4340 Billet Buick 350 Crank by Kings Crankshaft

needle bearing mains would be pretty dang interesting... doesn't matter what size the mains are, one could get bearings made for them but $$$

I wonder if anyone has been experimenting with this on a street driven engine??

Problem with needle bearings is when they fail, it is far more damaging than a babbit style bearing

 

First Guess: Utter and complete waste of time, money, effort, and enthusiasm.

By the time the crank is spinning fast enough to build a hydrodynamic wedge in the oil film, all the friction reduction of the needle bearing is moot. The load-carrying ability of the needle bearings will require main journals so huge that there'd be nothing left of the main saddles; the block would be horrifically weak.

 

>> I'm curious as to the vast area of expertise, you draw this conclusion ? Do you suppose Harley Davison and countless other four cycle motorcycle engines use "huge" needle/roller bearings? If nothing to gain, why do they bother ? The block is already weak for racing. It was never designed for racing. That's why it has 3" mains, to cut cost by using a cheaper cast crank. It was designed for good torque and reasonable hp, nothing else. Because the block is thin, it really can benefit from a good girdle design. Every stroke increase has additional parasitic losses, because increased inertia loads and windadge. Larger journals cost hp. through frictional losses. It seems few want to build a serious, stroked 300. TA heads,roller cams/etc. are available now. The block is likely stronger, by reason of shorter deck height. The 2.5" mains offer less friction. 350 exhaust ports side/side is not good for racing. Nearly all current designs, have moved away from this. 2 cents, roverman

 

I've looked into using split needle bearings for a steam engine application, but am stuck on the outer race. The split bearings just have split cages and do not include outer races. Not wanting to spend the time, $$$, and risk damage to the block by prepping and using it as a "race", how does one go about that? "Fracturing" a regular one-peice race?

Then there's the matter of the crank. I suppose a special hardening would be necessary for the journals?

Seeing that all of this would potentially be "custom" parts (though off the shelf sizes may be close), why not step it up and go with needle cam bearings as well?

Buicks would certainly benefit from the lower oiling needs of needle bearings. Making the oiling capacity available for other, more serious matters, like turbocharger(s):Brow:

 

The typical engine that uses roller-bearings on the crankshafts does so because they have multi-piece cranks and one-piece rods, instead of one-piece cranks and two-piece rods.

Thousands of years ago, there were aftermarket roller-bearing cranks for VW flat-four air-cooled engines, the crankshaft was pressed together from a fistful of precisely-machined forgings, the rod big-ends didn't have removable caps. The main point of one-piece rods was to eliminate rod bolt failure; a side benefit is somewhat reduced rod weight/mass/bulk. Another issue may have been the lack of forging machines in the aftermarket enormous enough to pop out a single-piece crank, but they had the tooling to forge smaller pieces--so they built what they could using a bunch of small pieces, and hydraulic presses to assemble the small pieces into a built-up larger item.

Seems to me Suzuki (and Kawasaki???) used roller-bearing cranks in the early-80's; about the same deal. The GS1100 cranks were multi-piece, pressed-together messes; Suzi eventually took to welding them together ('82--'83, I think) because earlier cranks had a tendency to twist slightly at the press-fit joints, then the engine vibrated like mad if not exploded. I'm also thinking that Suzi dropped the multi-piece crank and roller bearings when they introduced the GSXR engines in mid-80's.

If Harley is using roller-bearing cranks...all I can say is that perhaps it has some advantage in a fork-and-blade con rod arrangement. "I" would dump the fork-and-blade rods like a broken rubber, if I worked at Harley Engineering. I've never seen the inside of a Harley engine except for photos and drawings from years ago. I'd have expected plain rod bearings. Silly me. Maybe just the ends of the crank are supported in roller bearings--one roller bearing pressed into each case half??? Saves the cost of casting/machining main caps to hold the main bearings.

The roller bearings seem to appreciate huge amounts of oil volume, but don't require much oil pressure at all. Perhaps the choice of roller bearing is sometimes dictated by the choice of oiling system? (i.e., very tolerant of interrupted oil supply, and tolerant of aerated oil, totally intolerant of particle-contaminated oil.)

At any rate, NONE of these engines have the typical automotive engineering feature of a one-piece crankshaft with multiple main bearings along it's length. I'd expect that you'll have problems running a roller-bearing directly against a cast-crankshaft main journal, although it might work on a forged-crank main journal. Similarly, you'd have to have a hardened outer race, you couldn't run the rollers against the cast-iron of the block and caps. I have no idea how you handle the parting line of an inner or outer race--perhaps a diagonal (scarf-cut) or chevron-pattern split, so the bearings don't erode the parting line every time they roll across it???

If you consider that the plain bearing is--what?--maybe 1/8" to 3/16 thick; then you compare that to the thickness of the rollers plus the thickness of the outer race--how small does the main journal have to be?

All the engines that are originally designed for roller bearings have the thickness of the bearing designed-into the journal diameter, and the block/case bearing supports. Installing roller bearings into a block/crankshaft originally set up for plain bearings is going to introduce a whole bunch of compromises--either reduced journal diameter or increased main saddle diameter. The Buick cannot afford any more weakness in the block...so all the extra space is going to have to be carved out of the crank journals. Now the unit loading of the rollers is likely way beyond design specs.

I just don't see where the Buick has room for roller bearings on the crank. For that matter, I don't see where any automotive engine is a good candidate for roller-main-bearing conversion.

The fact that no V-8, one-piece-crankshaft automotive, light- or heavy-duty truck engine uses roller crankshaft bearings should be considered to be evidence that it's not a practical design type.




There was a time that folks were using roller-bearing camshafts. Another bit of wasted engineering as far as I'm concerned.

 

Fracturing the outer/inner bearing races has been done successfully for years, just not discussed much. I would grind a small part line v-notch, on each side of the bearing. Soak in dry ice or colder. Put in a vise and hit with a hammer,(somewhat risky), or use a "v" blade in an arbor or hyd. press. If using a hi-strength 4340 crank, the mains can be 2.500" dia. and be adequately strong. One need only look at the hp. and rpm., such cranks are supporting. FWIW, Chevrolet tried needle/roller bearings in a sbc. It was dropped because of excessive oil bleed off.Needle bearing rist pins will NOT work on 4 strokes,(too much point pressure). Bearing manufactures spec. books will note maximum rpm,(continuous), and minimum oil requirements, which are a "fraction" of what sleeve bearings require. Many pure race engines are using needlle bearings on the cams-currently. Perhaps .250" wall thickness is a suitable starting point, for needle mains ? I hear talk on this forum, of increased strokes over 3.85". How will you clear a cam with more lift, when a Honda rod saved you .075" maximum clearance increase ? Onward, roverman.

 

just for r&d; if you could cast a block that had wide castings, you could possibly groove it to fit a roller type of bearing. but the crk/sft redesign would also be needed. don't ever say nothing is impossible. lol
regarding camshaft bearings, nascar uses them and mutli sizes are available. i am looking at doing that now. there are a couple of little issues for the buick. but i think i can make it work. it will just drive my machine nuts. lol

 

Johnny, what kind of "issues" are you taking about? lack of path for oil to mains? Are you reducing the base circle of the cam at all?

Is it true that roller cam bearings can rely on lubrication from splash alone?

Inquiring minds want to know

 

don't have a clue on the subject. ou: it's just another r&d idea for the dragster engine that i think can be done. gotta go thru the motions before i can give you an answer.
good answer, huh. lol
btw, what about the valve train.......:Smarty:

 

I believe the ones in use, have 1+. oil feed holes in the outer shell. The 350 has the advantage of 1 size cam bearing, vs 215-340. This allows .12" larger base circle on cam, a good thing. If using a properly heat treated billet cam, journals could be "undercut/wide groove". to accept needle rollers, in an outer cage, while riding directly on cam. This might be thin enough to fit the cam tunnel without boring. Obviously, this would need "fractured" outer housings. Cheers, roverman.