More problems on the 425 Kohler CH25

[ponytug]

Thanks for the update, and congratulations on finding a few problems. Hopefully, it won't take much to make it right.

All the best,

Peter

 

[Modrob]

Geez…I’m blown away at how much crud and baked-on deposits I’m finding…later last night I was able to remove the exhaust valve from head and best I can tell it looked ok, just pretty cruddy. I THINK after cleaning it and the guide it looks like it’s settling better, but I’m not totally sure…
So, going forward from this point, what do you guys recommend? Clean up both valves, maybe relap the edge, of course new gaskets? Go ahead and do both heads while I’m at it? (and bleed those lifters too)

 

[MTGreen]

Considering what could have been wrong here you're getting off easy/cheap.

If by "relapping the edge" you mean spinning the valve against the valve seat with lapping compound, I would consider that a bare minimum for repair (in addition to a head gasket). I would eval your valve guides very carefully -why did the valve stick in the first place? Varnish? Guides shifted or oblong? Why did your pushrod bend? Was it indeed your hydraulic lifter and if so why did that happen when it's designed not to?

 

[Modrob]

Considering what could have been wrong here you're getting off easy/cheap.

If by "relapping the edge" you mean spinning the valve against the valve seat with lapping compound, I would consider that a bare minimum for repair (in addition to a head gasket). I would eval your valve guides very carefully -why did the valve stick in the first place? Varnish? Guides shifted or oblong? Why did your pushrod bend? Was it indeed your hydraulic lifter and if so why did that happen when it's designed not to?

I’m still holding out hope I’m “getting off easy/cheap”…LOL
Yes, that’s what I meant by “relapping”.
The guides—my thinking is the valve was sticking because of the buildup of crud, varnish, etc. I mean, it made a believer out of me to see how bad things can look with bad or wrong oils, lack of maintenance, etc.
The more I’ve learned about these lifters and then seeing the actual results before and after bleeding I could see how the rods would bend. (I cut off an end of an old rod and chucked it into a drill press, then tried to compress the lifter—I ended up having to use about as much pressure as my arms could do, to slowly push out/bleed the oil from inside. After a little while of doing that, they operated just fine, with finger pressure.)
Hope that helps explain a little better.

 

[MTGreen]

I’m still holding out hope I’m “getting off easy/cheap”…LOL
Yes, that’s what I meant by “relapping”.
The guides—my thinking is the valve was sticking because of the buildup of crud, varnish, etc. I mean, it made a believer out of me to see how bad things can look with bad or wrong oils, lack of maintenance, etc.
The more I’ve learned about these lifters and then seeing the actual results before and after bleeding I could see how the rods would bend. (I cut off an end of an old rod and chucked it into a drill press, then tried to compress the lifter—I ended up having to use about as much pressure as my arms could do, to slowly push out/bleed the oil from inside. After a little while of doing that, they operated just fine, with finger pressure.)
Hope that helps explain a little better.

I would consider replacing the lifters as well as they seem to be varnished internally.

Seems like this engine has seen crappy oil, prolonged oil change periods, extended operation at borderline high temps, or a combination of the above.

I don't have any personal experience with detergent oils but from the pics and what you're describing I'm wondering if running with one for the first 10 or 20 hours before changing the oil with a good synthetic might be a good idea to reduce some of the deposits/varnish. Maybe others with experience can chime in here

 

[ponytug]

I would consider replacing the lifters as well as they seem to be varnished internally.

Seems like this engine has seen crappy oil, prolonged oil change periods, extended operation at borderline high temps, or a combination of the above.

I don't have any personal experience with detergent oils but from the pics and what you're describing I'm wondering if running with one for the first 10 or 20 hours before changing the oil with a good synthetic might be a good idea to reduce some of the deposits/varnish. Maybe others with experience can chime in here

There are a variety of sludge / varnish remover products out there, e.g. SeaFoam in the oil, etc. I think any of them would help, and be a prudent course of action. I have used them to clean up various engines, and they all work, at least to some degree. My advice would be use one of them, run the engine hard for ten hours or so, change the oil and filter, add some more detergent / or Tuffoil, and do some accelerated oil changes for awhile.

It isn't my money, but having owned a number of engines with hydraulic lifters, I would change the hydraulic lifters. It is tough to get them clean without disassembly, and not all versions disassemble easily. They need oil to operate, and they really should not go in and out with finger pressure. I suspect that having forced the oil out of the lifter, where it was doing its job, you now have some air inside, allowing the motion with finger pressure. I think of the concept of a hydraulic lifter as using engine oil to expand the lifter to just the right height, keeping the valve clearance at the optimal height. If they are super springy, they won't keep the height up. (They need pressure to overcome the resistance of the valve springs after all.)

I think from the damage that your engine, @Modrob, has apparently had, there was probably a loss of lubrication, probably due to fuel in the oil, and you are working through the after effects.

I think that the good news is what you have found is all readily fixable.

All the best,

Peter

 

[PowerTracManiac]

Marvel mystery oil seems to work for me?
Have an Excursion with over 100k and a little valve train noise. Used the MMO and it runs like a sewing machine now-can hardly tell the engine is running.
I put MMO in everything now-including the PT1460.
Good luck.

 

[MTGreen]

I would also pull the other head and disassemble/clean the valve assemblies, lap the valves, and replace the lifters on the other cylinder as well. A sticky/intermittently closing valve on the other cylinder would explain the no compression one day then compression another day as you described

 

[2manyrocks]

I admire your persistence.

 

[Tchamp]

Marvel mystery oil seems to work for me?
Have an Excursion with over 100k and a little valve train noise. Used the MMO and it runs like a sewing machine now-can hardly tell the engine is running.
I put MMO in everything now-including the PT1460.
Good luck.

I am a FIRM believer in Marvels mystery oil, been using that stuff for over 35 years. Subaru dealers use it to free up sticking lifters, I put it in my gas and oil. It is good for lifters and seals, i have seen it free up a stuck oiling ring on a caterpillar engine. It’s the real deal.

 

[Modrob]

I admire your persistence.

LOL my wife laughs at me—I can’t let it go, like so many other things I’ve fixed…it might take a little time to dig into as much info/how-tos/videos as I can, but it always feels good to finally fix things. (Along with plenty of frustration and aggravation/4 letter words)
Wife says “just buy a new one” on about everything, (we are mid 60s and only married 3+ years) and I have to explain my brain can’t fathom paying the amounts of money to simply “buy” the new fixes…LOL

 

[Modrob]

I would also pull the other head and disassemble/clean the valve assemblies, lap the valves, and replace the lifters on the other cylinder as well. A sticky/intermittently closing valve on the other cylinder would explain the no compression one day then compression another day as you described

Yes I’m going to replace them as well.

 

[Modrob]

There are a variety of sludge / varnish remover products out there, e.g. SeaFoam in the oil, etc. I think any of them would help, and be a prudent course of action. I have used them to clean up various engines, and they all work, at least to some degree. My advice would be use one of them, run the engine hard for ten hours or so, change the oil and filter, add some more detergent / or Tuffoil, and do some accelerated oil changes for awhile.

It isn't my money, but having owned a number of engines with hydraulic lifters, I would change the hydraulic lifters. It is tough to get them clean without disassembly, and not all versions disassemble easily. They need oil to operate, and they really should not go in and out with finger pressure. I suspect that having forced the oil out of the lifter, where it was doing its job, you now have some air inside, allowing the motion with finger pressure. I think of the concept of a hydraulic lifter as using engine oil to expand the lifter to just the right height, keeping the valve clearance at the optimal height. If they are super springy, they won't keep the height up. (They need pressure to overcome the resistance of the valve springs after all.)

I think from the damage that your engine, @Modrob, has apparently had, there was probably a loss of lubrication, probably due to fuel in the oil, and you are working through the after effects.

I think that the good news is what you have found is all readily fixable.

All the best,

Peter

Wow! Yes, all very true and good, deeper thought. Replacing them and I believe “priming” them is in order as well.

 

[Modrob]

IF after replacing lifters, gaskets, etc…
Would trying to run some “cleaning” options to lessen the varnish, gumming, sludge, etc., cause some possible ring leaking??

 

[Modrob]

We’re FINALLY (hopefully) about to return home this evening after this Florida Amtrak train/bus round trip fiasco, and I’m now “recharged” and ready to tackle this motor with a renewed vigor!
(One more hour on this bus transfer, then board our last train for another 6 hours—let’s hope all goes as it should LOL)

 

[Modrob]

We’re FINALLY (hopefully) about to return home this evening after this Florida Amtrak train/bus round trip fiasco, and I’m now “recharged” and ready to tackle this motor with a renewed vigor!
(One more hour on this bus transfer, then board our last train for another 6 hours—let’s hope all goes as it should LOL)

(To be fair and honest, this was from Sunday evening depart to Friday evening return, 2 trains, 2 busses each way, but we spent our FL time visiting the new 18 month-old granddaughter and daughter, and even squeezed in building a heavy/duty swing/play set for them.)

 

[Modrob]

LOL my wife laughs at me—I can’t let it go, like so many other things I’ve fixed…it might take a little time to dig into as much info/how-tos/videos as I can, but it always feels good to finally fix things. (Along with plenty of frustration and aggravation/4 letter words)
Wife says “just buy a new one” on about everything, (we are mid 60s and only married 3+ years) and I have to explain my brain can’t fathom paying the amounts of money to simply “buy” the new fixes…LOL

2manyrocks and…her nice and polished stainless steel French door fridge ice maker went on the fritz awhile back. Ended up a couple of problems compounded the problem—after a couple weeks of hit-and-miss episodes of working on it, she was ready to just go buy a new fridge! What? I said…no way— it until I’ve given up…LOL (meanwhile I had bought a small countertop ice maker to get by with ) I continued on, and with more great forum members’ help and guidance, learned how the whole ice maker system worked, and I finally got it fixed. Yep, it only took about a month, but that was having to mix in with other fix-it projects that seem to keep popping up…but another success!

 

[MTGreen]

LOL my wife laughs at me—I can’t let it go, like so many other things I’ve fixed…it might take a little time to dig into as much info/how-tos/videos as I can, but it always feels good to finally fix things. (Along with plenty of frustration and aggravation/4 letter words)
Wife says “just buy a new one” on about everything, (we are mid 60s and only married 3+ years) and I have to explain my brain can’t fathom paying the amounts of money to simply “buy” the new fixes…LOL

I completely agree.
I also get a sense that when I buy something, sure I own it; but when I dig into something to understand it enough to repair, especially when it's an in-depth repair involving blood sweat and 4 letter words as mentioned, I have well and truly made the thing mine.

 

[ponytug]

IF after replacing lifters, gaskets, etc…
Would trying to run some “cleaning” options to lessen the varnish, gumming, sludge, etc., cause some possible ring leaking??

I would. If there are no major deposits, no harm would be done. If there are deposits, the detergents/ degumming compounds will help get them off. I wouldn't worry about them removing something important.

If you think that there might be gunk on your rings, I would use a product specific to that and run it hard for a while.

All the best,

Peter

 

[Modrob]

Sunday night…decided to disassemble a hydraulic lifter. I chose the intake side on this problem cylinder, and I had previously taken it out and bled it before putting back in. Tonight after pulling it, I found it to be stuck again—took an extreme amount of force to get it to bleed again…
Here are some pics of it in various pieces, in case someone else is curious too.
And then I’ll include the latest pics of the head and problem exhaust valve…