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Broken Con Rod Bearing / Moving Crankshaft
Posted: Sun Apr 08, 2012 10:38 am
by nms-georg
Morning!
First, happy easter to you all
Took a look at my engine.
First problem: con rod bearing broken at the 3rd cylinder. No big deal to change it. But! How do I find out, if it's the original size or already one of the three available oversized once?
Second problem:
I can move my crankshaft (back to front / front to back) about 2-3mm (0.08 inches). I think this is not normal?! Took a look into the oilsump and found this inside:

The small parts are plastik (don't ask me where they are coming from). And the big one is a thrust washer.
Did the crankshaft start to move because the con rod broke? How do I found out why the crankshaft is moving?
Thansk George
Re: Broken Con Rod / Moving Crankshaft
Posted: Sun Apr 08, 2012 11:37 am
by tom lad
good morning george
the images dont show up , not on my putter anyhow
my first instinct re. excesive end float on the crank shaft is worn thrust washers , if they've come out then thats prob the problem .
Question is i guess how did they pop out ?
to much end float will matter when u press down on the clutch , that pushs on the crankshaft .
Re: Broken Con Rod / Moving Crankshaft
Posted: Sun Apr 08, 2012 11:41 am
by tom lad
ow
i THINK , it should say on the outside of the bearing shell ( not wearing side ) the size , std. 10 th under ect. ones i've messed with did anyhow
Re: Broken Con Rod / Moving Crankshaft
Posted: Sun Apr 08, 2012 7:43 pm
by nms-georg
Sorry, wrong links. Here we go again:

Re: Broken Con Rod / Moving Crankshaft
Posted: Sun Apr 08, 2012 7:46 pm
by nms-georg
tom lad wrote:good morning george
the images dont show up , not on my putter anyhow
my first instinct re. excesive end float on the crank shaft is worn thrust washers , if they've come out then thats prob the problem .
Question is i guess how did they pop out ?
to much end float will matter when u press down on the clutch , that pushs on the crankshaft .
Have attached the pic now. If I take a look at the thrust wahser that fall down, it looks like new. So the question is, why did it come out?
What would you suggest: how can I start to check it?
Re: Broken Con Rod / Moving Crankshaft
Posted: Mon Apr 09, 2012 8:59 am
by tom lad
hi m8
was the other half of the thrust washer fitted on the crank ? do u think the loose one dropped out on a rebuild ??
re. the broken con rod photo , is that the little end out of the piston or the big end on the crank looks well worn either way , i guess the engine stopped suddenly
the plastic bits , does the dexta engine have valve cap seals ?? i dont know
Re: Broken Con Rod / Moving Crankshaft
Posted: Mon Apr 09, 2012 9:07 am
by nms-georg
Hi!
First, I think I have a wrong title. Not the con rod is broken, just the bearing.
The bearing you see at the photo is the one out of the piton (the small one).
Engine was running till the end quite good, just a bit noisy...
I don't care so much about the bearing at the con rod - this will be easy to fix.
My biggest problem is the movement of my crankshaft. Don't know how to start to search for the fault. Think I have to check later where the thrust washer is coming from and if I can re-fit it again. And then, check again for the movement of the crank...
Re: Broken Con Rod / Moving Crankshaft
Posted: Mon Apr 09, 2012 6:03 pm
by nms-georg
Hi again!
Have been again under my vehicle to check, where the hell the thrust washer came from. Unfortuneately nothing to see or I'm just to stupid to look at the right place.
As the crankshaft and everything else is still in place it's quite hard to see something.
This guy has been found in the oilsump under the first cylinder - so he must be in place somewhere there.
Can anyone of you pleeeeeeeeeeeeeeeease tell me, between which bearings (main bearings) and con rods this thrust washers are sitting?
Thanks a lot
George
Re: Broken Con Rod / Moving Crankshaft
Posted: Mon Apr 09, 2012 7:19 pm
by dexta roadless
i am afraid you have a slight problem. The trust bearing is placed on the rear bearing, and on that there is also the rear sealing bolted both to the cap and to the block. The only way to fix thi is to take split off the engine, remove the clutch and flywheel. then you gain access to the problem.

Re: Broken Con Rod Bearing / Moving Crankshaft
Posted: Tue Apr 10, 2012 7:53 am
by nms-georg
Morning,
think you're right

Took a look at my parts lists and they're really all next to the third cylinder. Don't know why I found it around the first one...
S***, that sounds like a lot more work

What I'm wondering is - if its all screwed together there, why did it fall out. And also, when did it fall out. May be I'm drving since weeks or months with it.
Thanks guys so far... Have a good one...
Re: Broken Con Rod Bearing / Moving Crankshaft
Posted: Mon Apr 16, 2012 8:57 pm
by nms-georg
Hi!
Took today a look At the place where the thrust washers are sitting (inner side to the sump).
I placed them back in but they are not sitting very tight and falling out again. Once fitting them back, how are they hold in place? How do they stay where they need to stay?
Or will them stay there once i place the right ones and the crankshaft is Not moving anymore?
Re: Broken Con Rod Bearing / Moving Crankshaft
Posted: Mon Apr 16, 2012 9:36 pm
by russelm
The thrust washers sit in a groove in the block and rear bearing cap as per you can see here:
The pic above also shows how they changed the thrust washer position, the early ones had the tab located at the 2 Oclock position (where the half moon cut out is) but you cant get those bearings anymore. I had to machine mine where the oil return holes are to get the later thrust bearings to fit.
Re: Broken Con Rod Bearing / Moving Crankshaft
Posted: Mon Apr 16, 2012 9:44 pm
by nms-georg
Thanks for the pic. And what keeps them in the groove - is ist just the crankshaft?
Re: Broken Con Rod Bearing / Moving Crankshaft
Posted: Tue Apr 17, 2012 7:58 am
by russelm
Yes, its a pretty deep groove!
Re: Broken Con Rod Bearing / Moving Crankshaft
Posted: Fri May 04, 2012 9:02 am
by nms-georg
Morning!
Just a quick update for you. Have finally fitted all back together. But it was a hard job to get the sump back in again - what a heavy piece....
And..... My baby is running again. Very smooth...
Thanks for your help.
George