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| Crankshaft "chatter" https://www.ausmini.com/forums/viewtopic.php?f=2&t=88789 |
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| Author: | VanMorrison [ Wed Mar 04, 2015 3:36 pm ] |
| Post subject: | Crankshaft "chatter" |
Hey Guys Just wondering if someone might shed some light on what this actually is, what causes it and if its ok to file it down on the end of the crank? Apparently its "common" on old a series crankshafts? Your thoughts? Darcy |
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| Author: | Mick [ Wed Mar 04, 2015 4:47 pm ] |
| Post subject: | Re: Crankshaft "chatter" |
Sorry, could you explain it again? I'm not sure what you mean? Not the idler gear float in the primary gear housing? |
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| Author: | VanMorrison [ Wed Mar 04, 2015 5:00 pm ] |
| Post subject: | Re: Crankshaft "chatter" |
im not sure i know what i mean.. but here goes.. So I'm looking for a new 1100 crank as when I crack tested mine it had a radius crack. Ive rang around all the local suppliers and prices range from 250 to 600 dollars. One mini supplier has one that was reground approx 5000km ago ( id still have it reground, tested and balanced ) but apparently it has "chatter" on the flywheel end. Im told this is caused by the flywheel not being tightened properly ( or perhaps squarely ) and causing some rubbing marks on the taper. My engine builder seems to think this is an issue but the mini shop says just to give it a light file with a rounded file and it will be fine as it is tapered and keyed so won't have any affect ( especially given I'm running a lightened flywheel ). He says its "common on old a series cranks" and to make sure that its all tightened correctly when we put it back together. I'm curious to know if this is as common as the mini shop says and if the solution is acceptable.. Hopefully that helps? Im not sure if it does or not.. Darcy |
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| Author: | TK [ Wed Mar 04, 2015 5:33 pm ] |
| Post subject: | Re: Crankshaft "chatter" |
find another crank |
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| Author: | drmini in aust [ Wed Mar 04, 2015 5:42 pm ] |
| Post subject: | Re: Crankshaft "chatter" |
What is common is metal `pickup' from the flywheel to the crank taper. Yes if minor it can `carefully'! be filed off (I'm a fitter), if worse a few thou only! cut can be performed to the crank taper on a lathe or cylindrical grinder. The flywheel should finally be lapped to the crank with fine grinding paste, until the tapers match over 75% or more of the taper. Notes: 1. The key is NOT there to provide drive, it is primarily for location. 2. The flywheel boss must protrude still past the crank end when assembled. 3. It may be necessary to deepen the recess in the back of the flywheel hub to clear the primary gear C washer. Do a trial fit before assembly. |
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| Author: | VanMorrison [ Wed Mar 04, 2015 5:48 pm ] |
| Post subject: | Re: Crankshaft "chatter" |
TK wrote: find another crank I wish it was that easy... |
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| Author: | drmini in aust [ Wed Mar 04, 2015 5:52 pm ] |
| Post subject: | Re: Crankshaft "chatter" |
1100 cranks are now getting thin on the ground. There are way more good 998 ones about, even I have a couple of spares. |
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| Author: | VanMorrison [ Wed Mar 04, 2015 5:53 pm ] |
| Post subject: | Re: Crankshaft "chatter" |
drmini in aust wrote: What is common is metal `pickup' from the flywheel to the crank taper. Yes if minor it can `carefully'! be filed off (I'm a fitter), if worse a few thou only! cut can be performed to the crank taper on a lathe or cylindrical grinder. The flywheel should finally be lapped to the crank with fine grinding paste, until the tapers match over 75% or more of the taper. Notes: 1. The key is NOT there to provide drive, it is primarily for location. 2. The flywheel boss must protrude still past the crank end when assembled. 3. It may be necessary to deepen the recess in the back of the flywheel hub to clear the primary gear C washer. Do a trial fit before assembly. Thanks Doc I had a chat the guys and it is what you have described above as "pickup". Ill chat to the engine builder again tomorrow and make a decision from there. Who thought an 1100 crank would be so hard to come bye !! Darcy |
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| Author: | drmini in aust [ Wed Mar 04, 2015 5:56 pm ] |
| Post subject: | Re: Crankshaft "chatter" |
1098s stopped building here 40 years ago. And were hardly used in UK Minis. |
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| Author: | kiwiinwgtn [ Wed Mar 04, 2015 7:11 pm ] |
| Post subject: | Re: Crankshaft "chatter" |
They are getting hard to get here to. No one wanted them when I was in my twentys. I have been trying to finding whole 1098 engine for my moke. |
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| Author: | drmini in aust [ Wed Mar 04, 2015 7:31 pm ] |
| Post subject: | Re: Crankshaft "chatter" |
I like 1100 cranks, but if you can't find one.. Why not just bore the block to 68mm, fit a 998 crank, = an 1108cc screamer. Would stand more revs reliably than a 1098 will. |
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| Author: | 69k1100 [ Wed Mar 04, 2015 7:36 pm ] |
| Post subject: | Re: Crankshaft "chatter" |
It will have to stand more revs to achieve the same power. I think I have an 1100 from a clubman banging around, just have to double check, it will need a rebuild though. |
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| Author: | boomini [ Wed Mar 04, 2015 11:40 pm ] |
| Post subject: | Re: Crankshaft "chatter" |
I rekon I got 4 or 5 good 1100 cranks here. None have been crack tested tho. |
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