very noisey tappets, or possibley faulty oil pump??

[stemid 0]

Caning it home from work the other day and suddenly started hearing this awful clattery noise from the engine, pulled over and the engine was idling very ropey then stalled.

 

Towed the car home and fired it up the next day. Only firing on 3 cylinders at idle speed, but pretty sure it's firing on all when I rev it.

 

Now if I rev it slowly up to high revs the noise does not happen, but if I rev the engine quickly the noise returns. Sounds like its coming from the cam area. I'm assuming its the tappets (but doesn't dissapear when warm) I've taken the rocker cover of and looked at the tappets with out removing anything else. Will I be able to test them like this, OR are they gonna need to be fully removed?

 

Or could it be a problem with the oil pump? Think I have 15w40 oil in at the moment. Could it be worth going up to 20w50?

 

The car is a 1.8 16v KR with 180k on it.

 

Any help/advice would be much appreciated.

 

Steve

 

oh i have replaced all 4 plugs and ht leads with spares, checked the dizzy cap and rotor arm, but still missfires.

[Crasher 3]

It may be head gasket failure; the noise could be the sound of the gasses passing between two cylinders, basically chronic detonation. A compression test will show this up and it normally happens between 1 and 2.

[stemid 0]

Crasher you were spot on. I whipped the head off to find that the head gasket had blown between the the two cylinders. It had also started to blow between the other two.

 

So I got the head skimmed and bought a new head gasket set and fitted it all back together. Now I have low compression on all 4 cylinders. 5.5 bar each. Should be more like 12bar / 180psi I believe?

 

My first thought was the valve timing was out. But I have checked and double checked and tripled checked but everything is spot on.

 

Does anyone have any idea why else the compression could be so low on all cylinders. Must be valve related surely?

 

Compression test on the two good cylinders before I took the head off were 175psi