Not me, I stop at .020, but since the piston is available, I'm sure some have tried. On the bright side, there is no water jacket to bore into. I've seen people try to bore small block Chevys .060 over and hit waterEver seen an AQS engine bored .040 over!Better yet, have you ever tried to bore one that big!
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Kohler K series short blocks
- Thread starter Greg Riutzel
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SIGH!
Up front: This is NOT a shade tree project nor my first time. All critical dimensions i.e. bore, taper, skirt, conn rod, journals, valve guide/stem, etc., have all been measured. All micrometer, dial bore gauge, feeler gauge, and indicator readings are recorded and compared to book tolerances. Even at this age this block is still well within tolerances and only needed a cylinder hone to restore cross hatch. The piston is in good shape with much of the original "tooling" marks still visible on the skirt.
As with any rebuild, I do not re-use rings. Hence my dilemma.
This is the confusing part. I'm not familiar with Kohler's internal variances and OEM specifics depending on customer call outs. I did find a Service Manual at the Kohler site which has much more information than my IH K341 Service Manual and particularly the 3 different pistons used. My "D" style piston according to Kohler was in the K 181, 301, and 321. I have it in a K341, and a short block at that. With that, no one recognizes my spec number 4552241. I was curtly informed without the "proper" spec number I can't expect service. I sent a picture of the data tag which displays the 4552241 as a spec number.
Today I did a Hail Mary and ordered the 45-108-10 rings. That number will forever be etched in my brain.
As to re-ringing old pistons; if the pistons passes all QA tolerance checks with skirt dimension, wrist pin dimension, and the often over looked ring in groove clearance, in this case .006", it's good to go. The last air cooled engine overhaul I did using these checks and machining was a 40 HP VW the owner got 180,000 miles on and could've gone more but for the cylinder studs pulling out of the magnesium case. We sort of regretted having not gone the extra $40 at the time for the better case savers.
As with any rebuild, I do not re-use rings. Hence my dilemma.
This is the confusing part. I'm not familiar with Kohler's internal variances and OEM specifics depending on customer call outs. I did find a Service Manual at the Kohler site which has much more information than my IH K341 Service Manual and particularly the 3 different pistons used. My "D" style piston according to Kohler was in the K 181, 301, and 321. I have it in a K341, and a short block at that. With that, no one recognizes my spec number 4552241. I was curtly informed without the "proper" spec number I can't expect service. I sent a picture of the data tag which displays the 4552241 as a spec number.
Today I did a Hail Mary and ordered the 45-108-10 rings. That number will forever be etched in my brain.
As to re-ringing old pistons; if the pistons passes all QA tolerance checks with skirt dimension, wrist pin dimension, and the often over looked ring in groove clearance, in this case .006", it's good to go. The last air cooled engine overhaul I did using these checks and machining was a 40 HP VW the owner got 180,000 miles on and could've gone more but for the cylinder studs pulling out of the magnesium case. We sort of regretted having not gone the extra $40 at the time for the better case savers.
I'm with Digger on the 'Ring or Bore' issue.
What I think he's running into is that in the 'OLD' parts BOOKS some spec. numbers list both 'early' and 'late' pistons and rings for that spec number. Meaning (I guess) it could have either and Kohler didn't know which ones your particular engine had in it for sure.
The parts books online don't have that info any more, for some reason Kohler deleted all their parts history on some parts. (You just try to come up with the black valve cover o-ring part number for the oldest Kohler command engines. But there are probably some still out there for sale and you need one unless you want to buy a new fuel pump.)
Ok, back to 'early' and 'late' pistons and rings. The 'early' pistons ran wider rings in wider ring grooves than the 'late'-er ones do. I used to know what the ring width dimensions were, but I don't any more. I should have written it down and the guy who told me retired.
I just know that the M16 in the Wheel Horse across the street runs an 'early' piston for some reason and I ordered the 'late' ring set for it, being it was a M16, and not a K341 and learning of my mistake the hard way. The 'late' rings lasted less than an hour. I had checked the end gap, but not the side clearance in the piston.
So the trick is to come up with a part number you can search for on Ebay or some other source for the correct piston rings.
What I think he's running into is that in the 'OLD' parts BOOKS some spec. numbers list both 'early' and 'late' pistons and rings for that spec number. Meaning (I guess) it could have either and Kohler didn't know which ones your particular engine had in it for sure.
The parts books online don't have that info any more, for some reason Kohler deleted all their parts history on some parts. (You just try to come up with the black valve cover o-ring part number for the oldest Kohler command engines. But there are probably some still out there for sale and you need one unless you want to buy a new fuel pump.)
Ok, back to 'early' and 'late' pistons and rings. The 'early' pistons ran wider rings in wider ring grooves than the 'late'-er ones do. I used to know what the ring width dimensions were, but I don't any more. I should have written it down and the guy who told me retired.
I just know that the M16 in the Wheel Horse across the street runs an 'early' piston for some reason and I ordered the 'late' ring set for it, being it was a M16, and not a K341 and learning of my mistake the hard way. The 'late' rings lasted less than an hour. I had checked the end gap, but not the side clearance in the piston.
So the trick is to come up with a part number you can search for on Ebay or some other source for the correct piston rings.
Yes sir, done that. Not knowing the difference yet, "early" rings I ordered for standard bore were .093" thick for p/n 4510806-S. My current piston has .063"-.064" wide grooves. Given the .006" clearance; the thinner rings I need should be near .057"-.060" thick? Fortunately I was able to return the rings
hydroharry
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Well, it looks like some of my info yesterday was not correct. There does appear to be 3 additional size ring sets for the new Mahle style piston - if my assumption is correct. I found this internet site and as you might expect this site is a little hard to deciper and doesn't specifically state the Mahle piston but besides the ring set part No. 45-108-10 STD and .003 (which we all know is for the new style Mahle piston) it also lists 45-108-11 for .010 over, 45-108-12 for .020 over and 45-108-13 for .030 over - which I'd certainly assume are for the Mahle piston.
https://www.ereplacementparts.com/kohler-k34171167-engine-parts-c-106503_106533_108486.html
Sounds like Greg is all set with the 45-108-10 set of rings, so I just wanted everyone to know, and for purposes of archive info.
Thanks. I've scoured the eReplacement Parts before for appliances. I don't use them. They seem to be the Amazon of the repair world.
I'm sorry to call you out on this but nobody knew how much experience you had on this ring issue.
Now that you have explained that you have checked all the tolerance measurements I will sit back and try to learn from this rebuild project
Now that you have explained that you have checked all the tolerance measurements I will sit back and try to learn from this rebuild project
I spent 36 years as a diesel mechanic and I've never heard of 1 set of pistons rings working with different size pistons, but I've only worked on my own Kohler engines so I am not going to state I know everything about these engines. I do know if gap is to tight you will have problems. Rings for a standard bore would have a bigger ring gap in an oversize bore. What ever you go with check your ring gap about a 1/2" down in cylinder. Use piston upside down to make sure rings are square in cylinder and check gap with feeler blades. My Kohler manual shows .010 to .020 in new bore and max of .030 in used cylinder for a K341.
Today the Kohler 4510810-S rings arrived. They're gonna work.
Here's some numbers to let you know I think I'm on the right track. The cylinder bore after honing last month meas. 3.751" with no taper and less than .001" ovality. Book limit is 3.753". The piston meas. at the skirt was 3.747 with a bore to piston clearance of .004". Book range shows .003-.005". Now to the rings. Right out of the box: the rings 1st and 2nd measured .062" thick and I have a land clearance just bordering on .0015" to .002" including the oil ring set. Top ring gap is .019", 2nd ring gap is .025" and oil ring gap is .020". Book limit for used cylinder bore is .030" though new bore ring gap is .010-.020". These were checked 1" or so down the bore and squared with the piston top. I also checked the rod to crank pin clearance with Plastigauge and that reading shows a .0015" clearance. I did not disassemble the wrist pin but it is silky smooth and not a hint of play.
After my new shim gaskets arrive and an offroad vacation I will start the assembly. The only thing weird besides the rings was getting the crank end play. Even with the 3 gaskets in the kit, there was none. So ordered more and will double check the crank bearing in the bearing plate.
Here's some numbers to let you know I think I'm on the right track. The cylinder bore after honing last month meas. 3.751" with no taper and less than .001" ovality. Book limit is 3.753". The piston meas. at the skirt was 3.747 with a bore to piston clearance of .004". Book range shows .003-.005". Now to the rings. Right out of the box: the rings 1st and 2nd measured .062" thick and I have a land clearance just bordering on .0015" to .002" including the oil ring set. Top ring gap is .019", 2nd ring gap is .025" and oil ring gap is .020". Book limit for used cylinder bore is .030" though new bore ring gap is .010-.020". These were checked 1" or so down the bore and squared with the piston top. I also checked the rod to crank pin clearance with Plastigauge and that reading shows a .0015" clearance. I did not disassemble the wrist pin but it is silky smooth and not a hint of play.
After my new shim gaskets arrive and an offroad vacation I will start the assembly. The only thing weird besides the rings was getting the crank end play. Even with the 3 gaskets in the kit, there was none. So ordered more and will double check the crank bearing in the bearing plate.
Update. Hard to believe my last post was in July. Assembly is going very well. I ended up using a .030 and a .010 gasket for the bearing plate to get the clearance for the crank to front bearing. Now I come to a line in the repair manual that says to soak the head gasket in water prior to assembly. Is that still true? I am using the metal sandwiched head gasket.
mgonitzke
Well-known member
Nope, no longer true. Install, run, and retorque.
Thanks. Minor assembly question here. How far does the cam pin get driven into the front of the block? I put the cam in back in July. Then summer adventures, firewood, work, etc got in the mix.. Now I'm down to final assembly and as I was installing the PTO I saw a hole/recess where the cam pin is. It is shy of 7/16" deep. I'm pretty sure I left the cam install a completed task, but now that recess bothers me. Add to that, I've read the newer blocks use a cup or welch plug there but I don't recall driving one out when removing the cam. This was a short block installed in 1995 by a PO.
I recall that when I first got into full time small engine repair, twelve years ago, that the Kohler parts lists for some of their cast iron engines listed 'early' and 'late' for pistons and rings. I am thinking that the difference between 'early' and 'late' was the thickness of the compression rings.
I only encountered this once, when I tried to overhaul my neighbor's Wheel Horse with M16 in it. Being a Magnum instead of a K series, it should be late, right? Well it used the early rings. And although I checked the ring end gap, I failed to notice they really didn't fit the ring groove tightly. Until it broke a ring and I had to pull it apart again.
So with this thread, I am guessing Mahle was either the early or late design of piston. So now we need to come up with a Kohler part number for the piston rings he needs for his piston.
Now we need to know the thickness of his rings. (to the thousandth of an inch.) And we need to know whether this is considered 'late' or 'early' as that is how I think the parts books call them. and then maybe somebody has access to a Kohler parts book that tells what part number we need to be looking for on Ebay or some other new old stock source.
And I am with Digger on this: Lots of these engines have been put back together with just a new set of rings and they are still giving good service.
I only encountered this once, when I tried to overhaul my neighbor's Wheel Horse with M16 in it. Being a Magnum instead of a K series, it should be late, right? Well it used the early rings. And although I checked the ring end gap, I failed to notice they really didn't fit the ring groove tightly. Until it broke a ring and I had to pull it apart again.
So with this thread, I am guessing Mahle was either the early or late design of piston. So now we need to come up with a Kohler part number for the piston rings he needs for his piston.
Now we need to know the thickness of his rings. (to the thousandth of an inch.) And we need to know whether this is considered 'late' or 'early' as that is how I think the parts books call them. and then maybe somebody has access to a Kohler parts book that tells what part number we need to be looking for on Ebay or some other new old stock source.
And I am with Digger on this: Lots of these engines have been put back together with just a new set of rings and they are still giving good service.
mgonitzke
Well-known member
The service manual is quite clear as to this. Surely you are referring to the manual while reassembling the engine?
It goes in the opposite of way it came out.
Driven out from the PTO side and in from the bearing plate side.
The later models have a shorter cam pin and the older ones have a longer pin.
The longer pins get driven flush with the PTO side and the shorter ones have a spec for depth from the bearing plate side depending on the engine model.
See section 10, 11, and 12 of the Kohler manual TP-2379
Driven out from the PTO side and in from the bearing plate side.
The later models have a shorter cam pin and the older ones have a longer pin.
The longer pins get driven flush with the PTO side and the shorter ones have a spec for depth from the bearing plate side depending on the engine model.
See section 10, 11, and 12 of the Kohler manual TP-2379
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Thanks so much for the reference to the Kohler manual. I am working with IH produced manuals, which apparently are a little out of step with newer blocks. As far as I can tell the tractor, a 1650, was new in 74/75. The chassis and engine manuals are from 1984 and 1985. A short block was installed in 1995. The Kohler book is much more in depth and detailed than the IH manuals. One of my conundrums was that no vendor has any listing for the block's serial number. That made nailing down parts difficult, especially the rings.
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