Technical Head Gaskets, Valves, Cams, Shims, blah blah.. Few questions please

[dbriglee]

Hi peeps,

Doing my blown headgasket on me Mk1 punto sporting at the weekend.

Just a question....
before it is sent to the engineers for the skimming, do I have to take out all 16 valves???? Or can they skim it with them still in and the inlet/exhaust manifolds still attached?

:-( Will the valves fall out when I take the cylinder head off????

And another thing. Could someone please explain what valve grinding is and how it works?? (I understand you use a compound to 'sand' the valve down so it's flush with it's seal, so no air is lost on compression, but what does this mean??)
Is it worth me checking/doing the valves?? or just simply oil the cam followers and put em back as explained in the Haynes.

Cheers Guys.
Any replies would be nice

 

[JonnyBoy]

Nah, they don't need the valves out for skimming. Probably needs the manifolds off, but this is a 2-minute job.

Valve grinding = spreading an abrasive paste on the valve-to-valve-seat contact, sticking this sucker thing on the valve, and spinning it round to get it flush. Unless it's had some new valves fitted, it won't need them grinding.

 

[faster4_tec]

if you want to rebuild head while your at it (cam shaft oil seals, valve stem seals, skim head and grind valves in) got for it, I didn't do mine and am now regretting it as I will have to have another H gasket and skim in order to do it all properly :bang:

 

[HFStuart]

The second pic from the bottom on this page shows valve grinding quite well.

http://www.davebence.co.uk/onyx_firefox/build_6_main.htm

I like the use on the sunday best crockery to store the valve parts !

If the engine has done lots of miles it's probably worthwhile doing a proper job as has already been said. If you get the double ended tin of paste you should only need to use the fine grade to clean up the seats.