sotal Posted January 30, 2010 Share Posted January 30, 2010 I want to make sure that my liners are all in the right place and that they haven't slipped. First Question - Which way do liners slip? Up or Down - or is it either? Second question - Should the top of the liner be perfectly level with the block, or should it sit up slightly or down slightly? Third question - What distance are we talking about them slipping, articles I have read mention words like "significantly" which makes me think it would be quite obvious. All this is with reference to a GEMS 4.6 V8 The reason I ask is I currently have both heads off, and I thought I could feel a very minute difference with my finger nail - my father-in-law who is more experienced with engines etc said he couldn't feel it. I think that 3 of the liners are perfectly level whilst 5 are ever so slightly raised. I'm not even talking a thou based on what I can tell with the feeler guages. Does this sound normal, or is it a sign of a problem? Quote Link to comment Share on other sites More sharing options...
g&t Posted February 1, 2010 Share Posted February 1, 2010 There's a lot of info. around on this subject so I'll leave you to do the trawling! Brief explanation: the block is alloy with pressed in steel liners. Back in '89 LR decided to bore the block to 94mm thus increasing the capacity to 3.9ltrs.(from the original 3.5L) & this bore size remained unchanged to the end of Rover V8 production. The 4.6L capacity was achieved simply by increasing the stroke, however this 'overboring' exercise left less 'meat' around the cylinder liners. If the block develops the slightest cracking (again a discussion on it's own!) the liner is no longer tightly gripped. As the block starts to warm up it expands, allowing the piston to carry the liner up & down with it & producing the dreaded 'tapping' sound. Two symptoms stop you confusing the sound with tappet noise: (1)the tap will not be audible from cold, only as the engine starts to warm up or even reaches running temp. (2) the tap will be at piston speed as opposed to valve gear which is half that speed. Those with experience of rebuilding V8's should be able to advise you re. your technical queries. Quote Link to comment Share on other sites More sharing options...
LandyManLuke Posted February 1, 2010 Share Posted February 1, 2010 FWIW, I've a v8 with all the liners perfectly level, but one cylinder has still 'slipped' - in that it lets water in to the cylinder. see here Quote Link to comment Share on other sites More sharing options...
sotal Posted February 1, 2010 Author Share Posted February 1, 2010 I've done a lot of reading on it, so have learnt the basics of why it happens, but what I couldn't find was any real detail on how far they would slip. From advice on another forum I have pretty much determined that they haven't slipped, but it's still unknown if the block is cracked behind the liner. The advice given to me is to pressure test the block before I proceed, but I'm in a similar position to LandyManLuke in that I don't really want to through money at it, I'm quite tempted to just but the new gaskets on which I have and rebuild, then check for problems then. Having it running in any state will also allow me to diagnose any other problems with the car such as gearbox or suspension problems which I am unable to check at the moment. If there is enough else wrong with the car then I may as well scrap it! The only sure way to fix this is to have it top hat linered, but it looks like it's going to cost £850+ to do that Quote Link to comment Share on other sites More sharing options...
q-rover Posted February 1, 2010 Share Posted February 1, 2010 There doesn't neccesarily have to be waterloss with a slipped liner. A friend of mine had this happen. Driving along merrily, then bag of spanners in a washing machine. We had a look at the block and there were even bits of pistonring on the intake side as well as in other cylinders. Quote Link to comment Share on other sites More sharing options...
Bull Bar Cowboy Posted February 4, 2010 Share Posted February 4, 2010 TBH the liner actually slipping in the block is quite rare. Also, some if the blocks are machined with a slight ridge at the bottom of the bore that the liner almost sits on. The much more common failure is a crack behind the top area of the liner into the coolant jacket which then leaves it open to pressurisation from gases that are forced between the liner and block casting due to the complete liner being within the fire ring. During the non compression / firing stoke the pressure is released back into the cylinder as coolant & steam. This generally gives all the symptoms of head gasket failure apart from one detail …………. a compression test will show up as OK, whilst a compression test on a faulty head gasket will show poor compression on one or more cylinders. Sotal – from what you have described the liners probably are sitting in the same position that they left the factory…………. More detail in my pm to you Quote Link to comment Share on other sites More sharing options...
p76rangie Posted February 4, 2010 Share Posted February 4, 2010 I want to make sure that my liners are all in the right place and that they haven't slipped. First Question - Which way do liners slip? Up or Down - or is it either? Second question - Should the top of the liner be perfectly level with the block, or should it sit up slightly or down slightly? Third question - What distance are we talking about them slipping, articles I have read mention words like "significantly" which makes me think it would be quite obvious. All this is with reference to a GEMS 4.6 V8 The reason I ask is I currently have both heads off, and I thought I could feel a very minute difference with my finger nail - my father-in-law who is more experienced with engines etc said he couldn't feel it. I think that 3 of the liners are perfectly level whilst 5 are ever so slightly raised. I'm not even talking a thou based on what I can tell with the feeler guages. Does this sound normal, or is it a sign of a problem? I had one motor recently with 3 slipped liners in it. They ranged from very obvious to very hard to notice. None were causing any coolant loss. Most of the slipped liners that I have been involved in had nothing to do with cracked blacks or coolant loss/pressurisation. All motors are decked as part of their building process. Therefore the top of the liners should be PERFECTLY in line with the block all the way around. If your fingernail can feel something on the join between the two, you most likely have a slipped liner. They can basically stop in any position, so they can stop right at the top of the bore. Quote Link to comment Share on other sites More sharing options...
vougese39 Posted February 7, 2010 Share Posted February 7, 2010 any movement is not good if you are unsure remove the block and seek a very good engineer shop who should be able to test the cooling system and check the linners for leaks normaly when they slip they chomp at the head gasket fire ring. also a knocking when the engine is running cn be heard usualy half engine speed just had a block relinnered for a customer £1750 with a balanced crank rods and pistons and flywheel. as for the coolant issue that can happeren even if the linner has not slipped Quote Link to comment Share on other sites More sharing options...
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