576xp sealed crankshaft bearing in 372xp case??

[weimedog]

Because the bearing is wider and the clutch is spaced off the bearing.

And those 372's have a "lip" cast into the case where the bearing will be seated on the clutch side, so unless that's hacked, the bearing won't be flush on the inside of the cases and push the crank off center to the flywheel side by 1mm or about .039"...if it even will let the case get together, I've got a set out in the shop, might go measure. Also the crank ends have a different diameter than the 372's on the flywheel end. So then back to the PTO side, if you machine the pocket, now the sleeve & worm would also have to be modified....if possible or the clutch would be pushed out .040 as well. So take your pick, that .039" is a deal breaker without some serious modifications.

 

[Yotaismygame]

I measured the bearings already and they're the same except the 576 bearing is 1 mm wider. I don't see why you're bringing up the crank ends on the flywheel side. The flywheel seals between the two saws have the same OD but different ID

 

[weimedog]

I measured the bearings already and they're the same except the 576 bearing is 1 mm wider. I don't see why you're bringing up the crank ends on the flywheel side. The flywheel seals between the two saws have the same OD but different ID

Because you aren't the only one reading this and others might want a complete description of the bearing differences. .040" is not a trivial amount relative to the rest of the parts and how they fit. The relevant part to you is the difference in width makes it a tougher problem than simply a bearings swap. I can only assume a reason to do this is the cases have been damaged where a standard seal no longer works. I guess there is no telling why folks do what they do. But the .040" creates a variety of issues that make a simple swap of the bearings impractical from what I'm seeing which was your original question and my humble opinion. I'm actually looking at a bearing set from a 576 and a pile of 372 cases as I type. Doesn't mean its impossible depending on what you have for skills and tools, I could force the situation and make it work; but not something the average person reading this will want to do. At a minimum would need to get another .040 depth on the pocket...and trim .040 from the sleeve and worm gear to keep the clutch were it needs to be and with the right length of bearing surface. probably other stuff as well. And I guess to your last question, don't ask a question on a public forum if you don't want to see or hear a variety of answers and/ or opinions.

 

[blsnelling]

There is not room between the case halves for anything close to .040".

 

[cuinrearview]

There really is no reason to do it. Parts are plentiful and the 372 bearing is much cheaper. I guess if you were in a desperate situation caught out in it and you HAD to chainsaw, but more than likely you wouldn't be able to reference this thread anyway.

 

[Yotaismygame]

Jim I agree. It seems like the only reason you would want to put a 576 bearing in a 372 would be if the case is damaged and you cant install a new seal in it. You could grind down the lip where the seal goes to gain 1 mm of clearance for the 576 bearing. Far from ideal.

The bearings only go in so far before they bottom out against the side of the pocket. Any extra width will rest up against the crankshaft which will likely be enough to keep the case halves from coming together tight. And if it does get tight there will likely be enough side load stress on the bearings to cause failure.

Weimdog I dont think you've been reading the whole thread. No reason to get upset, just having a simple conversation about chainsaw bearings. I'm not upset.

Came on here looking for a conversation about this and possibly an answer. I believe it was successful

 

[weimedog]

Weimdog I dont think you've been reading the whole thread. No reason to get upset, just having a simple conversation about chainsaw bearings. I'm not upset.

Came on here looking for a conversation about this and possibly an answer. I believe it was successful

Not upset, a question many might ask, and that 576 bearing MIGHT be the same as the 562 and a few others as well....346? I think it could be done as I stated (Rework parts to get 576 PTO bearings in a 372), just you would really want to make it happen and have some skills & tools. But to your point, a simple conversation gets viewed by many who might have more general questions than the original point focus. In fact a great question to address is what is the best bearing combination for those 372's, OEM, Steel caged Nachi and other similar quality brands, even hybrid's. Think there is a person in this conversation who has explored all those angles. That's relevant information that many can benefit from who also might be attracted to this thread because of the Text Strings related to 372 PTO bearings.. Threads like this appeal to a larger audience and some will get a life of their own....controlled by the interest of both those who answer and those simply looking for data.

 

[cuinrearview]

Not upset, a question many might ask, and that 576 bearing MIGHT be the same as the 562 and a few others as well....346? I think it could be done as I stated (Rework parts to get 576 PTO bearings in a 372), just you would really want to make it happen and have some skills & tools. But to your point, a simple conversation gets viewed by many who might have more general questions than the original point focus. In fact a great question to address is what is the best bearing combination for those 372's, OEM, Steel caged Nachi and other similar quality brands, even hybrid's. Think there is a person in this conversation who has explored all those angles. That's relevant information that many can benefit from who also might be attracted to this thread because of the Text Strings related to 372 PTO bearings.. Threads like this appeal to a larger audience and some will get a life of their own....controlled by the interest of both those who answer and those simply looking for data.

Nachi C3s metal cage from Shorenutz on Ebay. $9.50/pr. Like a sore pecker, ya just can't beat it. Ordered two sets today.

 

[weimedog]

Nachi C3s metal cage from Shorenutz on Ebay. $9.50/pr. Like a sore pecker, ya just can't beat it. Ordered two sets today.

C u have the right color of saw in the thumb nail.....building a 2171 from a new set of OEM cases........and deciding as we speak do I push out those nylon caged bearings that come with the OEM cases and replace them with Nachi's or even ceramic hybrids. Going to call it a 2171xpw because of the top end its going to have... SO this is a relevant discussion to me right now.

 

[Tor R]

I don't see how 1 mm is going to cause a problem, but that's merely speculation.

its some time since i last was inside a 362/372, I may have forgotten some details. And, I've never been inside a 576.
The first you should study is witch 576 parts who is bolt on, but the little I remember from my 372 builds I would think you may have to make a oil worm sleeve.

Its possible to machine a 372 case so a 576 bearing will work,if you're going that route you should also machine the 372 seal pocket up so you later can swap the 576 seal if needed.

Proprietary bearing engineering goal is mostly to make a crank a tad more compact, in this case the 346/550/562/576 bearing has the center of the balls offset, it is 12mm wide but it also contain the seal.
The traditional 372 has a 11 mm wide bearing, a seal either 3.6 or 3.9 mm wide (can't remember the exactly widht), and there is a security distance between those two parts.
I probleby doesnt miss by much if I'm saying the 372 b&s is 15.5-16mm wide.

Technically it is possible to do it, just alot of work.

 

[Yotaismygame]

I put a used 576 pto bearing in a junk 372 case half. Took a dremel to the lip. Just have to grind off 1mm from the sleeve for the clutch to space right. I don’t see why this wouldn’t work. Probably won’t take it farther than this unless the opertunity comes around. Could be a good solution to a spun or damaged seal lip.

 

[weimedog]

Mi

I put a used 576 pto bearing in a junk 372 case half. Took a dremel to the lip. Just have to grind off 1mm from the sleeve for the clutch to space right. I don’t see why this wouldn’t work. Probably won’t take it farther than this unless the opertunity comes around. Could be a good solution to a spun or damaged seal lip.
View attachment 715620

might have to make a sleeve now for the worm gear to ride on, and get the length right to keep the clutch alignment right. Also might need to take a little off the worm gear as well. Probably won't interfere with the pump itself, if you get the sleeve and worm gear right. Should be possible. Might be able to start out with the "sleeve" for 372's and cut the "seal" surface off? And last but not least, the washer, that thin washer is there keep the worm gear off the seal. You will need to figure out a new washer to keep the worm gear from chewing into the seal and ruining a good idea.

 

[Yotaismygame]

The bearing is only 1mm wider than the 6202 bearing. Why couldn’t the original sleeve be shortened 1mm and call it good? The worn gear would be the only concern I see. If I get bored one day I’ll try to put it all together and see if I can make it work.

 

[weimedog]

The bearing is only 1mm wider than the 6202 bearing. Why couldn’t the original sleeve be shortened 1mm and call it good? The worn gear would be the only concern I see. If I get bored one day I’ll try to put it all together and see if I can make it work.

Maybe if you take that from the seal surface end of the "sleeve". Might leave enough of a "top hat" to even hold that washer which would make it a workable solution I think. And only 1mm? That's = 0.0393700787" or .040. That is not an insignificant amount. But figure it this way. Starting from the end of the crank shaft and work back....the clip & washer to hold the sprocket, Clutch drum HAS to ride on the bearings and bearing surface on the crank....at the same point as stock. That has to be fixed. Then the clutch has to "seat" at the proper distance as well. It sits in front of the worm gear....and .040 would be a problem if its (the worm gear) pushed out by that amount. SO the end of the worm gear has to have clearance so its not jammed in to the clutch itself. Enter the "sleeve"...you can probably see the rest of where I was going with that. But you have to keep the worm gear from eating the bearing seal and you have to have a sleeve as a bearing surface for the worm gear, and that system has to be shorter by the .040 for the other parts to still be where they have to be. For a reference, if you have standard text, .040 is about as wide as an "e" on my screen, more than enough to jam stuff up But I think if you can trim that sleeve..things work out.

 

[Yotaismygame]

You could be right. But there’s a lot play after the clutch all the way out. It’s not like all the stuff is a tight fit there. I honestly think by just taking 1mm from the sleeve on the skinny side would get the job done. Sounds like some hands on experiment is in order. I could be making this sound much more simple than it really is.

 

[weimedog]

You could be right. But there’s a lot play after the clutch all the way out. It’s not like all the stuff is a tight fit there. I honestly think by just taking 1mm from the sleeve on the skinny side would get the job done. Sounds like some hands on experiment is in order. I could be making this sound much more simple than it really is.

Actually the "bearing" surface on the sleeve, washer and worm gear distance is tight to the back of the threaded on clutch when it hits bottom. There isn't .040" of slop in there. The premise of .040" is "slop" like numbers is totally off base. I've had to cut down AM worm gears simply over .015 as some came a bit too long. If you cut the seal surface end, that bearing distance where the worm gear rides will be correct and hopefully there is enough material to still have that washer in there to protect the new seal concept. Cut the small end then you do have to cut the worm gear and hope you haven't pushed the thing too far towards the bar oil pump...but you do what you do and post pics....