Rattling top end. HEEEELP

[vipergts]

My 4.2 had always been tappety. It wasn’t adjustable so I opted for a head rebuild.

Long story short, rattle was still there, thinking it was small ends I had the engine rebuilt.

Rattling top end still there.
Had tappets adjusted. Was ok for 50 miles and progressively got noisier.

Had them adjusted again as it only seemed like one.

Was ok then got noisier again and the same process again.

It seems that it’s noisy on throttle take up, a single tappet that is quiet at tickover.

I think over time they’ll all start to get noisy.

I’m at my wits end with it.

Any ideas???

[christopher storey]

What you have not mentioned is any replacement of the tappets and/or tappet guides themselves . What happens is that with extensive use the tappet buckets can become barrel shaped and rock in the guides , producing a clicking sound . The first thing I would do is to remove the camshafts and carefully measure each tappet diametrically at various points in its depth. If there is any variance, you have a barrel shaped tappet . In any event , since nothing has worked so far, i would replace all the tappets - they are not very expensive . You may well find that you have to reshim to get the appropriate clearances

[mgcjag]

You can get long skirt tappets which are longer than standard....if your tappets have worn barrel shape the long skirts replacements are a quick fix...or to do the job properly new guides......you could also have a loose guide that's hitting the camshaft..you should see signs of wear.......but first step is to measure your gaps....have they been set correctly...Steve

[vipergts]

What you have not mentioned is any replacement of the tappets and/or tappet guides themselves . What happens is that with extensive use the tappet buckets can become barrel shaped and rock in the guides , producing a clicking sound . The first thing I would do is to remove the camshafts and carefully measure each tappet diametrically at various points in its depth. If there is any variance, you have a barrel shaped tappet . In any event , since nothing has worked so far, i would replace all the tappets - they are not very expensive . You may well find that you have to reshim to get the appropriate clearances

Gotcha, it does come and go with revs.
The head builder said the tappets were good but I’m not inclined to believe him.
Is the tappet the softer item and how likely is it that the guid in the head with be worn? Obviously this would be more work.
Thank you for your advice

[vipergts]

You can get long skirt tappets which are longer than standard....if your tappets have worn barrel shape the long skirts replacements are a quick fix...or to do the job properly new guides......you could also have a loose guide that's hitting the camshaft..you should see signs of wear.......but first step is to measure your gaps....have they been set correctly...Steve

I fitted guide hold down thingies to eliminate that.

What do the long skirt tappets do to change things ?

[Gfhug]

Please don’t quote unless really needed and relevant, it just uses up valuable server space. Also you can edit the quote down to an important sentence.

Geoff

[mgcjag]

If your tappets are worn barel shaped then the guide will also have wear and they can rattle in the guide......by useing a longer tappet you useing part of the guide that has no wear and being longer there is less chance of it rattling....check the measure yourself or use someone that knows what they are doing

[vipergts]

Gotcha.
Makes perfect sense.
Thanks

[vipergts]

The only thing I don’t understand Is why each time they’re adjusted they’re quiet for maybe 5-10 miles and only then do I get the strange rattle

[vipergts]

Update
I’ve just been out in it again.

It wasn’t tapping when warm. Then mid point on my 10 mile trip it was clearly rattling again.
By the time I got home the rattle had ceased.

So it would appear it comes and goes, wonder whether this is consistent with an oval tappet?? As it turns in it’s guide??

[christopher storey]

The other thing that can give rise to noise of a variable nature is a timing chain tensioner problem . next time it rattles, stop immediately and check the tension on the upper chain - it only involves removal of the front dome and the filter screen behind it . The lower chain is tensioned by a slipper and by a hydrulically operated horizontal tensioner plunger. These are much more difficult to check since IIRC ( perhaps someone can correct me if I am wrong ) it requires removal of the front cover

[mgcjag]

Have you only heard the noise whilst your driving..or have you had the bonnet up and pin pointed it to under the cam covers...if only when driving it could be many things rattling..whats happening to your oil pressure when it's happening...Steve

[vipergts]

Yes it’s when stationary too. Bonnet up and pinpointed the noise