johny Posted January 31, 2023 Report Share Posted January 31, 2023 yes theyre not stretch bolts so if undamaged can go back in... Link to comment Share on other sites More sharing options...
KevinR Posted January 31, 2023 Report Share Posted January 31, 2023 2 hours ago, Pete Lewis said: loose flywheel sounds a good plan ................just a pain to get to the bolts would explain noise at idle when unsimpathetic vibrations are at their best and less as it revs does operating the clutch play on the noise ??? Pete Try GENTLY pressing the clutch to see if it disappears as the clutch is pressed - if it does, then loose flywheel bolts should go to the top of the list of possible causes. 1 Link to comment Share on other sites More sharing options...
cliff.b Posted January 31, 2023 Author Report Share Posted January 31, 2023 9 minutes ago, KevinR said: Try GENTLY pressing the clutch to see if it disappears as the clutch is pressed - if it does, then loose flywheel bolts should go to the top of the list of possible causes. Will look at this again tomorrow. Link to comment Share on other sites More sharing options...
cliff.b Posted January 31, 2023 Author Report Share Posted January 31, 2023 I noticed towards the end of last year that I was needing to fully depress the clutch pedal to ensure I always got a clean gear change, particularly when changing down to 2nd. Just thinking if a loose flywheel could contribute to this? Haven't worked out how at the moment 🤔 Link to comment Share on other sites More sharing options...
NonMember Posted January 31, 2023 Report Share Posted January 31, 2023 28 minutes ago, cliff.b said: Just thinking if a loose flywheel could contribute to this? Yes, the same way that worn out thrust washers do. If there's play in the flywheel then it will push the clutch release bearing further back than normal. When you press the clutch, the flywheel takes up the first bit of movement, causing extra "lost motion" and the need to push the clutch further down before it operates. Link to comment Share on other sites More sharing options...
cliff.b Posted January 31, 2023 Author Report Share Posted January 31, 2023 2 minutes ago, NonMember said: Yes, the same way that worn out thrust washers do. If there's play in the flywheel then it will push the clutch release bearing further back than normal. When you press the clutch, the flywheel takes up the first bit of movement, causing extra "lost motion" and the need to push the clutch further down before it operates. Yes, that's sort of what I was thinking. But trying to get my head around what would actually be happening to cause it. But the way you have explained it makes sense. Link to comment Share on other sites More sharing options...
Pete Lewis Posted February 1, 2023 Report Share Posted February 1, 2023 if a thrust has worn or even dropped out that would contirbute to clutch travel as you are pushing the crank forwards get a pry bar and give the pulley a good lever back and forwards should only be a few thou not 3mm Pete Link to comment Share on other sites More sharing options...
cliff.b Posted February 1, 2023 Author Report Share Posted February 1, 2023 47 minutes ago, Pete Lewis said: if a thrust has worn or even dropped out that would contirbute to clutch travel as you are pushing the crank forwards get a pry bar and give the pulley a good lever back and forwards should only be a few thou not 3mm Pete I am going to check all this stuff later. Would worn or missing thrust washer cause this sort of noise? Link to comment Share on other sites More sharing options...
Pete Lewis Posted February 1, 2023 Report Share Posted February 1, 2023 well certainly wont help it would seem a good call as the noise is more evident at idle and you are loosing clutch travel all begins to tie in with a lost thrust which is not overly common but does happen quite a lot the suns out you may even hear the clunk if you press the clutch before you crank it up Pete Link to comment Share on other sites More sharing options...
cliff.b Posted February 1, 2023 Author Report Share Posted February 1, 2023 24 minutes ago, Pete Lewis said: well certainly wont help it would seem a good call as the noise is more evident at idle and you are loosing clutch travel all begins to tie in with a lost thrust which is not overly common but does happen quite a lot the suns out you may even hear the clunk if you press the clutch before you crank it up Pete Ok, I have got the dial gauge out, put it on the crank pulley and set it to zero. If I lever the pulley forward or get the clutch pressed I am only seeing it move about 0.02mm (maybe 1 thou, I think) However, if I push the pulley hard rearwards it moves about 0.13mm (about 5 thou) and then springs back to exactly where it was when the pressure is released. So overall, the crank can move about 6 thou, although not in the way I was expecting. Is this ok? Link to comment Share on other sites More sharing options...
dannyb Posted February 1, 2023 Report Share Posted February 1, 2023 That's too much, the thing is with mine, the vibration also wore out the thrush washers and broke the front sprocket and woodruff key. This on a 20K engine. Although I did drive it hundreds of miles after I noticed the noise. It would be easy to remove starter motor and see if the flywheel is loose but I think you will have to take the sump off to replace thrust washers. Danny Link to comment Share on other sites More sharing options...
cliff.b Posted February 1, 2023 Author Report Share Posted February 1, 2023 10 minutes ago, dannyb said: That's too much, the thing is with mine, the vibration also wore out the thrush washers and broke the front sprocket and woodruff key. This on a 20K engine. Although I did drive it hundreds of miles after I noticed the noise. It would be easy to remove starter motor and see if the flywheel is loose but I think you will have to take the sump off to replace thrust washers. Danny I thought 6 thou was within spec. How much are you expecting it to be? Link to comment Share on other sites More sharing options...
dannyb Posted February 1, 2023 Report Share Posted February 1, 2023 26 minutes ago, cliff.b said: I thought 6 thou was within spec. How much are you expecting it to be? Oops your right Cliff, for some reason I thought it was on the limit of 6. So 6 is well in spec. Danny Link to comment Share on other sites More sharing options...
cliff.b Posted February 1, 2023 Author Report Share Posted February 1, 2023 5 minutes ago, dannyb said: Oops your right Cliff, for some reason I thought it was on the limit of 6. So 6 is well in spec. Danny Ok, you had me worried for a moment. What about the "centralising" bact to a zero position after being pushed in either direction? Is that normal? Any examples I have seen in YouTube show it moving and staying there, although they were always about excessive float. Link to comment Share on other sites More sharing options...
dannyb Posted February 1, 2023 Report Share Posted February 1, 2023 That is strange . As you say it normally stays in one direction. Seems something is forcing it forwards. My money is still on flywheel bolts. Danny Link to comment Share on other sites More sharing options...
dannyb Posted February 1, 2023 Report Share Posted February 1, 2023 It could be just one bolt. The other three could still be tight so the flywheel may still feel OK through the starter motor hole. Could try turning engine by hand to see if you can ear any knocking. Take the plugs out to make it easy. Or put it in 4th. And push it. Danny Link to comment Share on other sites More sharing options...
johny Posted February 1, 2023 Report Share Posted February 1, 2023 2 hours ago, cliff.b said: Ok, you had me worried for a moment. What about the "centralising" bact to a zero position after being pushed in either direction? Is that normal? Any examples I have seen in YouTube show it moving and staying there, although they were always about excessive float. Maybe thats just the thrust bearing pushing back against the clutch when you lever the crank backwards. Theres a spring in the slave cylinder that ensures theres no play in the mechanical linkage otherwise your pedal would be very floppy to start with. Your crank is probably very free so this force is enough to push it forward... Link to comment Share on other sites More sharing options...
cliff.b Posted February 1, 2023 Author Report Share Posted February 1, 2023 2 minutes ago, johny said: Maybe thats just the thrust bearing pushing back against the clutch when you lever the crank backwards. Theres a spring in the slave cylinder that ensures theres no play in the mechanical linkage otherwise your pedal would be very floppy to start with. Your crank is probably very free so this force is enough to push it forward... That sounds possible. It moved rearwards by pressing quite hard by hand. Link to comment Share on other sites More sharing options...
Pete Lewis Posted February 1, 2023 Report Share Posted February 1, 2023 6 hours ago, cliff.b said: is this ok? Yes Link to comment Share on other sites More sharing options...
cliff.b Posted February 1, 2023 Author Report Share Posted February 1, 2023 30 minutes ago, Pete Lewis said: Yes Excellent. One less thing to worry about 👍 Link to comment Share on other sites More sharing options...
thescrapman Posted February 1, 2023 Report Share Posted February 1, 2023 On 31/01/2023 at 16:16, cliff.b said: Just thinking, previously the but fell off and it was running without it making a similar sort of noise as the pulley was moving. Could that have damaged the keyway and if so, what can be done? Hopefully not a new crank. Yes and yes, BTDT Link to comment Share on other sites More sharing options...
cliff.b Posted February 1, 2023 Author Report Share Posted February 1, 2023 1 hour ago, thescrapman said: Yes and yes, BTDT Doh, that's balanced out Pete's comment 😟 Link to comment Share on other sites More sharing options...
thescrapman Posted February 1, 2023 Report Share Posted February 1, 2023 29 minutes ago, cliff.b said: Doh, that's balanced out Pete's comment 😟 I drove my Mk3 Spitfire without a crank nut for a few years, the pulley now clonks even with a nut fitted and tightened within an inch of its life. Link to comment Share on other sites More sharing options...
cliff.b Posted February 1, 2023 Author Report Share Posted February 1, 2023 3 minutes ago, thescrapman said: I drove my Mk3 Spitfire without a crank nut for a few years, the pulley now clonks even with a nut fitted and tightened within an inch of its life. After fitting the new nut the original clonking stopped. It now sounds similar but I'm convincing myself it's from the rear of the engine. Loose flywheel bolts could make sense and the crank nut isn't the first thing I have found loose on this car. Just it's not an easy thing to check, but at least I can do it myself. Not sure I'm up to lying under the car with the sump off these days 🤬 Link to comment Share on other sites More sharing options...
johny Posted February 2, 2023 Report Share Posted February 2, 2023 As said previously, I would have thought if its the flywheel holding the clutch disengaged with the engine running must make some difference to the noise.... Link to comment Share on other sites More sharing options...
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