Hi, all just pulled motor down to find out i had broken the crank what i would like to no what is required to stroke a crank thanks . The crank i got is a large jnl with nos 1505 stamp on it
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| Author: | crabby [ Sat Sep 24, 2011 9:15 pm ] |
| Post subject: | crank |
Hi, all just pulled motor down to find out i had broken the crank what i would like to no what is required to stroke a crank thanks . The crank i got is a large jnl with nos 1505 stamp on it
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| Author: | justfanginaround [ Sat Sep 24, 2011 9:20 pm ] |
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you will need a set of 521 cooper S rods, get your crank crack tested { cross fingers} hope its ok then get it offset ground to suit the cooper S rods. i think you end up with 83.8mm stroke if you use std bearings. |
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| Author: | drmini in aust [ Sat Sep 24, 2011 9:23 pm ] |
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I got mine to 84.33 stroke with std bearings- mind you, it was standard to start with. Could/should have got even more by grinding it a bit further undersize... 
Note- you will need to machine about 1/32" off the width of the S rods to fit the crank.. |
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| Author: | crabby [ Sat Sep 24, 2011 9:27 pm ] |
| Post subject: | crank |
how far under size do you go crank is at 30 under now needs machining again |
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| Author: | drmini in aust [ Sat Sep 24, 2011 9:42 pm ] |
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I am building a motor for an ausmini member at the moment, with a stroker crank. The crank was 1.750 -.060", it has now been offset ground to 1.625 -.030". Stroke increase was about 2.0mm. Bearings are still available at -.040", and the owner has a set of -.060" squirelled away, in case. Although the crank was already -.060" and obviously had done a lot of work, it was NOT cracked.. it's the 1st thing I check when I get a crank. 
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| Author: | TheMiniMan [ Sat Sep 24, 2011 9:49 pm ] |
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best to start with a std crank,,, that way you get the most out of it |
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| Author: | drmini in aust [ Sat Sep 24, 2011 10:32 pm ] |
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TheMiniMan wrote: best to start with a std crank,,, that way you get the most out of it
Very true- however if you do own a worn one it's still worth doing, rather than leaving the stroke at standard.. 
How's the stock of -.080" bearings going these days, Matt?
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| Author: | Convertible Mini [ Sun Sep 25, 2011 6:50 pm ] |
| Post subject: | Stroking Cranks |
Always make sure you get the crank Nitrided when stroking. Not cheap but worth doing. |
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| Author: | low n blown [ Sun Sep 25, 2011 9:03 pm ] |
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only problem is you run a good chance of it coming out looking like a banana |
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| Author: | mickmini [ Mon Sep 26, 2011 9:03 pm ] |
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Mine was -.010" and I ended up with 1cc less than Kevs at the end of all the offset grinding. |
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| Author: | drmini in aust [ Mon Sep 26, 2011 9:39 pm ] |
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I'm building a stroker (for a road car) at the moment with a `scatter crank'..
When the owner passed it on to me it was already at -.060", and we wondered why. Spiro then offset ground it to [S size -.030"] but found #4 crankpin had already been restroked in the past, probably because it had damaged a crankpin somehow. Anyway, long story short, this crank has been stroked 2mm on 3 cylinders and by 3mm on #4. I decked #4 piston more to keep deck height of all 4 the same. We'll keep you posted on how it runs..
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| Author: | TheMiniMan [ Tue Sep 27, 2011 9:07 am ] |
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OOooo,,, i don`t like thems ones, i had customers with "Thingts" like that before... not a very even "Banging" going on inside,,, not a very well balanced thing at all YUK but hey... if it`s only a little out then it`ll "sort-of" be like a low comp in one pot,,,sort-of 
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| Author: | drmini in aust [ Tue Sep 27, 2011 11:57 am ] |
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TheMiniMan wrote: OOooo,,, i don`t like thems ones, i had customers with "Thingts" like that before... not a very even "Banging" going on inside,,, not a very well balanced thing at all
YUK but hey... if it`s only a little out then it`ll "sort-of" be like a low comp in one pot,,,sort-of Don't worry Matt, it's only going in a Morris 1100. What's a few extra vibes...you probably won't feel em in that, they have real engine mounts.
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| Author: | TheMiniMan [ Tue Sep 27, 2011 12:52 pm ] |
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hee hee,,, yeah like a late model jap car, soft & goo-y,, no worries tho, they go & go & go,,, & not going to be reved so not really an issue,,, seen em plenty of times before, soooo may crank grinders make a boo-boo with differing strokes, happens all the time , especially on the old machines where it`s all left to the opperator to make em all the same length (& angle i might add ) just don`t like em is all
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