ausmini :: View topic - large or small journal 1275 crank

That is a forging number. Look closely at the webs for a stamped on number.
If it is a big journal Oz crank it should have 12G1505 on there somewhere.
.

Yep it's a small journal.
Primary gear endfloat- I aim for .004-.005".

drmini in aust wrote:

Yep it's a small journal.
Primary gear endfloat- I aim for .004-.005".

Lucky i'm rebuilding this engine it's pretty shagged, at the moment primary gear is .015, and the end float on the crank is .0098.

What is the difference wit 1505A and 1505 ?
Always wondered that.

What is the standard primary gear thrust washer size I'm not sure if the current one is worn or if the engine was built incorrectly the previous time.

Author:	Booglie [ Mon Oct 07, 2013 2:39 pm ]
Post subject:	large or small journal 1275 crank
I have a 1275 crank but cannot remember if it is large or small journal and the only number I can see on the crank is ESC1X does this number mean anything?

Author:	drmini in aust [ Mon Oct 07, 2013 2:48 pm ]
Post subject:	Re: large or small journal 1275 crsnk
That is a forging number. Look closely at the webs for a stamped on number. If it is a big journal Oz crank it should have 12G1505 on there somewhere. Otherwise, measure the crankpin diameter. 1.750" or slightly less is big journal. 1.625 or slightly less is a small journal.

Author:	Booglie [ Mon Oct 07, 2013 2:57 pm ]
Post subject:	Re: large or small journal 1275 crsnk
I have found a similar number it is very faint looks to have been almost removed for balancing but the numbers I can see are 12G128* the last number is ground off and can't be read. Also what should the end float on the primary gear be?

Author:	MiniVLT [ Mon Oct 07, 2013 3:13 pm ]
Post subject:	Re: large or small journal 1275 crsnk
Sounds just like my crank, 12G1288, the last 8 was barely noticeable! Small journal! Cheers Shane

Author:	drmini in aust [ Mon Oct 07, 2013 3:24 pm ]
Post subject:	Re: large or small journal 1275 crsnk
Yep it's a small journal. Primary gear endfloat- I aim for .004-.005".

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large or small journal 1275 crank https://www.ausmini.com/forums/viewtopic.php?f=2&t=83021	Page 1 of 2

Author:	John Smidt [ Mon Oct 07, 2013 6:56 pm ]
Post subject:	Re: large or small journal 1275 crsnk
drmini in aust wrote: That is a forging number. Look closely at the webs for a stamped on number. If it is a big journal Oz crank it should have 12G1505 on there somewhere. . Just a Note, On the large journal Crank, You Will often find 12G1505 OR 12G1505A Cast in the crank. not stamped

Author:	Convertible Mini [ Mon Oct 07, 2013 7:04 pm ]
Post subject:	Re: large or small journal 1275 crsnk
What is the difference wit 1505A and 1505 ? Always wondered that.

Author:	Booglie [ Mon Oct 07, 2013 7:07 pm ]
Post subject:	Re: large or small journal 1275 crsnk
drmini in aust wrote: Yep it's a small journal. Primary gear endfloat- I aim for .004-.005". Lucky i'm rebuilding this engine it's pretty shagged, at the moment primary gear is .015, and the end float on the crank is .0098.

Author:	drmini in aust [ Mon Oct 07, 2013 7:13 pm ]
Post subject:	Re: large or small journal 1275 crsnk
Booglie wrote: drmini in aust wrote: Yep it's a small journal. Primary gear endfloat- I aim for .004-.005". Lucky i'm rebuilding this engine it's pretty shagged, at the moment primary gear is .015, and the end float on the crank is .0098. If you are going to rev it, I'd want .006" crank endfloat, minimum. I built my 1360 with the recommended .003" the first time, after 3 laps at a Wakefield Pk track day the oil pressure went south. It almost spun the centre main shells, and I had to regrind the S crank to clean the centre main journal up. It has .007" endfloat now, all is good.

Author:	TK [ Tue Oct 08, 2013 10:40 am ]
Post subject:	Re: large or small journal 1275 crsnk
small journal cross drilled, large journal not. Well that's my experience anyway.

Author:	MiniVLT [ Tue Oct 08, 2013 11:32 am ]
Post subject:	Re: large or small journal 1275 crsnk
Mine was cross drilled too, I thought it was done on a rebuild, maybe! Maybe it was a factory job. Cheers Shane

Author:	drmini in aust [ Tue Oct 08, 2013 11:42 am ]
Post subject:	Re: large or small journal 1275 crsnk
Some small J cranks were cross drilled when new, the later ones were not.

Author:	Booglie [ Tue Oct 08, 2013 12:02 pm ]
Post subject:	Re: large or small journal 1275 crsnk
What is the standard primary gear thrust washer size I'm not sure if the current one is worn or if the engine was built incorrectly the previous time.

Author:	John Smidt [ Tue Oct 08, 2013 12:04 pm ]
Post subject:	Re: large or small journal 1275 crsnk
Convertible Mini wrote: What is the difference wit 1505A and 1505 ? Always wondered that. I do not think there is any difference, Also sometimes the A is there but not very clear

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Author:	drmini in aust [ Tue Oct 08, 2013 12:30 pm ]
Post subject:	Re: large or small journal 1275 crsnk
Booglie wrote: What is the standard primary gear thrust washer size I'm not sure if the current one is worn or if the engine was built incorrectly the previous time. There were lots of sizes selectively fitted. Karcraft now lists them from .122" to .128" thick. Matt Read `TheMiniMan' also gets them made up in Brissy. Note the steel `C washer/clip' wears more than the thrust washer, you can turn it over once to extend its life or go buy a new one.