I have a kohler cv490-27532. I just put a new head gasket on but am having a problem with the rods, rockers and lifters. It appears that one of the hydraulic lifters doesn't want to go all the way down. When I tighten the rocker bolt, it opens the exhaust valve about 1/4 inch, no matter where the piston is in the stroke. There's something keeping the lifter from going all the way back down that channel. It actuates otherwise during the exhaust stroke but never fully relaxes. Intake is fine. Could this be binding somewhere?
Kohler CV Lifter Problem
- Thread starter lefty2cox
- Start date
I'll try that if this fails. I actually have another question on this machine if you'll indulge me.
I'm a little stumped by this. I'm getting some weird results from a leak down test. I was at TDC and charged the cylinder slowly with about 60lbs of air in. I could hear air escaping into the crankcase and it would only hold about 28-30 pounds. But when I slowly raised the pressure up to about 68 or 70lbs in, I hear a faint hollow sound....like "thoop". And the holding pressure jumps up to 60. And as I add pressure up to 80 and 90, the held pressure follows about 10lbs behind. It sounds like something sliding a short way up a tube.... So I'm eventually getting to about 11% leakage? But initially at 60lbs in, it's like 53%?
Whatever this sound is, it seals off the cylinder. If I depressurize and repeat the process, I get the same result. I've tried this with the rockers and pushrods removed to eliminate valves.
Although there is an exhaust valve issue problem now because when this strange thing happens and the held pressure jumps, I get a little leakage from the exhaust valve. I did have the head off to change a blown head gasket. Didn't touch the valves but thinking I should lap them now. But that's a completely separate issue I think.
Without the faintest idea of what is causing this strange behavior, I had a theory that if the rings are worn, this strange sound and unexplained sealing of the cylinder that occurs may be the piston shifting and creating a better seal. Then when I deflate, the piston shifts back to its original position. I can't think of anything else that would cause this. When I had the head off, I was able to tilt the piston just a bit back and forth in the cylinder. I normally would not do that but thought it might be the issue. Am I way off?
Sorry for the ramblings. I should warn you that I'm not a technician. Just someone who enjoys working on this stuff....usually.
I'm a little stumped by this. I'm getting some weird results from a leak down test. I was at TDC and charged the cylinder slowly with about 60lbs of air in. I could hear air escaping into the crankcase and it would only hold about 28-30 pounds. But when I slowly raised the pressure up to about 68 or 70lbs in, I hear a faint hollow sound....like "thoop". And the holding pressure jumps up to 60. And as I add pressure up to 80 and 90, the held pressure follows about 10lbs behind. It sounds like something sliding a short way up a tube.... So I'm eventually getting to about 11% leakage? But initially at 60lbs in, it's like 53%?
Whatever this sound is, it seals off the cylinder. If I depressurize and repeat the process, I get the same result. I've tried this with the rockers and pushrods removed to eliminate valves.
Although there is an exhaust valve issue problem now because when this strange thing happens and the held pressure jumps, I get a little leakage from the exhaust valve. I did have the head off to change a blown head gasket. Didn't touch the valves but thinking I should lap them now. But that's a completely separate issue I think.
Without the faintest idea of what is causing this strange behavior, I had a theory that if the rings are worn, this strange sound and unexplained sealing of the cylinder that occurs may be the piston shifting and creating a better seal. Then when I deflate, the piston shifts back to its original position. I can't think of anything else that would cause this. When I had the head off, I was able to tilt the piston just a bit back and forth in the cylinder. I normally would not do that but thought it might be the issue. Am I way off?
Sorry for the ramblings. I should warn you that I'm not a technician. Just someone who enjoys working on this stuff....usually.
So no luck bleeding down over night. Should the lifter be removed before spraying it down? Or should I squirt it right there in the block? Should I at least remove it and inspect it? Can I just use a telescoping magnet to pull it out?
So I got this thing running, which is always stressful for me after I take something apart. After replacing the head gasket and before reassembly, I put a thin coat of oil on the inside of the cylinder. I also gave a quick spray of oil onto the lifters and the ends of the rods. I started it up and let it run for about 30 seconds just to see that it would.
I think this is normal but just wanted to verify, I'm getting a lot of smoke out the exhaust. Assuming that's the oil burning off and it should stop? And there's some clicking which I'm assuming is lifter noise. Although I didn't remove them, I read somewhere that it should go away after they find their happy place?
Thank you
I think this is normal but just wanted to verify, I'm getting a lot of smoke out the exhaust. Assuming that's the oil burning off and it should stop? And there's some clicking which I'm assuming is lifter noise. Although I didn't remove them, I read somewhere that it should go away after they find their happy place?
Thank you
Thanks. Smoking stopped. I haven't had it running for more than a couple minutes at a time so far. Lifter noise is only audible at idle and lower RPMS.
If the lifter noise doesn't stop, does that mean they need replacing? Or does it mean something else? To be honest, I really can't verify that the lifter noise is new because it wasn't running when it came to me. For all I know, it's been going on for a while. The oil was pretty bad, black and such.
If the lifter noise doesn't stop, does that mean they need replacing? Or does it mean something else? To be honest, I really can't verify that the lifter noise is new because it wasn't running when it came to me. For all I know, it's been going on for a while. The oil was pretty bad, black and such.