K series suspected cat problem???

[domster]

Hi guys

 

My second car, a Rover 414i MPi 16v, 75k miles on an N reg, is misbehaving.

 

It feels like a blocked cat to me, or maybe dodgy tappets, but what do I know?

 

The symptoms are:

 

- engine OK if I don't rev it past about 3.5k

 

- engine on overrun feels awful - if I back off the engine feels leaden and can even start to pink quite badly

 

- valve clatter is excessive

 

- engine not keen to rev above about 4k (even despite the fact I haven't fitted a Supersport kit to it!)

 

Any thoughts appreciated

Cheers

Dom

[John Howe]

If you have excessive valve clatter, why? Finding the answer to that riddle will most likely solve your problem.

 

I assume you have hydraulic tappets, do they all sound the same or is the noise specific to any particular cylinder? If the noise is across the range then perhaps they are not getting pumped up enough.

 

JH

 

 

[domster]

Hi John

 

My theory was that the valve clatter was being caused by the back pressure, or the heat build-up.

 

I had a new head placed on the car about 15k miles ago, but not sure whether the garage reused the old tappets. It was from one of those head places, and I can't remember whether they supply cams and tappets too, or whether you use your old ones. If old the tappets could have failed, I suppose... cheers for the thought.

 

Rgds

Domster

[John Howe]

You talk in the plural i.e. "old tappets could have failed" but it is most unlikely that a number of tappets would fail at the same time. Could it be that the oil supply (that pumps them up) is suspect?

 

You might try measuring valve lift, this would at least give you information from which to go forward with.

 

JH

 

 

[domster]

I may have mentioned 'tappets' in the plural sense erroneously - I need to check whether it is a problem with just one, as haven't confirmed that yet.

 

How do you measure the valve lift to tell if oil pump is working fine?

 

Cheers

Domster