Tapping noise might be from solid lifters
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Tapping noise might be from solid lifters
I took my 2002 S2000 by Honda today because I could hear a slight tapping noise from the engine compartment. The tapping noise was new (car has 6000 miles on it). It's very quiet -- I can't hear it at all above 3000 RPM, nor lower than 2000 RPM. It is much quieter than the gear lash from the differential. It's also not related to engine load.
Anyway, the service guy (Chris at Anderson Honda) and I drove around a bit, and he heard the noise, and he said, yeah, don't worry about it. I told him about the Honda Netherlands cylinder #4 thing, and I think he's heard about that already. Anyway, he pointed out that Honda will take care of the motor if something goes wrong, and this tapping wasn't anything wrong yet. Pretty much what I expected him to say.
But he did say something unexpected. The S2000 apparently has SOLID lifters! His theory is that the lifters are set fairly tight at the factory, and that during break-in the clearance opens up a bit, so that there is now a tiny gap at normal operating temperatures, hence the tapping, as the cam lobe makes contact with the roller.
I've had solid lifters before -- in my CBR600 motorcycle. I had to adjust the valve clearances every 5K miles or so. What a pain (literally -- bleeding knuckles every time). My understanding is that most cars have hydraulic (self-adjusting) lifters, which don't really need any manual adjustments.
So Chris said that while Honda doesn't recommend adjusting the lifters until 75K miles or so, that's because they want to spec very long maintenance intervals for the car. He recommended that I have the lifters adjusted every 15K miles!
I suspect he's saying that because keeping the lifters tight will cut down on valvetrain noise, which will keep me from whining about new noises. Fair enough.
Has anyone else had such a recommendation? Are the S2000 lifters really not self-adjusting? Has anyone else had their lifters adjusted, and actually noticed any change in engine noise or power delivery? What actually happens if you let solid lifters fall out of spec?
Anyway, the service guy (Chris at Anderson Honda) and I drove around a bit, and he heard the noise, and he said, yeah, don't worry about it. I told him about the Honda Netherlands cylinder #4 thing, and I think he's heard about that already. Anyway, he pointed out that Honda will take care of the motor if something goes wrong, and this tapping wasn't anything wrong yet. Pretty much what I expected him to say.
But he did say something unexpected. The S2000 apparently has SOLID lifters! His theory is that the lifters are set fairly tight at the factory, and that during break-in the clearance opens up a bit, so that there is now a tiny gap at normal operating temperatures, hence the tapping, as the cam lobe makes contact with the roller.
I've had solid lifters before -- in my CBR600 motorcycle. I had to adjust the valve clearances every 5K miles or so. What a pain (literally -- bleeding knuckles every time). My understanding is that most cars have hydraulic (self-adjusting) lifters, which don't really need any manual adjustments.
So Chris said that while Honda doesn't recommend adjusting the lifters until 75K miles or so, that's because they want to spec very long maintenance intervals for the car. He recommended that I have the lifters adjusted every 15K miles!
I suspect he's saying that because keeping the lifters tight will cut down on valvetrain noise, which will keep me from whining about new noises. Fair enough.
Has anyone else had such a recommendation? Are the S2000 lifters really not self-adjusting? Has anyone else had their lifters adjusted, and actually noticed any change in engine noise or power delivery? What actually happens if you let solid lifters fall out of spec?
#3
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I have 47k on my car. ~8k hard track miles. I adjusted my valves about 10k miles ago. They weren't that out of spec. I don't think they really walk that much.
#5
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The S2000 uses a lifterless design. The cam rides on a rocker arm (roller) that then actuates the valve directly. There aren't any lifters in it.
The concept of a "solid" design is the same, though- they are directly actuated. Honda allows for a lot of clearance (.010/.008 IIRC) which makes for a rather noisy valvetrain. This is a Honda trait.
The noise is nothing to worry about. If you don't like the noise, have the valves adjusted .001 or .002 tighter than the Honda spec. It will reduce the noise and actually increase the valve opening duration ever so slightly.
The concept of a "solid" design is the same, though- they are directly actuated. Honda allows for a lot of clearance (.010/.008 IIRC) which makes for a rather noisy valvetrain. This is a Honda trait.
The noise is nothing to worry about. If you don't like the noise, have the valves adjusted .001 or .002 tighter than the Honda spec. It will reduce the noise and actually increase the valve opening duration ever so slightly.
#6
I adjusted my valve clearances at about 5K miles, and found that they were all out of spec. Some of my intake valves had clearances that were too small to measure, since my smallest feeler guage was .005. Considering that the minimum spec for intake valves is .008, and ALL of mine were .005 or less, and the minimum spec for exhaust valves is .010, and ALL of mine were .006 or less, I recommend that everyone check them at least once in the first few thousand miles. I am pretty sure that mine were out of spec from the factory. After adjusting the valves, my idle was so smooth, I couldn't even tell it was running at a stop light, but the valve train is noisier. I was surprised that the adjustment didn't seem to have any noticeable effect on power.
I am going to check them again pretty soon, but hopefully they haven't changed much. It has been about 4K miles since I adjusted them, but it still idles and sounds the same.
I am going to check them again pretty soon, but hopefully they haven't changed much. It has been about 4K miles since I adjusted them, but it still idles and sounds the same.
#7
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My wife just picked up her new '02 S2000. Unless I have mis-read the owner's manual - it says to have the lifters checked at 105,000 miles "unless they are noisy". Is that for real?
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#8
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There was an excellent post by johev on valve adjustment that I can't locate even with search functioning again. The gist was that many of us had valves that were out of spec (5 of my 8 intake valves were too loose) and in general adjustment improved engine smoothness and decreased noise. My car had 23k miles on it when the adjustment was done. The job was pretty straightforward, it was a little challenging for me to wiggle the valve cover off and it really helps to have 45 deg. angled feeler guages. No skinned knuckles fortunately.
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Thanks, hecash, that's pretty much what I expected. My S2k sees regular autox duty (coming to the CenDiv this weekend, btw?) but I expect to do a leak-down and compression check over the winter, so if there is excessive wear on #4, it should show up then. I doubt I'll be in the mood to pull the pan, though
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