Author Topic: Bushed bearing replacement  (Read 8680 times)

Doug

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Bushed bearing replacement
« on: January 15, 2007, 09:45:17 PM »
Gus has issues....

How understated....

How to remove and install bushings in a Petteroid?

Here is a good shot of what the front bearing and replacement looks like ( the longer one is the rear )

http://www.putfile.com/pic.php?img=4525017

Please any thoughts and input.

Notice the smear of brass between one side of the split in the shell and the other. The rear still has a clearly defined joint but the front no longer does.

Seems to me there should be an easy way to get the old one out like pealing open the joint and knocking the new one in with a hard wood block. But Gus is stubborn and I suspect the machining tollerences aren't what they should be perhaps a little tight????

Doug

rmchambers

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Re: Bushed bearing replacement
« Reply #1 on: January 15, 2007, 10:55:45 PM »
Doug,
    Gus is giving you grief every step of the way eh?

You're going to trash the old bushing anyway right so you don't care if it gets beat up on the way out?  I'd take a triangle file and open up where that joint should be - that smear of brass as you put it.  if you can get some meat out of the way there and not damage the holder you should be able to relieve some of the pressures and press that bad boy out. 

You didn't mention if you had a drift the same diameter as the inner bushing.  If you had that, you could put the whole shebang in a vice (protecting the surfaces of course) and drive the drift in there and push the bushing out.  You'd have to stand the cast piece up away from the vice so the bushing had somewhere to go.

Slow and easy, but I think that's probably the way you work anyway being the perfectionist you are.

I doubt putting dry ice on the bushing would do you much good (shrink it) unless you opened the joint up a bit so it had somewhere to contract to.

Good luck

Robert

Doug

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Re: Bushed bearing replacement
« Reply #2 on: January 15, 2007, 11:10:19 PM »
Thought about cutting into it with a blade....

Its nice to have a sounding board. And I guess this should serve as a warning to others that Indian bushed type engines are a real bear to service....

Bearing shell diameter is about + 2 inches, I don't have anything that size. I can use the press at work....

Maybe I can match up something to press it with but I'm afraid that I may screw up the housing in the press and the cost of having to repair and then line bore the housing scares me.

Doug

Gus doesn't like me, the feeling is becoming mutual....
 

rmchambers

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Re: Bushed bearing replacement
« Reply #3 on: January 16, 2007, 12:22:02 AM »
It's a safe bet to say that the outer bearing holder is plain inside and since you have the replacement bushings you can see there's nothing special about the outside of them that's going to hang up and damage the outer bearing.

Do you have a drift at work the right size?  Can you turn one on the lathe at work (bit of government work we used to call that)?  I think once you got the right pressure on it with the right size drift she'd push out pretty easily.  If you're turning one at work I'd make a pilot piece a tad smaller than the inside diameter of the bushing so there's no chance of things crumpling up and getting in the way.

As long as the cast piece is well supported I don't see you having any trouble with the press..  Git 'er done!

Robert

hotater

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Re: Bushed bearing replacement
« Reply #4 on: January 16, 2007, 12:44:34 AM »
answered in another place....are you impatient or WHAT!? 
7200 hrs on 6-1/5Kw, FuKing Listeroid,
Currently running PS-Kit 6-1/5Kw...and some MPs and Chanfas and diesel snowplows and trucks and stuff.

Doug

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Re: Bushed bearing replacement
« Reply #5 on: January 16, 2007, 01:25:32 AM »
Impatient, frustrated, disapoint, disgusted, slight head acke, sore elbo, gassy.


Doug

biobill

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Re: Bushed bearing replacement
« Reply #6 on: January 16, 2007, 02:41:41 AM »
Doug
   Looks like something I used to see in British bikes.

1) Are you sure you need a new one? What's the clearance? It ain't no race motor, if the clearance is in spec, I'd run it. Looks easy enough to replace down the road if needed.

2) If it needs replacing, you don't care about it but you don't want to hurt the carrier. You need something smaller than the carrier bore but larger than the bearing bore. Pipe,socket, fitting, whatever. Preferably without sharp edges but if it's the right size don't sweat it. Cast iron is hard and you would really have to work at it to render it unservicable.

3) Get some blocking that will support the carrier high enough above your solid work surface that you can knock the old bearing free.

4)Put the new bearing in your freezer. You want to heat the carrier slowly and evenly. A propane stove works great for stuff that size, a torch, whatever it takes. Again, it's iron, it would be really hard to screw it up. 400-500F is good. Hot enough that a drop of water jumps off the surface.
 
5) Get a flat something that you can use to seat the new bearing in the carrier. It will go in quite easily, no BFH needed.

6) When carrier is hot, knock out the old bearing, quickly clean the bore with a dry rag, and seat the new bearing making sure to line up any oil holes

               Piece of Cake

  Lots of other ways to do it too.  But this will git er done              Bill
Off grid since 1990
6/1 Metro DI living in basement, cogen
6/1 Metro IDI running barn & biodiesel processer
VW 1.6 diesels all over the place
Isuzu Boxtruck, Ford Backhoe, all running on biodiesel
Needs diesel lawnmower & chainsaw

Doug

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Re: Bushed bearing replacement
« Reply #7 on: January 16, 2007, 02:51:31 AM »
Thanks Bill.

The gouges and metal/sand/carbide are the reason I want it out.
I got two new sets and want Gus starting over on clean good bearings.
I expressly order these bearings incase of a Rajkot moment as has happened to poor old Gus.
One more thing Gus spins at double that of a Lister. Any abrasives will lap it 4 times faster so why risk a bearing like this when i have new ones?

So far three 4 guys, very simmilar sugestions comfort level rising....

Tommorow I see about having a 2 1/2 driver made to push if the heat and cool fails to drop the bushing.

Thank you
Doug

mobile_bob

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Re: Bushed bearing replacement
« Reply #8 on: January 16, 2007, 03:07:27 AM »
clamp it in the vice, take a hacksaw and carefully cut the bushing in the groove and slip it out

find a flat plate and press in the new one,,, no big deal :)

certainly no hill for a climber!

bob g
otherpower.com, microcogen.info, practicalmachinist.com
(useful forums), utterpower.com for all sorts of diy info

Doug

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Re: Bushed bearing replacement
« Reply #9 on: January 16, 2007, 03:15:18 AM »
Thank you Bob:

Lots of solutions to this.

I'll start with the least radical heat and cold move on to puller and press and cut the grove if nothing else works.

Also waiting on Anand to provide the tollerence for the housing, I suspect this one is a little tighter than its suposed to be....

Doug

hotater

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Re: Bushed bearing replacement
« Reply #10 on: January 16, 2007, 03:22:29 AM »
Doug--

How can the housing be undersize if the crankshaft turns in the bearing?  The ID shrinks if the OD is swaged.
7200 hrs on 6-1/5Kw, FuKing Listeroid,
Currently running PS-Kit 6-1/5Kw...and some MPs and Chanfas and diesel snowplows and trucks and stuff.

Doug

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Re: Bushed bearing replacement
« Reply #11 on: January 16, 2007, 03:47:30 AM »
Maybe I didn't word this right.
I was thinking perhaps the housing was slightly smaller than it should be. A little more of an interference fit that needed.
Hey what do I know to be honest. But the joint on the rear main doesn't look like it compressed near as hard and there is no dragging of brass over the joint. I just took an uneducated guess there may be an machining issue too snug a fit or out of round slightly.

This kind of thing happened a lot to me in the electric motor shops on rebuilt end bells and shafts.
I could see and feel the effects of being off by less than .001 in some motors. Parts just wouldn't fit right and when you squeeze a ball bearing even with a C3 clearence they do wierd stuff.

I know this sounds like I need more fiber in my diet but I would reject machining of parts if the assembly didn't feel right. I could tell if things were egg shaped or just plane worn out by touch. I used to cringe when I say other guys heating housing to slip them on a bearing because I new it was too tight and that motor would be back.

I shouldn't even try and compare the two, its not even aples and oranges, more like apples and Arangutans.
When your mental tool kit is full of stuff from unrelated jobs what are you going to do?
And the old man ( my boss )made me a precison and cleanlyness freak.
Your nails had to be clean for bearings, bushing work assembling parts like oil slingers ect.
Lacing and laying of coils had to be done a certan way. I drove the old man made because I wound armatures and stators left handed and he would absolutely blow a gasket if I did a span down winding because you could tell where I started and finished ( still good just obvious how it was done and or looked like it was done in England ).

So in short I don't realy know what I am doing and make some uneducated guesses about deisel engine bushings based on rotating electrical machines and standards that aren't related.
 
Doug

hotater

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Re: Bushed bearing replacement
« Reply #12 on: January 16, 2007, 04:30:03 AM »
Good post, Doug---

I'm still not quite over my more 'precise' gunmaking life, but I'm working on it.   ;)

My old business partner, Brian, would say,  "We ain't buildin' no damn piano!"

There's a certain amount of 'self fitting' in any machinery.  You're right, electric motors are a different animal entirely, so are jet turbines gyroscopic friction drives, but engines have a certain amount of 'running clearance' that develops as the roughness wears off. 

In  my *opinion*, after hatching two of them and watching one grow old and retire--  It's better to clean it out, grease it good, and crank it up.  Run it 50 hours  or so and LOOK at it, and listen to it, ring it, and rub the goo out of the trash catcher between your fingers and determine if there's a canibal hiding in the engine somewhere.  If the answer is 'no', run it some more.  Put a thousand hours on it and then take it apart and see if something NEEDS doing.

  If a cam turns freely and doesn't rattle there's no reason to drive out bushings looking for trouble...yet.  It'll let you know without flinging parts in the neighbor's yard.  SLOW speed means there's time to identify what *might* be going wrong before it makes smoke, sparks, expensive noises, and adrenalin squirts.

I'm just suggesting figuring out what's wrong with it by running it instead of worrying about it.

Remember, it's only beurocrats and polititians that *fix* things that don't need it.     ;)
7200 hrs on 6-1/5Kw, FuKing Listeroid,
Currently running PS-Kit 6-1/5Kw...and some MPs and Chanfas and diesel snowplows and trucks and stuff.

rmchambers

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Re: Bushed bearing replacement
« Reply #13 on: January 16, 2007, 05:09:13 AM »
I guess you should be glad you weren't a watch maker in a former career then, you'd never get the thing finished. or if you did, it would keep perfect time.

My dad says "you can't make a silk purse with a sows ear" - you're getting some fairly rough stuff from India, you're making do with the best you can get and you're doing the best you can.  I think once you're finished you will end up with a decent little petteroid.  I want to hear what the QC guy says when it runs.  He's the guy going to have to worry about replacing parts in it when he's 40-50 years old.

Robert

mobile_bob

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Re: Bushed bearing replacement
« Reply #14 on: January 16, 2007, 06:48:38 AM »
Doug:

upon closer look at your brg situation i have a couple of observations but first a queston

is this a cam brg or crank brg, i assume it to be a crankbrg because of its size?

the carrier and bushing look for all the world very similar to what detroit used in their 2 stroke diesels for the outboard cam bgs
the support is very similar, the brg is as well.
they are almost never changed out! and the cams run at engine speed instead of half speed of a 4 stroke.

i am unclear here, why are you wanting to change the bushings? have you measured them to see if they are out of spec? or do they just not look real purdy?
(ok i should type "pretty" i can spell it and my spelling in general is not good, so i shouldnt try to spell wrong)

the petteroid has a gear oil pump doesnt it? likely more than enough oil for that bushing to do its job for a very long time, unless it is scored out or beat to death.
i certainly would not get alarmed about some gouges and scratches, there is far more oil wedge capability than the typical lister rod brgs with all their grooves, in my
opinion.

maybe they are useable and not so bad?

i just looked at your album, the oil pump looks pretty good, i think those bushing will likely run just as long as new ones


bob g
otherpower.com, microcogen.info, practicalmachinist.com
(useful forums), utterpower.com for all sorts of diy info