RobPearce Posted September 14, 2022 Share Posted September 14, 2022 If the seal is very hard it could well be quite old and past its best. They're not exactly soft when new but there should be some flex. 1 Quote Link to comment Share on other sites More sharing options...
glang Posted September 14, 2022 Share Posted September 14, 2022 1 hour ago, Banksy82 said: I decided the seal was bad as it is very hard indeed - I would expect some flex in the lip but there really isn't any - Is this normal? I dont think anyone is going to argue with you about changing seals as a matter of course if youve got everything opened up. As far as I know theres no problem with replacement seal quality... Also check where the seal runs as a slight channel can develop so even a brand new seal will struggle to be oil tight. If there is one you might be able to relocate the seal slightly to allow it to run on virgin metal. 1 Quote Link to comment Share on other sites More sharing options...
standardthread Posted September 14, 2022 Share Posted September 14, 2022 3 hours ago, Banksy82 said: I decided the seal was bad as it is very hard indeed - I would expect some flex in the lip but there really isn't any - Is this normal? Just checked a spare seal I have in my spares box, the lip is fairly hard. I also checked a seal in an old chain cover, that is very slightly softer. 1 Quote Link to comment Share on other sites More sharing options...
glang Posted September 14, 2022 Share Posted September 14, 2022 If you really want to make a judgement on a seal, apart from hardness of the rubber you can also look at the lip under a magnifying glass and see how much of a flat is worn on it as new they are quite 'sharp'.... 1 Quote Link to comment Share on other sites More sharing options...
standardthread Posted September 15, 2022 Share Posted September 15, 2022 19 hours ago, Banksy82 said: @standardthread Thank you for the useful tips. Oh the teeth are definitely worn - To give you an idea of tooth profile attached is a photo of a new set of gears. Quote Link to comment Share on other sites More sharing options...
glang Posted September 15, 2022 Share Posted September 15, 2022 My WS manual doesnt mention anything about assessing the sprocket teeth only the stretch on the chain so if its within tolerance I wouldnt do anything more. In fact I think its almost impossible to have a good chain with excessively worn sprockets unless the former has just been replaced and still wearing (rapidly) to match the teeth. Maybe wear will make the set up run a bit noisier (however we're not talking Rolls Royce here) so if the chain/tensioner is good I cant see theres any risk the chain will jump teeth... 1 Quote Link to comment Share on other sites More sharing options...
RobPearce Posted September 15, 2022 Share Posted September 15, 2022 54 minutes ago, glang said: if the chain/tensioner is good I cant see theres any risk the chain will jump teeth... When I bought my GT6, the timing chain had partially disintegrated. Most of the hardened shells around the link pins - the things that actually run against those gears - had broken, split in half and fallen off. Some of the fragments had been sucked through the oil pump (or got embedded in it). Some had made it to the crank bearings. The engine was still running and the chain had not jumped any teeth. So I suspect you're right. Quote Link to comment Share on other sites More sharing options...
glang Posted September 15, 2022 Share Posted September 15, 2022 I suppose it was difficult to tell Rob if the chain was still in spec? Even if it was any chain can fail early but if you replace them just in case you then run the risk of a poor quality replacement - damned if you do, damned if you dont😂 Quote Link to comment Share on other sites More sharing options...
RobPearce Posted September 15, 2022 Share Posted September 15, 2022 1 hour ago, glang said: I suppose it was difficult to tell Rob if the chain was still in spec? I suspect it was outside the free play tolerance because the reduced size of the pins meant it was running on a smaller radius at both ends. It was a long time ago and I don't think I even bothered to measure it. Quote Link to comment Share on other sites More sharing options...
Banksy82 Posted September 15, 2022 Author Share Posted September 15, 2022 1 hour ago, glang said: damned if you do, damned if you dont😂 Looking at the pictures of new items my gears don't look as bad as I thought - I'm used to involute gear profiles not chain drives and they looked very pointy. Given they will have worn into the chain and the chain looks to be in good condition and in spec. I am going to leave it all as it was including the original tensioner. For the sake of 4 quid I will probably acquire a new seal but for now I'm calling the timing setup 'good'! Crank and camshaft to check next! Quote Link to comment Share on other sites More sharing options...
Banksy82 Posted September 16, 2022 Author Share Posted September 16, 2022 Evening all. Does anyone have any idea on the below. This is the crank pin for cylinder 3 and there is an odd wear pattern running around the surface. it resembles a regular 'zebra stripe' running left to right in the image - it isn't quite as noticeable with the naked eye but shows up clearly in the photograph. It almost looks like brinelling from roller bearings but I have never seen anything like this on a plain bearing. The crank has had a 10 thou regrind at some point in its life - there are .010 under bearings installed and the pins mic up at 1.8657 which i believe to be 2 tenths oversize for 10 thou under. Any thoughts gratefully received. Karl Quote Link to comment Share on other sites More sharing options...
Clive Posted September 16, 2022 Share Posted September 16, 2022 The "best" answer is a complete regrind. However... I would get some wet/dry paper, 600 grit? and use some WD40. Cut some strips the width of the bearing, and have a go at lightly polishing (wrap paper around the bearing, and the back/forward technique) See if the marks disappear. And a pic of the bearing surface would be good. Don't rely on the book figures. Soem bearings (king I think) are a bit loose so that could be the reason for the journal being a tad bigger than expected. Quote Link to comment Share on other sites More sharing options...
Banksy82 Posted September 16, 2022 Author Share Posted September 16, 2022 20 minutes ago, Clive said: I would get some wet/dry paper, 600 grit? Thanks, I'll try with the finest I have first 1200 maybe as I don't think the marks are anything more than on the surface - interested to know what might have caused it to try and prevent the same thing happening elsewhere. 22 minutes ago, Clive said: And a pic of the bearing surface would be good. Picture of bearing cap shell below - these show the expected wear pattern - I plan on replacing these and the main bearings with new .010 under to get a little more life out of the engine. Do you have any idea what the working clearance should be between bearing and journal? I can't seem to find it in the book. Thanks Again Quote Link to comment Share on other sites More sharing options...
Clive Posted September 16, 2022 Share Posted September 16, 2022 I think 1200 may well do the trick. The bearing looks OK, so I wouldn't worry. I have always left measurement to a machine shop, but have replaced bearings in many engines with no grief. 1 Quote Link to comment Share on other sites More sharing options...
glang Posted September 16, 2022 Share Posted September 16, 2022 My Vitesse manual which has the same bearings dimensions says big end clearance should be between 1 and 2.7 thou. No idea what would produce those journal markings except perhaps a poor regrind but the bearing shell looks like its got plenty of life left in it, in fact I wonder if it hasnt done many miles since the regrind... Quote Link to comment Share on other sites More sharing options...
Banksy82 Posted September 16, 2022 Author Share Posted September 16, 2022 4 minutes ago, glang said: My Vitesse manual which has the same bearings dimensions says big end clearance should be between 1 and 2.7 thou. No idea what would produce those journal markings except perhaps a poor regrind but the bearing shell looks like its got plenty of life left in it, in fact I wonder if it hasnt done many miles since the regrind... Fantastic, thank you. It's all a little odd really. I had .040 end float on the crank and an annoying / worrying loud tapping / rattling audible at speed. With the end float being so large I expected to find similar wear throughout and a smoking gun on the noise. I can't believe a previous owner went to the trouble of a regrind and then reassembled with such a huge endfloat.. Some of the other shells show deeper scoring but the journals are all okay so I think it is worth replacing the bearings anyway? There is some pitting on some of the cam lobes and I imagine the same of the followers.. I wonder if this could be the source of my noise... I will continue to investigate Quote Link to comment Share on other sites More sharing options...
glang Posted September 17, 2022 Share Posted September 17, 2022 What were the findings with the thrusts then? They were of as supplied thickness but the PO hadnt chosen the right size to give the correct endfloat (taking into account a possible 10thou regrind)? Or the thrusts were probably the correct thickness to start with but had worn to give the 40thou play? Quote Link to comment Share on other sites More sharing options...
standardthread Posted September 17, 2022 Share Posted September 17, 2022 (edited) 11 hours ago, Banksy82 said: Thanks, I'll try with the finest I have first 1200 maybe as I don't think the marks are anything more than on the surface - interested to know what might have caused it to try and prevent the same thing happening elsewhere. I would be tempted to go finer if the marks are just surface 'stains' by using paint polishing compound. If you've had the camshaft out make sure you get the off-set on the distributor drive dog in the correct position. Edited September 17, 2022 by standardthread Quote Link to comment Share on other sites More sharing options...
glang Posted September 17, 2022 Share Posted September 17, 2022 Reading online those journal chatter marks are probably due to poor grinding as, if the grind wheel isnt properly set up or loose, vibration affects its contact with the journal. Is it the same on all? If not another possibility is a distorted conrod... The excessive crank endfloat could produce a rattling sound although it would most likely be at idle. Quote Link to comment Share on other sites More sharing options...
Banksy82 Posted September 17, 2022 Author Share Posted September 17, 2022 2 hours ago, glang said: What were the findings with the thrusts then? Actual end float is .037, front thrust is approx .094 and rear thrust .088. I believe that standard is around the .092 mark so they may be poorly measured standards or possibly very worn oversize. They have 0025 stamped on the back... which if a dimension I would read as .0025 but I didn't think they are available in this size... I will get a set of +10 and +15 and see what I can do.. Quote Link to comment Share on other sites More sharing options...
glang Posted September 17, 2022 Share Posted September 17, 2022 You should be able to judge wear on the thrusts as the oil channels in the face metal will disappear. I think the rear journal width should be 1.362" max so has probably been reground and then insufficient size thrusts used.... 1 Quote Link to comment Share on other sites More sharing options...
Banksy82 Posted September 17, 2022 Author Share Posted September 17, 2022 3 minutes ago, glang said: Reading online those journal chatter marks are probably due to poor grinding as, if the grind wheel isnt properly set up or loose, vibration affects its contact with the journal. Is it the same on all? If not another possibility is a distorted conrod... The excessive crank endfloat could produce a rattling sound although it would most likely be at idle. Very faint on 1, as you see on 3. Not visible (in my workshop lighting) on 2 or 4. The noise I was sure was valve train - definitely where the sound was at idle. Having had a look around the clutch release bearing carrier was not attached to the bell housing at all - no pin, no bolt, nothing. I am now wondering if my noise at idle is usual valve train noise and it was the clutch bearing carrier vibrating at speed.... Quote Link to comment Share on other sites More sharing options...
Banksy82 Posted September 17, 2022 Author Share Posted September 17, 2022 1 hour ago, standardthread said: I would be tempted to go finer if the marks are just surface 'stains' by using paint polishing compound. Good point - I will try the least abrasive things first! Quote Link to comment Share on other sites More sharing options...
Banksy82 Posted September 17, 2022 Author Share Posted September 17, 2022 Does anybody have a definitive value on the correct end float tolerance? Workshop Manual states 0.006 to 0.014 in the 'check and adjust section' (12.21.26) but then in the data on the very next page state 0.004 to 0.008 (12.21.33 - Sheet2) Obviously 0.006 to 0.008 fits in both of these but I just find it odd - am I misreading something? Quote Link to comment Share on other sites More sharing options...
glang Posted September 17, 2022 Share Posted September 17, 2022 My WS manual says 6 - 14 thou acceptable but 6 - 8 thou recommended Quote Link to comment Share on other sites More sharing options...
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