Hello, In this episode, I will show how I completely rebuilt a Kohler twin cylinder engine. If you have any questions, please feel free to ask me and I will be happy to answer your questions.
In case anyone wondered what engine this was, it was a CH25S. You can see the model on the cover during the assembly. Great video and very detailed!! Thank you for taking the time to make it! I have a CH20 to rebuild and generally expect it to be similar. Very helpful!!!!
I found your channel few days ago, by mistake. I watched one of your videos and subscribed right away! I then saw this video and watched it, glad I did! Since I have same tractor. You seem to be very knowledgeable about many things, especially engines and welding. Please keep the videos coming and Thank you for sharing your knowledge! Take care!
All the cleaning is absolutely worth it. My tool box and benches might be a mess, but what I'm working on has to be clean. The job is always harder when it's coated in filth.
This video has been invaluable to my CV20 rebuild. Thanks so much for taking the time and effort to put it together! Also the Arabic accent is top notch! 😉
Most excellent video. Have an 800 hour engine, slight knock, low power. Now, I know I can do this. I would suspect that rod and driveshaft bearings on these hold up well and the first rebuild should be similar to yours. Great teaching style with detail, to the point. New sub. Thanks!
Great video - for reference, you only need a valve stem seal on the intake side of the engine as that's the side under vacuum. The exhaust side is under pressure so no oil will leak. I confirmed by looking at the parts manual.
Thank you for the comment. I said it many times in previous comments. This engine originally came without a valve stem seal for the exhaust valves. Newer Kohler engines have seals for both intake and exhaust valves. I personally rebuilt many types of engine and always installed the valve seal on all valves. It is really up to you to do what you think is right. My thoughts are: The seal for the exhaust will prevent oil from getting into the composition area and prevent smoking and sludge buildup on the cylinder head and on the piston. The kit comes with 4 valve seals so you don't have to purchase any extra. The stem or bushing for the exhaust valve is designed to accept the seal. Either way your engine will run fine if everything else is installed and adjusted correctly. Be safe and have a great day
I'm curious to know how well those rings seated. I didn't see you use any honing oil and the cylinder walls still showed significant glazing/polishing after you honed it.
Good evening, The cylinders honing are okay for this project: 1- the cylinders are almost in new condition and the honing stones touched 100% of the cylinders walls. 2- I used new stones which was showing on the box they came in to only use dry. They were very fine grit. 3- the camera or footage may not show the actual hone and that due to the sand dust from the blasting. If you re-watch the video and see the cylinders after I washed the engine, they do look great. The rings are seated correctly and the engine is still running strong. I have had in the past using oil to hone cylinders for larger engines with more glaze or wear than this specific project. Please keep in mind, if the honing stones are wet/dry type, then using them with oil will give coarse cut and dry will give a finer cut. Thank you for watching
I very appreciated at your presentation which helps me to understand how rebuild kind of engine, I always follow your presentation, how's the governor cross shaft install??
I showed how the governor installed and adjusted in this video and on another video of this playlist. Please check the playlist and watch that video. If you have more questions, please let me know.
I've never seen anyone use a cylinder hone dry. The stones instantly can clog since they are so fine. Use a light oil in a decent supply when honing to achieve a good consistant pattern and slowly move it up and down to create a crosshatch.
Thank you for the tips. The cylinders were almost new. I just removed the glaze. The stones I used, it showed on the box to use dry or wet. FYI, when sanding or honing, dry will leave a finer surface and wet will leave corse surface. I usually hone the cylinders wet but for this project I decided to hone dry. It works and the engine is running finer than frog hair split into four ways 😂
One mistake. The lifters being hydraulic they must be bled down prior to installation. This is done by pushing the inner plunger to expel the oil. Best done with a drill press using an old push rod. There is no gap between the rocker arms and the valves. He shows gapping the rockers to .010 which is wrong. Simply tighten and torque the rocker arm stud to spec. I would like to know how this worked out for him. I'm also not a big fan of sand-blasting an engine. Too much potential for sand hiding in a crucial place. Blasting it with dry ice is a much better option if you can find a shop that does it. Always follow the Tech manual when doing this sort of work. It is readily available on many websites. It gives a very good step-by-step procedure. Other than that, it's a very nicely done video.
If you just install the rockers making sure neither piston is at TDC, the valve spring pressure will depress the lifter over time. Takes half an hour or so. Done many this way in the field. Can leave the lifter in the engine this way. Kohler says a valve can hit a piston if you do not bleed before starting and of course it will have no compression either.
I disassembled the lifters, they just have a disc or shim, very small spring to help keep pressure on the disc that contacts the rod. When the engine runs, the oil pressure will fill the lifter and apply force to maintain the small gap between the rocker and the valve without allowing the valve to open on TDC. I believe Kohler and some mechanics recommend pressing the new lifters just in case the shipping or store grease hardened and this may cause problems. Like I said, I disassembled the lifters and completely cleaned and dry prior to the installation. I haven't shown everything as recording everything will make the video several hours long and no one will watch. In the past I assembled many types of engines using new or used hydraulic lifters, I just cleaned the outside and assembled and I never had any issues. However, everyone is free to do whatever they believe is right. I am just showing my experience. Thank you for the feedback and for watching my video.
Great Video, One of the best I have watched, I love your engine stand so I made one for me However I made mine taller so I didn't need to bend over as my back is a little no good. Only thing I was wondering if you sandblasted all the sheet metal parts did you paint them to prevent rusting?
I sprayed the steel parts with a clear coat. They were rusted badly, that is why I sand blasted them. A better type of paint would be an engine paint as it will resist heat and fluids. thank you for the comment
I appreciate at your presentation it's help me a lot,yes I have same similar engine Kohler v twin engine 30 HP but I heard strange noises at end of shaft where pulley located , what are the problem or it can major problem to my engine.
Good evening, start by removing the belt and see if the clutch or ideal pulley bearings are going bad. Make sure the engine is clean. Hopefully it is external issue. Good luck.
Thank you for this excellent video. Your pacing and lighting and camera angles were extraordinary. I'm in the process of rebuilding this same engine. I do have one question about your process: Is it not necessary to bleed the hydraulic valve lifters before reinstalling them? I've seen mixed advice about this.
I disassembled these lifters and cleaned them, they just have a disc or shim, very small spring to help keep pressure on the disc that contacts the rod and a ring to keep everything together. When the engine runs, the oil pressure will fill the lifter and apply force to maintain the small gap between the rocker and the valve without allowing the valve to open on TDC. This also prevents clicking or hammering sounds as the engine runs (if the cap is too wide and this also will decrease performance) I believe Kohler and some mechanics recommend pressing the new lifters just in case the shipping or store grease hardened and this may cause problems. Like I said, I disassembled the lifters and completely cleaned and dry prior to the installation. I haven't shown everything as recording everything will make the video several hours long and no one will watch. In the past I assembled many types of engines using new or used hydraulic lifters, I just cleaned the outside and assembled and I never had any issues. However, if you want to press the lifter, just push in on the small disc until it bottoms out, the small spring will bring it back when you remove the pressure. This way you can verify free operation. On bigger hydraulic lifters for bigger engines, you can use drill press with a rod chucked on the drill (don't run the drill just apply pressure) or use a vice with small bolt or pin to allow pressing in the disc). Thank you for the feedback and for watching my video.
It is very easy. You just make sure to align the gears for the oil pump and the governor with the camshaft and crank shaft prior to pressing in the cover. Don't use force, it should go in easily. The only resistance you have is the oil seal.
Following your procedure, I lapped my valves and installed the head. Rotated cylinder to TDC and the valve rockers were very tight against the valve stem, not lose like yours. I am reusing the existing valves and rockers. There is no play in the rockers to get a .010 feeler gauge in. What am I doing wrong? Thanks for the help! Great video!
Good evening, 1-Did you remover the cam shaft or crank shaft? If so, did you time the gears correctly? If the cam shaft and crank shaft timing is off, this will lead to similar issue and your engine will not start and you may damage one or more of the engine components. 2- Did you use new lifters? This engine uses hydraulic style lifters and if they set for long time the shipping protective grease will dry and prevent the lifters from springing down to allow the clearance needed. If you use new lifters, you may have to remove, soak in kerosene then press them in with drill press (using push rod instead of drill bit without running the drill) and this will compress the lifters and free them up. 3- if the first two items are good, you may have to double check your installation. Let me know if this helped or if you have any more questions. Good luck
6:05 Rear main seal install, note oil hole here and SOP is to take note of old seal depth installed, reinstall to same depth. Maybe you didn't but it looks like you hammered it home as far as it would go. This if you did that would cause lubrication failure, but we give you benefit of the doubt and assume you did it right, it just looked bad to me in video.
I have ro rebuild a kohler LH685 liquid cooled im hoping its similar to this. They dont make these anymore apparently so we gotta bring it back to life
Very nice video. I am subscribing. So the rockers and pushrods, you start on cylinder one with the engine being on compression stroke with the piston being at its highest point?
Thank you for subscribing to my channel and I appreciate your comment. When installing the rockers or adjusting the valve lashes (if required) you must have the cylinder that you are working on on top dead center and in the compression cycle. This way, no pressure on the valves and you can install the rockers easier also when adjusting or checking the valve lashes you can insert the feeler gauge in between the rocker and the valve. This apply to any type of engine.
It's a craftsman valve spring press. I don't know the model or part number. I bought it from Sears about 22 years ago. You may be able to find it used or new or similar on eBay or other online sources.
Yes, I always check for about 0.0035 to 0.004 of inch for every inch of bore diameter as minimum or the ideal size and about 0.007 of inch per every inch in diameter as max or requires resize. I hope this answered your question.
Great video thank you, but I have couple questions, do you think I should put all 4 seals on valves. Even though had 2? Also my complete rebuild kit came with 3 red silicone tubes 1 is long I have no idea what they are or where they go ? Ideas?
Good morning, I always install all the valve seals. However, if you want to match the original factory installation then only seal the intake valves (this will help lubricate the exhaust valves and also will cause some smoke). The three silicone tubes are not needed for this engine. They are for different engines (the long one is for the fuel pump and should go to the valve cover). This kit is meant for many types of Kohler engines. Unfortunately some gaskets will not fit and some are not needed. Let me know if you have any more questions. Be safe and have a great day.
The 750 is very similar to the one I built in this video. I actually rebuilt one last year. I am not sure if someone built one and recorded it for RU-vid.
Good evening, do you remember if the block has a bushing in the block on the flywheel side?, my engine was leaking oil so I removed the covers and flywheel, the crank had play in it, if there’s no bushing or bearing I guess no need to take it apart cause the block is scrap😫
Good evening sir, unfortunately they built these engines cheaply, no bearings or bushings that you can replace. If you have play, you must replace the block. Thank you for watching
There are many reasons for the excessive wear of engine bearing areas: Wrong type of oil was used. Not replacing the engine oil on time. Bad oil filter. Weak oil pump. Contaminated oil. The engine was running at higher RPM than the engine specifications. The engine cooling passages were dirty and didn't allow the engine to stay within the recommended temperature. If the engine is new and this happened after a short period, then they may not assembled it correctly. The flywheel or the fan or the clutch is out of balance and cause excessive vibration. Many other factors. Maintenance is the key for the longevity of any type of engine. I hope this answered your question.
Question. I dropped a small bolt when changing the valve cover. It fell perfectly in the middle hole above the piston. Did it most likely fall into the crankcase. Would I have to take the whole thing apart or it would most like be at the bottom of the oil ?
I will not run the engine before extracting the bolt. This happened to me a long time ago on another twin engine and I was able to get the bolt out by tilting the engine to the dip stick side and I used a small strong disc magnet inside a clear hose. I taped the end of the hose so I don't lose the magnet. It took time but I was able to get it out. Otherwise you may have to disassemble the engine to get the bolt out as it may case damage to the engine.
For my engine, I only used a gasket maker because I was shooting for the minimum factory specified clearance between the crank case and the crank shaft. The gasket that came with the gasket kit that I bought didn't work, so I test fitted without it and I had enough play or clearance.
They sell oversize pistons and rings. You can take your engine block to the engine machine shop in your area and they will bore and hone the cylinders to the next size. Otherwise you can shop for new or used standard engine block. I hope this answered your question.
The cylinders honing are okay for this project: 1- the cylinders are almost in new condition and the honing stones touched 100% of the cylinders walls. 2- I used new stones which was showing on the box they came in to only use dry. They were very fine grit. 3- the camera or footage may not show the actual hone and that due to the sand dust from the blasting. If you re-watch the video and see the cylinders after I washed the engine, they do look great. The rings are seated correctly and the engine is still running strong. I have had in the past using oil to hone cylinders for larger engines with more glaze or wear than this specific project. Please keep in mind, if the honing stones are wet/dry type, then using them with oil will give coarse cut and dry will give a finer cut. Thank you for watching
It appears that the exhaust valve stem oil seal is the same as the intake valve stem oil seal. In the Kohler manual they say do not replace the exhaust valve stem oil seal. I am confused. Are the intake and exhaust valve stem oil seals the same?
Both seals are the same. My engine didn't have exhaust valve seal (from the factory). Newer models came with value seals for both exhaust and intake (same seal). Usually the new gasket kit comes with 4 valve seals. I installed the valve seal for both exhaust and intake for my engine. I hope this answered your question.
Good morning, it is down at the bottom of the block. This engine has the horizontal shaft. The way the strainer installed is the right way. Thank you for watching
@@SalamSayhood Ah ok, makes sense then. I may have missed you saying that it was a horizontal engine. I've only worked on vertical engines, and I forget they mount them horizontally. Great video!
Im currently trying to replace the gasket in between the block and the cover, Ive removed the engine from the chassis and removed the crank seal, removed all the bolts that hold the cover on but i cant seem to get the cover to separate from the block, is there something im missing that holds it together?
If you removed all the hardware, then you should be able to tap it and it should separate. Did someone rebuild this engine in the past or is it factory?
You just have to line up the two dots on the gears like I showed in the video. The two dots will set the timing for the crank shaft and camshaft. I hope this answered your question.
@@SalamSayhood Thank you for helping. I adjusted the valves to .004. want to tighten the rocker arms to 8.3 ft. lbs. Is there any certain way to do them.
Most likely overheating. They make these engines cheaply with tight tolerances. When the engine gets hot, the parts will expand and this causes them to seas. Other factors could be: No maintenance. No good cooling due to dirty engine. Low quality or wrong lubricant. I hope this answers your question.
I checked the new rings and they were within the specs. If I recorded everything, the video will be way longer and no one will watch. If you don't know the end gap for the rings, I usually go by the specific engine manual or I set it to about 0.004" as minimum for every one inch of cylinder diameter. I also set the ends of the rings about 120 degrees of each other on three rings pistons (top , mid, and the oil rings). Thank you for watching
am rebuilding a cv23s, having hard time finding oil pump,hear they are discontinued for my motor, its a 2004. Any idea,or where did you get your parts?
I found everything on eBay. Please check. If you can't find it using the search CV23S oil pump, then contact your local Kohler dealer and ask them for the newest part number. Then search eBay for the part number and you should find it. I hope this helps
These engines don't have replaceable bearings, if the rod has too much play, you must replace the rod, if the block has too much play, you must change the block. The casting itself is the bearing surface. Thank you for watching
I have a ch740 that’s developed a tap/knock. Thought it was lifters but replaced them and no change. Took off back cover and lower ends of rods do not have excessive play. Sounds like it’s on #2 cylinder. Has excellent oil pressure, 145-150 lbs of compression. Noise does get less after running hard, is worst upon startup. To me it sounds like a connecting rod moving back and forth on the wristpin enough to be smacking against the piston skirt, or rather the molding of the hole the wristpin goes through…is this possible? If so, would new rods and pistons fix it? Engine has 1800 hrs, been well maintained and does not burn oil to speak of. It seems like too good of an engine to just scrap. I did take #2 cylinder head off and there is wear/play in piston-to-bore but I’ve seen far worse. If it was very bad it wouldn’t it be burning oil and have low compression?
Since the engine noiser when first starting and getting better as it continues running, it sounds as if the piston is worn out. The aluminum will expand and this may result in the engine not knocking as bad when warm. Since you already started to disassemble the engine, go ahead and completely disassemble it to be able to inspect all the parts. Thank you for watching.
No I had ordered a new long block but now I find out they’re on back order for months so I had to put it back together so I could use the mower. It’s one I use for my spring cleanups. Will it eventually break the piston and is it worth it to try to rebuild it? Trying not to spend $3500 on a complete engine. Thanks!
It is hard to tell how long the engine will run while having a knocking sound. We are not sure of the issue as of yet without inspecting all the engine parts. You can rebuild the engine way cheaper than buying a new one. Unless the issue is with the block bearings (crankshaft or cam).
I believe the specs for this engine is 0.003" min to 0.020" max. The smaller the end play is better. Please verify this with your engine manual or manufacturer.
Good morning sir, if you can't rebuild it yourself, then I'll highly recommend you find a good used engine as replacement. A complete rebuild (material and labor) will cost almost what a new engine cost. If your engine doesn't require a complete rebuild to be repaired (cylinder head gasket, valve job, carburetor, or similar easy items) then you may be able to fix it cheaper. I hope this answered your question.
i rebuild these engines for customers about 900.00 parts and labor just to give you an idea. new engines cost around 3,500 installed. so that is the deference. im building one now for a customer
That is an excellent price to rebuild for parts and labor. I priced new engines prior to the rebuild, you are correct, the new engine, same HP costs about $3500.
Mine was standard and since the bore and piston are still in good shape and within tolerance, I just honed the cylinders and replaced the rings. If you are asking about the diameter of the piston, I am not sure 😊 I did measure it with the caliper when I was rebuilding the engine but I forgot. Thank you for watching
If the bolts keep snapping the problem could be: 1- defective torque wrench. 2- you are over torquing the bolts. For the second question about the engine is hard to turn. 1- did you verify the pistons, cylinders, crankshaft, camshaft and end play clearances and made sure everything is within specs? 2- if you remove the spark plugs, it should be easy to rotate the engine. Do not run the engine if there is a mechanical issue or you suspect something is wrong. If you haven't checked the clearances/end play/tolerances while assembling the engine, you may have to disassemble and re build. This will be cheaper in case you didn't assemble correctly or didn't use the correct sizes for the new parts.
@@SalamSayhoodokay I will tear it down again the new piston rings all are 0.15 so not sure and they are on the right way I did hone it also so not sure
If you have standard size cylinders, you must use standard. If you have 0.010" over size, then use matching over size rings. You also need to verify the new rings, install or insert each ring into the cylinder that you are going to install that ring and make sure the ring is square (as if it was installed in the piston) and make sure you have a gap between the ring two ends. This gap should be at minimum 0.004" for each one inch of diameter of the cylinder. For example: 3.5" diameter cylinder should have a minimum of 0.014" ring end cap. You use feeler gauge to measure the end gap. Minimum is 0.004" and max is 0.007" per inch of cylinder diameter. If the gap is too small, the engine will sease and you may damage the engine. If the gap is too big, the engine will have less power and will burn a lot of oil.
My apologies, I didn't understand your first comment. My coworker just explained it to me. I thought you meant ADs or commercials. Thank you and have a great day.
Have you never watched anyone hone a cylinder before? You want to use water to cause surface rust after you hone? I only pressure wash the components after disassembly, dry with air, then clean with diesel. After honing or valves work, I only use diesel or kerosene. The stones that I used showed on their box to use dry. Thank you for watching.