After 2000K of driving I have pulled down my 1275 to find the big end Journel on number 2 conrod has a problem.
The side faces of the rod journel have been rubbing excessively on the crank resulting in Blue heat marks and a bur that has been thrown up on the cap.
This can all be seen in the Photos Below
The Crank is unmarked.
Any suggestions as to what may have caused this please Guys?

Thanks,
TY

Bent rod is my first thought...
Crank is harder than the rod, that's probably why it's unmarked.

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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.

Post up a pic of the piston skirt.

<EDIT> I doubt it's a bent rod, it has rubbed in the wrong places, actually looks more like dirty assembly.

I'm also wondering why it's not scored further round? Is the cap on crooked?
ie dirty as GT says, or cap mismatched?
How does the other side look?

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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.

Here you go.



The side of the Skirt showing the wear is on the opposite side to the wear on the rod!
Thanks,
TY

Kevin,
Other side looks fine and normal.
Cap is original off rod.
TY

wierd how the bearing isn't damaged from the rod distorting....

did the rod 'belong' to the crank, or were they put in the same motor recently?

Not a bent rod. Either dirty assembly, the bearing shells and piston skirt also tell this same story or possibly as the Doc has also suggested, mis-matched caps.

Is that the only one like that?

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Rods Did not "Belong" to the Crank.
It is just the one Like it.
Note that the rod also has Blueing from heat ....
TY

There is a possibility there that at some stage the rod has been resized and when they cut the faces they were not faced square and the side of the rod circle is now not Flat. This usually happens if the rod is slightly bent. You will find that one side is leaning the opposite to the other. Taking a light cut off the side of the rod will normally fix that to square it up. But check the wear marks on the piston first. You are not using a 12G1505 stroked crank by any chance ?

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DID I MENTION THAT I AM THE BEST SUPPLIER FOR MINI ELECTRICAL PARTS AND REPAIRS?
"Let us remove your "SHORTS"

What prompted you to pull the motor after 2000kms?

Did you get the rods resized? It almost looks like the journal was too big for the rod??? strange.

cheers,'

Jacob

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'72 Clubman Van - 1022cc, 295 head, 731 cam - Daily Driver
'69 Morris 1100 S - Dinged by a bus, in shed under repair
'64 Morris 1100 - Early 1100, long term project

Not a stroker,

I pulled it down as the gearbox that I was using had a crook second gear. I had the box rebuilt and though that I'd check on the enginebefore putting it back together.

Sorry, didn't mean to suggest it was a stroker, was more interested if the rods were measured & resized to suit the journals or if the engine was assembled "as is"?

Cheers

Jacob

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'72 Clubman Van - 1022cc, 295 head, 731 cam - Daily Driver
'69 Morris 1100 S - Dinged by a bus, in shed under repair
'64 Morris 1100 - Early 1100, long term project

there are obvious signs of grit in the bearings, only small amounts of tiny stuff but still, it`s there

The side clearance on the rods/bearings is not enough for the journal width, hence the heat-blue, check the rods are centered correctly to the bore & crank journal

& i`d check the gudgeon-to-piston tightness, looks like you may have then a little to tight maybe?

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No offence intended here but--> anyone writing a book about minis 30 years ago may not have experienced such worn or stuffed-with components as we are finding these days.

You should put your heart & soul into everything you do.