Rep Power: 275

So, I did my valve clearance according to grey's DIY, and adjusted the exhausts to .009 (correct tolerance .009-.011) and intakes to .007 (correct tolerance .007-.009). No valve noise, and it runs like a top, with a idle a little different than usual, but I'm assuming thats the ecu needing to be retrained. This could also be the new NGK iridiums I put in, though...

I am very worried after looking around seeing what the consequences of too tight a valve lash are: burnt exhaust valves, head rebuilds, no compression because of busted valves, etc... How do i know if I have them too tight? I tightened the screws until the feeler gauge "dragged," but not so tight I had to use a bunch of force to rip the gauge out.

Questions:

1: Grey and others, why set the clearance in the DIY and on your rides to the tight set of tolerances? Does it really give better performance than a more middle of the road setting? Why not just set it at the middle gap and check clearances a bit more often?

2: Loose valve clearance = cheaply fixable noise, but tight valve clearance = burnt exhaust valves and expensive repairs. Any reason to risk this by setting the lash to minimum specs?

3: It seemed like all my valves were pretty tight... do valves on our engines tend to get tighter clearances or looser clearances with age?

4: Is there any visual / audible / whatever sign of too tight of a valve lash that i can check for without opening up the damn valve cover again and doing the feeler gauges again?

I just got to thinking that if the valve clearance has a range, and if having the clearance too much causes valvetrain noise, what happens when we set them too tight, and how do i know if I have them too tight?

Would a better DIY procedure be:

1: Loosen adjuster nut, adjust with "desired" gauge so it just drags. Tighten nut

2: Get the next thinner gauge and put it in - should have play

3: Get the next thicker gauge - should not be able to insert it.


Comments welcome...

 
Rep Power: 0

I'm all for your DIY procedure which is how I do valve lash when I tune a vehicle. I haven't read Gray's yet to see how he recommends doing it. You'll know if you have them too tight if your car runs like crap. We have enough clearance that a .001 mm or two won't cause piston slap, but it will throw off the compression and exhaust phases enough that the car will run crappy. Since the valves won't be closing all the way and opening too far, it will be off. In a worst case scenario they could float at high RPMs since they wouldn't have time to close before the next stroke. Things would get really complicated and expensive at that point.

Honestly, since the manual states between .007 - .009 anywhere between, and including, that range is fine. Honda wouldn't put a minimum spec of .007 if it hadn't tested it, and accounted for it in warrantied tune-ups.

 
Rep Power: 813

i havent adjusted mine in 55k miles and it runs better than new so idk, i thought that was an "adjust only if needed" thing.

 
Rep Power: 454

i have yet to adjust mine and have 132,000 miles. car still runs like new with a small ticking from the motor but nothing to worry about.

 
Rep Power: 275

Yeahhhhh...

Just re-did the clearance using my method, and the car runs a WHOLE lot better - especially when setting the clearance in the middle of the specs rather than the tighter end of them, so .010 in for exhaust, and .008 in for the intake.

Mods, can I get permission to post on the valve clearance DIY thread an alternate procedure, as it is a bit more specific than "just make sure the valves grab the feelers." I'd also lobby to put some more information on the consequences of having the valve lash set too tight vs. too loose. Tight valves don't make noise, but the car may have a rough idle and slightly more power in the high end, at the cost of having exhaust valves running hot. Loose valves, obviously are noisy and rob power. They also can lead to failed smog tests. (Burned valves, et al):

reddawnman's suggested procedure:

1: Loosen adjuster nut, adjust with "desired" gauge so it drags. It should take a bit of force to get the feeler out, but not so much that you need to use your whole arm strength. Tighten adjuster nut while holding the screw steady

2: Get the next thinner gauge and put it in - should have play and should take less force to move.

3: Get the next thicker gauge - should *not* be able to insert it at all.

4: Torque the adjuster nuts to the desired specs, and *Re-Inspect* using your desired feeler, the next thicker and the next thinner gauge. Again, if you can insert the next bigger gauge, you need to start over as the torquing can mess up the adjustment (generally makes the clearance a touch looser). if the next thinner gauge is really really hard to insert, you might also be too tight.

I can't stress enough the importance of taking some time to reinspect the clearances after you torque the bolts to 13 lb/ft (14 lb/ft for EX). The torquing tends to mess with the adjustment, and you don't want to have to wait another day for the engine to cool down after you've put the valve cover back together... Do it right the first time :-)

 
Rep Power: 0

Hey thanks for the info. I did my valves and it seems to have more ticking noises from the engine. I'm going to take it apart tomorrow and start over and take my time again....