Timing chain rattle

[Frd_thmsn]

My VN V6 s1 has had a rattle for ages , seems to get a bit worse towards the time when an oil change is due, and after the engine is hot.

I can't pin point it with a screwdriver to the ear method.
Noise is worse idling in drive .
Sounds a bit like pinging.
Worse when hot.
If I remove the belt I can't notice the noise.
Changed harmonic balancer pulley to a series 2 one I had lying around just in case.
Alternator pulley and bearings seem quiet.
Tensioner pulley and water pump seem quiet.
I noticed the Power steering pump has a slight growl but not a rattle.

So would a timing chain problem be less with the belt removed?

************************************************** *******
ADDED 9th APRIL 2006.. Problem fixed ,was due to the timing chain tensioner had disintegrated and there was no chain tensioner.
Have included a smaller sound file of the noise to help anyone with this type of engine noise.

[vpads]

I had a very similar problem could have sworn it was the timing chain or maybe cam bearings, was annoying me for three months. anyway it didnt end up being the timing chain.

try changing the oil to mineral 20/40, change oil filter and get some trade strength nulon lifter free-up from your mechanic and put it in with the oil. I ran my car for 1000ks after doing this and the rattle has basically disappeared. I also added a bottle of nulon e10 worn engine treatment.

in another 1000ks i will change the oil back to semi synthetic and put new filter and off i go.

[Frd_thmsn]

I had a very similar problem could have sworn it was the timing chain or maybe cam bearings, was annoying me for three months. anyway it didnt end up being the timing chain.

try changing the oil to mineral 20/40, change oil filter and get some trade strength nulon lifter free-up from your mechanic and put it in with the oil. I ran my car for 1000ks after doing this and the rattle has basically disappeared. I also added a bottle of nulon e10 worn engine treatment.

in another 1000ks i will change the oil back to semi synthetic and put new filter and off i go.

Thanks for that.
I'll give it a try , I haven't got anything to lose.

Will post here in a month or so and let you know if it worked.

[ScottB_33]

The rattle will usually come in at about 1500rpm and increase in loudness and consistency as speed increases and revs increase as well, but will bge hard to hear at greater speed due to all the other engine and exhaust noises around. It's like a metallic rattle/ringing where a lifter noise is more like a real tapping sound and is quite distinct in its sound. The timing chain rattle can also be heard quite easily in the cabin especially on acceleration as a light metallic rattle building in loudness and intensity as you accelerate. I have replaced many timing chain tensioners in VN motors and it is quite common.

[Frd_thmsn]

I'll try and record it tomorrow/today. Maybe we could start a library of commodore engine noises .

This is what bad big ends sounds like etc

from your description it sounds like a chain/tensioner. I've heard tappet noise before and this doesn't have that clacky sort of noise , sounds more like I had left a clamp loose on the exhaust or pinging. Sounds in the engine.
But what I can't understand is why with the belt off I cant hear it at idle.


It's bloody hard to describe noises

[Frd_thmsn]

Here's an mp3 sound file of the noise.
Could you have a listen please and let us know if it sounds like timing chain /tensioner noise.

[greenfoam]

argh sounds nice :P, I don't know what a timing chain rattling sounds like but I can't imagine that sound being anything else in a motor. I'd like to know what the "tink tink" noise in my 5 liter is (only when warm and idling) it sounds like it's comming from the top of the motor somewhere under the manifold or so.

Goes like this two sound channels right overlay these

"BOP BOP BOP BOP BOP BOP BOP BOP BOP BOP BOP"
"______tink_tink_________tink_____tink_tink___ __"

[ScottB_33]

Its very hard to hear from the MP3 playback but from all accounts the noise is constant with engine idle and definately doesnt sound tappety from my guess but I'm so used to listening for the rattle inside the car and rattles more as the revs build. My guess is that the tensioner has broken but would need to confirm in person to make final decision. Sorry I couldnt be more definate!!

[Frd_thmsn]

argh sounds nice :P, I don't know what a timing chain rattling sounds like but I can't imagine that sound being anything else in a motor. I'd like to know what the "tink tink" noise in my 5 liter is (only when warm and idling) it sounds like it's comming from the top of the motor somewhere under the manifold or so.

Goes like this two sound channels right overlay these

"BOP BOP BOP BOP BOP BOP BOP BOP BOP BOP BOP"
"______tink_tink_________tink_____tink_tink___ __"

You gotta love our descriptions of sounds

I'd say your noise is the heavy metal rock group you keep under your bonnet.
Bee bop a lulla a bop bang boo

[Frd_thmsn]

Thanks for listening to that noise ScottB.
The microphone on my laptop is very sensitive , the engine doesn't sound as bad as the sound file makes it seem .

I,m leaning towards something in the chain area.

I have a series 2 motor as a spare, and the manual says that S2 chain tensioner is better and can be fitted to S1. So might give that a go.
Hopefully its not too big a job.

[greenfoam]

hehe, I dunno what my sounds is but my old air cooled two stroke bikes you to make similar tink tinky sounds so I guess it's something near the surface, I can't imagine anything inside the block being such a clear and crisp noise, so in that case it doesn't matter if it breaks anyway

[genIIIbandit]

not that hard a job, i'll give ya a step by step ;disconect battery and remove battery shroud, remove belt, empty radiator coolant, remove upper rad hose, fan shield and radiator shroud, remove water pump, disconnect temp sensor, oil pressure sensor, timing sensor, remove crankshaft bolt (good luck will be tight) and balancer (will need puller), remove front bolts from sump, remove oil filter (drain oil first), remove timing chain cover. Also note when refitting crankshaft balancer bolt must tensioned to at least 270Nm

[mouce]

Whatever it is it progressively gets worse as the sound clip goes on. It's almost not there at the start of the clip, and by the end of it I couldn't help but wonder if you'd actually thrown the belt!

How much do the timing chain tensioners go for?

[Frd_thmsn]

not that hard a job, i'll give ya a step by step ;disconect battery and remove battery shroud, remove belt, empty radiator coolant, remove upper rad hose, fan shield and radiator shroud, remove water pump, disconnect temp sensor, oil pressure sensor, timing sensor, remove crankshaft bolt (good luck will be tight) and balancer (will need puller), remove front bolts from sump, remove oil filter (drain oil first), remove timing chain cover. Also note when refitting crankshaft balancer bolt must tensioned to at least 270Nm

Thanks for the help everyone.
I,m ok with the balancer, have the series 1 on at the moment, they are a hand fit. When I put the series 2 pulley on as I thought it was that , they are a bugger to get off , made myself a puller up.
I hope I'll see the problem when the cover is off, engine still goes great , no smoke, uses no oil , plenty of power, just its had this noise since I,ve had it .
Do they use a gasket for the cover or just silastic/gasket goo.
I'll take the cover off my S2 spare motor , and see whats in there.

In case anyone wonders why I don,t put in the S2 motor, I don't have all the accessories to go with it , wiring ,t/stat housing etc , all the annoying bits that would be a hassle to get, and I am a couple of hundred k's from nearest wrecker.

[mouce]

^^^That and the series 1 motor kicks arse

[Frd_thmsn]

^^^That and the series 1 motor kicks arse

yep and that.

Timing cover gasket kit which includes crankshaft seal is $25 , ordered 1 today.

[BLOWN-VP]

cant use series 2 harmonic balancer on series 1.engines are balanced differently.

[Frd_thmsn]

You can use series 2 pulleys on series 1, been confirmed by GM ,the manual
says it is ok too.The only reason I put series 1 back on is because it is easier to do a roadside change of the CAS if that ever goes on me.

Anyway the point of this post is the source of the problem was a disintegrated timing chain tensioner, totally no chain tensioner at all.
Good to know the engine still runs without it, it was probably altering the cam timing a fair bit too.

I used a series 2 tensioner, they are a better design than the original s1.

As a note , it looks like the chains for series 1 & 2 are different profile, the gears also have a different profile.
You can't use a series 2 timing cover, cam, cam gear , chain in a series 1, without changing all the gears and the cam , so it is probably better to stick with all series 1 parts except for tensioner.. Cam thrust bearing is different too.

I've updated the first post to show what the problem was , and included a smaller sound file
Thanks everyone for your help in finding the problem.