bloody hell
could only mean the flywheel isn't seating on the crank - IE the taper has worn off the inside of the flywheel to the point where the tapers don't meet and the keyed washer bottomed out on the crank
doesn't it?
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| It was not the clutch thrust bearing https://www.ausmini.com/forums/viewtopic.php?f=2&t=71742 |
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| Author: | mickmini [ Sat Jul 09, 2011 11:50 am ] |
| Post subject: | It was not the clutch thrust bearing |
Managed to break the keyed washer and the flywheel has spun. Yet to get it off and see the damage. Hope I can salvage both. Weird seeing as i spent about 10 hours lapping the bloody thing and making sure the keyed washer was not putting the torque load on the crank instead of the flywheel. Also had made sure that the bolt was not bottoming in the thread. Clearly I got something wrong because the ends of the key washer that have broken off show no evidence of fatigue failure, just ductile and bruising from being thrown around inside the diaphragm spring area. But it means that the engine has to come out now, which I was hoping it would not. Bugger. Ideas on what to look for and measure as it comes apart so I can make sure I don't stuff it up again? cheers michael |
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| Author: | simon k [ Sat Jul 09, 2011 1:22 pm ] |
| Post subject: | |
bloody hell
could only mean the flywheel isn't seating on the crank - IE the taper has worn off the inside of the flywheel to the point where the tapers don't meet and the keyed washer bottomed out on the crank doesn't it? |
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| Author: | Phat Kat [ Sat Jul 09, 2011 1:59 pm ] |
| Post subject: | |
I can't tell you what the Taper is (as in ratio)... If you have a lathe I can tell you how to measure your taper to within... well... what ever your dial gauge is graduated? If you don't really care that much but just want to sort it so it doesn't happen again... I too usually spend ages lapping mine in... but then I check them with a light smear of bearing blue... obviously 100% contact is ideal,, but I'll settle for as low as 75-80%.... If you check it like this, you can physically see how much contact it has, so there is no guess work involved, and you can be assured that if there is a problem again, it wasn't due to the taper.. If you're not getting enough pre-loading out of your nut and washers.... well.. you can fix it properly by assembling it, checking with a feeler gauge and facing of the appropriate amount.... or... theres the "good enough for the bush" method that will work fine, but it might sound a little dodgy..... colour in the last 10mm of the tail with a texter..., put the flywheel on as far as it will go... using a scribe mark out where the edge of the flywheel is.... remove flywheel and use an angle grinder to grind (not cut) the excess off... go to the line and then another 1mm past..... Sounds dodgy, kinda is,, but it will get you out of trouble and It works on industrial machines when they break down so I don't see why it won't here 
<edit> I don't see why I should have to point it out.. but if you're going to do it with an angle grinder, don't let the tail change colours, don't let it get too hot,,,, so don't push to hard and take light bits off at a time and allow it to air cool |
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| Author: | GT mowog [ Sat Jul 09, 2011 2:07 pm ] |
| Post subject: | |
Bummer! Lapping the flywheel / crank too much can produce a step inside the taper of the flywheel, so when it's torqued down, instead of seating on the taper, it seats on the step. Check for that, note it will only be very fine. |
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| Author: | mickmini [ Mon Sep 26, 2011 9:11 pm ] |
| Post subject: | It was not the clutch thrust bearing - update 26/9 |
Got my shaft polished on friday 
Spiro at St George cranks did the job when I dropped in. What a gentleman. All I need to do now is get a new flywheel centre and put it in the lightened flywheel, get that rebalanced, check the assembly etc etc. I think it was bottoming out on the C-washer and torquing up on that instead of the taper. Although it may have wobbled when it span on the shaft to cause the damage. GR reckons he has seen this before. Now I know to check that and have the centre of the flywheel relieved if it is too close. cheers michael |
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| Author: | TheMiniMan [ Tue Sep 27, 2011 9:18 am ] |
| Post subject: | |
yes , flywheels are tending to move further & further onto the cranks now-days,,, they`ve been on & off a few hundred times & go further & further on each time machining the inside of the flywheel is becomming more & more common because of that easy check (once the flywheel has been fitted) is to make sure the clutch plate actually spins free... stick a long thin screw driver in-between the flywheel & the backing plate & you will be able to "Jab" the edge of the clutch plate,,, then try to turn it obviously you can`t have the tin-hat tightened up to do this , but it`s a simple test to make sure before bolting it all together & wondering why the clutch doesn`t diss-engage... then of course having to rip it all apart again to effect repairs every engine should have this check done,,, whether you think you`re good or not,,, if you don`t do this simple check then you`re bonkers 
so,,, if your clutch was diss-engaging,,, then i doubt that your flywheel was button-ing on the C-lock,,, more likely you had a lip from lapping as GT said,,, OR you just didn`t have it tight enough... Or maybe the key-washer was already cracked,,, or maybe your flywheel center was crap to start with,,,or,,,or,,,or ,,, but hey i`m not looking at your engine so i can`t really tell what your particular problem is,,, so go with what you can find/see/sort & try again |
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| Author: | GT mowog [ Tue Sep 27, 2011 9:47 am ] |
| Post subject: | |
TheMiniMan wrote: easy check (once the flywheel has been fitted) is to make sure the clutch plate actually spins free... stick a long thin screw driver in-between the flywheel & the backing plate & you will be able to "Jab" the edge of the clutch plate,,, then try to turn it
Good tip there Matt. I trial fit the Flywheel on it's own before I fit the Transfer Housing. I fit up the Flywheel - no clutch plate, no backing plate - with the Primary Gear Thrust Washer, C Clip and C Clip Thrust that I am going to use in the final assembly. You can actually look up in to the back of the Flywheel and see how much clearance you have. With something like plasticene, you can even measure the clearance. I do the Bolt up tight, but usually no need to go 'all the way' with it as once it's 'tight' it will - at best - only come down another 1 to 1.5 thou. when tightened 'all the way'. You can also check that the Primary Gear is still happy to spin. |
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| Author: | TheMiniMan [ Tue Sep 27, 2011 10:03 am ] |
| Post subject: | |
yeah they can be a pain these days,,, 20 years ago this problem was a very rare thing, but now they`re all "Worn-in" you should try the big stroke cranks (91mm stroke) with no C-lock groove,,, no C-lock,,, the flywheel & primary gear washer both needs to be "set" at a certain tension/distance,,, any tighter & have to trim the back of the flywheel , or the washer some more,,, next time it comes off & goes back on, it needs another trim pain in the Ar$3 |
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| Author: | drmini in aust [ Tue Sep 27, 2011 12:08 pm ] |
| Post subject: | |
Michael I have a very good spare flywheel hub, PM sent. |
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| Author: | mickmini [ Tue Sep 27, 2011 10:09 pm ] |
| Post subject: | |
TheMiniMan wrote: every engine should have this check done,,, whether you think you`re good or not,,, if you don`t do this simple check then you`re bonkers
Ah the benefits of so many engine build experiences. I think I have read every possible thing about rebuilding these engines here and other sites and books, and I never came accross this before. Oh well, live and learn. Or can I just come and do an apprenticeship with my long service leave (i.e. you won't have to pay me)  I am a fast learner on the job 
cheers michael |
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| Author: | GT mowog [ Tue Oct 04, 2011 10:17 am ] |
| Post subject: | |
GT mowog wrote: You can actually look up in to the back of the Flywheel and see how much clearance you have.
Matt, this is what you can see;- 
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| Author: | TheMiniMan [ Tue Oct 04, 2011 12:12 pm ] |
| Post subject: | |
yeah but i couldn`t be bothered to fit, tighten & remove the flywheel twice if i don`t have to,,, checking that the clutch plate spins easy (with a long thin screw driver between the backing plate & the flywheel) is easy as & good enough for me
we have to plasticine the "non C-locked" cranks/flywheels, because there is no datum to start from, so we simply have to do them twice, bugga-it 
& even then, if you tighten the flywheel up more than you did the last time , it can still grab-up on the dam primary gear,,, they really are a pain in the butt Butt... generally the std issue mini flywheels & cranks are easy enough, once you have done 400 million of the damn things & yet you can still get caught out
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