Briggs and Stratton crank bearings

[frascati]

I'm looking into a 21hp single cylinder engine listed for sale. In the description is this..

Heavy-duty Teflon coated bronze sleeve bearing withstands twice the belt load of standard bearings to reduce wear

Really? Bronze sleeve bearing on the output shaft is superior to ball and races?

[mwerles]

Standard bearings are probably bronze,not teflon coated
Les

[bgsengine]

I'm looking into a 21hp single cylindar engine listed for sale. In the description is this..

Heavy-duty Teflon coated bronze sleeve bearing withstands twice the belt load of standard bearings to reduce wear

Really? Bronze sleeve bearing on the output shaft is superior to ball and races?

Ball bearings are not particularly standard - they are premium. They probably refer to the standard "DU" Bearing or plain old everyday aluminum bearings

[frascati]

Ball bearings are not particularly standard - they are premium. They probably refer to the standard "DU" Bearing or plain old everyday aluminum bearings

Where the heck have I been? Every small engine I've ever worked on, from the very cheapest weed trimmer, has had ball bearings on the crankshaft. Non-Premium? For a 600 dollar vertical shaft engine?

Maybe I've misapprehended the description? They are referring to the bearing on the output side of the crankshaft...no?

I just googled "briggs and stratton bronze bearing" and hit this link...
http://www.jackssmallengines.com/small_ ... Horizontal

Teflon-coated, self-lubricating bronze PTO ball bearing

Teflon-coated...bronze pto ball bearing???? Misprint?

I google image searched "tecumseh crankshaft bearing" and they were all ball bearings.
Are we talking connecting rod bearing on the crankshaft? Or are we indeed talking about the crankshaft/case bearing? As I said, I'm not that well seasoned with repair of small engines but I've never ever come across a bronze sleeve on the crankshaft/case output bearing.

[bobodu]

A six hundred dollar 21 horse ain't what I would call premium.

[jgflawn]

Heavy-duty Teflon®-coated bronze sleeve bearing reduces wear and withstands twice the belt load of standard bearings

I'm assuming you're looking at the B&S Intek vertical OHV from northern tool?

Briggs & Stratton Intek Vertical OHV Engine with Electric Start — 540cc, 1in. x 3 5/32in. Shaft, Model# 331977-0001-G1

A bronze sleeve bearing will withstand twice the belt load because it is longer (probably 1" versus 12 mm for a bearing), holding more of the shaft from movement. Being bronze, it will wear itself instead of the shaft it is holding. Think of the front auger on a 2 stage snowblower. Bronze bearings on either side (before they were replaced with plastic). Ariens still uses in their 2 stage. Hold up well with low speeds. self lubricating - once upon a time they were called 'oil-lite' or some such thing. Bronze bearings are used in MTD 2 stage on the rear wheel axle as well - outer hexagon shape to fit a stamp in the housing. Again, self lubricating - but a wearable part - cheap enough too ($5 a piece). Usually TSC carries them in the bearing isle - at least here in Can. Tractor Supply I think in the US. My local repair shop has them hanging on the wall in-stock inside the door along with all regular bearings.

That being said, be prepared to replace them under high speed loads. Max on the above engine is only 3300 rpm, and assuming lawnmower belt driven, probably only 1800 in practical use. Note also the specs (as opposed to the marketing wording) describe 'bearing type' as 'plain'.

So twice the belt load - sure - horizontal force on a vertical shaft is larger. Longevity - not so much in my opinion.
happy hunting

[Mek-a-nik]

Ball bearings are found in two strokes, I believe, because of their RPM potential. Not sure, though.
You are correct, though, you haven't worked on many small engines. The cheapest ones don't have bushings or bearings. The crank/cam ride on the aluminum case.

[bgsengine]

Ball bearings are not particularly standard - they are premium. They probably refer to the standard "DU" Bearing or plain old everyday aluminum bearings

Where the heck have I been? Every small engine I've ever worked on, from the very cheapest weed trimmer, has had ball bearings on the crankshaft.

Hmm must be a sheltered life.. LOL! When I started out in this business 30-some years back most engines *I* worked on were a sleeve bearing - DU style most often, Ball bearings were a "Premium" Extra - More common to see ball bearings on 2-strokes (Obviously, sleeve bearings don't hold up well under high RPM ) and Horizontal Shaft engines (they tend to have a lot more side loading) - The *bigger* the engines got, the more likely you would encounter ball bearings. as well. but still sleeve and DU bearings typically still outnumbered ball bearings.

Non-Premium? For a 600 dollar vertical shaft engine?

600 bucks aint a premium when you're talking about 21 H.P. You want a premium quality 21 HP engine, you gonna be wanting to think about spending twice to three times that amount.

Maybe I've misapprehended the description? They are referring to the bearing on the output side of the crankshaft...no?

Yes, that is generally the "important" bearing for application purposes.

I just googled "briggs and stratton bronze bearing" and hit this link...
http://www.jackssmallengines.com/small_ ... Horizontal

Teflon-coated, self-lubricating bronze PTO ball bearing

Teflon-coated...bronze pto ball bearing???? Misprint?

Probably a typographical error, yes.

I google image searched "tecumseh crankshaft bearing" and they were all ball bearings.
Are we talking connecting rod bearing on the crankshaft? Or are we indeed talking about the crankshaft/case bearing? As I said, I'm not that well seasoned with repair of small engines but I've never ever come across a bronze sleeve on the crankshaft/case output bearing.

Then you probably never worked on a 5 HP Horizontal Briggs or older cast Iron Tecumseh engine

[Deere2me]

I'm looking into a 21hp single cylinder engine listed for sale. In the description is this..

Heavy-duty Teflon coated bronze sleeve bearing withstands twice the belt load of standard bearings to reduce wear

Really? Bronze sleeve bearing on the output shaft is superior to ball and races?

No, it's not.
BUT it IS compared to the "standard" hole punched in the aluminum case. ( as mentioned by Mek-a-nik)

[bobodu]

Conestoga wagons didn't have balls bearings....