john242 Posted November 16, 2011 Share Posted November 16, 2011 just checked a cyl head and got a gap of .5mm between cyl 2/3 is it acceptable to skim the head that amount? the only shaft in there is the rocker shaft. thoughts and advice please. Quote Link to comment Share on other sites More sharing options...
davek0974 Posted November 16, 2011 Share Posted November 16, 2011 .5mm seems quite bad. AFIK it all depends on valve stand-down and piston stand-proud, if these values go out of spec then you get valves hitting pistons etc. I'm sure someone will be able to offer more info. Quote Link to comment Share on other sites More sharing options...
Bowie69 Posted November 16, 2011 Share Posted November 16, 2011 That's 'only' 20 thou, but you don't say what engine it is, if it's a V8, then I am positive it would be OK. Diesel may be another matter. Quote Link to comment Share on other sites More sharing options...
john242 Posted November 17, 2011 Author Share Posted November 17, 2011 Sorry should have said its a 300tdi ive had it skimmed yesterday head gasket etc arrivrd today looking at the cyl block and pistons im hoping to get away with reseting tappets.if this dont work probably take the engine out of other disco Quote Link to comment Share on other sites More sharing options...
Les Henson Posted November 18, 2011 Share Posted November 18, 2011 Resetting the tappets will make no difference to the valve stand down I'm afraid. lapping the valves in further if necessary is the only way to do that.Head thickness can be restored if necessary by the use of a head saver shim, which would be the same thickness as the material that has been removed from the head. Les. Quote Link to comment Share on other sites More sharing options...
john242 Posted November 18, 2011 Author Share Posted November 18, 2011 never used a head saver shim before so i'll look into it definitly dont fancy lapping valves that much regardless of the alleged theraputic nature of the job. thanks for all the help will let u know if it goes t--s up. Quote Link to comment Share on other sites More sharing options...
Les Henson Posted November 19, 2011 Share Posted November 19, 2011 I've had heads skimmed that didn't need the stand down adjusting, but 20-though may require it on some of them, if not all. You can measure the stand down before the skim to determine if they will need lapping. Les. Quote Link to comment Share on other sites More sharing options...
john242 Posted November 20, 2011 Author Share Posted November 20, 2011 we put the head back on yesterday setting the tappets to 12thou runs sweet at the moment but havn't tried under load yet.Should know how it performs latter today. Quote Link to comment Share on other sites More sharing options...
Range Rover Blues Posted November 20, 2011 Share Posted November 20, 2011 Load will make no difference to the valve clearence unless they start to bounce, so sounds like you are ok. We had ours skimmed and it's bene fine, but the LR manual says the head cannot be skimmed at all. Quote Link to comment Share on other sites More sharing options...
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