Ausmini
It is currently Mon Jul 28, 2025 6:17 am

All times are UTC + 10 hours




Post new topic Reply to topic  [ 14 posts ] 
Author Message
PostPosted: Tue Apr 26, 2011 7:13 pm 
Offline
1275cc
1275cc

Joined: Wed Jan 19, 2005 1:52 pm
Posts: 2582
Location: Brisbane
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
Image
Image
Image
Image
Image


Top
 Profile  
 
 Post subject:
PostPosted: Tue Apr 26, 2011 7:17 pm 
Offline
religious status
religious status
User avatar

Joined: Fri Mar 19, 2004 6:19 pm
Posts: 39757
Location: near Baulkham Hills, NSW
Bent rod is my first thought...
Crank is harder than the rod, that's probably why it's unmarked.

_________________
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. :mrgreen:


Top
 Profile  
 
 Post subject:
PostPosted: Tue Apr 26, 2011 7:21 pm 
Offline
Mods rock!
User avatar

Joined: Fri Oct 03, 2008 9:02 pm
Posts: 5079
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.


Top
 Profile  
 
 Post subject:
PostPosted: Tue Apr 26, 2011 7:29 pm 
Offline
religious status
religious status
User avatar

Joined: Fri Mar 19, 2004 6:19 pm
Posts: 39757
Location: near Baulkham Hills, NSW
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?

_________________
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. :mrgreen:


Top
 Profile  
 
 Post subject:
PostPosted: Tue Apr 26, 2011 7:40 pm 
Offline
1275cc
1275cc

Joined: Wed Jan 19, 2005 1:52 pm
Posts: 2582
Location: Brisbane
Here you go.
Image
Image

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


Top
 Profile  
 
 Post subject:
PostPosted: Tue Apr 26, 2011 7:44 pm 
Offline
1275cc
1275cc

Joined: Wed Jan 19, 2005 1:52 pm
Posts: 2582
Location: Brisbane
drmini in aust wrote:
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?

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


Top
 Profile  
 
 Post subject:
PostPosted: Tue Apr 26, 2011 7:47 pm 
Offline
Yay For Hay!
User avatar

Joined: Wed Sep 08, 2004 9:27 pm
Posts: 15912
Location: Wodonga - Vic/NSW border
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?


Top
 Profile  
 
 Post subject:
PostPosted: Tue Apr 26, 2011 7:48 pm 
Offline
Mods rock!
User avatar

Joined: Fri Oct 03, 2008 9:02 pm
Posts: 5079
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?

_________________
Image


Top
 Profile  
 
 Post subject:
PostPosted: Tue Apr 26, 2011 8:01 pm 
Offline
1275cc
1275cc

Joined: Wed Jan 19, 2005 1:52 pm
Posts: 2582
Location: Brisbane
Rods Did not "Belong" to the Crank.
It is just the one Like it.
Note that the rod also has Blueing from heat ....
TY


Top
 Profile  
 
 Post subject: Looks like..
PostPosted: Tue Apr 26, 2011 8:47 pm 
Offline
1275cc
1275cc

Joined: Thu Dec 09, 2004 6:57 am
Posts: 3022
Location: JIMBOOMBA QLD.
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 ?

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


Top
 Profile  
 
 Post subject:
PostPosted: Tue Apr 26, 2011 8:51 pm 
Offline
998cc
998cc
User avatar

Joined: Sat Mar 13, 2010 4:19 pm
Posts: 840
Location: Ridin' the rails somewhere
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

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



Image


Top
 Profile  
 
 Post subject:
PostPosted: Wed Apr 27, 2011 8:59 am 
Offline
1275cc
1275cc

Joined: Wed Jan 19, 2005 1:52 pm
Posts: 2582
Location: Brisbane
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.


Top
 Profile  
 
 Post subject:
PostPosted: Wed Apr 27, 2011 1:08 pm 
Offline
998cc
998cc
User avatar

Joined: Sat Mar 13, 2010 4:19 pm
Posts: 840
Location: Ridin' the rails somewhere
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

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



Image


Top
 Profile  
 
 Post subject:
PostPosted: Wed Apr 27, 2011 3:17 pm 
Offline
Bimmer Twinky
User avatar

Joined: Mon Sep 06, 2004 4:36 pm
Posts: 8606
Location: Brisbane
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?

_________________
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.


Top
 Profile  
 
Display posts from previous:  Sort by  
Post new topic Reply to topic  [ 14 posts ] 

All times are UTC + 10 hours


Who is online

Users browsing this forum: No registered users and 92 guests


You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot post attachments in this forum

Jump to:  

© 2016 Ausmini. All garage work involves equal measures of enthusiasm, ingenuity and a fair degree of irresponsibility.