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1275 CRANKSHAFT ID
https://www.ausmini.com/forums/viewtopic.php?f=2&t=67134		 Page 1 of 2
Author:  ronniemac [ Sat Nov 20, 2010 9:13 pm ]
Post subject:  1275 CRANKSHAFT ID
I HAVE DECIDED TO REBUILD MY 1275 AS IT HAS BEEN SITTING FOR A COUPLE OF YEARS.
THE CRANK SHAFT HAS ( AEG ) CAST ON IT BUT AFTER THAT IT HAS BEEN GROUND DOWN AND ( 12G1288 ) STAMPED INTO IT. BY THE WAY THE NUMBER 1 IN 1288 IS UPSIDE DOWN. IS THIS NORMAL ON THESE CRANKS TO HAVE THE CAST NUMBER GROUND OFF IF THEY WERE NOT TO BECOME COPPER S CRANKS?
I AM ALSO RUNNING AEG521 COOPER S CON RODS.
Also each main and big end bearing has 2 oil holes drilled. across and diaginal.
Author:  subwayseth [ Sat Nov 20, 2010 9:16 pm ]
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capitals = yelling :wink: :lol:
Author:  ronniemac [ Sat Nov 20, 2010 9:24 pm ]
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Woops, sorry.
A long day and didn't notice the caps lock on.
Author:  drmini in aust [ Sat Nov 20, 2010 9:51 pm ]
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It's an EN16 crank, Morris 1100S or similar.
I have a mint one the same numbers? that was in an early thin flange 1100S block. They are good cranks, early ones were tufftrided.
AEG521 rods were used, they are not only in Cooper Ss.
[edit] I just checked it, my cross drilled 1100S one is 12G1392, not 12G1288.
Author:  ronniemac [ Sat Nov 20, 2010 10:19 pm ]
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How can I tell if it has been Tuftened and is it cross drilled?
Author:  wild_willy [ Sun Nov 21, 2010 7:50 am ]
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[quote="drmini in aust"]It's an EN16 crank, Morris 1100S or similar.

Correct me if I'm wrong but weren't Cooper S cranks forged EN40B. If this is the case then the AEG316 (non cross-drilled Cooper S crank) forging mark shouldn't appear on a EN16 crank or was the EN16 crank forged as well using the same forging die?

I was under the impression that the factory used up a lot of left over components from Cooper S's in the 1100S motors.

Like ronniemac and you Doc, I also have a couple of these STD STD and they clearly have the Cooper S number forged on them, ground off slightly and over stamped with the part number 12G1288
Author:  dodge [ Sun Nov 21, 2010 8:37 am ]
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My crank is a EN40B , AEG 480 , i also have a spare EN16T crank
Author:  GT mowog [ Sun Nov 21, 2010 1:10 pm ]
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All the A series cranks were forged, the Cooper S crank was made from EN40B steel and then nitrided. These had 1 5/8" Big Ends. The 1100s was fitted with a few different cranks, the early ones also having 1 5/8" Big Ends, but forged from EN16 Steel. I think some of these were tuftrided. Later 1100s Cranks went to 1 3/4" Big Ends and the cranks were not treated, and they had those strong but bloody heavy rods on them.
Author:  drmini in aust [ Sun Nov 21, 2010 5:56 pm ]
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Not all Cooper S cranks were nitrided EN40B, many of the Mk2s were tufftrided EN16.
I don't believe any EN40B S cranks went into the Morris 1100S, history seems to indicate the opposite and my preceding sentence is mentioned in Parnell's book.

My 1100S `small J' std/std crank I mentioned is cross drilled, however I have another `small J' one from a slightly later 1100S that isn't cross drilled.
Both motors have AEG521 S rods in.
From engine number 12YD/Ta/H10488 the `big' J 12G1505 crank and lumpy rods were used.
Author:  justminis [ Sun Nov 21, 2010 6:31 pm ]
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I too have small journal 1100S cranks stamped 12G1288 that are cross-drilled. I also have a small journal 1100S crank stamped 12G1392, it is also cross-drilled. The webs of this crank looked "grey" compared to the others, which I took to mean it had been tuftrided.

Kev, that non cross-drilled crank, is it stamped 12G1288?
Author:  drmini in aust [ Sun Nov 21, 2010 8:40 pm ]
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I'd have to go drag it out, will check tomorrow.

BTW,
One of my books says the p/no for the EN16 tufftrided S crank is AEG 624.
Author:  GT mowog [ Sun Nov 21, 2010 8:54 pm ]
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I have for a AEG 749, AEG479 (but I'm sure this is a Leyland Typo), and AEG 622 for the Cooper S crank, this latter one being the tuftrided EN16T one.

Doc are you sure that the late Cooper S Engines we got out here had the EN16T Cranks? The English records show that to be the case, in the UK however the Early GT engines that I've pulled down (based on the MKII Block) all had EN40B Cranks.

<EDIT> The GT Parts book also quotes the AEG 749 as the crank in the early GT engines :D
Author:  74snail [ Sun Nov 21, 2010 9:06 pm ]
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The crank in my 1970 Morris Nomad 1300 - ( 1275 auto ) is definitely tufrided , not sure what part No is ( its a bit hard to get to )
.
Author:  drmini in aust [ Sun Nov 21, 2010 9:07 pm ]
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I have a 1970 Mk2 S motor that had an EN40B crank in it, various people on this forum (those who would know, and some who race em) have stated that it should be a EN16 tufftrided one. I was told my crank would likely be a Mk1S.
It's a good `un though, has been in 4 of my motors now and is still at -010/-010. Bugger just won't wear.. :lol: 8)
Author:  ronniemac [ Mon Nov 22, 2010 12:35 am ]
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As mentioned earlier about the color of the crank, I have an 1100 crank which is a burnt oil color and my 1275 crank has a dull grey look. Is this an indication of what it is?
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