Installing crank bearings using heat

[pioneerguy600]

I think I remember my 026 service manual calling for heat to be used to put bearings in the cases

Some repair manuals do mention heat, one that comes to mind is the manuals for the Sachs Dolmar saws, I actually rember reading them back around 85-87.
Pioneerguy600

 

[pioneerguy600]

Jerry deserves a nice belgian beer and a pat on the back...a good allround saw tech he is

Why, thank you Roland, a Belgian beer would go down rather well, just wish it was a little warmer here right now, ah raining and +6 is not that bad for the end of March.
Pioneerguy600

 

[teacherman]

Installing crank bearings using heat may not be for you!
If you have to follow a manual word for word then this method may not be for you, this thread is just for info. I have used the method described here for over 45 years now and had no problems show up by doing the install this way.
A source of heat is required, a hot plate with a piece of plate steel on it, a hot air heat gun ,a oven of any sort or even a torch will do.
Have the two bearings and the crank cleaned and ready.
I place a heavy piece of angle iron and clamp it in the vice, mine is 3/8"X4X4X 12" long and leave 6" of it stick out from the vice jaws. The throw of the crank sits on over the end of the angle iron and supports the crank, either end up will do.
Heat the bearing up to 200-220*F and with a welding glove I pick it up and drop it over the end of the crank that is sticking up, it will almost fall into place but if it does not I have a length of 3/4" black iron water pipe cut to length and a hammer ready, slide the pipe over the crank end and a light tap will seat the bearing. The pipe must contact the inner race only.
Do both bearings this way and let them cool.
Next heat the PTO crankcase half up, the heat gun will do but an oven is better, 210-220 *F is plenty hot. I have a set of blocks set up that supports the case half up about 6" off the bench.
When the case half is hot pick it up with the welding gloves on, sit it on the blocks and then drop the crank with the bearings already on it into place, you won`t have to hit it.
Let that side start to cool down and start heating the opposite side up to 210-220*F . Turn the crankcase open side up. Place the case gasket on the case half and I use the dowel pins for the Stihls or a couple of long case bolts with the heads cut off, these need to be long enough so that they can be removed later, threaded rod pieces work well also. These studs work very well as a guide to help guide the case halves together.
After the case gasket is in place put the gloves on and pick up the the hot flywheel side case and drop it down over the upended crank. They will usually go all the way into place with a hollow clunk sound if done right. Once in a while I have to bap the case with the side of my fist to settle it but not always.
I now install the case bolts and draw the cases tight. Let the assembly cool for 5-10 mins and then try the crank for axial stress, if it needs relief then tap each end a good rap with a brass hammer. That usually relieves the stress and if the assembly is now cool enough start to put the seals in place. I have pieces of pipe cut to length that clears the end of the crank by at least an inch and fits the outside diameter of the seal, very easy to drive the seals this way.
Now reassemble the rest of the saw as required. Happy sawing.
Pioneerguy600

Oh yeah, that is some good stuff. I will try it on two saw projects. Thank you!

 

[pioneerguy600]

Oh yeah, that is some good stuff. I will try it on two saw projects. Thank you!

You may want to put the heavy padded gloves on and then handle the parts a little before starting the final assembly, the parts seem a lot smaller and a little more difficult to hold and manouver when you have the thick gloves on. Me I don`t have that much trouble,I have worn welding gloves for so long that I have developed a feel for small parts through them.
Pioneerguy600

 

[Cantdog]

Just outside the city of Dartmouth on the Eastern shore.
Pioneerguy600

Great, The wife and I travel up that way as often as we can ( actually spent our tenth aniv. at the Prince George) But the last time we went up the east shore we were on an 18 day motorcycle trip. Came over on the CAT, up the east shore on to Cape Breton stayed in Baddeck for a week and took 200 mile day trips from there. Then started back and came back into Maine at Houlton This was 2003 or 4 I bet you remember the heat it was around the second week in Agust. It was almost to darn hot to ride. It was that way for about a week. We love it up there, people are super. We were on my 1959 FHL Full Dress Harley 2300 miles total on that trip and never laid a wrench on her. Who says chrome don't get ya home???

 

[pioneerguy600]

Great, The wife and I travel up that way as often as we can ( actually spent our tenth aniv. at the Prince George) But the last time we went up the east shore we were on an 18 day motorcycle trip. Came over on the CAT, up the east shore on to Cape Breton stayed in Baddeck for a week and took 200 mile day trips from there. Then started back and came back into Maine at Houlton This was 2003 or 4 I bet you remember the heat it was around the second week in Agust. It was almost to darn hot to ride. It was that way for about a week. We love it up there, people are super. We were on my 1959 FHL Full Dress Harley 2300 miles total on that trip and never laid a wrench on her. Who says chrome don't get ya home???

Great ride, I made a lot of trips on two wheels myself, kept a rough log book on trips and have close to 83 thousand miles under my belt on bike trips. Started riding at 14 on a BRE then graded to a Norton SC and on to a XLCH 60 cube. Next came an Electraglide and a slew of Honda bikes until I got married, had children and the bikes went away. LOL. Oh, and I carried a Pioneer chainsaw on one of my bikes once or twice to cut windfalls outa the way. He He!!
Pioneerguy600

 

[Cantdog]

Great ride, I made a lot of trips on two wheels myself, kept a rough log book on trips and have close to 83 thousand miles under my belt on bike trips. Started riding at 14 on a BRE then graded to a Norton SC and on to a XLCH 60 cube. Next came an Electraglide and a slew of Honda bikes until I got married, had children and the bikes went away. LOL. Oh, and I carried a Pioneer chainsaw on one of my bikes once or twice to cut windfalls outa the way. He He!!
Pioneerguy600

HAHAHA you got me there Jerry!! I carried a lot of weird stuff on a bike but I don't think I ever took a chainsaw with me!! Skil saw maybe!!
That old panhead has been with me quite a spell. Bought it in the fall of 78 to upgrade from my first bike a 1942 45" 70's stlye chopper suicide clutch jocky shift wild rig!! Took my drivers test on that one!! Got my first and only new Jonsereds in 77 still have them both.

The pan is in the best shape it's ever been has about 15,000 mlies since a total rebuild which was completed the day before the above mentioned trip up your way. Even treated her to a new speedometer when she turned 100,000!!!

She is reserved for road trips and Sunday afternoons these days. I've got a Ducati 916 SuperBike and a Ducati 900 SuperSport that keeps me in the wind around here on short hauls.

When I bought that pan I was young and she was old, now we're both old!!LOL!!! Me being a bit older even!!HAHAHA!! If I get up that way sometime perhaps I'll look you up. Haven't been far from home the last couple yrs with this economic crunch!

 

[mpurdy]

Please Help!

Thank you for the informative post! This is my first project saw and am having a blast so far. I have successfully seated the bearings on the crankshaft using the heat method described here.

I am having trouble dropping the crankshaft into the case halfs. I am using an oven and heated the case half for up to 25 minutes at 220F and the bearing would not go in. I am unsure of how much pressure needs to be exerted to get the bearing to fall in. I did not want to tap the crankshaft without asking here first for tips.

What am I doing wrong?

Thanks for the help!

Matt

 

[pioneerguy600]

Thank you for the informative post! This is my first project saw and am having a blast so far. I have successfully seated the bearings on the crankshaft using the heat method described here.

I am having trouble dropping the crankshaft into the case halfs. I am using an oven and heated the case half for up to 25 minutes at 220F and the bearing would not go in. I am unsure of how much pressure needs to be exerted to get the bearing to fall in. I did not want to tap the crankshaft without asking here first for tips.

What am I doing wrong?

Thanks for the help!

Matt

What saw are you working on?
Pioneerguy600

 

[mpurdy]

What saw are you working on?
Pioneerguy600

Stihl 034 Super, Sorry i forgot to mention that!

Thanks!

 

[pioneerguy600]

Stihl 034 Super, Sorry i forgot to mention that!

Thanks!

Take the heat up to 250F and handle the caes halves with welding gloves, the bearings usually slip in with just me pushing them in, push on the crank. Just dropped two bearings into a 460 today.
Pioneerguy600

 

[Mastermind]

I've been using this method with great success since Jerry first posted this thread. I even take some saws apart using heat, especially if I don't plan to reuse the bearings.

One thing I may mention at this point is the fact that I have no problems hitting stuff with a hammer.

Seriously though, I have watched people in the shop be so careful with things they are working with that they end up messing up parts. At times a nudge, or well placed tap in the right direction is all that is needed to prevent the parts from becoming stuck in a nearly inseparable position. It also helps to have the right drivers, drifts, brass hammers, etc in place and ready while the parts are hot. Oil pump on the case.........

Jerry, you should write a book on this subject, it would take a book to cover the topic. LOL

 

[mpurdy]

Take the heat up to 250F and handle the caes halves with welding gloves, the bearings usually slip in with just me pushing them in, push on the crank. Just dropped two bearings into a 460 today.
Pioneerguy600

Thanks Guys! First half done, at 250F dropped right in! I'll keep ya posted on the second half

Matt

 

[souliog]

Nice info Jerry, but you know the rules: without pictures, or even a video, this thread is irrelevant! :greenchainsaw:

Now, a serious question for you Jerry, as well for the other experts. Did you try to insert a "frozen" (home freezer goes down to a temperature of -22ºC) bearing into the hot crankcase ? What were the results ? If not, why not do it?

The same principle can be used to insert the bearings onto the crank. Freeze the crank, warm up the bearings, no?

This is the way I always did 2-stoke dirt bike main bearings.

 

[pioneerguy600]

I've been using this method with great success since Jerry first posted this thread. I even take some saws apart using heat, especially if I don't plan to reuse the bearings.

One thing I may mention at this point is the fact that I have no problems hitting stuff with a hammer.

Seriously though, I have watched people in the shop be so careful with things they are working with that they end up messing up parts. At times a nudge, or well placed tap in the right direction is all that is needed to prevent the parts from becoming stuck in a nearly inseparable position. It also helps to have the right drivers, drifts, brass hammers, etc in place and ready while the parts are hot. Oil pump on the case.........

Jerry, you should write a book on this subject, it would take a book to cover the topic. LOL

Randy,..I can`t recommend hitting anything with a hammer, I do it all the time but I know how hard and when to hit, it is an acquired feel so that no damage is done. I have posted picts over the years of busted up parts that have come in to me from someone that got carried away with a hammer.
I actually use a big right hand to settle bearings in place using heat to swell the appropiate part. I have tried the parts in the freezer route but was never impressed with the results. We used dry ice in the marine fitters trade to shrink shafts and heat on the bearings or collars we intended to slip over the shaft. Just putting parts in a regular home freezer does not make much difference over just room temps, it wouldn`t hurt but just not worth the effort.
Pioneerguy600

 

[Cantdog]

I concur 100% Jerry,,,,,Never had much luck with the freezer thing myself either...right theory but not enough degrees of change to make very much difference on steel. Now dry ice will definitely cause enough change to be used with great success. But it's becoming harder to get these days with reefer trucks etc. My father worked as a welder at Quincy Navel Shipyard during the big one (WWII) and always told this story.... Seems the ring gears for turret rotation on the 16" guns had to be frozen in dryice in order to fit them in the holes in the deck. They were only an interference fit with no other fastenings. So when the end gap (just like a piston ring) reached a certain measurement from cooling they unwrapped the gear and slid it into place. It took a dozen men or so. Then they beat the warming and expanding gear all the way around on the inside with mauls as it expanded which helped it not get caught and move smoothly until the end gap was zero. This didn't take very long on a hot ship deck in the sun. One day a newbe struck to close to the gap and got his maul stuck. First he broke the handle off trying to free it and then a couple older guys tried beating the maul out of gap but to no avail. The old man said the ring expanded and the gap closed and pinched the piece of maul head right off. Now that's usable temp change!!!

 

[pioneerguy600]

I concur 100% Jerry,,,,,Never had much luck with the freezer thing myself either...right theory but not enough degrees of change to make very much difference on steel. Now dry ice will definitely cause enough change to be used with great success. But it's becoming harder to get these days with reefer trucks etc. My father worked as a welder at Quincy Navel Shipyard during the big one (WWII) and always told this story.... Seems the ring gears for turret rotation on the 16" guns had to be frozen in dryice in order to fit them in the holes in the deck. They were only an interference fit with no other fastenings. So when the end gap (just like a piston ring) reached a certain measurement from cooling they unwrapped the gear and slid it into place. It took a dozen men or so. Then they beat the warming and expanding gear all the way around on the inside with mauls as it expanded which helped it not get caught and move smoothly until the end gap was zero. This didn't take very long on a hot ship deck in the sun. One day a newbe struck to close to the gap and got his maul stuck. First he broke the handle off trying to free it and then a couple older guys tried beating the maul out of gap but to no avail. The old man said the ring expanded and the gap closed and pinched the piece of maul head right off. Now that's usable temp change!!!

Metals do have wicked expansion and contraction power when either heated to expand or frozen to contract. My early days were spent in the forge, I helped forge weld many wagon wheel rims. In the wood shop we would block out the rim woods,turn the spokes, fit up the rim woods, turn out the centers and bore the radiating spoke holes. Once all the woodwork was done and tightly fitted the steel rim would be buried in the cokeing and heated cherry red, grabbed with 4-6 sets of tongs when ready and carefully dropped over the wood rim, a few quick bumps of the hammer set the rim and it was then quickly dropped into a tub of water to put out the fire, pulled out again and allowed to complete cooling down, the steel would contract and force all the wooden parts together with great compression, that wheel was then ready to put on the axle and would run for many years until rot usually would take its toll. I did see a few return with the center wallowed out but we could turn it oversize and make a bushing from Lignan Vitaee , that would outlast the rest of the wheel if plenty of tallow was kept in the axle socket.

Pioneerguy600

 

[Cantdog]

Yep... not many have that type of knowledge and firsthand experience these days. Much less elaborate and specialized but that's the same way you properly handle a peavy. Set the point, scrape the handle taper for a fair fit, mark the handle where the dog attaches then throw the peavy head in the stove or outdoor fire until cherry red. Pick it out with the point, align the mark with the dog, and slam the handle end down firmly 2-3 times on the butt end of a chopping block or similar to drive and set the head. Then hit it with a bucket of water or toss it in the snow to stop the burning and to cool and contract the iron. The handle and head will stay put and never loosen until, like you said, rot will finally prevail unless you take real good care of your peavey and don't leave it out doors when not in use. Another case where the correct amount of heat and cooling will work wonders and make a long tedious task quick and simple.

 

[mpurdy]

Axial Stress

When assembling the case halves I had to draw the case the last little bit using the case bolts. As Jerry mentioned, I now have some axial stress and the crank is not moving as smoothly as it should.

how hard should I have to hit the crank at both ends to relieve this stress? if all of the stress is not relieved, will operating the saw relieve the remaining stress or will this damage the bearing?

I do not own a brass hammer, would a piece of hardwood and a hammer suffice? Or a brass punch?

Thanks for the help!

Matt

 

[pioneerguy600]

When assembling the case halves I had to draw the case the last little bit using the case bolts. As Jerry mentioned, I now have some axial stress and the crank is not moving as smoothly as it should.

how hard should I have to hit the crank at both ends to relieve this stress? if all of the stress is not relieved, will operating the saw relieve the remaining stress or will this damage the bearing?

I do not own a brass hammer, would a piece of hardwood and a hammer suffice? Or a brass punch?

Thanks for the help!

Matt

Sorry Matt, I answered your question but I see it did not post, this has been happening off and on now for a while, I see many times where it just gets hung up and times out.
You can use anything that is softer than the steel in the crank, it may take a good bump to move the bearing aside, this is what you want to happen, it moves outward just a tiny bit and when done in both directions it relieves the stress of the balls on the sides of the races so you are actually trying to get the ball bearings exactly centered on the races.
Pioneerguy600