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 Post subject: Crankshaft "chatter"
PostPosted: Wed Mar 04, 2015 3:36 pm 
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848cc
848cc

Joined: Mon Nov 24, 2014 11:47 am
Posts: 110
Location: Adelaide , South Australia
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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 Post subject: Re: Crankshaft "chatter"
PostPosted: Wed Mar 04, 2015 4:47 pm 
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SooperDooperMiniCooper ExpertEngineering
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Location: Under the bonnet son!
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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 Post subject: Re: Crankshaft "chatter"
PostPosted: Wed Mar 04, 2015 5:00 pm 
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848cc
848cc

Joined: Mon Nov 24, 2014 11:47 am
Posts: 110
Location: Adelaide , South Australia
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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 Post subject: Re: Crankshaft "chatter"
PostPosted: Wed Mar 04, 2015 5:33 pm 
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1275cc
1275cc

Joined: Wed Jan 19, 2005 1:52 pm
Posts: 2582
Location: Brisbane
find another crank

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 Post subject: Re: Crankshaft "chatter"
PostPosted: Wed Mar 04, 2015 5:42 pm 
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religious status
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Location: near Baulkham Hills, NSW
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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DrMini- 1970 wasaMatic 1360, Mk1S crank, 86.6HP (ATW) =~125 @ crank, 45 Dellorto (38 chokes), RE282 sprint cam, 1.5 rockers, 11.0:1 C/R. :mrgreen:


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 Post subject: Re: Crankshaft "chatter"
PostPosted: Wed Mar 04, 2015 5:48 pm 
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848cc
848cc

Joined: Mon Nov 24, 2014 11:47 am
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Location: Adelaide , South Australia
TK wrote:
find another crank


I wish it was that easy...

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 Post subject: Re: Crankshaft "chatter"
PostPosted: Wed Mar 04, 2015 5:52 pm 
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religious status
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Joined: Fri Mar 19, 2004 6:19 pm
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Location: near Baulkham Hills, NSW
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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DrMini- 1970 wasaMatic 1360, Mk1S crank, 86.6HP (ATW) =~125 @ crank, 45 Dellorto (38 chokes), RE282 sprint cam, 1.5 rockers, 11.0:1 C/R. :mrgreen:


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 Post subject: Re: Crankshaft "chatter"
PostPosted: Wed Mar 04, 2015 5:53 pm 
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848cc
848cc

Joined: Mon Nov 24, 2014 11:47 am
Posts: 110
Location: Adelaide , South Australia
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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 Post subject: Re: Crankshaft "chatter"
PostPosted: Wed Mar 04, 2015 5:56 pm 
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Joined: Fri Mar 19, 2004 6:19 pm
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Location: near Baulkham Hills, NSW
1098s stopped building here 40 years ago.
And were hardly used in UK Minis.

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DrMini- 1970 wasaMatic 1360, Mk1S crank, 86.6HP (ATW) =~125 @ crank, 45 Dellorto (38 chokes), RE282 sprint cam, 1.5 rockers, 11.0:1 C/R. :mrgreen:


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 Post subject: Re: Crankshaft "chatter"
PostPosted: Wed Mar 04, 2015 7:11 pm 
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1098cc
1098cc
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Joined: Sun Feb 20, 2005 8:11 pm
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Location: Wellington,
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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 Post subject: Re: Crankshaft "chatter"
PostPosted: Wed Mar 04, 2015 7:31 pm 
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religious status
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Joined: Fri Mar 19, 2004 6:19 pm
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Location: near Baulkham Hills, NSW
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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DrMini- 1970 wasaMatic 1360, Mk1S crank, 86.6HP (ATW) =~125 @ crank, 45 Dellorto (38 chokes), RE282 sprint cam, 1.5 rockers, 11.0:1 C/R. :mrgreen:


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 Post subject: Re: Crankshaft "chatter"
PostPosted: Wed Mar 04, 2015 7:36 pm 
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998cc
998cc

Joined: Sun Sep 04, 2011 10:46 pm
Posts: 526
Location: S.A
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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 Post subject: Re: Crankshaft "chatter"
PostPosted: Wed Mar 04, 2015 11:40 pm 
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1098cc
1098cc

Joined: Wed Jun 26, 2013 10:05 pm
Posts: 1500
Location: perth WA
I rekon I got 4 or 5 good 1100 cranks here.

None have been crack tested tho.

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