Sachs Dolmar 100 big end

[Ricko]

Hi,

Help, whilst attempting to fit a new piston to my project Sachs Dolmar 100 the big end bearing seems to have collapsed! I've retrieved the 12 rollers, what do I need to do??

Cheers

[lurkalot]

It hasn't collapsed, you just let it slide off and the rollers fell out.  You'll need to stick them back on the big end journal with a dob of grease, and carefully (very carefully) slide the con rod back in place.   Some of the older Stihls such as the 011 use a crank / big end of the same design.  Not the nicest system imo.

Edited October 29, 2018 by lurkalot

[Ricko]

21 minutes ago, lurkalot said:

It hasn't collapsed, you just let it slide off and the rollers fell out.  You'll need to stick them back on the big end journal with a dob of grease, and carefully (very carefully) slide the con rod back in place.   Some of the older Stihls such as the 011 use a crank / big end of the same design.  Not the nicest system imo.

Please tell me I can do this without splitting the crank case....

[lurkalot]

Yes I would think so, although it's a bit fiddly.  I haven't actually touched a Dolmar one, but have done many Stihls this way over the years.   

[Ricko]

On 29 October 2018 at 19:52, lurkalot said:

Yes I would think so, although it's a bit fiddly.  I haven't actually touched a Dolmar one, but have done many Stihls this way over the years.   

So, if I've got this right; wriggle the conrod off, blob the rollers into place with some grease, slide the conrod back on??

 

I've tried feeding the rollers into the space with the conrod in situ and after about 6 or 7 out the 12 rollers I can't squeeze anymore in.

[lurkalot]

Yep, you have to have the rollers in place on the crank before sliding the con rod on, because the con rod holds them in place when in position.  I did say it's fiddly.  

[Ricko]

Done it!

I think...

The con rod only slides on and off in one direction, I obviously pushed it off whilst tapping at the gudgeon pin.

Slide the conrod to the side, grease in a plastic syringe, blob of grease, place the needle roller, and repeat, pushing down occasionally on the rollers to keep them tight against the journal, carefully slide on the conrod, and check to make sure none have dropped out!

 

Terrible system used by one of my favourite manufacturers!

[lurkalot]

Yes it's a (excuse my French) shit system, especially when you strip something for the first time not realising it's like that.  Air can turn blue quite suddenly. 

 

Mission accomplished then.  Nice one.