Stihl MS362 crankshaft not turning freely after installing new bearing.

[TRTermite]

I used look at women, and think to myself....

"I'd tap dat"

USED TO??

 

[TRTermite]

If one does not have a brass hammer then a piece of brass or aluminum can be held against the crank stub and then whack the metal with a regular ballpein or other steel hammer, I have even used a piece of very hardwood like yellow birch for the drift. Haven`t come upon one where the bearing cannot be shifted over with a good solid blow from any hammer.

I will take that as sound advice. Most of my bearing experience comes from sawmill, automotive, farming repairs been around a lot of it. This CAD thing is a new thing to me I used to take my saws to a few different "OLD GUYS" most of em are gone now.. I must be getting to be one of 'em.

 

[pioneerguy600]

I will take that as sound advice. Most of my bearing experience comes from sawmill, automotive, farming repairs been around a lot of it. This CAD thing is a new thing to me I used to take my saws to a few different "OLD GUYS" most of em are gone now.. I must be getting to be one of 'em.

We all are and now I find myself to be the , old guy , that growing up and all through the years they held the experience and knowledge that I pried from their grip on most things mechanical that through necessity mostly I had to do myself.

 

[HarleyT]

USED TO??

I have to keep my bad heart in mind.

I live vicariously through you guys, which is why I am always requesting pics.....
I haven't been to a mammary bar in 20 years, it would likely kill me.

 

[Bob Hedgecutter]

I have to keep my bad heart in mind.

I live vicariously through you guys, which is why I am always requesting pics.....
I haven't been to a mammary bar in 20 years, it would likely kill me.

Least you would go out smiling!

 

[sand sock]

pour some stihl 2 stroke mix oil onto the bearing shaft. keep those lubed whie your working on it. you dont want teh bearing seizing and spinning in teh housing. good job

 

[Joisey]

Not familiar with your engine, but on 2 stroke motorcycle engines I always put the bearings in a ziplock bag in the freezer overnight and the case halves in the oven at 160 degrees. The bearings then literally slip in place.
If the crankshaft is an interference fit in the bearings, freeze the crankshaft and heat the case halves with the bearings to 160 degrees and it will slip into place.

 

[Captain Bruce]

...And my MS362 rebuild continues to creep along at a snails pace.

I finally got the crankcase reassembled with new bearings. I used the hot and cold method. I heated the bearings and slid them onto a chilled crankshaft, then chilled that unit and seated it into a heated clutch half of the crankcase, then chilled that whole assembly and pushed on the heated remaining case half and bolted it all together. It seemed to work great! I was very impressed, but as I was bolting the case together I noticed that the crankshaft had become very stiff to turn. I wasn't concerned as I remembered hearing somewhere that this is common and that you just need to wack the crankshaft back and forth a few times with a soft-faced hammer in order to free things up after assembly. NO LUCK! It doesn't seem to matter how much I rap on the crank in either direction with my dead-blow mallet. No improvement! Any thoughts?

You go on the web, and freely admit you beat on ANY engine componet, with a hammer? You could have started this joke with a 6 word sentence, not a 4th grade essay......Hammer? Wow!

A picture might help!

I have a bad feeling that it has something to do with how the ignition side bearing appears to not be seated all the way into the case. *Groan* And I thought it was going so well!

View attachment 951313

I applaud you for taking a leap outside your skill set. As to any part that has been mis-installed, toss it, and start over. Any job is worth doing right the 1st time......

 

[Bob Hedgecutter]

You go on the web, and freely admit you beat on ANY engine componet, with a hammer? You could have started this joke with a 6 word sentence, not a 4th grade essay......Hammer? Wow!

I applaud you for taking a leap outside your skill set. As to any part that has been mis-installed, toss it, and start over. Any job is worth doing right the 1st time......

Many thousands of chainsaws have had their cranks removed and reinstalled with a hammer of some variety and will continue to be so, either by those that know and have trusted this method for decades- or those new to the rebuilding stage of saw ownership that do not have access to the likes of hydraulic presses.
I will happily raise my hand and admit I have many a time disassembled and reassembled engine components on various machines from simple chainsaws to more complex tractors with the aid of various hammers and I think you will find many experienced builders here have done the same and continue to do the same.

 

[HarleyT]

Yes, it can also be noted that some of the "purists" here spend a horrendous amount of time and effort trying to remove a flywheel or clutch, and still have to come back on here and start a thread about how to fix their saw they just screwed up.

 

[T.Bird]

Hitting it harder was indeed the answer! I set a large punch in the hole at the end of the crankshaft so as to at least not damage the outside of the shaft and managed to get it pretty centered by bashing away on the punch with my trusty Estwing. Then I knocked if back and forth a few times from either side and got it really spinning nice and free. Or... maybe I just broke something beyond repair... We'll see!

 

[William Balaska]

If he's not going to split it again, I would heat the race up externally with a propane or map gas torch and then carefully center punch it.

 

[T.Bird]

Side note: How centered is centered? Like... do I need to make sure that it is in the dead center for proper engine function?

 

[frank_]

Side note: How centered is centered? Like... do I need to make sure that it is in the dead center for proper engine function?

the piston will bind if its too far

 

[12fergus]

Side note: How centered is centered? Like... do I need to make sure that it is in the dead center for proper engine function?

If you put the crank lobes in the up position, then put a large cold chisel between the lobes and give them a good tap , that should center your bearings.

 

[pioneerguy600]

If you put the crank lobes in the up position, then put a large cold chisel between the lobes and give them a good tap , that should center your bearings.

That would spread the crank counterweights thus bending the crank but it wouldn`t have any effect on moving the bearing over.

 

[Bob Hedgecutter]

Side note: How centered is centered? Like... do I need to make sure that it is in the dead center for proper engine function?

Personally I normally use eyeometer to check crank lobe clearance is even with the internal case sides- but you can measure it with feeler gauges slipped between outside of lobes and inside face of the cases, so it is even gap each side.
Once the cylinder is bolted down, the piston is pretty much governed to that space to travel in- if the crank is severely off centre, the lobes can scuff the case face internally and the lower conrod can be pushed hard over to one side, so it rubs on contact with the crank and transfers heat to the conrod, uneven loading on the lower bearing and heat speed up bearing failure.
Personally if the gap looks good and even on both sides- I run with it, but no harm in measuring the gap to check.
Did that bearing that was sitting proud slip in to place- or is it still hanging out there?

 

[T.Bird]

Personally I normally use eyeometer

I like that. I'm definitely going to go with the eyeometer on this one!

Did that bearing that was sitting proud slip in to place- or is it still hanging out there?

Yes... ish... It is certainly LESS proud and the crank is approximately centered and spinning freely, so I was planning on being happy with that and moving forward. That means installing piston and cylinder next, so expect to see me back here with another round of silly questions soon!

 

[Joisey]

Side note: How centered is centered? Like... do I need to make sure that it is in the dead center for proper engine function?

The same thickness feeler gauge blade will fit on both sides of the crank. Plus or minus a few thousandths is great if you don't want to split hairs.

I always measured the distance between the assembled crankcase with the screws snug and the main bearings in. Then measure the distance between the thrust faces on the crankshaft. Subtract this distance from the crankcase measurement and divide by two. That is the thickness of your feeler gauge blade that you need to have the correct clearance. If you want to be exact, you could subtract .001 from the crankcase measurement to allow for gasket compression.

 

[Vintage Engine Repairs]

The few times I’ve measured it - the distance between the centre of the cylinder bolts in the case halves do not align with the centre of the crankshaft when it’s evenly between the cases / crankshaft bearings.

The lateral play between the big end and small end will make up for any slight misalignments anyway.


I now just follow the manual which says pull the crank in the flywheel side until it stops, then pull the other. That more often than not actually aligns the crank and the cylinder better.

A couple of gentle taps and it’s good to go.