S2000 Under The Hood S2000 Technical and Mechanical discussions.

valve adjustment cold

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Old Mar 22, 2008 | 09:48 AM
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Default valve adjustment cold

I had posted awhile back on this subject and I am sorry I know this topic of lifters has been beat to death but I have an interesting question. When the motor is cold about 33 degrees, valve clearances were on intake side:

cyl1- .4
cyl2- .4
cyl3- .6
cyl4- .4

now I went and drove down the freeway and around town came back and engine was hot(I pulled right into the garage and poped hood and started taking valve cover off takes about 5min. and checked intake clearances and were as follows:

cyl1- .10
cyl2- .09
cyl3- .12
cyl4-.09

So I was told some race engines adjust to almost zero spec cold and when the motor heats up clearance is added. So what would happen if I adjust cold to .2 or so, my hot readings would be about .08 or so wouldn't it? which would be perfect. anyhow if anyone has done this feel free to share experiances.
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Old Mar 22, 2008 | 01:18 PM
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bump...
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Old Mar 22, 2008 | 04:30 PM
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They have you set the adjustments at x amount of play because they know what it will expand to when warm which is the proper amount of clearance. If they say .07 intake .08 exhaust cold, it's so they will expand to the proper clearance when warm.

1 of many reasons not to beat your car when cold
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Old Mar 22, 2008 | 10:15 PM
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you're supposed to adjust when cold...

so it appears that your clearance is WAY off...
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Old Mar 23, 2008 | 10:08 AM
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no they still tick terrible and it's not the tensioner. It's just that when at operation temp theoretically the clearance should be closer that's why I thought we had clearance was because metel expands and at operating temp the gap should be close to none. Is there gap for another reason i.e, optimal lift or something? Even hot it ticks bad but some of that is injectors.
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Old Mar 23, 2008 | 12:01 PM
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Originally Posted by sharptech,Mar 22 2008, 11:48 AM
<Snip>
So what would happen if I adjust cold to .2 or so, my hot readings would be about .08 or so wouldn't it? which would be perfect. anyhow if anyone has done this feel free to share experiances.
Do you think Honda took that into consideration? They have spent a buck or two in racing over the years.
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Old Mar 23, 2008 | 12:07 PM
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Originally Posted by sharptech,Mar 23 2008, 12:08 PM
<snip> It's just that when at operation temp theoretically the clearance should be closer that's why I thought we had clearance was because metel expands and at operating temp the gap should be close to none. <snip>
If the metal is the same, it will expand at the same rate. Dissimilar metals will expand at differant rates. In our heads, the rocker shaft is mounted in the head. It is AL. As it heats, it would move the shft further from the valves. So assuming that the head to block location is always at 0, the heat would also cause the head to swell. That would cause the clearance is widen as well.

Really Honda built a great motor, and spent alot of time getting it to run right. Second guessing them on this specs may cost you in the long run. I think Honda already paid that price.
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Old Mar 23, 2008 | 01:25 PM
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attn gernby
you should have sent him a pm vice asking for his help on the public forum. Other people are very knowledgeable, you know?
Because of that, I will publicly be an ass and not provide you answers to questions you have that don't concern me.

I will say that I have checked my valves (3X) when the engine is cold. I
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Old Mar 23, 2008 | 02:52 PM
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I personally think 33 degrees is way to cold to adjust valves.

In my book, room temperature (50-70 degrees)
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Old Mar 23, 2008 | 05:00 PM
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Originally Posted by Stratocaster,Mar 23 2008, 12:07 PM
If the metal is the same, it will expand at the same rate. Dissimilar metals will expand at differant rates. In our heads, the rocker shaft is mounted in the head. It is AL. As it heats, it would move the shft further from the valves. So assuming that the head to block location is always at 0, the heat would also cause the head to swell. That would cause the clearance is widen as well.
You have the right concept here, but remember that the valves are going to be much hotter than the head itself. Their expansion will reduce the clearance, probably to near zero.
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