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Quadras, roller main bearings, questions...

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Quadras, roller main bearings, questions...

Old 05-18-2009, 06:46 PM
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av8tor1977
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Default Quadras, roller main bearings, questions...

Hi,

Well, I have this cute little "Eager Beaver" 21cc McCulloch blower that I was taking apart. I got kind of excited, as it was looking like it was not only a serviceable engine, but that it would turn out to be a quite light conversion engine as well. Things were going along quite well, and I was thinking it might make a good .60/.90, if not .90/120 engine, but when I got down to the last part, I found roller bearings on the crankshaft. AARGGGH...

But then I got to thinking, hey, the roller bearings are lighter than ball bearings, and the Quadras used them with a brass thrust washer, so why not set it up that way???

The Quadras and their brass or bronze thrust bearing washers were popular before my time. Well, not before I was a mechanic and playing with airplanes, but before I was playing with BIG airplanes.

So anyway, what help/advice can you guys give me on using roller bearing mains with thrust washers??? This engine has me interested because it has nearly the same port sizes as an Echo 21cc engine, and very generous transfer ports, but in the end will come out even lighter.... Where would I even source the thrust washers?

Anyone?

AV8TOR
Old 05-18-2009, 09:41 PM
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Default RE: Quadras, roller main bearings, questions...

Thrust washer= the right material and your lathe!!!!!
Old 05-19-2009, 03:19 AM
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Default RE: Quadras, roller main bearings, questions...

Figure where you want the crank to ride then make a washer to fit. Oilright brass bushing material should do the trick.

Most Thrust Washers I've seen have oil grooves to help in the lubracation.

What holds it in place now?

Ralph
Old 05-19-2009, 04:34 AM
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Default RE: Quadras, roller main bearings, questions...



Apparently there was very little thrust in the blower application.  The crankshaft just floats in the roller bearings.  No thrust washers; just the roller bearings and the crank riding next to them.  It has about 1/8" or a little less fore and aft "play".



AV8TOR



.

Old 05-19-2009, 07:34 AM
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Default RE: Quadras, roller main bearings, questions...

Pop the botom off that Mac beaver and post a photo.....seems like a cure is possible! Capt,n
Old 05-19-2009, 08:41 AM
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Antique
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Default RE: Quadras, roller main bearings, questions...

I think Ralphbf has the right answer.  ACE carries OILRIGHT bushings in many sizes, get a large one and machine it to meet your specs...............
Old 05-19-2009, 12:44 PM
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Default RE: Quadras, roller main bearings, questions...



Now that's helpful.  Ace and "Oilright Bushings."



Thanks, I'll look into that.



AV8TOR



Old 05-19-2009, 10:54 PM
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Default RE: Quadras, roller main bearings, questions...

Two of these might make a nice size twin.
motorhd
Old 05-19-2009, 11:24 PM
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Default RE: Quadras, roller main bearings, questions...

Well,since i know you have a lathe,heres what i would do.
Locate one of my brass punches.I have some fairly large ones for large bushings and bearings,ect..
Drill center out to fit crank.
Face off the front square.
Use cutoff tool to make my washer.
Use a file to cut X grooves on booth sides of the washer for extra oil.
This way you can make the washer thickness exactly the size you want.All the thrust washers i have put in engines looked like this unless they where in halves and where installed in the center main crank bearing.But even those had oil grooves in them.
Ace would be good start and a great suggestion but i doubt you will find the exact thickness you need.
If ya want illpull one of my spare quadra 35s apart and take a look and post a pic for ya.I have a couple in a box with some extra parts.
Old 05-20-2009, 11:12 AM
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Default RE: Quadras, roller main bearings, questions...



Sure Buck, if you have the time a pic or two would be nice.  Thanks.



AV8TOR

Old 05-20-2009, 09:57 PM
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Default RE: Quadras, roller main bearings, questions...

Heres a pic of the crank,ect...
You can see the thrust washers next to the bearing.They have a grove cut into the case to support them.
The seals are on the outside.
What i would dois make 2 thrust washers and just run them between the counterweight and bearing,or between bearing and case if possible.Bearing and case would be best.
The counterweight shouldnt be actually flat but have a very slight half dome to it so it doesnt rub on the case.
ooops,i dont thnk you could run them between the counter weight and bearing,it might block the bearing from getting some oil.But they are on the Quadra.Maybe the grooves do it.
.
Theres also brass ones next to the couterweight but i believe there their to keep the CWeight from rubbing the bearing.The outside steel washer next to the seal keeps the crank from walking.
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Old 05-20-2009, 10:37 PM
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Default RE: Quadras, roller main bearings, questions...



Ok, thanks Buck. That's about what I was thinking. I am sure some radial grooves in the thrust bearing washers would supply enough oil to the roller bearing. I found some bronze thrust washers on McMaster Carr. I'll probably order them and modify as necessary to fit. That bronze bar stock is expensive!!



AV8TOR
P.S. Actually, as I study your picture more, I see that the steel washers are there to keep the bearings from moving. The "thrust" is taken by the bronze washers.

Old 05-21-2009, 12:17 AM
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freeair
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Default RE: Quadras, roller main bearings, questions...

gee that engine has some case volume, half crank weight etc. if you can pack the case this little beaver should gain alot more power.
Old 05-21-2009, 11:15 AM
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av8tor1977
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Default RE: Quadras, roller main bearings, questions...



That's not my McCulloch in the picture.  It is a Quadra I believe, of Buck's.



AV8TOR



Old 05-21-2009, 11:07 PM
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Default RE: Quadras, roller main bearings, questions...

Its the pic of the early Quadra 35.The rear bolts that hold the mount on.The top 2 are closer together than the bottom 2.
Old 07-15-2009, 10:24 PM
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Default RE: Quadras, roller main bearings, questions...

Anyone need a Quadra 35 crank, Rod, piston and ring. These parts are in very good shape and were just removed from a Husky 35 chain saw. The crank is the CD version. I used to sell these all the time. They are becomming extremely rare and hard to find. The Husky 35 and Jonhnsered "little John" had CDI, and the Pionier P10 had points.

Pm me

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