FObangah

Ive heard alot of people complaining of valvetrain damage by over-reving there F20.
Of course I heard of this AFTER quite a few sprints to redline. Heres the thing though, ever since I bought it ( USED) about 6 months ago, cutting the car off to go in a store or something then starting it back up while still hot results in a terrible rattling noise that I cant pin-point. All I know is that if I listen close, I here a click, then a " weee" sound like something is powering up, and it stops. Plus, I dont have the clicking noise when it is cold. I went back to the dealership and they said it is the heatshield on the header and that all they would do is take it off. So I wasn't gonna pay them to take it off. Any ideas what it could be???

MXDesa

That weeeee sound you hear as you so cleverly put it is a emissions system known as secondary air injection. It injects air into the exhaust stream in order to aid in the chemical reaction that takes place inside the catalytic convertor. Now as far as the rattle, it most likely is a heat shield of some sort because if the rattle was engine related, it would rattle always, cold, hot, high revs, etc... And the s2000 does not suffer from valvetrain damage from over revving. The problem lies mostly in spun bearing damage, but that is rather rare in comparison to the amount of S2000's out there.

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FObangah

Dont take me as being a smart ass because any advice is appreciated but, there are a few posts here and many other places, not to mention magazine articles that state how alot of people suffer from valvetrain damage on completely stock motors, usally to the retainers. So to say " the s2000 doesn't suffer from valvetrain damage from over revving" would be a bold statement right? plus, if it was DEFINITLY the heat sheild, wouldnt it rattle the whole time i was idling and not when the " secondary air injection" decided to ingage warp drive? It does stop as soon as i here that " weeee" sound. Oh and to say that " ... if it was engine related it would rattle always,cold, hot,high or low revs" would be hard to believe also because poorly adjusted valve springs will be quiet when cold and rattle when hot. Now maybe this clicking sound is some sort of effect in the cat. when there isnt enough air and when the " air injection" is introduced it smooths out??? Ive never heard of " secondary air injection" before and I sure as hell dont understand how it works... or even if there is such a thing. But I'll take your word for it and look around down there.

MXDesa

Well there is the difference from what people say happens to the engines and, from what someone who works on them everyday says happens. I get a lot of blown S2000 engines, and one has been valvetrain related and all the rest were spun bearings or low end damage. Heat shields rattle are strange because it is only audible when at a certain vibration point. Thats why you dont hear it throughout the RPM band. Secondary injection systems are only used on the S2000 and no other honda. Not many people know about it so thats likely why you have never heard of it

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reikoshea

when it comes to weird noises on the hondas....i tend to listen to mx....ive heard of the valve train problem (springs and retainers), but spun bearings are far mor common.

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FObangah

word.....I was outside a little while ago and ran the car up to temp. cut it off, went inside for approx. 5 minutes, came back out and had my girl start it while I was under it and i couldn't locate it because as soon as the secondary air injection comes on it goes away but the cars idle doesn't fluctuate at all. For example, the rattle starts as soon as the car starts( combustion starts), it gets loud as the RPM goes up to 2000, then quiets down with it returning to idle ( 1200 ). approx.1.5 seconds after this I here the "click-weee " sound that MXDesa says is the SAI, then the sound stops completely until my next 'hot-start'. Any suggestions?

Z6CRX

I had a rattle much like that on my crx with the stock exhaust till I replaced it.
I also Spun a bearing on the stock motor due to lack of oil, and it wouldn't idle rought at all, but it would sound horrid almost like a rattling heatshield when you gave it throttle.
Take a few rags and stuff em in between a few of the parts of heatsheild on the piping on the underside if you can locate it, just dont run it long so you dont ignite stuff.
I think its the heat shield from the sound, but i would have no doubt that i could be wrong in this case.
I'm just throwing random stuff out there hopefully it may help.

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Havok

Hmm, sounds like that's what mine is doing--after the engine is warm, and I start the car, I hear a 2-3 second rattle.

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Calesta

Maybe the pump is going bad?

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FObangah

havoc; it only does it when its warm right? but it just all of a sudden stops? thats what Im tryin to understand... I've found plenty of rattles in exhaust systems, and never have I heard one that has such a fluid rattle at a certain RPM then all of a sudden stop even though the RPM hasn't changed, the car hasn't moved, or anything. I start it, it rattles,clicks like a switch , and then stops. Maybe calesta is on to something. Secondary air injection would have some kind of pump to push air into the cat right?

totalautosports

I worked for honda for about 12 years or so. i had 1 s2000 that someone dropped the oil cap inbetween the transmission and tunnel and made a noise at times the car was used and had a new oil cap it wasnt something that i expected otherwise it very well might be the secondary air assist