PeteH Posted February 23 Report Share Posted February 23 (edited) 2 hours ago, johny said: He says factory spec and that recommends 6 to 8 thou so reckon hes up to around 11... So if 6 to 8 is "factory", I assume O/E assembly tolerances? I would hazard that 3thou of wear IS tolerable. How much more is debateable? I would be inclined to the opinion that it is unlikely that it only takes 3thou of wear to reach the point at which the thrust washers would displace Is the same tolerance good for the 13/60 engine?. If so I have one (running when last fitted, engine) out of a car at this time and a Dial Micrometer, it might be an easy check? ( if I can find the damn Magnetic stand!!) Edit:- The 4cyl (12/50) engine end float is listed at 4to8thou. Pete Edited February 23 by PeteH Link to comment Share on other sites More sharing options...
Wagger Posted February 23 Report Share Posted February 23 (edited) I do not know what the 'Thinnest' standard thrust washer measures. However. if it wears it will be even thinner than when new. The gap between the bearing cap and crank may become equal to that thickness and that is when it can drop out. Also, if the crank has worn the gap may have increased even further. It is very difficult to measure externally. Mounting a dial indicator on a magnetic base near to the pulley is one way, but the rubber mounting of the engine confuses matters. It requires pull and pushing the pulley from the front. Pressing the clutch just moves the engine forward on the mounts unless you can jam it. Has anyone had any joy using feeler gauges? Edited February 23 by Wagger Link to comment Share on other sites More sharing options...
johny Posted February 23 Report Share Posted February 23 no its alright as the clutch slave is mounted on the gearbox operating it shouldnt move anything other than the clutch thrust bearing and so through onto the crank and its thrusts. You just need to push the front pulley back, mount plus zero the DTI and press the pedal... Link to comment Share on other sites More sharing options...
Wagger Posted February 23 Report Share Posted February 23 (edited) Pressing the clutch pushes the crankshaft against the thrust bearing. That is what causes the wear if you sit in traffic with the clutch pedal down. Ok, but I am never sure what has moved if I do not watch it all of the time when pulling the pulley back and forth. Getting into the seat and depressing the pedal always seems to move soething so the the dial doe not return exactly as I set it. Edited February 23 by Wagger Link to comment Share on other sites More sharing options...
johny Posted February 23 Report Share Posted February 23 Yes but no movement of the engine as a whole so you can fix your DTI to the chassis and measure the movement of the pulley as you press the clutch no problem👍 Link to comment Share on other sites More sharing options...
Works Spitfires Posted February 24 Report Share Posted February 24 18 hours ago, Pete Lewis said: I repaired a 1300 fwd with dropped thrusts , welded replacement lugs on the brg cap reground the crank and it went from stalling with the flywheel fouling the back plate to a life of over 100k till the body fell apart , not all make for a scrap block Pete John Kipping used to offer this service to customers. He would drop off some worn mains caps to me, and I would weld them up as per the above. I'm not sure what he was charging his customers, but I always did it as a favour as it only took a couple of minutes. I suspect most of the people doing it though were swinging it with badly worn crank thrust faces in the hope it would last long enough to flog their cars. Link to comment Share on other sites More sharing options...
JohnD Posted February 24 Report Share Posted February 24 There's one craftsman who can build up the main cap for you. Here's another in the US. "Custom Thrust Washers" specialise in making, well, custom thrust washers, of whatever thickness you require. See: https://customthrustwashers.com/ or email Scott Helms at thrustwashers@gmail.com or sportycars@britishcarweek.org. John Link to comment Share on other sites More sharing options...
johny Posted February 24 Report Share Posted February 24 Hmmm what a long winded story of his thrust failure but there are some good points: After the initial drop out of his thrusts and subsequent crank to bearing cap contact he deemed the crank still ok and put in new washers which in 150 miles had worn to a clearance of 45 thou but it appears they STILL hadnt dropped out. However we've been worrying about the wrong risk and its the thickness of the white metal thats most important. Its likely to be approx. 12 thou and once worn through the steel backing contacts the crank resulting in damage. Note even if this is all thats happened just replacing the thrust, as in the above case, is probably not going to work for long.... Unfortunately unless you know what the end play was when the thrusts were installed you cant know how much metal has worn off the thrusts. Basically youve got to assume the initial clearance was set to the minimum 6 thou and all the increase now measured has come off one of the thrusts! Link to comment Share on other sites More sharing options...
daverclasper Posted March 7 Author Report Share Posted March 7 (edited) Thanks for all your replies. About 15,000 miles ago, there was a very slight, just noticeable to my eyes, movement when the clutch was operated. I temporarily fastened a steel bar in front of the rad, which left a gap of about 1/4" between the bar and the fan bolts. I pushed/levered the pulley/crank rearwards, took a feeler gauge measurement of the gap between a fan bolt head and the bar, then pressed in clutch and measured again. It was showing around 10thou (3 thou more than WSM specified tolerance?) less, so took this as a rough idea of the crank float/movement. Repeated this process a few more times, and it was the same measurement. Just did a visual test recently and the movement was again, barely noticeable, as it was previously. I am therefore assuming it is not getting drastically worse and will take the risk of it causing damage. Dave Edited March 7 by daverclasper Link to comment Share on other sites More sharing options...
johny Posted March 7 Report Share Posted March 7 Thats it Dave, sounds reasonable... Link to comment Share on other sites More sharing options...
Pete Lewis Posted March 8 Report Share Posted March 8 thanks Dave at 0.010" you wont get a problem its probably been like that for years the only way to stop wear is to not use the clutch ...thats not very practical !! pete Link to comment Share on other sites More sharing options...
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