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Aftermarket Crankshaft and rod bearings?

27K views 44 replies 12 participants last post by  MichaelDelaney 
#1 ·
Are there any companys that produce aftermarket crankshaft and rod bearings? I heard the stock ones are preaty strong. Im planing on rebuilding my engine this summer and want to go with all preformance.
 
#27 ·
the less mass you have to throw around, the faster things will happen. that's correct.

a lightweight crank will have the same effect as a lightweight flywheel.

but cost is the huge limiting factor--which is where i think MD and i have focused our attention against aftermarket cranks.

you *might* be able to shave 5lbs---10lbs tops, if you include knife-edging---from the crank... but at what cost? 2500 dollars? 3000 dollars? while you can shave 10-12lbs from the flywheel for under 300 dollars.

sure, you could do both, and shave a total of 15-17lbs, but then you've spent well over 3 grand, and you've only shaved parasitic losses, and you haven't MADE any new power yet.

that 3 grand for the crank could have bought your entire P&P'ed head package, with cams, pistons, rods, and probably your aftermarket fuel injection computer--the whole kit-n-kabootle.

....or you could spend that 3 grand to save 5lbs of rotating mass in the bottom end.

and notice that i only focus on mass here, b/c you're not going to get much more strength in the crank region--honda stockers are just about bullet proof as it is.
 
#31 ·
they're one and the same.

most modern engines run internally balanced cranks.

you want internally balanced. you don't see externally balanced motors too much anymore, because it makes parts replacement a chore, eg, to replace a flywheels or crank pulley, you have to get the whold bottom end rotating assembly rebalanced.

you can't buy a "counter balanced" crankshaft as that's a problem with nemonics--there's no such thing. you can buy fully couterweighted crankshaft, like the ITR crank, with 8 couterweights instead of 6, but it's really overkill, as you can balance a 4-banger crank fine with just 6 weights.
 
#34 ·
FYINew on the market -> Scat 92 & 95 mm stroke crankshafts for the Bseries ($650-670 retail) :




To run with these cranks without a deck plate and stock deck height, you'll need a 140 mm length rods and custom pistons with 0.939 in. compression height for 95mm stroke one and 0.998 in. compression height for 92mm stroke one, assuming stock to zero deck clearance. That'll net you with the 92 stroke crank a 1.52 r/s.

If you can get a hold of the 143 mm rods and even tighter compression height pistons (without running the pin relocation into the bottom-most oil ring and keeping to 3 rings and not 2 or 1 ring racing one off pistons), then the 92 stroker crank begins to look real appealing at an r/s of 1.55 (8000 rpm is plenty) .

You'll have to use non-Honda rod/main bearings with these I believe but not sure....will have to ask Scat about the actual numbers for the clearances and bearing thickness needed and whether Honda has them thin enough for those needs.

Definitely will need block notching and the big adios to the block oil squirters since they'll get hit for sure, so that not good news for the road racers.
 
#35 ·
MD: i asked people in Utah and in Vegas about balancing a crank and they say it cant be done. something about when 2 pistons are up 2 are down so it is balanced. does anybody know of a person that will do that or how to explane to these people that i am not insane.
 
#38 ·
Hey I have a question for everyone:

Has their been a solution to the "skinny" rod bearing journal problem? The problem is that when you run your engine up to 8100 rpms for 100,000 miles your con rod bearings start to wear tremendously. This is because on the exhaust stroke - your piston and rod assembly being flung straight up in the air is like over 4000lbs of force stretching on the rod bearings. I saw MD talk about teflon coating or micro polishin them. That sounds like a good idea in theory, does it work for the long hall racing and extreme rpms?
 
#42 ·
Since we're on the topic of internally balanced engines and how the crankshaft's counterweights offset the weight of the rods and pistons, I thought I'd show you a "balls out" fully lightened Scat racing crank made for a 4 banger with the counterweights drilled out for minimal mass and knife-edged to reduce windage losses.:




Ultra-light pistons and rods would be selected blueprinted to within 0.1 grams of one another and the counterweights would be drilled out until they individually matched each piston and rod at each crank journal.

The crank would have the strength to withstand the hp and torsional (twisting) loads made with this racing motor at the rpms needed but would allow the engine to rev to that higher rpm without as much parasitic loss restriction.


Use of Mallory weights to balance these small counterweight racing cranks.


 
#43 ·
MichaelDelaney on Feb/19/05 said:
Since we're on the topic of internally balanced engines and how the crankshaft's counterweights offset the weight of the rods and pistons, I thought I'd show you a "balls out" fully lightened Scat racing crank made for a 4 banger with the counterweights drilled out for minimal mass and knife-edged to reduce windage losses.:





Ultra-light pistons and rods would be selected blueprinted to within 0.1 grams of one another and the counterweights would be drilled out until they individually matched each piston and rod at each crank journal.

The crank would have the strength to withstand the hp and torsional (twisting) loads made with this racing motor at the rpms needed but would allow the engine to rev to that higher rpm without as much parasitic loss restriction.


That things a work of art. You can see they shaved an incredible amount of metal next to the main bearing saddles.

What's longevity like on a crank like that? Is it a replace after a couple races kind of thing?
 
#44 ·
I don't know. It's something I have to chase down with Scat to see if they have a toned down version of that for the street. If it's milled from a billet core rather than a forging or casting, it wouldn't necessarily be a 1 race throw away deal though, especially if you didn't detonate or spin a bearing with it.

Billet Core "logs" from which Crankshafts are to be machined into:



CNC Machining/Milling of a crankshaft counterweight into it's final shape:







Partially Cut Billet logs starting to take the shape of a crankshaft with the journals, saddles, counterweights being formed.:



you'll notice in the superlight racing crank, the saddles & counterweights are drilled out to save weight. if you order the pistons and rods and blueprint them, the crank maker can make the counterweights exactly match those pistons and rods and be precise enough to lower the weight of the entire crank and balance the entire crank.

This is the level of precision we're talking about here for internally balanced race engines who want that extra weight savings to reduce parasitic losses and all for more rpms without sacrificing strength.

it's not like these are continuously hollowed out cranks that are then welded together section by section. It's all one piece that is from a molded forging or is cut from a billet core. The hardcore super light strong hollowed cranks from the "high end" racing guys are welded billet core sections although I'm sure they'll figure out a way to have a continuous hollowed out log made from one piece without welding sections together soon enough. The trick is to figure out how macine the hollow center when you have all those 90 degree bends for the crank journals.
 
#45 ·
new Pocket Rockets lightened nitrided OEM crank for Tegs for serious people wanting to reduce their crankcase windage & pumping losses. :




Polished, Lightened




Nitrided




Balls Out, Lightened, Race




Pocket Rockets Racing on Jan 3/06 said:
frank@pocketrocketsracing.com


I am proud to introduce our sophisticated lightweight cranks and crank service.

We are very serious, professional and only produce very high quality work/engines.

The work is not done offshore or Mexico, we do not use sweat shops or virtually free labour to produce anything we do. You cannot buy these cranks at Walmart
The cranks have been researched, developed and tested in-house.

The Factory Honda crank forging has proven to be quite strong.

I believe this to be a superior design to anything available anywhere, in a factory forging.


This is not merely spun on a lathe and "knife-edged".


The weight is strategically removed in a way that retains the torsional stiffness, while maximizing weight reduction and substantially decreasing windage losses.


Zero deflection is experienced during the process.

The Cranks are professionally balanced to ~0.5g
Oiling holes are teardropped chamfered for superior oiling properties. Teardropping the rod journal oil holes is specifically configured this way to feed oil to the piston wrist pins.

As an example, the H22 series cranks we have taken from 40 lbs to 33.5 lbs, or metric 18.0 kg to 15.2 kg.
This makes a HUGE difference in Acceleration !

Offset grinding and big radius rod journals available.
Ion Plasma Gas Nitriding also available.

6.6 lbs off this crank.

"Most" honda forged cranks can be processed.


The oiling holes go through a number of other process before being finished.

There are a couple pics of of a crank having been gone through some rod journal work, finishing processes and the nitriding process.: Distortion free nitriding process, surface hardening process and provides more wear resistance. Nitriding is a surface hardening that induces zero deflection during process, it enhances the honda quality forging, it does not affect the core hardness of the factory forging.


I do remove all the check balls, every crank has them removed....its one of the last steps in the process....the picture I posted simply had not had that finished yet. even this pic below is not completed....but it shows the gallery opened/threaded and ready to accept a plug.

I made a "special" tool for that myself some time ago to test it, to clean the galeries out, using compressed air, solvents and numerous cleaners, and after opening the galley up to verify the effectiveness, there is still dirt in there....and I want it 100% clean, no matter what, no guessing and no "hoping" it is actually clean, so the only way I have been satisifed that 100% clean is achieved is the way I do them....thats the way I like it. to each their own.

It is well proven for many decades that reucing the weight of the rotating assembly improves throttle response, which only happens when the engine has an increase in its acceleration...which means getting from A to B in a shorter period of time...deceleration is also increased.......if you disagree, then I guess you have not used a light weight crank yet.

To me, a primary cause of oil pump gears shatter as a result of contact/grinding themselves one way or the other, higher than stock rpm levels also plays into the equation....50 to 100 psi of oil pressure is the same whether the engine is a 200 hp engine or 1500 hp engine.....harmonics has some play into it as well.....an energy transfer that exceeds the capacity of the gears happens.

The ITR weighs more than the gsr crank, ITR places weight in different quanties in different spots, a compromise to maintain low rpm driveability as well as to manage and dissipate some of the harmonics present above 8250+ rpm.
I am not here to compete against Eagle, scat cheap cranks.
We take existing Cranks and make them better, or we make billet cranks.

Crower is not even going to offer a K series forging cause Eagle will flood the market with cheap sweat shop cranks.
If your thinking this to be a replacement for an "aftermarket crank" then your missing the point. if an aftermarket crank such as Crower has already been knife-edged, then less weight can off of it.

This is more geared towards the high end street and race customers, who want to run different bearings/ stroke or destroke, lighten, toughen cranks, make small but significant modifications............the s2000 crank would be a good candidate, the K series cranks, H series cranks....I think if you are in the market for an eagle crank and then want to do somehting like this, you might as well just get a billet crank from the getgo.

The stuff we make is custom low volume items,high quality, very accurate modifications, be it on cranks, injection specialty components, manifolds, sleeved blocks, heads, wheels, chassis components, so on so forth. Eagle and companies like that cannot produce this, they are into the mass market.

This work is intricate...the crank cannot be subject to forces that will cause deflection..these cranks run at high RPM and must be done properly.

I will say that depending on which crank is done/options...lightening, journal grinding/polishing work, nitriding hardenening process, balancing....Prices start at $689 and can go to $1289.








Bone Stock Crank Oil galleys with plugs in, for comparison to the above.

Stock Crank:






Polished Nitrided Lightened Crank with Galleys Fully Cleaned Properly.





Frank May recommends that these get taken out and cleaned by hand carefully since they trap dirt and if you get the counterweights polished, they also trap the abrasive polish paste which are then released into your oil when the engine fires back up again.
 
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