EDIT: car is like it says below, 99 Civic Ex coupe

A couple months ago I had a mechanic do a side job for me to change out my timing belt. After he did it I noticed a weird sound when the engine is under load. It wont make the sound when I rev the engine just during acceleration. The car never made the sound before. The best I can describe it is maybe something to do with the valves chattering or something?Ive tried a couple times to get him to ride with me and listen but we've both had things go on that stopped us. It didnt bother me too much when it was 10 degrees outside cause I could hardly hear it but now that its windows down kind of weather it is really annoying and sounds terrible. Does anybody have any idea what could cause this kind of sound from changing a timing belt? He is supposed to ride with me tomorrow or Thursday but I'd like to see what you all have to say about it. Thanks

 

Sounds like you need a valve lash adjustment.

 

How much does something like that run?

 

Free.99, if you have feeler gauges and basic hand tools. It's a pretty easy process, and there's a how-to in the FAQ's sticky. If you want to have it professionally done, call around - different shops charge different amounts.

 

or could be a cracked exhuast manifold or exhaust leak

 

An exhaust leak wouldn't sound like a chattering, though, and would still be audible during no-load revs.

 

I guess I should add that he rode with me after my first post. As soon as he heard the noise 100' out of his driveway he said it was a detonation issue caused by bad gas. I was skeptical of that cause I've put 2K miles on the car since and ran quite a few tanks of Shell or Exxon gas through it. He recommended I run a couple tanks of 93 octane with some kind of cleaner through the fuel system. The next day I filled up an empty tank with 93 and the sound almost instantly went away for most of that tank. I only heard the sound maybe 10 times out of the whole tank instead of 20 times on one ride to work. I haven't run anything through the fuel system yet but after a few tanks the sound is becoming more regular again. Thanks for your replies and input on this.

 

If you can hear detonation while sitting in the car, the motor is fucked. I'm going to go out on a limb here and say this "mechanic" of yours works under a shade tree somewhere.

 

He works for a shop that is well known in the area for modifying bad *** GM LS motors. they work on everything though but the owner got his start tuning LS engines. Just sayin. This guy workes with some nice cars. Not saying he wont do something half assed on the side

 

There's a reason I don't trust muscle heads to turn wrenches on imports. This is that reason - diagnostically, they have no clue what they're talking about a lot of the time. Detonation loud enough to hear when sitting in the car would be harsh enough to destroy a head gasket (or motor) in very short order.

 

Hey easy now, we aren't all that bad.

 

Haha, that is true. Just cause they are good with a V8 doesnt mean they know Hondas. I really hate to have a stealership look at it cause it'll be $$$ and the closest one is 40 miles in a direction i rarely drive.

 

I know this is coming way out of left field... but let me bounce this thought off someone. (incase Mechanical timing checks out)

If the sound goes away when you add 93 octane fuel, and the car runs "better", wouldn't that point to an issue with the ignition, or ignition timing? Since the car is intended for 87.

 

I think the timing belt is off one tooth. this is easy to check with a timing light.
your tech should be able to do this. you did not report if the check engine light was on or not. if it is check the codes and repair that too. if this model has a EGR valve it could be problematic.

 

Im going to go with the timing belt being off a tooth. I had a similar problem with my 1.6L. (Was off by a tooth, it was my first TB job, so give me a break) So for about 50k I had clattering valves but oddly phemnominal gas milage (Go fig) I did the belt again at 50k because the crappy non oem pump started pissing itself from the weep hole. Got the timing perfect this time and no more noise.

 

I have no check engine light on.

 

We're now 18 days later. Have you checked valve lash, like I said? Is it within spec?

 

Sorry, That is something I don't have money to have somebody look at nor do I have the ability to check it myself. If I had that confidence I would've done that timing belt myself

 

Mine being off a tooth didnt set a CEL either. Like I said, I had a little bit of valve clattering (Somes sounded like things were jingling under the hood) Realisticly the higher octane gas was probably just masking the sound by having a different reaction point. I would check valve lash in the mean time. You can goto NAPA, Advance, Autozone, Ace, basically any hardwre store or autoparts store and get a cheap socket set and some feeler gauges.

 

Being off one tooth won't exactly set off the CEL.

1. Engine noise appeared when timing belt was changed.
2. "Valvle Clatter" beaing heard". Not either the timing itself was advanced too far, or that's a symptom of the timing belt being off a tooth.
3. I bet it doesn't idle as well and probably performs a little doggish on take off too.
4. Valve lash doesn't change radically overnight, and I wouldn't try checking it unless I was absolutely shure those timing gears are all aligned.

A timing belt, you have to have all the stars in perfect alignment or the universe of that engine will not be right. From what I'm seeing I would put dime on it that it's your timing belt...

Been there done that many times.... It's a very easy mistake to do. Only one way to know. Someone's got to take the valve cover and timing belt cover off and look.

Check it out on youtube it's not that hard.

 

OP, if things are that much of a bother, I recommend finding a friend who has both the tools and knowledge, and not the shady tree guy who did it in the first place to confirm your timing belt timing is 100% correct and not off a tooth or some other issue. I hear beer and pizza are wonderful payments (If you're 21 and over)