ms880 Rebuilding 2007 ms880

[spudulike]

Shame you aren't a bit closer and had thought you had already removed the parts and fitted new.

Removing the seals...you can do that with a simple seal wrench once the crankshaft is out. 

Shifting the crankshaft is going to be difficult without the correct tool and clouting it with a copper mallet isn't that great. You need a big C crankshaft remover and they aren't cheap to purchase.

I did a MS660 strip, split and rebuild on my "Whats on my bench" thread which shows you the process....it is on there somewhere.

I guess one option is to remove the seals and flush the bearings out in situ with white spirit, WD40 and blow them through. It may work but the only issue is having to restrip the engine if it doesn't. It is an option in absence of the correct tools. 

 

 

[openspaceman]

1 hour ago, spudulike said:

I guess one option is to remove the seals and flush the bearings out in situ with white spirit, WD40 and blow them through. It may work but the only issue is having to restrip the engine if it doesn't. It is an option in absence of the correct tools. 

It is not something I have done but if it has just been left with the pot off I would expect to be able to flush any debris out of the bearings like you say but the issue is can it be done with that crankshaft still in the RHS casing?

 

I would have no qualms about cleaning up the cylinder and using oven gel to dissolve off the aluminium pick up ( I spend days applying a little and leaving it, cleaning off, then re applying until no white marks appear, to show the aluminium is gone), then circumferential "honing" with wet and dry 150, as I do not have a hone.

[bmp01]

3 hours ago, TimberTickler said:

Cheers spud, the issue I have with going further doing the saw myself is removing and replacing the bearings as I have no special tool for removing and installing. Also would need to purchase the 2nd Stihl tool (£100+) to remove the crankshaft from the flywheel side. 

 

 

I think you need to make use of differential expansion, ie. heat the assembly up. Whats going on here is the casing will expand more than the bearing so as assy gets hot the interference between parts is reducing. The pullers make for a quicker route, heating and all that waiting is slower. Heat the assembly in an oven to 150 deg C, (maybe a tad more), let it get hot through then give the crank a clout. Plan it out before you start, have everything ready, support the crankcase around bearing housing and use soft headed hammer or a piece of aluminium to protect the crank.

[Macpherson]

18 minutes ago, bmp01 said:

 

I think you need to make use of differential expansion, ie. heat the assembly up. Whats going on here is the casing will expand more than the bearing so as assy gets hot the interference between parts is reducing. The pullers make for a quicker route, heating and all that waiting is slower. Heat the assembly in an oven to 150 deg C, (maybe a tad more), let it get hot through then give the crank a clout. Plan it out before you start, have everything ready, support the crankcase around bearing housing and use soft headed hammer or a piece of aluminium to protect the crank.

 

Heat it in the oven till yer spit bounces off.. it used to annoy my mother a lot 50 years ago😄

[adw]

I recon the Husqvarna g clamp style tool will push that out no problem, i can loan you one if you want to try it. 

[spudulike]

3 hours ago, adw said:

I recon the Husqvarna g clamp style tool will push that out no problem, i can loan you one if you want to try it. 

Yes, that is the jobbie!!

[spudulike]

The other possibility is a BIG G clamp, some support blocks to lift the cases off a bench and a thick bench top. It is possible to rest the cases on the blocks toward the edge of the bench and use the clamp on the underside of the bench with the other end on the crank end.

I did make a rough rig once to do this before a kind gent sent over a clamp like ADW mentioned above.

His offer is a nice one TBH, probably your best offer.....you may have to open the lower clamp feet a little to go over the big end part of the lobes!

[TimberTickler]

4 hours ago, adw said:

I recon the Husqvarna g clamp style tool will push that out no problem, i can loan you one if you want to try it. 

ADW, that would be a big help if you could let me borrow it, thank you! 

 

[adw]

Pm me with your address.

[TimberTickler]

On 11/12/2022 at 17:48, spudulike said:

OK....... I have done a few of these big bangers, loads of 660s, 395s etc and brought back many saws with similar cylinders and often worse.

The cylinder doesn't look too bad in my book...sorry chaps but that is my opinion based on experience and reusing the OEM cylinder is always best if it is possible...read on-

I would clean the bore up with a light abrading with 400 grit paper and then apply brake cleaner to degrease.

You then use caustic soda (Sodium Hydroxide), brick cleaner HCL or something similar. Any fluid that eats aluminium will do. Apply it and watch the streaks on the cylinder fizz. Once it stops, clean with a cloth, abrade and do the above again.

Once the bore is clean, I hone the bore with a three legged hone...just lightly, some use ball hones but they are relatively expensive.

Once this is done, run a diamond file around the exhaust port edge and lightly rub with a bit of wet and dry.....just to make a nice job.

After this, the bore should be smooth and you should not feel any high point with your fingertip. Visually, you should see where the hone has been but don't worry if it doesn't look perfect, those black marks are often difficult to remove completely.

Fit your new piston - get the direction right...arrow points to the exhaust port...Meteor....excellent choice.

Pressure and vac test - this is damn difficult with the sprung muffler seal if it is of this type but it can be done. Assemble the saw, tune the carb and keep reasonably under the max spec...1.0 - 1.5k is safe and gives the engine a fine chance. 

Use it hard but not for too long cuts. You want those rough surfaces to bed in quickly whilst they are rough but not generate too much heat. 

If you do this, you should end up with a top job and with minimal costs....that's why I was always so busy!!

I did have a 460 I rebuilt fail after 4 years....the owner dropped a tree on it.....made me smile....the rest are probably still out there working.

 

Hi spud, so I've had a crack at cleaning up the cylinder.. I didn't use acid but everything else you suggested I did  this is the result I have. 

Looking at the bottom of the exhaust port is my concern. And just wondered what you thought. Or anyone else for that matter. I'd like to avoid getting a new cylinder as that blows my budget massively. 

Still having trouble with the bearings so will take it to a shop and hopefully they can do the work there. 

Cheers 👍