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1412 stroker- motor build: MORE pics P4,5
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Author:  drmini in aust [ Wed Sep 26, 2007 5:02 pm ]
Post subject:  1412 stroker- motor build: MORE pics P4,5
Well the Morris 1100S block (12YD/Ta/H) is bored to 73mm, the 84.33mm stroker crank is now in, and the Hypatec pistons and S rods attached.
Rods and pistons were all balanced within 1g, then the rods straightened.
Rod bolts are modified ARP Big Block Chevy, because I've had a set sitting here for years.
Crank was wedged on my mill, then balanced by GR.
The centre strap is EN25 high tensile steel, shaped to fit the surface ground cap- instead of milling heaps off to make the cap flat and weakening it. It has .001" preload so it actually supports the cap. 8)
Overkill probably, but I built it years ago so I'll run it still.
Crank end float is set at .006"- I've been caught before running too little- that's a recipe for cooking the centre main.

Bearing sizes are std/std, this 12G1505 crank sat on someone's shelf for 30 years I bet.

Image
Image

<edit> This is going in the wife's van, if/when body is finished. :lol:
Author:  Smokie [ Wed Sep 26, 2007 5:25 pm ]
Post subject: 
Well I can look after it for you Doc until your wife's van is finished.. I will make sure it's run in perfectly for a few years until you want it back... :D
Author:  Smarty [ Wed Sep 26, 2007 5:46 pm ]
Post subject: 
Sweet as, should go alright.

hehe I am sure that plenty of people on here would be happy to 'run' it in for you....

yep me included.

good luck with the rest of it,

What head etc is going on?
Author:  sociallydisabled [ Wed Sep 26, 2007 6:25 pm ]
Post subject: 
Hey whats the standard bore size and stroke for these engines. i got 72mm diameter bore and 84mm stroke...im not sure how accurate you have to be but i used a steel rule.. its all i have .i think my engine may have had some work?
Author:  drmini in aust [ Wed Sep 26, 2007 7:06 pm ]
Post subject: 
sociallydisabled wrote:
Hey whats the standard bore size and stroke for these engines. i got 72mm diameter bore and 84mm stroke...im not sure how accurate you have to be but i used a steel rule.. its all i have .i think my engine may have had some work?

A stock 1275 is 70.6mm bore and 81.33mm stroke. :wink:
Steel rule is not good enough- you need a vernier caliper at least.
And when measuring down the bore to get the stroke, take away the deck height (distance from piston to top of block at TDC) to get accuracy. Some motors have the pistons 1mm or more below deck at TDC.
Author:  drmini in aust [ Wed Sep 26, 2007 7:14 pm ]
Post subject: 
Smarty, the head is a 12G1316 (1275LS) that has had about .080" taken off, Mk2 S inlet valves fitted, and ported a la Vizard.
C/R is 10.6:1.
It's nowhere near a race head, but is pretty noice inside.
It flowed 116CFM @ .450" lift on GR's flowbench.
With an RE13 cam it should have bags of torque.
Rocker gear is modified Toyota Corolla, 1.46:1 ratio.

Redline will be 7000 MAX. Most likely it won't go past 6500.

<edit> info added
Author:  sociallydisabled [ Wed Sep 26, 2007 7:15 pm ]
Post subject: 
okay, ill just let gr sort it out i think.

but just out of curiosity the block and gear box looks like it has has some parts ground out to clear way for the crank, are they all like this? just little bits and pieces like this make me think that this isnt a stock 1275..
Author:  gafmo [ Wed Sep 26, 2007 7:29 pm ]
Post subject: 
put in haha..you know you will want to see how it goes before putting it into the van
:wink:
Author:  drmini in aust [ Wed Sep 26, 2007 7:32 pm ]
Post subject: 
gafmo wrote:
put in haha..you know you will want to see how it goes before putting it into the van
:wink:

Nah it'll go on GR's engine dyno.
He suggests we might make it an excuse for another GR BBQ... :wink:
Author:  gafmo [ Wed Sep 26, 2007 7:42 pm ]
Post subject: 
8)
Author:  9YaTaH [ Wed Sep 26, 2007 7:43 pm ]
Post subject:  Re: 1412 motor build
drmini in aust wrote:
Well the 1100S block is bored to 73mm, the 84.33mm stroker crank is now in, and the Hypatec pistons and S rods attached.
Rods and pistons were all balanced within 1g, then the rods straightened.
Rod bolts are modified ARP Big Block Chevy, because I've had a set sitting here for years.
Crank was wedged on my mill, then balanced by GR.
The centre strap is EN25 high tensile steel, shaped to fit the surface ground cap- instead of milling heaps off to make the cap flat and weakening it. It has .001" preload so it actually supports the cap. 8)
Overkill probably, but I built it years ago so I'll run it still.
Crank end float is set at .006"- I've been caught before running too little- that's a recipe for cooking the centre main.

<edit> This is going in the wife's van, if/when body is finished. :lol:


Very nice Doc...but you could have beveled that centre main strap on the verticals a little more so that it looked a little more part of the scenery :lol: :lol:
Author:  drmini in aust [ Wed Sep 26, 2007 7:54 pm ]
Post subject: 
Mick,
I only had that 1 offcut of EN25 and yes it was a little short. But it does the job... :wink:

It's a bloody sight thicker than some of the aftermarket ones I've seen too. At least I know what this one is made of, EN25 is tuff stuff. 8)

<edit> all the mains cap bolts are new, Grade 8.
Author:  dove grey 64 [ Wed Sep 26, 2007 8:30 pm ]
Post subject: 
should make some more up doc........ :wink: :wink:
Author:  9YaTaH [ Wed Sep 26, 2007 9:20 pm ]
Post subject:  Good Stuff
drmini in aust wrote:
Mick,
I only had that 1 offcut of EN25 and yes it was a little short. But it does the job... :wink:

It's a bloody sight thicker than some of the aftermarket ones I've seen too. At least I know what this one is made of, EN25 is tuff stuff. 8)

<edit> all the mains cap bolts are new, Grade 8.


Only yanking your chain....where do you get all this unobtainium from anyway 8)
Author:  drmini in aust [ Wed Sep 26, 2007 10:14 pm ]
Post subject: 
1970 mini K wrote:
should make some more up doc........ :wink: :wink:

Really a strap is not `needed', particularly on a road car- centre caps only break if you change down at a zillion rpm and use the motor for braking. Not a great idea really, thet's what brakes are for. :lol:
Plenty of Minis are racing out there with no strap.
I built this strap setup years ago when I was absorbing Vizard's musings- I've got it so I'll run it... :wink:
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