CURLY Posted January 26, 2009 Share Posted January 26, 2009 hi there, just got a 300tdi disco with a head gasket gone on it, had the head skimmed this morning and they had to skim off 40 thou. are the valves going to hit the pistons now? that seems an awful lot of meat to take off!! I have read on here that the head gaskets come in different thicknesses? spose i'll need the thickest one will i? and the inlet manifold is full of sooty black sludge. is this from the egr valve? cheers in advance! CURLY Quote Link to comment Share on other sites More sharing options...
BogMonster Posted January 26, 2009 Share Posted January 26, 2009 The proper way to do it involves measuring the piston protrusion accurately and working out the gasket thickness from that (detailed in the workshop manual I think) but yes I imagine you would need to allow for any head skimming. Yes the sludge is probably from the EGR valve. EGR stands for Extremely Gungey Residue Quote Link to comment Share on other sites More sharing options...
CURLY Posted January 27, 2009 Author Share Posted January 27, 2009 The proper way to do it involves measuring the piston protrusion accurately and working out the gasket thickness from that (detailed in the workshop manual I think) but yes I imagine you would need to allow for any head skimming.Yes the sludge is probably from the EGR valve. EGR stands for Extremely Gungey Residue thought so! i hate those EGR valves, i had one on my petrol vectra and it buggered up the inlet manifold flap valves and cost me a fortune! i have just been reading through the RAVE cd and found the correct procedure for choosing the head gasket, so i'll have to do that. if i am scraping the top of the block, how can i stop the carp falling down the holes? and what if a bit goes down them? will it bugger the engine or just go in the filter? i'm new to all this incase you hadn't guessed! does anyone have a 'how to replace the cylinder head' thread? CURLY Quote Link to comment Share on other sites More sharing options...
Les Henson Posted January 27, 2009 Share Posted January 27, 2009 Re-set the valve stand down and use the same thickness head gasket. I would say that 40-thou is the maximum material removal from a standard thickness head. If you want to restore the head to it's original thickness, then a head saver that's the same thickness as removed material can be used. (a lot of thickness in that post ) Les. Quote Link to comment Share on other sites More sharing options...
BogMonster Posted January 27, 2009 Share Posted January 27, 2009 Check out the tech archive forum on here I think there is stuff on changing head gaskets in there which will be a start for the info you need. Quote Link to comment Share on other sites More sharing options...
rocky Posted January 27, 2009 Share Posted January 27, 2009 Hi, i did mine a few months ago, i had the head pressure tested and skimmed. I can't remember what the valve stand-down was but was told by the engineer that the amount taken off was within set limits and wouldn't cause any damage to the pistons or valves etc. I would advise using a genuine landrover headgasket and tighten the head down as per manual. I've done about 3000 miles since and so far had no problems. I had a lot of help from this forum and you should find it in previous posts. Good luck, rocky. Quote Link to comment Share on other sites More sharing options...
CURLY Posted January 28, 2009 Author Share Posted January 28, 2009 Re-set the valve stand down and use the same thickness head gasket. I would say that 40-thou is the maximum material removal from a standard thickness head. If you want to restore the head to it's original thickness, then a head saver that's the same thickness as removed material can be used.(a lot of thickness in that post ) Les. les, what is a head saver? CURLY Quote Link to comment Share on other sites More sharing options...
Les Henson Posted January 28, 2009 Share Posted January 28, 2009 It's a sheet of Shim steel that's the same shape as the head gasket and the same thickness as material removed from the head (in your case 40-thou). You place it on top of the new head gasket and bolt the head down as normal. Head savers to a specific thickness are usually around £40. Some head savers come with a layer of adhesive and are stuck to the block - underneath the head gasket and become permanent once the head has been bolted down/affected by engine heat. I don't think it really matters if they are on the head or the block, as the end result is the same. Les. Quote Link to comment Share on other sites More sharing options...
CURLY Posted January 30, 2009 Author Share Posted January 30, 2009 It's a sheet of Shim steel that's the same shape as the head gasket and the same thickness as material removed from the head (in your case 40-thou). You place it on top of the new head gasket and bolt the head down as normal. Head savers to a specific thickness are usually around £40.Some head savers come with a layer of adhesive and are stuck to the block - underneath the head gasket and become permanent once the head has been bolted down/affected by engine heat. I don't think it really matters if they are on the head or the block, as the end result is the same. Les. where do i get one of those from? CURLY Quote Link to comment Share on other sites More sharing options...
Les Henson Posted January 31, 2009 Share Posted January 31, 2009 Whoever skimmed your head should be able to get them. Not an off the shelf item I'm afraid. Les. Quote Link to comment Share on other sites More sharing options...
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