Tigger Posted May 7, 2007 Share Posted May 7, 2007 I need a little help and advice with a Head Gasket replacement on my K-Series (not my Caterham but the MGF), if failed a few months back at a Brands Hatch track day, but thankfully, rather than going it a catastrophic manner on track it happened 5min later when the car was still idling in the pits. This is not the first replacement HG (it's the 3rd!) and this time rather than getting a garage to do the work I thought I would take the plunge and do it myself. The head is now off and from what I can see still seems to be OK, there is no pitting or indentation in the head, however there does seem evidence that gasses have been passing the firing rings: Gasket Pics: here Head Pics, I'm really hoping this will be OK since it's a very nicely flowed head. here here here I have now measured the height of the liners and I think they might be a little low. (Counting from the Cambelt cover) Cylinder one - 1Thou & 2Thou here Cylinder Two - 2Thou here Cylinder Three - 2Thou Cylinder Four - 2Thou So my question is what do I do about the liner height....? I'm also considering using the new Land Rover Multi-Shim gasket and replacement ladder, will this have any bearing on the height of the liners...? Many thanks for any advice given. Tim Link to comment Share on other sites More sharing options...
oilyhands Posted May 7, 2007 Share Posted May 7, 2007 Tim, Have the head hardness tested. If the liners are less than 4 thou then you are doomed to repeated failures. Thwe latest MLS gasket/shim is *less* tolerant of wayward liner heights so you would be better with the latest Payen Elastomer seal type gasket. If your liners are low the solution is to remove the sump, oil rail, pickup, roda, linera and pistons, remove the dowels and linsih the top fo the block until the liners have the correct protrusion. Make sure you mask the block thoroughly so that the spoil is contained. Also make sure that the oyu mark the liners so you know both the cylinder number *and* the raidal orientation of each liner so that they go back in exactly the same position. Thr big-end bearings will require replacement when you re-assemble. Since I have started correcting liner heights in this way I havent had a single incidence of HGF. Oily Link to comment Share on other sites More sharing options...
Tigger Posted May 7, 2007 Author Share Posted May 7, 2007 Dave, Many thanks for the advice, I thought this would probably be on the cards. So that I know what I'm getting myself into, what can I expect the hardest part of the disassembly and will I need any special tools or can I rely on a BFH to move the immovable objects? Tim Link to comment Share on other sites More sharing options...
Bozz Posted May 7, 2007 Share Posted May 7, 2007 Tim I don't mean to be rude or dismissive of your abilities as a mechanic but it may be prudent to let someone like Dave Andrews do the job and for you to watch and even help. Then the next time you need to do it (if you do) at least you'll know all the pitfalls and the tricks and tools you'll need to work on the 'K' Bozz McLaren Orange and Black 1.6SS 6 Speed here Link to comment Share on other sites More sharing options...
Tony Whitley Posted May 7, 2007 Share Posted May 7, 2007 On the other hand, if you've managed to get the head off yourself you're probably have as much mechanical skill as me and I sucessfully linished 4 thou off my block on Oily's advice. Despite my doubts! (Sorry Bozz, I seem to be contradicting you today ) Link to comment Share on other sites More sharing options...
Bozz Posted May 7, 2007 Share Posted May 7, 2007 Tony No you're probably right 😳 I didn't realise that Tim had already got the head off. It was the reference to a BFH that worried me a little 😳 😬 😬 But then I is an engineer so what do I know Bozz McLaren Orange and Black 1.6SS 6 Speed here Link to comment Share on other sites More sharing options...
Tigger Posted May 7, 2007 Author Share Posted May 7, 2007 Bozz and Tony, I completely support both of your comments and if I was a little nearer to MK my first option would be to ask Dave to do the business. However, I was heartened to read Tony's account of undertaking the same task and in the past Dave has given me the confidence to work on the engine myself which I previously considered to be a black art only to be undertaken by those with Magnatec running through their veins. I see this as a new challenge although I may need to make a couple of calls to Dave (hope you don't mind) Tony, did you by chance document or even photograph the process as you were doing it:) Tim Link to comment Share on other sites More sharing options...
oilyhands Posted May 7, 2007 Share Posted May 7, 2007 Tim, two parts that will give grief. Retiming the cams (which I know you have done before) and refitting the pistons/rod assemblies where care, precision and cleanliness are paramount. Phone any time if you need remote assistance. Oily Link to comment Share on other sites More sharing options...
Tigger Posted May 7, 2007 Author Share Posted May 7, 2007 Many thanks Dave, So I can leave the BFH in the tool box then This might be a little ahead of myself but how will I know how much to linish off? Tony also mentioned something about a piece of glass to check flatness, something of a decent thickness, un-toughened and about the same dimensions as the mating surfaces I imagine. How do I use this...? The fact that Tony did this on a nice accessible 7 is going to be a little different to struggling in the deep recesses of the MGF access panel Edited by - Tigger on 7 May 2007 16:12:51 Link to comment Share on other sites More sharing options...
Tony Whitley Posted May 7, 2007 Share Posted May 7, 2007 More information here Bozz, what sort of engineer are you if you don't have a BFH (or "Brummigum Screwdriver" as I was brought up to call them 😬) Link to comment Share on other sites More sharing options...
Bozz Posted May 7, 2007 Share Posted May 7, 2007 Tony Actually I do possess various BFH's including a 14pounder for use with flogging spanners 🙅🏻♂️. Not found a use for one of these on the K yet though 😬 😬 Bozz McLaren Orange and Black 1.6SS 6 Speed here Link to comment Share on other sites More sharing options...
Tony Whitley Posted May 7, 2007 Share Posted May 7, 2007 I hadn't come across "flogging spanners" (I just belt ordinary ones ) but in searching for them I found "Monday hammer" (If they couldn’t get it undone with that, we used a flogging spanner and a “Monday” hammer) so called because it weighed 28 (or 32) lbs, and if you used it on a Monday, you were on the sick for the rest of the week, or because on Mondays you come to work fresh and strong, having rested over the weekend and therefore are able to wield this heavy hammer. I have to confess to nerves whenever tightening anything on the K. I was much happier replacing the gearbox on the Midget Link to comment Share on other sites More sharing options...
Tigger Posted May 7, 2007 Author Share Posted May 7, 2007 Now what this does mean is a fine excuse for some shiny new tools which until now I haven't been able to justify to SWMBO. I already have an E12 socket and break bar used to remove the stretch bolts but are there any other 'special or uncommon tools required for the bottom end, I'd like to buy these before the event rather than discover I need a 'EB20 Widget' when I'm lying covered in oil under the car Shopping list: Piston Ring compressors (Is this the right one?) Wet'n'Dry - grade? and where from? Sanding block - anything particularly special? Tim Link to comment Share on other sites More sharing options...
Tony Whitley Posted May 7, 2007 Share Posted May 7, 2007 I used a breaker bar to do up the stretch bolts. I wanted to make sure I got them nice and tight. (Watches Bozz run off screaming ) I think I used an ordinary socket on them though I do have an E12 - they're not E12 but bi-hex or something. That Piston Ring compressor looks like the one I used. Ordinary wet and dry. I started very tentatively with 1200 but soon realised I was getting nowhere and switched to (I think) 400. I used a whetstone as a block as that's what I happened to have around. No other special tools as I recall. The only pictures I have (Still don't know how that lump of grit got in my sump ) Link to comment Share on other sites More sharing options...
Bozz Posted May 7, 2007 Share Posted May 7, 2007 Tony Must admit I do remember the fitters going all 'misty eyed' talking of the 28LBer but never actually saw one. Had enough trouble swinging a 14 especially when perched on a scaffold board 60ft up in the air. 😳 😬 😬 Bozz McLaren Orange and Black 1.6SS 6 Speed here Link to comment Share on other sites More sharing options...
oilyhands Posted May 8, 2007 Share Posted May 8, 2007 The head bolts are E12, the big-end bolts are just a regular bi-hex 10mm (M6) socket. I always use P150 wet/dry when doing this job with a large piece (6inch by 4inch) flat piece of aluminium. Make sure you block the bolt holes and in particular maks the fron oil drilling. Oily Link to comment Share on other sites More sharing options...
Tigger Posted May 9, 2007 Author Share Posted May 9, 2007 I've just been in touch with my local machine shop who haven't got a clue how to test a head for hardness, does anyone know of a company in London (preferrably SE) who might be capable. Tim Link to comment Share on other sites More sharing options...
oilyhands Posted May 9, 2007 Share Posted May 9, 2007 Err.. not in SE London, but I have a hardness tester here... Oily Link to comment Share on other sites More sharing options...
Tigger Posted May 9, 2007 Author Share Posted May 9, 2007 I'll pursuade SWMBO that a trip to MK would be a nice outing one weekend... It'll give me a chance to get a bunch of bits for re-assembly. Should I strip the head before coming up....? Tim Edited by - Tigger on 9 May 2007 15:16:47 Link to comment Share on other sites More sharing options...
Tigger Posted October 21, 2007 Author Share Posted October 21, 2007 Time has ticked on and I have finally stripped the engine in-situ and have the liners and pistons sitting in a plastic box beside me. The stripping down was a bit protracted and as a result the liners were exposed at the atmosphere/coolant interface a little too long I fear, with the result of some pitting around the top 'damp' part of the liner. The bit in the block is absolutely fine. Therefore my query is, should I re-fit these or buy new ones. here and here Also, what is the tolerance on the overall liner heights, the dimension between the shoulder of the liner to the top of the liner varies by .01mm is this a problem...? Thanks Tim Edited by - Tigger on 21 Oct 2007 16:33:22 Link to comment Share on other sites More sharing options...
oilyhands Posted October 21, 2007 Share Posted October 21, 2007 The liner outside is OK, dont worry, I hope you marked their radial position. The important dimension is how much the liner protrudes from the top fo the block when fitted dry. If it is less than .12mm (4-5 thou) then the HGF will happen again. dont concern yourself too much with the overall step height, adjusting the block to suit will make this dimension irrelevant. As it happens the step height is OK, it should be 50.01mm, 49.97 is 1.5 thou shorter than spec. Oily Link to comment Share on other sites More sharing options...
Tigger Posted October 21, 2007 Author Share Posted October 21, 2007 Yep! liners marked radially and to their relevant piston/cylinder. For reference later how accurate should the radial orientation be? Now, my next task is the linnishing. I am assuming that I need to keep the block face flat and hence the use of the piece of glass suggested earlier in the thread, but I'm curious what kind of tolerance I have in overall flatness? Thanks for your help Dave, I do still need to pass by your place to test the head for hardness before re-fitting. Tim Link to comment Share on other sites More sharing options...
oilyhands Posted October 21, 2007 Share Posted October 21, 2007 I find a block of ally a bit easier, flatness is important but the surface is forgiving because the liners provide the cylinder sealing, the block is sealed by sandwiching an elastomer bead which is quite compressible, just be careful to make sure you have 4-5thou at 6 points around the circumference of each liner. Radial orientation has to be close, it would be impossible to get it 100% accurate, but within 2-3 degrees should be OK. constant checking should ensure the block is pretty flat. oily Link to comment Share on other sites More sharing options...
Tigger Posted October 24, 2007 Author Share Posted October 24, 2007 Dave, You mentioned a while ago that I need to take care to stop metal filings dropping down the oil-ways, what method do you use to bung them up...? Do you also bung up the cyclinders and waterways... or do you just protect the oily crank? This may be the weekend I start the linnishing. Tim Link to comment Share on other sites More sharing options...
oilyhands Posted October 24, 2007 Share Posted October 24, 2007 If you lubricate with soapy water then the filings end up bound in suspension, block the bolt holes and oilway with workshop wipe, also pack newspaper in the bores and top off with workshop wipe, use some wipe in the exposed crank oilways, use compressed air in the main bearings feeds for 2 and 4 to blow anything that might have seeped into the crankpin oilways. thoroughly clean afterwards... Oily Link to comment Share on other sites More sharing options...
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