Engine rattles between 3k & 4k RPM

[Garry 0]

My 80k FSH G60 has a very slight engine rattle between 3k & 4K RPM. :shock:

 

Having listened to the lump with my stethoscope the rattle appears to be coming from from the bottom end. :(

 

I have just fitted a brand new oil pump to see if it was that which was packing up but it has only quietened the rattle down a little - however the noise reduction could be due to new Quantum Silver oil.

 

It does'nt sound like the lifters to me (It's not tinny enough - it's more of a dull rattle if you know what I mean) but I will need to investigate this further by inspecting them. The motor also seems to tick over a little lumpy which again could indicate lifters. But I have my doubts as the noise appears to be from the bottom end.

 

So it looks like it may be the bottom however I will need to investigate this when I get back from my holiday in 2 weeks time.

 

The motor on mine is tuned to around 220bhp so the bottom end may be seeing an excelerated life cycle causing it to wear quicker.

 

Has any one got any other theories on this or had a similar problem at 80K :?:

[Kevin Bacon 5]

I had the same thing on my VR at the same revs... does it worsen under load? I spoke to Vince about it and he said it defo wasn't big ends as they're a heavier knocking sound than a cammy rattle, which is what mine sounded like (the latter noise!). With the windows up and stereo off, there was a grinding sort of noise coming through the bulk head past 3K, regardless of load.

 

I assumed it was the BEs as I had new cams put in last month, but the main man reckons otherwise....

 

Anyway, ever since I reset my ECU recently, the noise has gone and the engine is now smoother at the rpm range and pulls harder, so I reckon it was running lean, giving a rattle kind of noise.

 

Might be worth looking into the fuelling of your G60, as it could be related. I wouldn't expect big ends to go at 80K to be honest, but if they are, it's not a big job...... just do it quickly before the worn bearings damage the crank journals.

[dr_mat 0]

I've heard that little ends go fairly regularly on the G60s. Henny would know better than I, however..

[Henny 0]

yeah, with Kev here... Big ends rumble, they don't rattle.... Are you absolutely sure that it's coming from the bottom end of the engine and not somewhere else like the clutch or exhaust? Funny noises are THE most difficult thing to sort out over a forum as everyone describes sounds slightly differently and it's quite subjective...

 

Have you checked your knock sensor? As daft as it sounds it could be that your timing's been set somewhat aggressively and 'cos your sensor's died, you've got a slight permanent pinking occurring which is the rattle you can hear... :|

 

*Edit* I've no experience of little ends going on a G60 though, I do know that they give a knocking sound from the top end, not dis-similar to having a small foreign object in the cylinder... :oops: :roll:

[Kevin Bacon 5]

Have you checked your knock sensor? As daft as it sounds it could be that your timing's been set somewhat aggressively and 'cos your sensor's died, you've got a slight permanent pinking occurring which is the rattle you can hear... :|

 

That's exactly what I suspected too, but VAG-COM seems to think mine are OK.....

 

Gotta be fuelling/timing related as that's the only thing that would change during an ECU reset - in my case at least. Unfortunately it's not as easy to return the G60 managment back to base settings as the VR.

 

Could also be a tank of duff petrol.... you'd be surprised what affect that can have on an otherwise good engine, especially when there are no obvious faults.

[dr_mat 0]

Are you even sure the G60 ECU has adaptation? AFAIK it has no long term memory, so it adapts from cold each time you start the engine.

[Henny 0]

that's why I suggested knock sensor,dr_mat, the G60 hasn't got adaptation, so I'm with you there... 8)

 

I still reckon that it's a good place to start for Garry, even if that wasn't the problem on Kev's completely different engine and ignition system... ;)

[dr_mat 0]

I was busy untangling the threads just as you were typing that one Henny... ;)

[Kevin Bacon 5]

The VR and G60 may have different whip masters, but they work the same mechanically - i.e. reciprocating parts! The VR just lacks a leaf blower in reverse :wink:

[Henny 0]

kevhaywire, :lol: 8) True, I was just making the point that the knock sensors are a known weak point on the G60 and not to rule it out as a possibility just 'cos it wasn't the problem on a possibly similar case in your car... 8)

[h100vw 0]

I have a known good knock sensor if you are interested Garry. Firstly I'd undo and retorque the one you have just to be sure.

In my experience the BEs knock at about 2K.

 

When I did the ones on my Golf at 100K someone had already done 3 of them? So IMHO they can go anytime, especially with infrequent oil changes and chip changes. At 10 quid and a couple of hours, it would be worth doing them to eliminate them from the list. You can re-use the rod bolts/nuts once as per the Bentley but if you are doing big numbers then maybe another 20-25 would be money well spent on news ones.

 

Gavin

[Garry 0]

Hmmm.. Knock sensor sounds like a good place to start!

 

Where does it live, whats involved and how much? etc (will check Bentley manual tonight)

 

Note -

When I bought the car it was badly overfueling (12mpg) so I took it to Jabba to sort the problem out - which they did. However it has always had this little rattle ever since which has started to get worse. Either that or I'm becoming more & more paranoid about it.

[Garry 0]

Can anyone tell me more about the knock sensor ie. where it lives, what it looks like etc.....

 

Ta

[Henny 0]

Knock sensor is on the front of the block just below and between where No.1 and No.2 spark plugs are... it's a round(ish) block which has got a 13mm head bolt holding it onto the block and has a single thickish cable coming off it which goes over to the gearbox area where it then has a green multiplug on it.... A lot of places cable tie the cable to the boost return pipe which causes the cable to chaffe through the insulation and bugger up the sensor's signals... :roll:

 

Check the cable for damage on the insulation, if it's damaged, buy a new one from VAG, the bolt should be tightened to 15Lb/Ft torque to get the correct signals to the ECU... 8)

 

See pic for better idea... red arrow (ish! done in paint!) is where the knock sensor lives, and the red dots indicate where the cable goes... 8)

[Garry 0]

Cheers Henny - will take a look tonight and check that the torque is correct.

 

Any Idea how much a new one is?

 

Ta

[dr_mat 0]

Good grief, Henny, is that an engine or a surgical implement? Bit clean ain't it? You wanna spray some old dirty oil around it a bit or somethin.. ;)

[Henny 0]

Good grief, Henny, is that an engine or a surgical implement? Bit clean ain't it? You wanna spray some old dirty oil around it a bit or somethin.. ;)

 

That was actually quite mucky when that was taken as I'd just driven from Skipton to Bruntingthorpe in the rain... Normally she's a bit cleaner and the black bits look better! 8)

 

Hey, if you're gonna rebuild an engine, why not clean it while you're doing it?!? ;)

[h100vw 0]

Cheers Henny - will take a look tonight and check that the torque is correct.

 

Any Idea how much a new one is?

 

Ta

 

Garry, I think they are around £40. Could be wrong tho, bell your local dealer to find out. They are common on most digifant mk2/mk3s of the era.

Gavin

[Henny 0]

yeah, that rings a bell cost wise with me too Gav... 8)

[Garry 0]

I've just got back from my holiday and have now had a chance to take a look at my motor.

 

What I found was...

 

The Knock sensor wire had been tie wrapped to the adjacent cooling hose. When I removed the wrap I found that the insulation had chaffed right through to the braiding underneath!

 

So I will start by replacing the knock sensor - which hopefully should cure the rattle (fingers crossed)

 

Gavin you have e-mail

[solomk1 0]

the little ends do go as i found out !!! if it has ran low on oil and had a good run No4 went on my old raddo i went down the knock sensor,timimng avenue,and to no avail........this sounds just like my prob ,i had to have little ends and a set of rings i also put a set of mains in whilst it was appart its not major league difficult just a pain in the asss

 

cheers dale

 

ps . i do hope you arew lucky ( knock sensor ) :roll:

[Garry 0]

I will be really dissapointed if the bearings have gone as my motor has only done 82K with FSH.

 

Still you never know - I just might be that unlucky. :(