reversed. The pistons came out with a wooden dowel without much effort but I can catch the ridge with a fingernail so maybe I need to get the block done. Just hate to because Ive heard these blocks get funny because of casting issues. But something cant be right because she smoked pretty good out of the vent tube and was blowing oil out of it. No cracked pistons or broken rings tells me the compression was going somewhere to cause that much blow by.
 
(quoted from post at 18:40:32 03/07/22)
Im starting to second guess myself. I did measure again and yes I had the top and bottom reversed. The pistons came out with a wooden dowel without much effort but I can catch the ridge with a fingernail so maybe I need to get the block done. Just hate to because Ive heard these blocks get funny because of casting issues. But something cant be right because she smoked pretty good out of the vent tube and was blowing oil out of it. No cracked pistons or broken rings tells me the compression was going somewhere to cause that much blow by.
would just use the ridge reamer & get on with your plan. I was successful doing same.
 
(quoted from post at 17:40:32 03/07/22)
Im starting to second guess myself. I did measure again and yes I had the top and bottom reversed. The pistons came out with a wooden dowel without much effort but I can catch the ridge with a fingernail so maybe I need to get the block done. Just hate to because Ive heard these blocks get funny because of casting issues. But something cant be right because she smoked pretty good out of the vent tube and was blowing oil out of it. No cracked pistons or broken rings tells me the compression was going somewhere to cause that much blow by.

Was it blowing a little oil out of the exhaust as well, it's starting to sound like the engine was wet stacking, this happen at times if the tractor isn't worked hard
The rings will become unseated allowing compression and oil to leak by, a good hard work out usually fixes it, but since you have it apart a refresh would be the think to do

The rings on this site are CFPN6149BC and probably a plain steel ring
The note below that listing says you can call them to check on availability of US made Hastings rings, those are the ones I get with the moly coated top ring
 

I have ringed a boat load of old engines what stopped us from doing it was the labor cost if it came back on us.

We use to never have a rod reconditioned till one ate our lunch. A little piston slap are a worn piston pin knock who could tell it when it had solid lifters.

Hydraulic lifters took the excuses away. Once we found out folks will pay for all the additional work we went full kilt. About that time 50K was considered high mileage then it all changed. Folks started having a little more money and would not put up with a little noise.

I just went thru a old engine I had it was on the edge of needing to be bored I ordered 10 over pistons and knocked the dust off my Sunnen hone. I would not reuse the old pistons the ring lands were worn out worst case it would have got new pistons. Long story short it was a EZ job and will last as long as I need it... I would not do it that way if it was a customer pay job : )
 
(quoted from post at 18:45:19 03/07/22)
(quoted from post at 17:40:32 03/07/22)
Im starting to second guess myself. I did measure again and yes I had the top and bottom reversed. The pistons came out with a wooden dowel without much effort but I can catch the ridge with a fingernail so maybe I need to get the block done. Just hate to because Ive heard these blocks get funny because of casting issues. But something cant be right because she smoked pretty good out of the vent tube and was blowing oil out of it. No cracked pistons or broken rings tells me the compression was going somewhere to cause that much blow by.

Was it blowing a little oil out of the exhaust as well, it's starting to sound like the engine was wet stacking, this happen at times if the tractor isn't worked hard
The rings will become unseated allowing compression and oil to leak by, a good hard work out usually fixes it, but since you have it apart a refresh would be the think to do

The rings on this site are CFPN6149BC and probably a plain steel ring
The note below that listing says you can call them to check on availability of US made Hastings rings, those are the ones I get with the moly coated top ring

She had bad valve seals. I would get a good bit of smoke and oil smell when it started. it was also down on power. I could tell when running the 7" tiller.
 
Bern, how do you know when a motor is a bad risk to reassemble? He could put this thing back together and have water in the oil the following day. I recently sleeved my 9700 that I had since new, never had dirty coolant. No one could give me an answer on the odds that the other cylinders were ok so I did all 6.
 
You were very wise to do all 6, especially if one had already pinholed. My machinist likes to use thick-wall sleeves, and he has told me more than once that he saw through holes appear on the other cylinders as he was boring for the sleeves.
 
(quoted from post at 18:25:39 03/08/22) Bern, how do you know when a motor is a bad risk to reassemble? He could put this thing back together and have water in the oil the following day. I recently sleeved my 9700 that I had since new, never had dirty coolant. No one could give me an answer on the odds that the other cylinders were ok so I did all 6.

How would doing a ring job cause water to get in the oil?
 
The ring job doesnt cause it. Nobody knows how deep the pits are around the base of the cylinder. I dont know 100% how cavitation occurs, but cleanliness of the system apparently has nothing to do with it. My 9700 water jackets looked like the day they were cast and I had water running into the crank case nearly as fast as I could pour it into the radiator. Had a group of holes, number 6, in an area about the size of a 50 cent piece and they all went at once. The time and money spent to get the block sonic checked was better spent sleeving all the cylinders and eliminating the guesswork entirely. I have a 4500 with coolant so filthy the balls cannot be seen in the antifreeze tester. Im afraid to flush it out for fear it will uncover some holes before Im ready for the overhaul.
 
The point of that windy story and my question to Bern was, what are the odds that you may have a pit deep enough that you could poke a hole in the cylinder wall with a seal pick? As Destroked says, it will last many years.... if you were certain the cylinder wall is sound.
 

Cleanliness of the coolant doesn't matter much but PH levels are very important, proper coolant conditioner will greatly reduce the pitting issue.
 
Ford anyone wondering the rings I ordered from this site were New Holland rings. Not marked where they are made but seem to be of good quality.
 

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