Chatter at 2500 rpm

Am I experiencing a problem at approx 2500 2700 rpm when there is a lot of chapping coming from the top end.. There has been on accasion a bit of smoke as well, is there something wrong with the cam timing , normally when at engine tick over, there is a quiet engine but rev it a bit it chaps too much, usually at 2500, 2700 revs or above,and it starts smoking like burning oil.
By the way the car was completely rebuilt from bottom up and I don't suspect bottom end , seems to be an electrical sensor affecticting upper end valve timing?

Please any help appreciated!

If you're getting smoke coming from the exhaust then suspect worn piston rings/bores or worn valve stem oil seals. The excessive top end noise may be worn valve guides and/or worn hydraulic tappets and/or worn cam lobes. It would be worth at least taking off the cam cover and checking the state of the camshaft lobes for wear.

Thanks for the reply I will check that out, I think I will get a diagnostic on it to see if there is something electrical affecting it.

Untill I get a diagnostic , diy style I am still looking for clues?

The car loves to trundle under 2500- 2700 revs and pulls well up to there if you go to beyond that and feather the throttle the chatter comes in. If you accelerate right through the peak torque range it behaves normally and pulls reasonably well .
It can smoke if the car is revved at standstill to above 2700 so there is a chance that oil rings are gone but the overall symptons tell me there is something wrong with the cam timing?
The engine will not smoke at normal driving but will so at standstill and high revs, but not always.
I guess its time for component testing if I can get a diagnostic tool also to point me in the right direction, any more clues out there?

Originally Posted by GialloEvo94

If you're getting smoke coming from the exhaust then suspect worn piston rings/bores or worn valve stem oil seals. The excessive top end noise may be worn valve guides and/or worn hydraulic tappets and/or worn cam lobes. It would be worth at least taking off the cam cover and checking the state of the camshaft lobes for wear.

Well to reopen a wound, we did that tonight, both cams replaced (they needed it) and a Variator built from the best bits of 3 (9and shells replaced as they were shot too). The noise however is still there, myself now after hearing it twice and crawling round the engine bay to hear it and with studying the breakdown on ePER am convinced that it's the rear balance shaft bearings, guess we'll test that theory tomorrow night.

But as a taster here's some pics of the cams, and if anyone can see where the lobes have gone could they please tell us.

That doesn't look good.

You are probably correct on the balance shaft bearings at the back of the engine.

Do you think that the metal from the cam lobes has got into them and hastened their demise? It sounds like the bottom end has been re-built, possibly for a similar reason.

You've got my thinking exactly there Sy, the best of the pictures is yet to come, the #8 lobe on the exhaust cam had me thinking it was a bearing when I had a quick glimpse the first time, it is almost perfectly round (had to do a double take as I couldn't believe the wear) the surprising thing was that apart from this chatter at @2500 rpm there is no other symptoms, there's a bit of smoke but it actually smells fuelly so I think the Lambda may be dead, other lucky things we found las night were that we suspect the balance belt wasn't on correctly (there are white marks that don't line up with the timing, not a big problem though) and then there was the Exhaust cam pulley, which had the location peg missing, this was so close to being refited that it caused a stir, and a "oh christ do we have a spare???" moment. We did, an hour later (and a few stellas) she was purring again, the variator was silent (more luck than judgement on the choice of bits to build it), the tick over is gentle, quite and steady, the acceleration is steady and undramatic till 2500 rpm, when that infernal noise returns, carry on through to @3000 rpm and the noise goes and no more sign of it at all till the red line, accelerate aggresively and there is no noise at all, studying the entire build up of the engine and using my built in sonar, the noise is certainly from the mid area at the back of the engine, tonight the balance belt comes off and hopefully that will be definitive.

In this blury pic (I appologise)you can see lobes 7 and 8 of the exhaust cam and an opend variator.

That is seriously worn

I will be interested to know what the noise is for sure when you find it.

I know it is unlikely but I don't suppose it could be the thrust bearing on the gearbox end of the crank could it? This might allow the crank to vibrate at certain RPM.

Originally Posted by symonh2000

That is seriously worn

I will be interested to know what the noise is for sure when you find it.

I know it is unlikely but I don't suppose it could be the thrust bearing on the gearbox end of the crank could it? This might allow the crank to vibrate at certain RPM.

Now we had that thought, and by doing the clutch test, hopefully eliminated that as an option, Whilst the clutch was depressed (forcing the flywheel to the right) the noise was exactly the same, completely no variation to it. The only thing I can really say the noise is like is big end knock, but to not have it anywhere else in the rev range rules out the big ends, I'm hoping it is the balance bearings on the rear shaft (not that it's an easy job... engine out or leave belt off...Mmmm??) but there is still the option of piston slap with broken rings. This really is the first time a snag hasn't jumped out and been obvious.

I'll get some better pics of both cams, they really are the worst ones I've ever seen, just aswell there was a spare 1.8 TS in the corner.

BTW this is a mint black 2.0 TS Cloverleaf 145 we're trying to keep on the road here. Really don't want it to die.

Originally Posted by symonh2000

That is seriously worn

I will be interested to know what the noise is for sure when you find it.

I know it is unlikely but I don't suppose it could be the thrust bearing on the gearbox end of the crank could it? This might allow the crank to vibrate at certain RPM.

Now we had that thought, and by doing the clutch test, hopefully eliminated that as an option, Whilst the clutch was depressed (forcing the flywheel to the right) the noise was exactly the same, completely no variation to it. The only thing I can really say the noise is like is big end knock, but to not have it anywhere else in the rev range rules out the big ends, I'm hoping it is the balance bearings on the rear shaft (not that it's an easy job... engine out or leave belt off...Mmmm??) but there is still the option of piston slap with broken rings. This really is the first time a snag hasn't jumped out and been obvious.

I'll get some better pics of both cams, they really are the worst ones I've ever seen, just aswell there was a spare 1.8 TS in the corner.

BTW this is a mint black 2.0 TS Cloverleaf 145 we're trying to keep on the road here. Really don't want it to die. It's the tea-boys drive, haha.

I might have missed something somewhere in amongst the discussion but assuming you've not already tried this (can't see any mention of it) then the way but to confirm if the noise problem is definately balance shaft related or not is to just leave the balance belt off and see if the noise disappears when the engine is running. Have you tried this?

Were the previous camshafts OEM ones? If not then they may have been some cheap aftermarket ones made of butter and not been through the correct hardening process which would go some way to explaining their shocking condition

I've never heard a TS big end knock but on other engines I've heard they mostly knock at low revs. Some don't even knock on idle but if revved up as the revs fall when the engine is unloaded then they knock at ~3000-2000, then the knock disappears at idle again. When loaded they don't knock (or at least as badly).

But one thing - why has this camshaft worn? Bad oil feed. I guess the bearings in the balance shaft help increase oil pressure to the head to lube the cams. If low oil pressure then I guess it also could have done the bottom as well. Whip the sump off to look for metallic sludge, but if a proper filter has been used it does do a good job of catching the metallic particles. Cheap oil filters don't have (or don't have as strong) a magnet in them.

Originally Posted by ajcarter

I've never heard a TS big end knock but on other engines I've heard they mostly knock at low revs. Some don't even knock on idle but if revved up as the revs fall when the engine is unloaded then they knock at ~3000-2000, then the knock disappears at idle again. When loaded they don't knock (or at least as badly).

But one thing - why has this camshaft worn? Bad oil feed. I guess the bearings in the balance shaft help increase oil pressure to the head to lube the cams. If low oil pressure then I guess it also could have done the bottom as well. Whip the sump off to look for metallic sludge, but if a proper filter has been used it does do a good job of catching the metallic particles. Cheap oil filters don't have (or don't have as strong) a magnet in them.

It's not that, but we know why the cams went this way, apparently the engine had been run low on oil, last night was the first time I'd laid my hands on the car properly and though I'd listened to itbefore andsuggested running it with the belt off, it hadn't been done. so tonight, the belt is coming off (was too late last night even if the nieghbours are 200 yards away and working by canlelight isn't best on TS') and if it is the B' shafts, then the belt can stay the hell off.

My big thanks to Smaky sop far , in a way I am glad its been difficult to diagnose but its all a good knowledge of what can happen, I myself rebuilt the bottom end of this engine, assuming that the top end was rebuilt after a bill received by the previous owner for to the tune of 1200 pounds I placed it on the block and carried on . It looks like man oversight now but you can be misled.
What I don't understand is the large consumption of oil in the last 5-800 miles which was shared between My friend and I and took us by surprise and looking back the consumption may be due to to the new crank and shells wearing in before they bedded, I don't know that may be a defence of guilt to what we now see as the outcome , dramatic as it is.
Any way the removal of the balance belt has not removed the noise.
I will let smaky tell the rest.

Hooray, noise found, after having the cams out for the second time in 2 days, we solved it, wear inlet 1 and 2 tappet guide holes, fitting newer, less worn tappets to the positions has gotten rid of the noise, the only way to solve it properly will be to bore out and fit inserts or replace the head. Pics to follow.

We did try the Balance belt off run but with no effect on the noise.

I am glad you both got to the bottom of it.

Those metal particles from the cams reak havoc where they settle don't they...

Wait till I get these next pics up, they really show the damage to the cams and followers/tappets. It's always nice to remove cams when the BBQs on too, the smell of burgers gently being incinerated allways spurs me on.

More damage pics.

I have flushed the engine through with wynns now and refilled with new engine oil and of course new filter, unfortunately the chatter is still there but of a less harshness, sudden throttle up is less noisy and when I back off the throttle I get a small chatter now , overall the engine ticks over very smoothly.
Will do a road test tomorrow once I get some fuel!