Flat Xantia

Post by **Peter.N.** » 04 Apr 2006, 22:23

citroen XM

I am sure you have as much to contribute as anyone else, your a 'hands on' man like myself.

Regards

Peter.

Post by **Peter.N.** » 04 Apr 2006, 22:31

foolzz :

A louder 'knocking' noise can just be indicative of higher compression. Have you used the same thickness head gasket as before? if so, and you had the head machined, you will now have a higher compression ratio. Did you re seat the valves or adjust the clearances? this to could increase the compression

The only way you could have advanced the timing without being a tooth out, is if you have altered the pump position. If it was advanced by one tooth it would make a considerable difference, in fact the engine would be very uncouth - if you could start it!

Kowalski · Post by **Kowalski** » 04 Apr 2006, 22:53

The heads on the XUD are pretty much flat so machining doesn't affect the compression ratio. The gasket thicknesses are there to compensate for different amounts of piston protrusion through the block. I suspect its something to do with how the blocks get machined or reconditioned.

Post by **Peter.N.** » 04 Apr 2006, 23:06

It does bring the valves a bit closer to the pistons, but I take your point.

f00lzz · Post by **f00lzz** » 05 Apr 2006, 08:15

Thanks for the replies guys.... I had the head reconditioned by a reputable company .... www.motorcast.com they did all the machining, new cam, valves, supplied bolts, gaskets etc. so am confident that they did the job properly. I thought maybe I had got the pump timing out slightly, but your replies virtually dispell that theory, but i'm sure my engine sounds noisier than my brothers 1994 TD

Post by **Peter.N.** » 05 Apr 2006, 09:14

If you have had the head fully reconditioned the compression probably will be higher which will increase the 'cackle' but it should quieten down when warm. Replacing the injectors will also make it noiser as the injection pressure is higher. A good 'cackle' is generally a sign of a healthy engine, as long as its not excessive.

f00lzz · Post by **f00lzz** » 05 Apr 2006, 09:30

Ok I feel better for that now... thanks

dnsey · Post by **dnsey** » 05 Apr 2006, 10:46

Just decoking an engine can noticably change its running noise - I suppose the carbon buildup absorbs some of the higher frequencies - so it's not surprising that yours sounds a bit louder.