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Discussion Starter #21
Wow it looks like some major pitting on the ends. I would say that needs to be looked at because that will change cylinder volume, thus air fuel ratio for those cylinders
Not enough to make a difference on these engines.

In stead of a broken oil ring, from looking at the valves, and being they are both intake, it looks like it's been pulling oil in from the top end. Is it possible the valve guides are worn so bad, it sucking oil down around the valve stem, on the intake stroke..?? Looks like it literally just baked some oil on the valve stem over a period of time, until they seized.

Have you ever had this engine torn down before? With the serious pitting on 1 & 4, I'm wondering if a PO somewhere back the line, put a sleeve kit in it, because it had gotten water in the cylinders, and was stuck. Even at that, I've pulled several heads off of tractors that have been stuck for a good many years, and have never saw pitting like that before. Just thinking again, somewhere back the line, someone did a quicky fix with a sleeve set, and to heck with the cylinder head, other than maybe lapping the valves in, then sold it.
I need to measure the valve guides and stems to see where they are at, but they appear to be good. I was amazed at how easily some carb & choke cleaner cleaned the black goo off of the valve stems. Normally it would be baked on and need to be wire brushed off.

Years ago(15-20) when we were getting ready to rebuild the original engine my dad made an engine trade with his brother(my uncle) who also had a SC with a non running engine. When we opened it up we found the pitting in the head, but checked for leaks and it checked out good. We put hardened seats in along with a new valve kit. The bottom end got a full sleeve kit, reground crank, and all new bearings. You can still see the cross hatch in the bores and never consumed oil. It had always run great until we fired it up last year after sitting for several months.
 

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Its a old engine, and god knows what might have caused that pitting in its past. Really on a low speed, low compression tractor engine I wouldnt sweat it at all. As for the oil.. those are in the two cylinders that had the stuck valves right? Im thinking there was just a little blowby and the little oil you got in there chamber just wasnt burning off, Stuck valves used to be pretty common. We see it less now with the unleaded gas. I think its just varnished up and stuck, just from a little wear, and not a ton of use. Make sure the guides are good, re seal, and I bet your fine. Does that engine use valve seals?? Make sure you replace if so.. Do you plan on doing the lower end at all??
 

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Discussion Starter #23
Its a old engine, and god knows what might have caused that pitting in its past. Really on a low speed, low compression tractor engine I wouldnt sweat it at all. As for the oil.. those are in the two cylinders that had the stuck valves right? Im thinking there was just a little blowby and the little oil you got in there chamber just wasnt burning off, Stuck valves used to be pretty common. We see it less now with the unleaded gas. I think its just varnished up and stuck, just from a little wear, and not a ton of use. Make sure the guides are good, re seal, and I bet your fine. Does that engine use valve seals?? Make sure you replace if so.. Do you plan on doing the lower end at all??
These engine didn't have valve stem seals from the factory. When we rebuilt this engine years ago we decided to not add the seals since it got new valves and guides. We may add them this time, but thats up to Dad, its his tractor. We came to the same conclusion on the oil in the dead cyl. not burning off. On the lower end we aren't going to go into it at this time.
 

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These engine didn't have valve stem seals from the factory. When we rebuilt this engine years ago we decided to not add the seals since it got new valves and guides. We may add them this time, but thats up to Dad, its his tractor. We came to the same conclusion on the oil in the dead cyl. not burning off. On the lower end we aren't going to go into it at this time.
Well if it was mine and the guides seem tight, and we know its getting oil in it somewhere.. I would definitely add the valve seals if you can. It can only help, cant hurt.. and in most cases they are cheap. If it was me... lap the valves, toss some valve guide seals on in, slap her together and run it! Odds are it will out last all of us on this board.
 

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These engine didn't have valve stem seals from the factory. When we rebuilt this engine years ago we decided to not add the seals since it got new valves and guides. We may add them this time, but thats up to Dad, its his tractor. We came to the same conclusion on the oil in the dead cyl. not burning off. On the lower end we aren't going to go into it at this time.

What make, type. etc of valve stem seals would you add? (if none write ever used from the factory)

Would you only pit them on the intake valves.

Reason I ask is I have a Super C and I've had automotive truck engines that were operated or idled a lot at low rpm and the spark plugs would foul and just replacing bad valve stems seals only would correct the issue.
 

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What make, type. etc of valve stem seals would you add? (if none write ever used from the factory)

Would you only pit them on the intake valves.

Reason I ask is I have a Super C and I've had automotive truck engines that were operated or idled a lot at low rpm and the spark plugs would foul and just replacing bad valve stems seals only would correct the issue.
I don't know about this model, but just going on past engines ive worked on, even just a plain oring type seal, what would be pretty much universal depending on valve size should work. Only issue would be if there is space for the valve to open fully, and I doubt highly that this engine would have enough lobe lift to get anywhere near max valve travel. Depending on valve guide shape a basic umbrella seal would work also.. again depending on valve travel, and inner spring clearance. Either would be a huge step up from none, and a little measuring, and catalog searching I'm sure would come up with something that would work if there was no listing for this engine. As for why just intake... That is the most common place to leak. The vacuum that draws the fuel mixture in can also draw in the oil from the guides. The exoust does not have that vacuum source sucking through the guides. Also the exoust valves being hotter, some seals don't survive the heat. So while both are better..... the intake has the most benefits.
 

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All I have ever gotten in rebuild kits for valve seals for these engines, were the umbrella type. They slip over the valve stem, and you slide them down to seat on the top of the valve guide.
 

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Discussion Starter #28
The valves in this engine have clip's on the stem. I have been told that these will keep a valve from dropping into the cylinder if a spring or retainer fails. I don't know if these will interfere with a seal or not.
 

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Discussion Starter #32
I thought I remembered seeing a valve grind gasket set for this engine. A little searching and I found it. Dad stopped at the local tractor salvage yard and they just gave him a pushrod. It larger diameter than the original, but looks like all of the replacements that you can buy new.
 

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Discussion Starter #33
Sprayed some epoxy primer on the SC Head this afternoon.
 

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Discussion Starter #34
Shot some 2150 on the head this morning.
 

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Discussion Starter #35
Painted the head with some Glyptal. Just need to do a final cleanup before assembly.
 

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Discussion Starter #36
The valves in this engine have clip's on the stem. I have been told that these will keep a valve from dropping into the cylinder if a spring or retainer fails. I don't know if these will interfere with a seal or not.
Actually, I believe they keep those umbrella seals from rising up.
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My thoughts also.:tango_face_wink:
ya the seal would go below the clip.
Just for information sake, I found this in the IT manual referencing the clips on the Valves.

It Says: On all models except the Cub, valves are equipped with safety stem retainers to prevent the valve from dropping into the combustion chamber.
 

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Discussion Starter #37
My brother came over and helped me with a final cleanup on the head and installed the valves. We decided to check how well the valves were sealing since we didn't touch them other than wire brush the carbon off. We did this by filling the chambers over the valves with solvent. Only one port showed any dampness after sitting for 10 minutes. I need to clean the top of the block next and then the head should go back on.
 

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We decided to check how well the valves were sealing since we didn't touch them other than wire brush the carbon off. We did this by filling the chambers over the valves with solvent. Only one port showed any dampness after sitting for 10 minutes.
Does that mean 3 need more work, or 1 is too tight????:tango_face_glasses:
 

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Discussion Starter #39
Does that mean 3 need more work, or 1 is too tight????:tango_face_glasses:
It means they are all OK. Just to be clear This is the valve to seat sealing which means it doesn't need the valves and seats ground.
 
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