Constant metallic tapping sound 1ZZ

[Optimus prime]

Hi Guys,

The 2 has developed a problem and i'm not keen on driving it at the moment.

It was running fine a few weeks back, I was on a spirited country drive when I noticed a tapping sound coming from the engine, at a similar time i also noticed what sounded like the exhaust blowing.   
When i got home I left the car in the drive way for a few hours and started it up again to see if the noise was still there. It seemed to be worst and more obvious when revving (noise follows the frequency of revs and sounds more like tappets).
I left it for a few day whilst i pondered what it could be. I started it up again and noised white 'smoke' coming out of the back. Not too sure if the head gasket had gone I took it for a short drive to see if i ended up with water in the oil or oil in the water. when i returned the white smoke was gone... phew, i think i was over sensitive and it was just condensation!

I changed the chain tensioner but that didn't solve the problem.

it's an '06 1ZZ with the newer design pistons so i really done think it's bore score, plus the frequency of the noise and location is in the head.

the noise is now worse than before and present all the time, it becomes very obvious when accelerating and it's now quite a loud metallic rattle that follows the revs.

I'm now thinking it could be oil starvation or a shot bearing.
I plan on doing the following tests:
Compression test
Spark Plug check.

if both of those test come back OK then I think i'll,
Check the OCV
preform an oil flush and replace main oil filter.

Am i missing something? could the exhaust blowing sound be a problem with the manifold gasket that causes the tapping noise? 

[shnazzle]

Not being funny but this has come up a lot and a lot of the times it's the heat shields rattling. Particularly the cat

[Joesson]

That sounds suspiciously like a loose cat heat shield.
Many have dark thoughts when hearing this but if it is the case it is aneasy fix.
Typically the shield comes loose just below the three Amigo's (The manifold to cat joint), also the  fixings welds IIRC along the length of the shield break.
I removed the cat drilled the welds through and bolted the shields together and used two U shaped exhaust clamps at the joint to hold the shield.
Others have put large Jubilee type clips around the cat and/ or stuffed wire wool between cat and shield.
Hope that isthe case for you.

PS answered as above by  Mr Shnazzle.

[Optimus prime]

Cheers but it's definately not the heat shields, I have removed them all for testing. It's definatelty an internal noise.
I forgot to mention I also removed the aux belt momentiarly to see it it was something feed from that. Unfortunately not, definatelty something in the engine causing the sound.

[jonbill]

You could take the cam cover off and measure the valve clearances.

[Joesson]

So not so simple as heat shield rattle.
Maybe a result of your " spirited country drive" in which case it will likely get worse while you , or the clever ones on here, diagnose it.

[shnazzle]

Is the noise in-beat with the rpm or is it off slightly, as in 1 noise every 2 rpm?

[Optimus prime]

It's not the klunk of the bottom end turning over, definitely more cam related eg 2 beats per rev. I will check the clearances after I've done the less evasive tests

[Optimus prime]

here's a video of the problem I just recorded:

https://youtu.be/1k7DZPH160E

In the real world the tapping sound on acceleration is quite loud. 

[Carolyn]

Humour me:

start her up.  reach in and grab the throttle cable as it goes to the throttle body.

Use it to bring the revs up to around 2-3,000 rpm.

Does the rattle get more pronounced at those rpm?

really can't tell from Youtube sound...

[Optimus prime]

Nope, the noise is not as loud when not under load. It's more pronounced when accelerating

[Carolyn]

I very much doubt it's a valve clearance that's 'gone off'.

By all means check, though.  Might as well check compression too.... but it's unlikely to tell you much.

Chain tensioner failure is one possibility.

The other requires dropping the sump and inspecting rod bearings.   

[shnazzle]

Can't tell from that vid. Just sounds like yet another 1zz that needs a valve job. Like most of us
What doesn't check out is that it started suddenly.

[Call the midlife!]

If the chain tensioner has gone could the chain be catching the retaining channel cast in the bottom of the block?


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[shnazzle]

I plugged in my good headphones to have a good listen.
If you're saying it genuinely suddenly started, then I'm afraid it sounds like you've spun a bearing. Especially as, as you say, you were on a spirited country road drive.
Was oil level nice and high or is it a bit on the med-low side?

Maybe a case of changing mains from below. Remove sump and change bearings? Quite low-impact

[Carolyn]

I plugged in my good headphones to have a good listen.
If you're saying it genuinely suddenly started, then I'm afraid it sounds like you've spun a bearing. Especially as, as you say, you were on a spirited country road drive.
Was oil level nice and high or is it a bit on the med-low side?

Maybe a case of changing mains from below. Remove sump and change bearings? Quite low-impact

That would be changing rod bearings, not mains, Patrick, but I know what you meant.

Sadly I also think ya bearing has spun.  It's not too bad a job to drop the pan and find out. 

[shnazzle]

I plugged in my good headphones to have a good listen.
If you're saying it genuinely suddenly started, then I'm afraid it sounds like you've spun a bearing. Especially as, as you say, you were on a spirited country road drive.
Was oil level nice and high or is it a bit on the med-low side?

Maybe a case of changing mains from below. Remove sump and change bearings? Quite low-impact

That would be changing rod bearings, not mains, Patrick, but I know what you meant.

Sadly I also think ya bearing has spun.  It's not too bad a job to drop the pan and find out.

Bah! You're right. I'll get a post right at some point.
I meant the ones in the big end

[james_ly]

Does it do it at full throttle? Mine's got a tappy type noise under light load, disappears when you go faster.

[Optimus prime]

the noise on mine is under acceleration, part or WOT. i haven't taken it past 5000RPM in testing since the noise appeared, it's not a nice sound.

OK, i've never had the bottom end off the 2. if i take the sump off what am i likely to find if it's spun a bearing beyond metal in the oil?

[Optimus prime]

BTW i really appreciate your help. I'm guttered i cant drive it, especially when i just saw someone else in their 2 driving with the top down on this sunny day  

[Call the midlife!]

the noise on mine is under acceleration, part or WOT. i haven't taken it past 5000RPM in testing since the noise appeared, it's not a nice sound.

OK, i've never had the bottom end off the 2. if i take the sump off what am i likely to find if it's spun a bearing beyond metal in the oil?

If it's the con rod bearing you'll be able to feel the play against the shaft by hand. If you take the sump off and reach up to each one in turn you should be able to "rattle" the bad one up and down ever so slightly.
If one has gone you can replace them in situ, it's fiddly but possible.


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[Carolyn]

the noise on mine is under acceleration, part or WOT. i haven't taken it past 5000RPM in testing since the noise appeared, it's not a nice sound.

OK, i've never had the bottom end off the 2. if i take the sump off what am i likely to find if it's spun a bearing beyond metal in the oil?

Little flecks of white metal in the sump. 

Get your self a pack of cheapo Stanley knife blades.  Take all the sump bolts and the two sump nuts off.  Carefully knock Blades into the sealant between the pan and block with a small hammer.  Break as much of the seal as you can before prying it off.

You'll doubtless bend the pan a bit, but it'll hammer straight very easily.

It's worth taking a couple of bearing caps off.  You'll need a torque wrench to put them back, but it's only 15 ft lbs, so check the wrench goes that low.

Take pics of shells and post them on here.

Odds are the crank will be fine.

[Dev]

I have herd this sound before on a few older examples. It turned out to be a broken downpipe flex section.
The flex section will have a little tear which is just enough to allow the sound of the valves to be amplified and it will get worse as it progresses.
  Since you discovered this right after a  spirited run its possible that an already weakened flex section was under extreme stress and gave way.

[Optimus prime]

Well, it just so happens that I have a spare Cat! I'll swap it over to see if that cures the problem.

[Ozzy]

Sounds like a broken flexi/midpipe to me as well.

I've destroyed 3 midpipes/flexis so yeah lol... 1 from a spirited drive and 2 from scaping on big speedbumps. It's sounded like that and worried me also each and every time. You may need new gaskets if it is as mine still continued to leak and sound horrible without them.

Also, what's the oil level on now?