S2000 engine rattle(help I'm scared!)

I have a 99 s2000 owned for about a year, it now has 50k. it was perfect but about 6 months ago the engine started rattling at idle but only when it was warmed up and had been given a bit of welly(embarassing when at the lights) but absolutely no noise when starting cold or when revs above about 1300rpm. i've seen another topic on s2000 rattle where the guy says it sounds like chop sticks in a plastic cup! now i dont think its same problem cos i'd say this sounds like a bag of spanners kind of like a "drrr drrr drrr" in time with the engine speed. blipping the throttle quite high can get it to stop but i dont want to do that cos i think something serious is startin to develop. when i took it for its first service in my possession my local honda dealer told me it had missed product updates one of which was an updated oil gallery and it was only after this that the problem started(could that have something to do with it?). i mentioned to him the timing belt and he told me it doesnt have one it has a cam chain instead and this is internal (is that right? i know how to drive dont know about engines). he also reckoned the rattling was coming from the cam chain. when it got its next service i asked him to check it out but it miraculously stopped after the service, however now i'm about 5 or 6k on and two half litre oil top-ups later and its started rattling again and to be honest i'm terrified my engines gonna implode.not bein funny but i think the service manager is clueless and not interested in helping me he's just interested in his commision and if i have to buy a new engine he doesn't care. please please please can someone help me, ive tried to give as much details as possible, i'm a nice lad and i dont deserve the indignity of having to get a loan to buy a new engine. i still owe for most of the car so I could end up screwed big time. please help. PLEASE

 

Probably timing chain is a bit loose, or a timing chain tensioner. Chains
wear out, just like a bike chain does, even when lubricated.

Coming to this NG is good idea to start. You are likely correct that the
service manager is clueless. Why do you think he's the manager? Do the
following:

1. Check your Yellow Pages for a local aftermarket Honda specialist. For a
99 there's no need to go to the dealer. Many Honda oriented speed shop techs
are very knowlegable about VTEC twin cam engines. The rattle is probably not
terminal, but get it diagnosed (if not fixed) soon.

2. Look on Ebay or go the dealer for the last time and buy an S2000 workshop
manual. Its will cost you a few bucks, but having it to refer to (or letting
a mechanic refer to it) will be worth it.

3. Any S2000 you see on the street or parking lot, ask them (or leave a
note with phone number) where they get it serviced. Most owners will be only
too happy to offer advice.

Stewart DIBBS

 

but about 6 months ago the engine started rattling at idle but only when it
was warmed up and had been given a bit of welly(embarassing when at the
lights) but absolutely no noise when starting cold or when revs above about
1300rpm. i've seen another topic on s2000 rattle where the guy says it
sounds like chop sticks in a plastic cup! now i dont think its same problem
cos i'd say this sounds like a bag of spanners kind of like a "drrr drrr
drrr" in time with the engine speed. blipping the throttle quite high can
get it to stop but i dont want to do that cos i think something serious is
startin to develop. when i took it for its first service in my possession my
local honda dealer told me it had missed product updates one of which was an
updated oil gallery and it was only after this that the problem
started(could that have something to do with it?). i mentioned to him the
timing belt and he told me it doesnt have one it has a cam chain instead and
this is internal (is that right? i know how to drive dont know about
engines). he also reckoned the rattling was coming from the cam chain. when
it got its next service i asked him to check it out but it miraculously
stopped after the service, however now i'm about 5 or 6k on and two half
litre oil top-ups later and its started rattling again and to be honest i'm
terrified my engines gonna implode.not bein funny but i think the service
manager is clueless and not interested in helping me he's just interested in
his commision and if i have to buy a new engine he doesn't care. please
please please can someone help me, ive tried to give as much details as
possible, i'm a nice lad and i dont deserve the indignity of having to get a
loan to buy a new engine. i still owe for most of the car so I could end up
screwed big time. please help. PLEASE.Sounds very much like rod bearings that were starved for oil at some point
and have run. When they go bad you will get a rattle off idle when revving.
Had it happen to me on a '64 XKE years ago. You need to have your Honda
mechanic listen to it. If they don't have to pull the engine it is possible
to replace the bearing shell by removing only the oil pan. However, if the
bearings have gone completely, the crank is probably scored which means a
lot more expensive work,

 

An indication of whether this is happening or not is to fit a pressure guage
in place of the oil pressure sender. If the warm idle oil pressure is 30 lbs
or more the rod bearings are *probably* good, if less then I'd expect the
bearings are worn. This is only a rough check, but if the warm idle oil
pressure is okay there must not be a lot of leakage at the bearings.

My own experience with rod knock is that it sounds pretty much the same at
various speeds and throttle openings, and warm or cold, but the possibility
still exists. My first thought is the valve clearances, though. My
recommendation is to check the owner's manual for the valve inspection
interval and compare it with how long it's been. If it's due, or you don't
know, I suggest you start with that. As for the cam chain, it could be.

Mike

 

Not that often people draw on their XKE knowledge to diagnose Hondas!

 

>Sounds very much like rod bearings that were
starved for oil at some point

Extremely unlikely.

The orginal poster said the noise went away for about 6K, so its not a
bearing problem. If a bearing is damaged enough to cause an audible knock on
idle, it won't fix itself, and it will just get worse, as well as being
audible under load. I'd guess that the dealer put in some better oil or an
additive and this quietened the chain rattle (?) or a while.

Stewart DIBBS

 

Rod bearing rattles are the same whether it is a XKE or a Honda.
Apparently, his problem was something else, but the description seemed to
fit. Having owned an XKE gave me an insight into things that can and do go
wrong. On the E it was most of the time. As a Prelude owner and also a
long-time Honda owner, however, the work bullet-proof comes to mind.