K-series top end rattle (Ongoing saga)

[Bobthebeard]

As previously mentioned on here the MG ZS has a top end rattle. Quite loud at all engine speeds. The inlet manifold gasket had gone and was leaking coolant into No.4 cylinder and also leaking externally. Have drained coolant, replaced the inlet manifold gasket, filled up with water and drained and changed the oil (10/40).

After a bit of a hooha bleeding the cooling system all appears well regarding coolant loss. But the top end rattle remains. Have tried idling the engine for 30 mins as suggested but still the same! Took cam cover off to look inside but nothing obviously amiss. All cams look fine and nothing stands out.

What do I look for next??

Ta!

 

Edit. No 'look for a scrap man' or similar comments please!

[jbz2079]

I would guess that one of the tappets has been damaged or has failed.

I would start by checking No4 cylinder.

You might do a compression test just in case one of the valves got bent due to coolant in the cylinder.

[Bobthebeard]

^^

Sounds logical! Will try that.

Thanks.

[Station]

I reckon a gummed up hydraulic lifter is the problem and there's nothing wrong with the rest of the head.

There is a pair of tiny holes in the bottom of the lifter - one late oil change and they're jammed. It then literally becomes a shim/tappet like on old engines with little play in the sprung part.

 

You can get to these by removing the cam ladder on the top of the engine and then remove the cams. Take the lifters out, submerge in petrol or whatever and then put it all back in.

 

Or do a MLS HG change and put a newly rebuilt head on (I bought new parts - stems and lifters - for under 100 quid). It took me about 2 hours to do the whole job. Even the valve collets weren't an issue (they're usually a PITA). Very easy.

[Station]

PS If you choose to do the full thing, I have a set of Payen head bolts that were on the engine once. Think they're about 40 quid new - they've been sat in my garage for about five years.

[Bobthebeard]

PS If you choose to do the full thing, I have a set of Payen head bolts that were on the engine once. Think they're about 40 quid new - they've been sat in my garage for about five years.

Am going to do the full thing. Peace of mind and all that! Are they ok to re use if fitted once? If so am wanting em.... How much please?

[solid61]

Usually a good (high speed) run will get rid of a gummed up lifter on a k series,ive never known one to completely fail.Piston slap can also happen but that usually goes quiet  when the engine is warm unless its really bad,this can be caused by the engine having been overheated/cooked.

[saucedoctor]

Usually a good (high speed) run will get rid of a gummed up lifter on a k series.

Yep. I just had 16 new ones put in mine, and it took a decent run up the coast road to shut them up. I'd tried letting it idle until the fan came on, but it seems doing that just doesn't get the oil hot enough.

[Bobthebeard]

Yep. I just had 16 new ones put in mine, and it took a decent run up the coast road to shut them up. I'd tried letting it idle until the fan came on, but it seems doing that just doesn't get the oil hot enough.

Tried that today....

Still rattling just the same! Grrrrr.

[Lankytim]

Noisy injector?

[Bobthebeard]

Noisy injector?

Would that sound the same?

Clutching at straws here!

[saucedoctor]

Maybe just give it time, Bob. All the other K Series I've owned have shut up eventually.

The 45 I had was tappy, I wanged a pint of ATF in it with 4 litres of cheapo engine oil and ran it for a couple of hundred miles. Changed the oil properly after that and it shut up. Having said that, I was told that so doing was a BAD IDEA.

 

Low mileage K's do make a knocking noise, though. "TADT,S".

[Bobthebeard]

Maybe just give it time, Bob. All the other K Series I've owned have shut up eventually.

The 45 I had was tappy, I wanged a pint of ATF in it with 4 litres of cheapo engine oil and ran it for a couple of hundred miles. Changed the oil properly after that and it shut up. Having said that, I was told that so doing was a BAD IDEA.

 

Low mileage K's do make a knocking noise, though. "TADT,S".

Thanks!

Although the mileage on this one is 165K....

Will running it with the rattle do any damage? If not ( once I eventually get the V5 ) am prepared to use it daily if further engine mayhem is unlikely.

[jbz2079]

The honest answer to this is find out what is making the noise first.

As someone could say yeah, drive it thinking it's just a sticking tappet, but if it isn't anything might get broken.

 

Personnally I'd like to know what it was before carrying on.

[Mr_Bo11ox]

18/10 for that great tip, what do you think he's trying to do???

[Barry Cade]

99% shure it's tappets- if it's a later (02 on) engine with the twin coils, these seem to be worse for it somehow. Stethoscope can be a handy tool in cases like this... 'snot a VVC is it?

 

I'd check compressions just to rule out anything sinister first. Anything top end will be half crank speed so can be an indicator as to where the noise is coming from. Check cambelt tension and all tensioners are OK- later ones have the auto tensioner, early ones have a small spring,which can drop off- I do without them.

 

Once you are certain it's tappets, just go and drive it-hard. Live with it, it may go away, it may not- either way it's no big deal. K series are still plentiful, and not worth throwing hundreds and hundreds at a 165k motor.

 

If it's a loose liner then it'll let you know eventually.... when you get a cupholder in the cam cover    (Joke)

 

And MLS gaskets are still shite.

 

 

How's yours getting along Mr B?

[jbz2079]

18/10 for that great tip, what do you think he's trying to do???

Yes I know how you read that, but what if this engine has a broken cam cap or something else fractured after having coolant in the combustion

space?

It just might possibly fail in a big way, usually at the most incovieniant time / place.

 

Just as an example, a friend had a SD1 2600 that had a noticable tap from the engine top end, he ran it anyway and it picked a shim up and drove it through the cam cover side, snapping the cam belt.

At the very moment he was overtaking a long line of wagons on the A69 at Hexam.

[solid61]

Small end bearing/bush? it will be a fast tapping noise and can be singled out by pulling the ht leads off one at a time if its got leads and not coil packs.

[Barry Cade]

Small end bearing/bush? it will be a fast tapping noise and can be singled out by pulling the ht leads off one at a time if its got leads and not coil packs.

Coil packs are piggy backed, so still possible to do this.

[HH-R]

Someone on MacD/Rover 400-45 forum puts diesel oil in his kettles when he gets them and runs for 1000 miles or so then changes to the correct petrol grade (they were all 10W 40 semi synth as far as I remember) and seems to get good results. I've never tried it myself though. The 45 I had was the only noisy K I've had but I reckon that was piston slap and had been cooked due to HGF, it went away when it was warm and all was well.

[Station]

Am going to do the full thing. Peace of mind and all that! Are they ok to re use if fitted once? If so am wanting em.... How much please?

Yeah they are fine to use again I only did about 20 miles before realising the block was cracked!

[twosmoke300]

Diesel oil isn't a bad idea as it has a better detergent package in the blend.