Engine rattle/vibration noises

[Bigsi15]

Hi guys
Sorry for the long post but I was wondering if anyone could help me troubleshoot a noise.

Basically when the engine is at low rpm but under some load (low to medium throttle seems to make the worse noise) I'm getting a mild metallic rattling style noise from the front. Can hear it in the car and quieter outside the car. Doesn't do it at idle or revved up in neutral. Seems to do it worst in 4th and 5th gear. It can't be heard at all in 1st and 2nd gear, bit more in 3rd but much more noticeable the rest.

It almost sounds like it's coming from the left (transmission) side. My drivetrain is very clunky anyway when changing gear and engaging the clutch but the clutch and bearing are all new Volvo 850r and bites fine no juddering.
Engine is newly rebuilt now done 700 miles (500 of which were very light then oil change and now some full throttle and higher rpm driving). All bearings are Volvo and sized as per the markings on the crank and block. Engine is bored to the size of the Pistons (83mm now as bores were worn) and new rings. New forged rods (max speeding) and big end bearings (Volvo). Top end has only had lightly ground valves and new stem seals. Only other thing not replaced were gudgeon pins but they seemed to fit in with a light thumb pressure.
New timing belt kit, damper and water pump from Volvo.
Timing is apparently 7% advanced according to the tuners laptop. Knock sensors are not being activated at any point. No problem codes. Stock tune. Running shell optimal fuel. Using 5w30 Castro Gtx oil currently with an aim to go to Fuchs 5w40 in another few hundred miles.
Engine runs fine no large vibrations or harsh knocking noises, compression is 150 over all cylinders and uses no oil or water to note.
Changed oil in transmission (Volvo own) but not replaced driveshafts.

I wonder if this noise is actually from the transmission or turbo rather than the engine. Turbo is stock and not been reconditioned but seemed to be working ok however Wastegate was quite loose/wobbly when disconnected so could this be rattling as it begins to open or close? Seems to make the most noise at low rpm but when boost is about neutral beginning to build into low positive figures. More throttle worsens the noise slightly and full throttle if anything may quieten it.
Iv tried to get a video of the sound but it is so hard to hear it's hardly worth listening for.

I'm fairly sure the old engine (which wasn't rebuilt just removed) made a similar sound but can't be sure.

Do they just make this noise??

Thanks very much!

[Bigsi15]

Best way I can describe it is that it sounds a bit like an older diesel when accelerating under load and you get that tapping rattling noise

[960kg]

Best way I can describe it is that it sounds a bit like an older diesel when accelerating under load and you get that tapping rattling noise

As you have rebuilt the engine did you remove the Knock Sensors as they have to be reassembled to the correct low torque of 7nm i believe? ...and should also be in the same aspect on the engine as when you removed them otherwise they won`t detect the knock?

Only maybe a chance as i had trouble with my knock sensors on one of my 740`s and it gave the same symptoms as yours no error codes also.......of course only a chance?

[Bigsi15]

Thanks for your reply :) and a good question! I definitely labelled the front and rear sensors and located them as such and tried to 'point' them the right way if that makes sense. Torque wise not so sure. Iv tried to use Haynes torques as much as possible. If they were incorrectly fitted and not sending right would it throw a code??

Have another friend who is pretty convinced it is gearbox related and have to say I'm on those lines too but who knows! Lol

[dant5r]

Two things jumped out at me reading your post,

83mm pistons and stock tune.

The 8mm pistons will make it a 2.4 so is the stock tune for a 2.3 or a 2.4 ?

If it's a 2.3 then you are running lean.

[Doingitsideways]

Two things jumped out at me reading your post,

83mm pistons and stock tune.

The 8mm pistons will make it a 2.4 so is the stock tune for a 2.3 or a 2.4 ?

If it's a 2.3 then you are running lean.

^^^^
Could have a very good point there.

Does sound like detonation from what you're saying. Metallic rattle especially.

[Bigsi15]

Excellent point guys. I'm not sure to what what extent the ecu can adapt. Would this not cause activation of the knock sensors though and be present in all gear during load etc? My plugs despite being new are already quite black if that means anything?

[LeeT5]

Excellent point guys. I'm not sure to what what extent the ecu can adapt. Would this not cause activation of the knock sensors though and be present in all gear during load etc? My plugs despite being new are already quite black if that means anything?

You mean...'Would the Knock sensors not detect knock or pinking and their signal, interpreted by the ECU, cause the ECM to advance/retard the ignition accordingly???' Yes would be the answer to that question.

It does sound like pinking or pre detonation in the cylinders and as you say, it IS more noticeable under light load rather than hard acceleration.
If the timing belt was incorrectly fitted, even 1 tooth out either way, will cause the VVT to not function correctly, from my understanding.

It sounds like everything is fine with the build, but you possibly have a Map issue?

I'm afraid, with no fault codes I'm unable to help you further. If it is pre detonation, then I'm sure you know not to drive the car :wink:

[Bigsi15]

Thanks lee, this was my worry at first so I took it to a tuner locally to me to see if anything could be detected and read codes as my reader won't read them. We found no codes at all, no usage of the knock sensors and the timing at 7% advanced which they seemed to think was a good thing if anything. How would I tell if I'm getting pre det or pinking or knock??

Thanks again guys

[Bigsi15]

And no vvt as far as I'm aware on the 850? Know what you mean though as when I did my s60 it was a right Arse pain to get the light to go away and all align! Lol

[LeeT5]

And no vvt as far as I'm aware on the 850? Know what you mean though as when I did my s60 it was a right Arse pain to get the light to go away and all align! Lol

Sorry, I didnt know it was an 850. Thought it was late V70 P1.

Pinking is normally heard as a crackling sound under light load acceleration. Very distinct!

Have you checked your turbo for play in the shaft? If there is too much play, the impeller will foul on the turbo housing and that also manifests itself as a tinkling noise. In fact, I went out to a Focus last week doing exactly that. he had no smoke and only a slight lack of power but when i removed the intake hose to the turbo is was shagged and the impeller vanes had worn on the edges.

Worth a punt mate!?

[Bigsi15]

Again a very good thought. My top 3 ideas were pinking/detonation etc, gearbox noise or turbo. Il try and have a look but when I removed it I didn't notice much other than some movement in and out as supposed to side to side. That being said having removed it and fiddled a bit it's plausible it's developed new play as it's the original as far as I know.

Only reason I'm still leaning away from engine is something in my mind makes me think it did this a bit before the engine change. Could a different exhaust manifold (s60r) change any rattles from a turbo that were already there?

Would any pinking etc show as a code or knock sensor usage?
Il try uploading a vid to YouTube when I can but tbh it's so hard to hear probably won't show much!

Thanks!

[Bigsi15]

Ok so changed gearbox oil to no effect, checked turbo and tbh it has very little movement so unlikely. Found a lose clip on the air box which didn't solve it.
I'm leaning more towards pinking again but I find it odd I'm getting no usage of the knock sensors as I would have thought they would be working on it when it does it?

Are there any other ways to detect pinking or detonation other than knock sensor usage? Would faulty knock sensors throw a code?
Other thing would be the timing. As the tuners said it was advanced by 7% at idle what does that actually mean in real life in relation to timing belt positions?
Also wondering how to check the air fuel ratio??

Thanks guys!

[dant5r]

The ecu will being it's hardest to make the engine run at the correct air fuel ratio.

The knock sensors detect knock and the ecu then either adds fuel or retards the ignition to overcome the knock but as you are running a 2.4 engine on a 2.3 ecu it can't add enough fuel to overcome the knock.

I would strongly recommend fitting a afr gauge before you end up melting a piston.

[Bigsi15]

Thanks dant5r any top tip on how to do this and what ratios are normal??

Thanks again

[Bigsi15]

So this is the best I can get video wise. Few clips rolled into one. One of harder driving with no noises present and the other of the noise as best I can record. Only there when accelerating, oddly though got a much better recording with the phone down by the footwell that up by the steering wheel where you can hear anything


https://youtu.be/7vHG8PNSxMQ

[Bigsi15]

https://youtu.be/z55bVqkyBrQ

[Bigsi15]

https://youtu.be/WubtzWFWe6s Sorry first isn't really relevant

[dant5r]

Thanks dant5r any top tip on how to do this and what ratios are normal??

Thanks again

The sensor needs to be fitted to the downpipe with the aid of a weld on boss.

The correct reading at idle and normal driving is 14.7 - 15.0

[Bigsi15]

Thanks buddy il get on this when money allows. Other thing may be trying to adjust my timing, if I'm 7% advanced how does that correlate to timing belt positions or is it not that simple? Il happily give the timing another go to see if that helps

[960kg]

Thanks buddy il get on this when money allows. Other thing may be trying to adjust my timing, if I'm 7% advanced how does that correlate to timing belt positions or is it not that simple? Il happily give the timing another go to see if that helps

I gave you the wrong torque for the Knock Sensors it should of been 20Nm for your model.

You cannot adjust the Ignition Timing as the ECU does it but at 1420 revs, a fast idle, it should be 4 to 8 degrees BTDC

You won`t get detonation or pinking while revving from idle you have to have a load on the engine....driving.

To me the noise doesn`t sound like pinking or ignition trouble as it seems to do it on a light throttle ....but the type of rattle sounds to me like the turbo heat shield rattling where the nuts are not tight enough or a clamp on the exhaust not tight or even a Cat. starting to rattle.... Had one go on my 960.

If you think you have ignition advance problems try moving the distributor cap the way the rotor turns,retard, if there is play in it and even clean off any carbon on the rotor or contacts in the cap and it will lessen the spark to jump early!.......old school ways, but the ECU may still try to correct any adjustment?

I think your engine sounds great.

[Bigsi15]

960kg thanks for your helpful comments and kind words, I'm also very relieved to hear you say that! I hadn't even thought about Cat rattle but plausibly this is a very good point as it does seem to sound like it comes from the back of the engine and that is probably the original one fitted 170,000 miles ago! The turbo took a little bit of effort to remove shall we say so it's quite possible it got disturbed in the process. Interestingly I had my next door neighbour come out with me briefly today to have a listen, although not a mechanic he's done a few engine replacement in his time mainly on older cars and he didn't seem to think it was pinking either but probably more transmission.

If I get some time tomorrow afternoon I'll check the torque on those knock sensors (thanks for the updated measurement) and I'll have a look at my timing. The distributor cap and rotor arm are all new from Volvo so hopefully should be working okay but Il remove them and line up the crankshaft mark and see how horizontal the slots are in my head. Because I had to remove the gears from the camshafts I lined my timing up using the slots rather than the notches on the gears and once I was happy everything was in line I adjusted the gears to match the timing belt marks on the cover just in case I ever had to remove the belt again. Probably not the correct way to do it but it seems to have worked. If I remember rightly The belt teeth would not properly engage on where the camshaft gear had been lined up so I may have moved one of the gears ever so slightly for a proper fit but the camshaft shouldn't have moved because it was locked. Having the slight advancing timing does seem to have made a difference at the higher rpm as I always Felt the old engine felt very flat especially for a turbocharger engine as it never really surgged and went and if anything it slowed down at higher rpm so maybe the timing has altered this.

Thanks again

[Bigsi15]

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[Bigsi15]

So checked the timing and with the crank lined up, the top 2 photos show the position of intake and exhaust (2nd photo) cams. The intake seems out of line which I think was caused by a bent locking tool which must have bent while holding against the torque of the vvt cam when I did my s60. Anyway Iv straightened it up (3rd photo) slightly so will see how that drives and if it changes any noises.

Am I right in assuming once the crank is set you want these grooves to run in line with the seams in the head??

Thanks again

[AstroS60R]

Newbie here, Sorry for the old thread revival. I have been chasing the EXACT same rattle you described in your original couple posts. Did you ever figure out what it was? Thanks!

[Bigsi15]

Hi! To be honest after fiddling with pretty much everything from what I remember it continued so I just ignored it LOL. I drove the car today to see if I could hear it and I don’t think I can anymore however I have upgraded to a new turbo back exhaust and my old downpipe had a small crack in it, so whether it is now not audible due to the louder exhaust or as suggested above catalytic converter rattling or something to do with the crack perhaps I’m not too sure. Before all of this my money was on the transmission or the turbo but it seemed to drive like this fine for a long time And is still okay, and a look down into the cylinders did not show any pitting on the pistons. It sounds like you’ve done most troubleshooting but it’s so hard to know. could simply be a loose bolt somewhere but perhaps check your exhaust is all done up properly and in good condition. If your car is tuned it might be worth getting the AFRs checked as well just in case as that would be a more worrying problem!

Sorry I can’t be more help

[AstroS60R]

Thanks for the reply sir! Any info is helpful at this point. I have tried and replaced more things than i care to share trying to figure this out. Lol.The cat is one thing i havent removed yet to check. My other thought that i havent checked was my forged cbv chattering. Those were the 2 remainging items on my check list when i found this thread. Afrs seem good, pretty sure its not detonation or ping. It does seem to run fine, but i'm gonna have a hard time ignoring this sound. Haha.

[Bigsi15]

Yeah that’s a good point it could be something like that, I have to be honest though mine was not that noticeable unless you up near a wall or something solid with the window down while driving. Otherwise you could hear if you listened out for it but someone else in the car wouldn’t notice it. I suppose perhaps on a slightly different note it might be worth checking the rubber boot that seals the steering column through the floor as when mine popped up it made a significant amount of extra noise in the cabin

[AstroS60R]

Mine has gotten a tad loud, I can hear it with all windows, doors shut. Its very loud against a wall, which is my most of commute home. Haha. Good point on the steering bushing. Will check it out this evening. At least i have a few more things to try now. The saga continues...

[Bigsi15]

Hmm if it’s getting louder then it may not be the steering column boot although that will effect cabin noise. Let us know how you get on good luck!

[AstroS60R]

Checked out the steering boot, it looked to be in place. Just to add to the mystery, it was silent on my 40 mile compute home and still quiet on the trip in to work this morning. First time it hasn't rattled in months. I guess I'll find out if this is good news or bad soon enough. Haha.

[LeeT5]

Checked out the steering boot, it looked to be in place. Just to add to the mystery, it was silent on my 40 mile compute home and still quiet on the trip in to work this morning. First time it hasn't rattled in months. I guess I'll find out if this is good news or bad soon enough. Haha.

Uh oh, that could be the calm before the storm! :B_steerin :yikes: :hbomb: :jaw: