timotei1980

iTrader: (1)

Hi,

Recently experienced a tappet failure and am gathering the parts to rebuild but what would cause this damage:





Have read on a website that the tappet not spinning in it bore can cause this as it overheats it.

What should I look out for when putting it back together to try and make sure it does not happen again?

Thanks.

stevieturbo

Some history would be useful ? Miles, are the cams/lifters OEM or has someone been at them etc ?

And is the tappet able to rotate freely in the bore ?

Are any others showing signs of damage ?

What condition is the valve and spring in ?

costina

iTrader: (1)

Looks like the oil has been changed at regular intervals.

timotei1980

iTrader: (1)

Engine has done approx. 80000 miles, Std cams / followers. Engine is a VW ABF 2.0 16v and was made in 1996 and all original parts I suspect.

before dismantling it / finding the problem I carried out a compression check and all were good at between 175 - 180 psi.

Did not have any problems removing the damaged follower and when putting another in, it rotates freely. All others look normal.

Engine has always had very good oil pressure according to the gauge fitted.

Thanks.

stevieturbo

It certainly is a plausible argument that a sticky lifter could cause that...but that would make no sense if it was not sticky lol.

I'd say a broken spring would also be possible, or if it is a hydraulic lifter, if it perhaps was broken causing clearances to get too large etc. Although surely the engine has been making a hell of a noise for some time to get to that state ?

timotei1980

iTrader: (1)

No, engine was quiet one minute then tick tick tick... At the time I was was out checking fuel ratios were good through the rev range, done a 7000 rpm run then slowed down to idle that's when I noticed it.

timotei1980

iTrader: (1)

Was thinking this last night, if the spring broke and then has spun around slightly basically coil bounding when trying to compress it. This engine from std also has inner and outer valve springs.

stevieturbo

Unless your cam magically developed more lift, then no there is no possible way a broken spring could then have been coil bound by the cam etc.

But losing control of the spring/valve/lifter would have the lobe bashing the fuck out of the lifter.

Although I dont believe for 1 second that damage has occurred during 1 single pull without any prior symptoms. Not a chance in hell that hasnt been making noise for hundreds if not thousands of miles.

Although it hardly matters, it all needs to come apart and replaced, and I would be pulling the head and checking the valves and springs too.

timotei1980

iTrader: (1)

It could become coil bound if the inner spring broke and got between the outer spring coils though for example.

I guarantee you the noise was not there at the start of the drive but then was after that certain pull. I'm not saying it suddenly went from prefect lifter to failed lifter, it was probably gradually wearing away and that was the particular pull where the metal was so thin it let go.

Anyway, like you said I will find out more when the valve springs come out.