A question about hydraulic tappets?

[Taipan]

Hi All

Apparantly my 1980 air cool 2.0 has hydraulic tappetts. Are these a reliable unit or do they need servicing/replacing periodicaly?

Many thanks.

[Dan Wood]

I suppose they'll give up eventually, but I would have thought they would start to leak and lose pressure gracefully first, rather than just fall apart and ruin your engine!

So, if you've not got a nasty clattering bag of spanners in the bag of your van, I wouldn't worry. Just keep up with the regular oil changes.

[DiscoDave]

what he said^^^ just make sure you have the right oil and he right amount and they should be just fine!

[..lee..]

i`ve got the same problem with my air cooled. before i laid her up it used to tap ocasionally and clear once warm but since its been parked up i cant get it to be quiet. the engine is bearly run in as it was fitted brand new in germany a few months before i had it so its not worn out. i`m concidering converting to mechanical tappets as the van will not be used every day.

if it is indeed possible.

[cumbriankeith]

I'm afraid you can't just change the followers for solids - you have to change not only the pushrods as well, which is easy enough; but also the cam shaft, which is not! It's to do with the profile being wrong.
Running the engine regularly is all it needs...

[Taipan]

I suppose they'll give up eventually, but I would have thought they would start to leak and lose pressure gracefully first, rather than just fall apart and ruin your engine!

So, if you've not got a nasty clattering bag of spanners in the bag of your van, I wouldn't worry. Just keep up with the regular oil changes.

If they lost pressure would they then fail to open the valve properly and be a possible cause of a misfire?

[kevtherev]

no

[Dan Wood]

...possibly, but what usually starts to happen first is that they don't quite 'pump up' enough so that there is a bit of extra lash in the valve train.

You get a clattering sound as the cam slaps the followers on to the pushrods which in turn slap the rockers. It's that sound that most people notice and it usually kicks in before there is so much slack that the valves don't open.

Far more serious (probably - I'm making this up(!) ) is if the initial setting has been over done. In this case as the tappets pressurise, they end up holding the valves open for too long.

Someone who actually know what they're talking about will be along soon...

[jason k]

if they do clatter once in a while , just take the bus out , give it a bit of welly for five mins and it will all go quiet again, its just one of them things, it sounds worse than it actually is too................