The o'l V6 top-end "rattle"

[Salad-Dodger]

Hi. have we got a thread on here for the V6 top-end "rattle"? I think I have a dodgy cam tappet rattle that is driving me bonkers!
Its not there on tick-over but makes itself heard about 1800 rpm. Doesn't matter if the engine is hot or cold and I'm wondering if I have a broken valve spring. Not had the covers off yet, but that's the thinking so far. Steve

[ProfDave]

what oil are you using??

I had a rattler recently changed the oil and filter and used 0W 40 rattle gone

[Salad-Dodger]

Well the rattle was there when I got the car just over a month ago. In fact there was a number of noises but Ive got rid of most of them when I did the belts last weekend. I changed the oil at the same time and I used 10/40 semi-syn. Not ever used 0/40 though.

[Sebastienclement]

I had something that sounds very similar on a v6 and it was the inlet manifolds :)

[Salad-Dodger]

I had something that sounds very similar on a v6 and it was the inlet manifolds :)

The inlet manifolds? How were they rattling?

[Phil-T4]

Its the power valve flaps that wear and rattle inside the manifold.

[stocktake]

Remove the power vis , this will reveal a brown arm with a slot in it. This arm connects to the 6 flaps in the inlet manifold. This arm should be free but firm in its action from passengerside to driverside. Any up and down movement accompanied by a clicky feel is wear and could be the source of the rattle :)

Do not start the car with the Vis removed

D....

[Salad-Dodger]

Hi Dave. No, its not the flaps. When I did the belts I had the rattle before I did them. The top manifold that was fitted had no rod or flaps in it. I have fitted another manifold that has no rattles. I have a spare set of motors here ready to send you next month as none out of the four I have are working. Believe me, this is a metallic noise that comes in about 1800 rpm and is hanging on noise as you slowly rev up to a peak. Its not there at all on tick over hot, or cold.
I and a trusted mechanic friend of mine have been over it with a audio scope and found that it s coming from the rear cylinder head. So I'm looking here for any other members that have had this happen to their V6s. I thought maybe someone may have had a problem with hydro followers or a broken valve spring.
I went on the XP side last night and found a thread started in 2007 about this and its a long one! As far as I can tell, there's a lot of this rattle about on V6s and nobody has found out why. They are just living with it.

[Ps3000]

I have a rattle but it's very intermittent. It's most apparent on startup from cold and usually goes, but not always - however mine's in the lower rev range. When I listened to the engine, it did seem to be coming from the rear bank.

I also get a different ticking noise that I suspect is the VIS - that only happens on tickover after a long motorway run.

Can't offer anything but kinship at this stage I'm afraid :)

[Salad-Dodger]

I'm thinking now, to get the oil pressure checked. If I can find a pressure gauge, probably a pipped type, I could at least rule it out assuming it was still good. its pretty pointless changing parts inside the engine if the oil pressure is too low.
Anyone know where the take-off point would be for a KV6? Steve

[murphyv310]

Piston slap when cold has to be common both my V6 engines do this for 30-60 secs.
Could the OP have a tapping little end?

[Salad-Dodger]

Piston slap when cold has to be common both my V6 engines do this for 30-60 secs.
Could the OP have a tapping little end?

Duly noted murphy. The thing is though, I can get this rattle from cold and it doesn't change when it gets hot either. The throttle is opened very slowly. When the revs get to 1800, this is when this noise starts. Its not there on tickover at any temperature. If its a small end, then I think that,that would be the end! The cost of sorting all six may be a bridge too far.

[KWIL]

Not all KV6 engine rattle, I am pleased to report:D

[Salad-Dodger]

Another thing about it being unlikely its a small-end failing is that like all K series engines, the gugeon pins are pressed into the con rods, so the piston supports the pin on both sides, inside the piston rather than say a "floating" bearing in the rod. Its quite a strong location.

[murphyv310]

Is the tapping at crank speed or half engine speed (valve train)?

[murphyv310]

Not all KV6 engine rattle, I am pleased to report:D

Once warm above about 35c both mine make no tappping or rattling sounds :D

[SD1too]

Is the tapping at crank speed or half engine speed (valve train)?
That's a good question.

Steve; be careful about working yourself up into a state of depression based on nothing but speculation. You began by suspecting a faulty hydraulic tappet, yet you appear to have done nothing to pursue that. If a tappet is seriously contaminated, and that's a possibility since you've just bought the car and cannot be absolutely certain of its service history, then it will take more than a single oil change to clear it. I have used Comma flushing oil on all my cars with very beneficial results. I suggest that you try one or two treatments of this. It's inexpensive, easy to do, and is a useful diagnostic tool.

If that makes no difference at all, move on to your own findings:

I and a trusted mechanic friend of mine have been over it with a audio scope and found that it's coming from the rear cylinder head.
So, whip off the cam cover for starters and have a look! You might be surprised what can be discovered with the basic tool of careful observation.

One other thought as this is a 190. Were the cambelts renewed recently? If so, I wonder if the correct specific tool was used.

Simon

[DMGRS]

I'm working on a K16 that has a sticky tappet at the moment - despite 2 oil changes, lots of oil flush and a few other tricks, it's still not quieting down.
The next step is a new tappet - I've given up. :D

If you come to the same conclusion, they're not too expensive:
K Series Follower / Tappet - Inc KV6 (http://www.dmgrs.co.uk/collections/valvetrain-components/products/k-series-valve-lifters-tappets-lgr000050-oem)

[Salad-Dodger]

Right.....lots to answer! Could be a long one....
A bit of history first. The clicking/tapping noise was there when I purchased the car about six weeks ago. The seller had no idea what it was and was really open about it both before and after the sale. Personally, I've heard worse in the past and wasn't too troubled by it.

As there was no evidence that the belts had been done and there were a few "rattles" I thought I'd start by changing the belts and the inlet manifold. This I did over the Easter weekend. Incidentally, the opp rod and the flaps were not present in the first manifold. I now have flaps and rod.

If I can I'll get a decent vid of this engine running using my iphone.
The rattle, as this is what it is, makes itself known at the mid rev-range. I can just barely hear it from cold on tickover. I slowly bring the revs up to about 2000rpm and this is where it makes the most noise. Hot, or cold. It actually quietens down as the revs rise.
Its definitely not a noise that's inside the main block. Its almost like someone playing the "spoons"! on top of the cam covers.
I inspected all the service belt pulleys and they are all good and the crank pulley looked good as well.
The last thing I did yesterday was to add some of that Winns hydraulic lifter treatment as that is another base I haven't been to yet.

Hiya SD1. I won't be working myself up into a state mate. lol. Its only a car! It may appear that I've done nothing, but I can assure you I've been "on it" since the belt change last weekend.
My plan is to MOT my MGF and use that while I start looking under cam covers. After all, if I find anything bad, I'll still need a car to use. I work for TPS and I'm in touch with quite a few mechanics who have been very helpful. They generally aren't too pro on the use of additives though but I've used the hydro lifter stuff as some have had good results. I'll give the Comma flush stuff a go as well. After all, its done 100K miles and as you rightly say, I don't know its past history and I'll try all that before I start undoing any covers.
When I've cracked it, it'll be a very nice car to drive about in.
Any more input is very welcome..Steve

[SD1too]

Its almost like someone playing the "spoons"! on top of the cam covers.
That's how pinking is usually described. ;)

Simon

[kaiser]

Firstly it might make a bit of sense locating the sound. That is easily done with a long screwdriver. Place it different places on the engine and put your ear to the (handle) end!:D

Pinking is unlikely to occur except under heavy load and wide open throttle, if it occurs at all.
This sounds like a mechanical noise, and I would be surprised if we can't hear it if you make an audio file and upload that.

A good Diesel (engine) oil would not be a bad idea, if you want the engine cleaned out. Lots of detergents to cope with dirt in Diesel engines. Should do a good job of cleaning your engine out and maybe even the hydraulic lifters.

Will be of no use if the manifold is rattling however.

[minimutly]

Default
Another thing about it being unlikely its a small-end failing is that like all K series engines, the gugeon pins are pressed into the con rods, so the piston supports the pin on both sides, inside the piston rather than say a "floating" bearing in the rod. Its quite a strong location.
Well this may be true, but they do fail, something to do with birminghams finest letting engines through with slack little ends. They don't run too well once the pin edges out of the side of the piston. BTDT
The engine still drove though, even with a hole in the block. And the crank survived.
Huw

[Salad-Dodger]

Ah, pinking eh? Whilst on the drive without driving up the road. If its doing that then there would be a drop in compression I would think. Other than this problem it runs and drives very well. But worth a thought and a compression test.
This car is a 54 plate 190. When did the factory turn out engines with poor small ends? Lovely build quality!
I've even had a call today from someone who said, watch out for a crack in one of the exhaust manifolds as this can make some quite sharp noises.

I have spent the last three days with a large screwdriver in one of my ears! Plus a few other guys have done the same for me. Generally, I'm pretty competent at finding the causes of these noises and I can often say, with some accuracy, that I will know what's up with whatever vehicle comes my way. But there's a lot to learn about these V6s and I've not had any experiance with them. So here I am!
I've made a a very short vid here. I hope its usable.
http://i25.photobucket.com/albums/c83/aircoolsteve/th_009_zpswo9nptvl.mp4 (http://i25.photobucket.com/albums/c83/aircoolsteve/009_zpswo9nptvl.mp4)

[kaiser]

I think there are two noises, one sounds like a leak at low revs.
However the noise that you have on higher RPM (about 14 seconds into the vid) is neither that nor the VIS, from what I can tell.

It sounds like metal against metal. A bearing, valve/spring/lifter or maybe even a broken camshaft?

[Salad-Dodger]

Well I was holding the throttle up a little when I clicked the phone so it wasn't on tickover. The crackling noise you heard 14seconds in is the noise it has had since before I took it on six weeks ago.
I'm kinda hoping that it may be a valve spring/lifter problem but I'm not sure about the broken camshaft probability. Were the camshafts an issue? I've done a thousand miles since I've had it and it drives really nice.
When I did the belts last weekend I used the tools and I think I may have noticed a broken shaft! And no glitter in the oil either. Wont be that much to slip the inlet manifold off and have a look at them though. Problem is that you can only see one on each bank due to the sandwiched carrier arrangement.
Think i'll get the MGF on the road! Steve

[Anon3]

I very much doubt that's a worn or sticky tappet, as it doesn't quite sound regular enough.
I agree with Kaiser and if I had to guess, I'd go for a broken spring.

Hard to say though and you'll have to take a look, I guess.

[Salad-Dodger]

Yes, a poke about is on the cards. I'll get the other car out and get stuck in.
Its not a noise you hear usually so will always be harder to find, but its always a good thing to get some input from others just in case someone else has had the same problem. i did suspect the crank pulley at first but it looked really solid when I took it off.
Just as an aside. The one and only problem I ever had with a small end rattle was with a Ford V6 Essex 3.0 in 1980. I had a crankshaft break on a 1275 S cooper. It broke across a web and still drove home from the rally we were competing on! that was 1970. Lots of work on Jaguar engines but they never broke.
I will of course come back with whatever it is. Steve

[Salad-Dodger]

I'm going to have this KV6 apart soon and I'm getting the parts in I think I'm going to need.
What I need to know is what glue do I use when replacing the cam carriers. Anyone know what and where to get it from?
Cheers. Steve

[SD1too]

Steve,

You can make an initial inspection of the camshafts just by lifting the cam covers (no sealant necessary for reassembly).

If you have to replace a camshaft, the MG Rover manual contains a lot of detail so I would not attempt it without this information. The specified sealant is part number GUG 705963GM.

Simon

[Salad-Dodger]

Many thanks for that Simon.
I've been looking into this rattle all this time and as far as I can see, the very next thing is to have a good look at the top end of each bank for something that is not working, like a broken spring or a faulty lifter.
I have a new spring and lifter in case I do find a broken one, plus an air-line connection to hold the valves closed while compressing the spring. I realise this won't be just a mornings work.
As far as I can see, I will only get a look at the inlet camshafts by taking the top covers off and even then, the shaft will be well in the way of any reasonable tests that I'll be able to do.
I've done a fair bit of work on other multi-cam engines with broken springs and even if you can see the lifters, you don't always see which one is broken, mainly due to them being hydraulic as they just pump up to make up the difference. It won't be very easy working as both exhaust cams are quite close to the bodywork but lets not get too negative, it may go very well! One things for sure, if I leave it, a valve may drop and I'll have a lot more work to do.
Steve

[Salad-Dodger]

Oh, I for got. Where do I find this goo, A land rover dealer perhaps? Steve

[Salad-Dodger]

Another thing that has crossed my mind are the damper mechs on the ends of the exhaust cams. how do they work and could one of these be breaking down to make this kind of noise? Steve

[Salad-Dodger]

Well I now have the rear bank apart as I think this is where the rattle is coming from.
The carrier was a real prob to get free and doesn't just rise with the springs of the open valves but came off in the end with a bit of jiggling. Its on dowels and has to rise parallel with the head.
Once the cams were out of the way I started by turning each tappet in turn just using my fingers to see if any of them were binding. One of the inlet valves was more than a bit binding so I got it out and it obviously hasn't been turning as it should and has the marks on it to prove it. Tomorrow I'll mic the corresponding lobe to see how that compares to the rest. If anyone has a 190 inlet cam they want to sell I may just be up for a purchase.
This looks like a bit of surplus goo in the oil-way to this follower. I've tried pushing the valve open and the spring feels ok. If it was broken it would be a bit "crunchie" I think but it may be a good idea to get it off and have a look.

Just one small question. Do we coat just one surface (carrier)with glue on re-assembly? Although there doesn't look like there's a lot of goo there, It does look like a case of the partially blocked oil-way.
What a way to spen one's weekend! Steve