Ovr8ted

Hello All,

I've had my AP1 s2000 for about 4-5 years. Over the course of 4 years I've done about 10,000 miles on it (summer only car).

The previous owner said he had a valve adjustment done shortly before I bought the car. I drove it and everything seemed fine, car drove great no issues. Last summer it started getting a little loud on the "ticking" noise, which seems counter intuitive because I was under the impression valves would get tighter over time. After picking up the car from winter storage I did a valve adjustment a few weeks ago.

I'm no mechanical wizard by any means but to me the exhaust valves were in spec. The intake side however, must have been WAY out of spec, because trying the go-no-go method, the 0.010 and subsequently the 0.011 gauge slipped in with no resistance at all. I probably should have kept going with larger gauges but alas I didn't. These were all measured on an engine that rested 3 days before checking. I tightened them up to the loose end of the spec, 0.011 won't fit, 0.010 slight drag, 0.009 moves freely. I did not do a compression or leakdown test.

The car feels like it has slightly more power and is much quieter on the ticking, but now sometimes in 1st or 2nd gear going through a parking lot the car will start jerking until I push the clutch in and re-engage the gear. Additionally, while driving in the high 2000 rpm range, the car will almost "jitter" (not quite a bog) if you will. The exhaust will burble/pop shortly, and the revs dip just slightly before the car re-catches and picks back up. If I'm hard on the throttle this doesn't happen, it only happens when I'm cruising. It almost feels like there's a misfire happening at those RPM, but I don't have a CEL or any codes.

Assuming I didn't completely botch the valve adjustment myself, this leads to my ultimate question: would the valves being loose for an extended period have caused some damage in any way that's causing my symptoms now? If so what would that damage be and how can I check? Why would these symptoms happen now after tightening the valves, and not before when they were too loose?

A few anecdotal things:
- I've Map Whack'ed and zip-tied
- I did not ECU idle relearn after the adjustment
- The car starts up just fine, no unusual RPM drops in neutral (warm or cold engine)
- I'm 99% sure I have an exhaust leak somewhere, haven't tracked it down yet
- My car would throw an o2 sensor code (before adjustment). Maybe once every few months. I just clear it
- It's been 85+ and humid almost every day since I've done the adjustment. Although one night I was out later and it was about 75 and the jittering at high 2k rpm happened

Thanks in advance

B serious

I'm sure you didn't do damage from driving 10K miles with loose valves.

Which O2 sensor code did you have before?

Chuck S

Near consensus here is to set intake valves to the max spec (0.009") and set exhaust a "thousandth over" (0.011" + 0.001" = 0.012"").

Shamelessly plagiarized. Valve train wear seems to be the major liability of loose valves.

• Too much valve clearance:
  - Valve noise: Excessive valve clearance can lead to increased valve noise or tapping sound as the valves strike against the rocker arms or camshaft.
  - Poor engine performance: Too much valve clearance can result in poor engine performance, including reduced power output, decreased fuel efficiency, and rough idling.
  - Valve train wear: Excessive valve clearance can cause accelerated wear on the valve train components, such as the camshaft lobes, rocker arms, and valves themselves.

-- Chuck

Ovr8ted

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Had to scour my phone pics. P0420, which makes my original statement disingenuous as I believe this is a CAT code and not an o2 code.

Apologies, another car of mine has an o2 code right now and it's scrambling my brain.

Ovr8ted

Appreciated. I believe I've read that same sentiment posted somewhere else here on the forums.

I suppose I never really noticed poor engine performance, but that's with no comparison. It has never idled rough, ever.

The last bullet point is what makes me the most weary. I don't know if I'd be able to visually tell if any of that wear has happened.

ruby2k

Does this sound normal? Do you think I need a valve adjustment? Tct? “Sorry for the short vid it took me forever to cut the video down enough to pass the 20mb limit.

ruby2k

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ruby2k

I’m sorry it not letting me post the video I’m new here how do I delete these reply’s lol

windhund116

You need to message the admin to remove posts or change titles. Videos need to be posted to a video sponsor site, like YouTube, and then paste the link into the message box.

As for very loose valves, I remember old-school valves would sometimes "cup" from excessive play --- wearing the valve seat over time.


This would lead to leaking valves.

I'm not sure that this is still a problem with today's metals used in valves and seats.

B serious

Correct, P0420 is a catalyst code. Does the car have an aftermarket cat? Or a test pipe?

I wouldn't worry about the previously loose valves. You adjusted them and they're good now. If the cams were galled or something, you would likely have seen it.