types of crankshaft steel

Discussion in 'Rotating Assemblies' started by grumpyvette, Sep 22, 2008.

  1. grumpyvette

    grumpyvette Administrator Staff Member

    Crankshafts:Stock and Performance



    by Larry Carley - Apr 1, 2005


    The crankshaft is the working arm of the engine. All the force generated by combustion and the downward motion of the pistons is focused on the crank throws.

    The leverage effect of the force exerted on the crank journals twists the shaft and converts the up-and-down reciprocating motion of the pistons into rotational motion of the crankshaft. This creates torque that the crankshaft uses to turn the flywheel and rest of the drivetrain.

    The rotating mass of the crankshaft combined with that of the flywheel and harmonic balancer also creates inertia and momentum that keeps everything spinning. This gives the crankshaft enough energy to push the pistons up on the compression and exhaust strokes, and to pull air and fuel into the cylinders on the intake stroke. It’s basic physics in motion and the torque that’s produced is what propels every gasoline and diesel-powered vehicle on the road today.

    As those vehicles chalk up the miles, though, their crankshafts take constant pounding. Engine builders have to pay close attention to the condition of the crankshaft because it bears the brunt of the power produced by the engine.

    Crankshaft wear is a concern as the miles add up. Journals must be carefully inspected and measured for wear, out-of-roundness, taper, hour glass or barrel distortion. If worn beyond specifications (typically more than .001″ of specified diameter), the journals must be reground to undersize and polished to restore the bearing surface.

    The amount of grinding that can be done on the crankshaft journals is limited by the depth of the case hardening as well as the availability of undersize bearings for the application. Bearings for ten, twenty or even thirty thousandths undersize journals are usually available, but on some passenger car engines ten thousandths may be the limit due to the thin case hardening or the small size of the journals.

    When journals are too badly damaged to be reground or are worn beyond a certain limit, the journals can be built back up by hard chroming, metal spraying or welding – if the cost is justified. Welding large diesel and industrial engine cranks often makes sense because of the high cost of replacement cranks, but on most passenger cars and light trucks it’s usually much less expensive to replace a worn or damaged crank than to weld and repair the original crank. Welding a crank also requires straightening and redoing the heat treatment, which adds cost. It all boils down to how much a customer is willing to spend on the repairs.

    Every piston fires at a different instant in time, which creates vibrations in the crankshaft that grow in magnitude with the number of cylinders, the length of the crankshaft and engine speed. The constant pounding and stress may cause small hairline cracks to develop in and around journals, and particularly around oil holes. That’s why crankshafts should always be examined with a magnetic particle inspection machine to check for cracks before they are reused.

    Used crankshafts also have to be checked for straightness. The constant loading and pounding combined with wear in the main bearings may result in a bent shaft. Straightness can be checked by placing the ends of the crank in V-blocks and using a dial indicator to measure deflection in the center main bearing as the crank is rotated. If the crank is bent more than about .0015″ (specifications will vary depending on bearing clearances), it must be straightened in a hydraulic press or replaced. Forged steel cranks will typically accept more correction than a cast crank. But if the crank is bent beyond the point where it cannot be straightened without weakening or cracking it, it must be replaced.

    When To Upgrade
    For stock engine rebuilds, a reconditioned stock crankshaft should be more than adequate. Most passenger car and light truck cranks are cast iron and have enough strength to handle the loads produced by a stock or slightly modified engine. If the OEM crank happens to be a forged steel crank (which are used in some high output engines as well supercharged, turbocharged and light diesel engines), so much the better, because forged steel is much stronger and not as brittle as cast iron.

    Stock crankshafts are engineered to handle typical loads generated by a stock engine, say 250 to 350 hp in a small block V8, or up to 400 hp in a big block V8 with a redline of 5,000 to 5,500 rpm. But there is a limit on how much additional torque and rpms a stock crank can safely withstand if the engine is modified. Most stock cranks have enough built-in margin of safety to handle your typical aftermarket “bolt-on” modifications such as a street hydraulic cam, a performance intake manifold, larger carburetor, exhaust headers and even aftermarket performance heads.

    But when an engine is being built to produce serious power or will be used for racing, a stock crank may not be up to the task. When the loads experienced by a crankshaft start to double or triple over that of a stock crank, all bets are off as far as durability is concerned.

    According to most of the performance crankshaft suppliers we interviewed for this article, engine builders should seriously consider upgrading from a stock crank to some type of performance crank when the horsepower output of a smallblock V8 is pushed beyond 400 to 450 hp. For a big block Chevy, Ford or Chrysler motor, a stock crank can usually handle up to 550 hp. But beyond that, a stronger performance crank is needed to handle the additional power.

    Often the weight and profile of a crankshaft is determined by the class rules for the type of racing. In Hooters Cup racing, for example, the rules dictate a stock crankshaft to keep the costs down.

    Engine speed is also a critical factor in crankshaft loading. The loads on the crank go up exponentially with rpm. Consequently, if an engine is built with a valvetrain and connecting rods that can push the redline beyond 6,000 rpm, a stronger performance crank will probably be needed. And if the engine will be spinning in excess of 7,000 rpms (like running flat-out at 9,500 rpm lap after lap in a NASCAR race), a performance crankshaft is an absolute must.

    Performance Cranks
    Performance cranks do several things for an engine. First and foremost, they improve durability. The improved strength of a performance crankshaft allows it to safely handle higher loads and rpms without twisting, cracking or failing.

    Performance cranks are also finished to a much higher standard of accuracy and precision than ordinary cranks. Tolerances are much tighter, journals are polished to perfection, and counterweights are given knife-edges or other special profiles to reduce windage, aerodynamic drag and to improve oil control. Oil holes are cross-drilled and chamfered to improve lubrication. Special slots to direct the oil flow may also be machined into the journal surfaces.

    Performance cranks are usually treated to improve strength and durability. Nitriding and nitrocarburizing are two low temperature, low distortion “thermochemical” heat treatments that are appropriate for crankshafts.

    Nitriding can be done by heating the crank to 950° F in an oven filled with nitrogen. Nitrocarburizing is accomplished by soaking a crank in a hot “ferric nitrocarburizing” salt bath. Nitrogen reacts with the metal to case harden the crank to a depth of .020″ to .030″, depending on the duration of the process. Nitriding roughly doubles the hardness of the surface from about 30 to 35 Rockwell C to 60 Rockwell C without affecting the base metal underneath. Nitriding may add about $200 to the cost of the crankshaft.

    Special coatings may also be applied to non-journal surfaces so oil doesn’t stick to the crank and high rpm and increase drag. Some cranks are also cryogenically treated to relax and improve the grain structure of the steel.

    The strength of the crank not only depends on the base alloy (typically 4340 steel) and how it was made (whether it was drop-forged or machined from a solid chunk of billet steel) but also the size and design of the fillets at each journal, the size, shape and placement of the counterweights, how the oil holes are located and drilled, the heat treatment, case hardening and shot peening of the crank surfaces and cryogenic treatment (if used).

    Lighter Weight
    Performance cranks are also available with reduced weight. A lightweight crank with cut down counterweights and drilled throws may be as much as 20 lbs. lighter than a comparable stock crank (say a 33 lb. SB Chevy racing crank versus a 54 lb. stock crank). Most crank suppliers say the trend to lighter and lighter racing cranks in recent years may have bottomed out because most of the weight that can be safely taken out has already been removed and there’s not much room left for further reductions.

    The theory here is that reducing the weight of the crankshaft by machining off any “unnecessary” metal reduces weight and inertia, allowing the crank to change rpm more quickly and rev faster. But the ability to do this depends on the location of the weight with respect to the center axis of the crankshaft. Weight that is closer to the center of the axis of rotation has much less effect on inertia than weight located out on the crank pins or counterweights.

    A super light crank makes sense in an application like a sprint car on a short dirt track where the driver is constantly on and off the throttle in the corners. But in a drag motor or a NASCAR motor that runs at full throttle, inertia is much less important than durability. Because of this, many crank suppliers recommend running a heavier crank that has added stiffness and strength in a drag motor or NASCAR motor to keep the bottom end of the motor intact.

    Stan Ray of Ohio Crankshaft Co, Greenville, OH, says his company only sells a big block Chevy crank with center counterweights because it’s more durable than cranks that lack the center counterweights. “An extra 10 or 12 lbs. of weight in a drag motor will have virtually no effect on inertia but will have a big impact on how long the crank holds up. Most drag racers want durability.”

    A crankshaft that’s too light can also flex and lose horsepower – or fail, which is something to keep in mind, too.

    “Most every application is generating more power than ever before,” says Duane Boes of Callies Crankshafts, Fostoria, OH. “Stresses from increased rpm and greater gas loads are forcing people to invest in crankshafts made of better material. The Gen III small block engine by General Motors is rapidly gaining popularity. It’s yet to be seen which four-cylinder engine will become the future standard of the performance industry. In terms of acceptance and aftermarket support, there may never be another small block Chevy.”

    Forged Vs. Billet
    Is a forged steel crank better than a machined billet crank? Some say yes, some say no – and it depends on what you mean by “better.”

    Forgings generally produce a flowed grain structure that provides great strength parallel to the lines of flow. The metallurgy of a forging also depends on the alloy used and the heat treatment that is applied to it after it has been shaped. The one drawback of a forging is that it requires a die to shape the metal. Dies and forging presses cost a lot of money, so the availability of forgings for various applications depends on their popularity and how much people are willing to pay for a forged crank. According to Boes, “The vast majority of performance-related cranks in use today are made from forgings, even some that are claiming to be billets.”

    Brian Adix, of Howards Cams in Oshkosh, WI, says his company sells two basic forged crankshafts, a “Track Smart” forged crank, for SB/BB Chevy (their least expensive cranks), and “Pro Series” cranks that are also 4340 forged steel, have drilled rod throws for lightness and are “Permatuff” heat treated for SB/BB Chevy racing engines.

    He says these forgings are done by Trenton Forging, one of the few remaining U.S. forging operations.

    Billet crankshafts, by comparison, are CNC machined from a solid chunk of metal. The machining process cuts through the grain structure so there are fewer residual stresses in the metal as there are in a forging.

    Proponents of billet cranks say billet steel alloys also tend to be “cleaner” in terms of impurities and inclusions, which improves strength and durability of the finished product.

    The main advantage of billet cranks, however, is that CNC machining allows the supplier to custom fabricate a crankshaft for virtually any engine. No mold or forging die is necessary, so there’s no limit on the shape or dimensions of the crankshaft.

    A one-of-a-kind crankshaft can be created to any specifications. This gives high performance engine builders a great deal of flexibility in choosing stroke lengths, journal diameters, the positioning of the journals and counterweights, and the configuration of the crank itself.

    If somebody needs a performance stroker crank for a sport compact engine or an oddball application, a billet crank can be tooled up from scratch. Of course, billet cranks require a LOT more machining than forged or cast cranks. As a result, they cost more. Billet cranks typically fetch anywhere from $1,800 to $3,000 (or more) depending on the amount of work required to make it. A typical street price for a small block Chevy stroker billet crank is around $1,900 to $2,000. A comparable big block Chevy crank would be a couple hundred dollars higher.

    Joe Squires of Bryant Racing, Anaheim, CA, explains that 90 percent of the crankshafts his company produces and sells are billet cranks. “Billet gives us the flexibility to control every aspect of production, from the placement of the crank pins and size of the journals to the location and profiles of the counterweights. We use two different alloys depending on the application, either 4340M or EM30B. We also do our own heat treating in-house and cryogenically treat every crankshaft to improve durability.”

    Different Strokes
    In recent years, the trend has been to bigger and bigger displacements thanks to the increased availability and affordability of aftermarket blocks. As blocks have grown, increased internal clearances have also allowed for longer stroke crankshafts.

    Ohio Crankshaft’s Ray says that, a couple of years ago, his number one selling crankshaft was a stroker to create a 383 Chevy small block. Today it’s a stroker crank to build a 434 small block – which will be going to a 468 soon. He says it’s the same story with big block stroker cranks. The best-selling big block stroker crank used to be for a 496 cid motor. Last year, that increased to a 555 cid motor, and now they’re selling stroker cranks for 632 cid motors.

    The new IHRA Prostock rules will allow up to 5 inch cylinder bores with a maximum displacement of 820 cubic inches! That’s a lot of motor, and it requires a lot of crankshaft to create and handle that much displacement.

    New Applications
    Small block and big block Chevy V8s followed by small block and big block Fords, a few Dodge/Chrysler V8s and a handful of Oldsmobile and Pontiac V8s have been the mainstays of the performance aftermarket for many years. But as time marches on, other engines are starting to develop a following and demand for performance replacement parts, including cranks, grows.

    “The engine remanufacturing business has changed in recent years,” says Tom Lieb of Scat Enterprises, Redondo Beach, CA. “The demand for everyday replacement engines is down, and traditional rebuilders need other opportunities to grow their business.

    “One such opportunity is the restoration market: muscle cars and popular cars from the 1950s, 1960s and 1970s. The demand for crankshafts and connecting rods for these engines is up, but the cores are not available,” explains Lieb. “We have cast cranks, forged cranks and billet cranks. We’ve been supplying engine builders with standard cranks and continue to add coverage.”

    As for performance cranks, Lieb explains that Scat has been building performance cranks since 1966. “We’ve been doing Volkswagen cranks since day one, so we know what makes performance cranks work.”

    The technology needed to make a performance crankshaft for a V8 or any of today’s sport compact engines is really no different than what has been learned from building VW crankshafts, says Lieb. The basic technology is the same.

    “One of the problems with most of the OE crankshafts in many Japanese engines is that the oiling system is not drilled for higher loads or horsepower. A lot of guys are burning up rod bearings in these engines because the bearings aren’t getting enough oil. When we do a performance crank, we redo the oiling system so durability isn’t an issue.”

    Lieb says Scat currently offers a forged crank for Honda, as well as forged cranks for small and big block domestic applications, and can make billet cranks for virtually any other sport compact engine.

    In many cases, competitive race rules put limitations on what customers are able to install in their engines.

    “We’re receiving more calls from people who want a 50 lb. small block Chevy crank than a 30 lb. crank,” says Wendy Carr of Callies Performance Products, Fostoria, OH. “The rules really dictate what kind of crankshaft our customers buy.”

    Carr says Callies offers several lines of crankshafts, including Magnum X-L, Magnum, Racemaster, DragonSlayer, SC-4 Sport Compact, Chrysler Hemi and CompStar.

    “Our newest offerings are the DragonSlayer 4340 forged cranks, which are made in the U.S.A., and are available with up to a 4″ stroke for small block Chevy, and 4″ and 4.250″ strokes for big block Chevy. We also have a DragonSlayer crank for Mopar 340 engines, too.”

    Carr says the new lower priced CompStar crank line uses imported 4340 forgings that are final machined by Callies. The CompStar is currently available for small block Chevy only, but will soon be available for big block Chevy as well.

    Also new is the SC-4 Compact crank line for Mopar 2.0L and 2.4L engines. The crank is available with a 3.543″ stroke. According to Robert Loftus of Eagle Specialty Products, South Haven, MI, there is a growing diversity in the performance market. “A lot of people read that to mean imports or sport compacts. But it has really spread into the less-than common domestic V8’s.

    “We are seeing a growing interest in imports and sport compacts, of course, but also in Pontiacs, Ford FE’s, even other domestic V8 from years gone by that most of the country had forgotten about,” Loftus says. “Maybe these enthusiasts have just started coming out of the closet because they are encouraged by the aftermarket’s renewed acceptance of products other than a Chevy or Ford small block. This is opening new doors for expansion for our company and new sources of revenue. As we make new products, the customer base grows. This, in turn, encourages new products.”

    Loftus explains that his company has recently added small block Chrysler cranks in cast steel and forged 4340, and Buick 3.8L V6 in forged 4340. “We are developing cranks for Mitsubishi 4G63 and 4G64, Ford 4.6L and 5.4L modular engines. We are exploring the possibility of making cranks for several other imported 4- and 6-cylinder engines as well as some domestic 4-cylinder, 6-cylinder, and V8s,” he says.

    Several other companies not currently offering a performance crank or stroker crank for sport compact cars indicated they are looking at this market and/or are developing cranks for these applications. But one supplier said the sport compact car market is a “different” kind of market than the traditional small block/big block Chevy market. For one thing, the stock cranks are fairly strong and seem to hold up well under the rigors of turbocharging and nitrous oxide. Also, the type of engine modifications that owners of these vehicles are typically making are induction bolt-ons and head swaps – not modifications to the block or bottom end. But as power goes up, so does the load on the crankshaft.

    Balancing
    Balancing is a must for any high revving performance engine, and with stroker engines it is a must to offset the increased reciprocating mass of longer rods. Stroker cranks often require the addition of heavy metal plugs to the counterweights. On a very light crankshaft, having to add several pounds of heavy metal to a counterweight may also offset much of the weight advantage of the lighter crank. So for many stroker applications, a lighter crank may be more difficult and expensive to balance.

    Eagle Specialty Products’ Loftus says many engine builders lose a lot of time and money guessing what to charge for a balancing job. “They need to be able to quote the customer a price for balancing beforehand. They do not want to charge too much and lose the sale, but they can’t be too cheap and run into a problem and lose money.”

    Loftus explains that, to help engine builders, his company has started publishing a “target bobweight” for its cranks. This allows the engine builder to estimate how much work he’ll have to do to balance the crank. “Our cranks are guaranteed to be within 2 percent of this target bobweight. Customers should not confuse this with actual balancing, though. Our cranks do need to be balanced. This just gives the shop an idea of what they will need to charge before they actually do the job.”

    Sourcing A Sore Spot
    For many crankshaft manufacturers, the world’s steel supply has had a direct effect on business. Rising steel prices, high labor rates and a loss of forging facilities in the U.S. have created market conditions that favor importing lower cost raw forgings or even totally finished crankshafts from overseas manufacturers.

    Kerry Novak of Crower Cams, San Diego, CA, says steel is a major issue. “China has sucked the U.S. dry of steel. They are buying up all the steel they can, creating a shortage for U.S manufacturers. As a result, our costs to do billet cranks has risen dramatically and we have steel on backorder.”

    Steve Slavik of Lunati Crankshafts, Memphis, TN, says his company was forced to raise prices in December because of the increase in the cost of steel. “We use a 4340 non-twist forging alloy that is made in the U.S.A. Our Top Line Pro Series cranks are a very precise, zero tolerance design that require extensive machining so they are expensive ($1,998 for a SB Chevy). To compete with the influx of import cranks, we have introduced a ‘Sledgehammer’ series of performance cranks for small block Chevy (a big block crank is planned) that sell for half the price of our Pro Series cranks.”

    “The Sledgehammer cranks are still made with a 4340 forging right here in the U.S.A., but we are not doing as much machining to keep the cost down. These cranks don’t have a contoured leading edge on the counterweights, for example, and are available in two different strokes,”

    Crower’s Novak says a growing number of crank suppliers are now importing forgings and even completely finished cranks from overseas suppliers. This has created a lot of price pressure on crank suppliers who still use only U.S. forgings. Some have been forced to raise prices while others have been able to hold the line – at least for now.

    Raul Negrete of Cola Performance Crankshafts, Whittier, CA, says this has created some serious issues within the industry.

    “The main issue,” said Negrete, “is that some people are selling performance crankshafts that they claim are made in the U.S. when, in fact, the cranks were not manufactured here. They are made with imported forgings that are finish ground and polished here. But the cranks are not manufactured here and shouldn’t be labeled as such. It’s misleading.”

    Negrete says the lower price of imported crankshafts makes those who are selling only domestically forged cranks look bad because there’s no way the domestic cranks can complete on price. “You can buy completely finished cranks for as little as $140 each. Yet for a U.S-made forging, my cost for the raw materials is $240.”

    Howards Cam’s Adix expresses concerns that “A lot of people are bringing in forgings from overseas but selling their cranks as ‘Made in U.S.A.’ because they do the finish work here. I think that’s misleading.”

    Says Negrete, “California law says any product that claims to be made in the U.S.A. must be totally made in this country, not just part of it or the final machining,” Negrete hints that within the next few months legal battles over labeling concerns may bring the subject to the attention of the industry.

    Duane Boes says his company avoided the use of off-shore products for as long as it could, but says the company could eventually no longer overlook the needs of its engine building customers. “We do offer an independent line of products that are forged and semi-finished at various offshore locations,” says Boes. “Out of respect for our customers and their integrity, Callies will not hide this fact or disguise these products with an American sounding brand.”

    Pricing-pressure aside, Boes says imported products don’t necessarily have to be of lower quality. “Our efforts to evaluate potential suppliers have been extensive. We have personally visited most crankshaft and connecting rod manufacturers in China, Europe and India. To ensure consistent product quality, specialists have been retained to systematically review our suppliers’ processes and capabilities.

    “Because all of our CompStar components are finished at Callies, we are able to maintain proper geometry while monitoring both metallurgy and design,” Boes says.
     
  2. 87vette81big

    87vette81big Guest

    I have learned to ignore all written & geared for the Chevy V8 Grumpy when applied to a Pontiac V8.
    Accoarding to them the stock crank will fail at 350-400 Hp.
    HO Racing wrote the Pontiac V8 race build books.
     
  3. philly

    philly solid fixture here in the forum


    look man, when you sell performance cranks... you gotta sell performance cranks. that means fudging the numbers a bit. however... putting a forged piece down stairs, with titanium rods and forged pistons, just means one thing... you arent gonna have to worry about that shit breaking anytime soon.

    that article grumpy posted with the turbo big block at 28ish PSI had all stock rotating parts but seriously... who wants to drive around wondering WHEN not if their bottom end is gonna fall apart? i think in the context of building a street driven racer, its a good investment in peace of mind... maybe just wait till ya bust the stock crank before making the jump to forged or billet... i mean if it aint broke dont fix it.... and when it breaks, upgrade!
     
  4. 87vette81big

    87vette81big Guest

    Those stupid Fuckasses Phil.
    What about a Bone stock Pontiac 1970 455 ?
    360Hp & 370 Hp rated.
    Beswick cranked out over 1400 Hp on Nitro with 455's in his 1970 Trans Am Funny car SNOWBIRD.
    STOCK CRANKSHAFT. CAST NODULAR IRON.
    HE TOLD ME SO.

    TAKE 800 HP ALL DAY LONG A 455 STOCK CRANK.


    IF THE FORD 5.0 GUYS LISTENED TO CHEVY GUYS DO YOU THINK THEY WOULD HAVE EVER RAN 8'S , 7'S & 6'S ?
    BE TOLD NOT TO REV OVER 6K.
    NOTICE WE HAVE ZERO 5.0 NMRA NHRA NMCA GUYS HERE ?
    I HAVE PHIL.
     
  5. philly

    philly solid fixture here in the forum

    those poor sbc and their shitty lifter problems... the ford motors just needed somebreathing room to be real screamers in mostly stock form.


    dont get me started on clevelands (can you say 10,000 rpm?)
     
  6. 87vette81big

    87vette81big Guest

    Fords have always been built tough too.

    One of my 1st lessons as an apprentice mechanic being taught from a 30 year GM Corvette Master Mechanic, my late Bud Bill....
    Brian when its time to Go Racing You might as well throw the Entire Small Block Chevy Engine Away because there is not A Single Part you can Reuse.
    But A BBC You can Reuse near All.
    The SBC is a Tin can throw away engine. Junk as is for drag racing.
    ....
    But Bill I am a Pontiac Guy...Pontiac V8 is just as good as a BBC. Maybe better.
    Let me tell You about my 1967 GTO, 1961 Pontiac Ventura with a 421 SD 4-speed, & 1968 Firebird 400.
    Chevy don't have anything over Pontiac.
    I raced against them Chevies with Pontiacs and WON.

    17 Years old then Phil. 1987.
    Look around .
    What is left SBC Factory stock on what you see here & elsewhere ?
    Zeron on SBC.

    BILL WAS RIGHT.
     
    Strictly Attitude likes this.
  7. Grumpy

    Grumpy The Grumpy Grease Monkey mechanical engineer. Staff Member

    SBC stroke lengths & cubic inches
    http://www.chevydiy.com/1955-1996-chevy-small-block-performance-guide-crankshafts-manual-part-2/#
    Cubic inches Bore & stroke*
    350 4.000 x 3.48
    346 3.900 x 3.62
    364 4.000 x 3.62
    383 4.000 x 3.80
    400 4.125 x 3.75
    377 4.155 x 3.48
    383 4.030 x 3.75

    BBC stroke lengths & cubic inches

    Cubic inches Bore & stroke
    396 4.096 x 3.76
    402 4.125 x 3.76
    427 4.250 x 3.76
    454 4.250 x 4.00
    477 4.500 x 3.76
    502 4.466 x 4.00
    540 4.500 x 4.250
    557 4.500 x 4.375
    632 4.600 x 4.750



    from what I've seen in the past EAGLES balanced assembly's are not as well balanced as they could be and yes, your machine shop is probably correct.
    personally I've found the SCAT rotating assemblies to be a better value with closer tolerances
    that being stated I don,t think you would have major issues if you carefully verify clearances , and installed it without additional,balance work.
    (personally Id cough up the extra $240 as insurance the jobs done correctly, it beats pulling it down later




    READ THESE THREAD's

    and don,t skip the sub linked info
    http://garage.grumpysperformance.co...a-scat-rotating-assembly-be.11495/#post-52962

    http://garage.grumpysperformance.com/index.php?threads/409-pontiac-build.1434/

    http://garage.grumpysperformance.com/index.php?threads/engine-balancing.3900/

    http://garage.grumpysperformance.com/index.php?threads/engine-balancing.3900/#post-57940

    http://garage.grumpysperformance.co...big-block-stroker-big-enough.6132/#post-19023

    http://garage.grumpysperformance.com/index.php?threads/measuring-crank-bearing-journals.5478/
     
    Last edited: Jan 9, 2021
  8. 87vette81big

    87vette81big Guest

    The Scat 9000 series crank is the best value for the $ Grumpy.
    Still holding up just fine in my 1994 K1500 Suburban 350 TBI.
    40,000 Miles later Zero issues.
    80-90 psi Oil pressure cold start drive away down the road.
    1967-70 Chevy Camaro Z28 Melling M55A oil pump used.
    Best $200 spent on a New Crankshaft all made in the USA.
     
  9. Grumpy

    Grumpy The Grumpy Grease Monkey mechanical engineer. Staff Member

    fabricating a crank shaft straightness and journal concentric test fixture
    http://www.insize.com/products/tools/pdf/plate-l/6888.pdf










    [​IMG]
    Mallory metal
    From Wikipedia, the free encyclopedia
    Mallory metal is proprietary name[1] for an alloy of tungsten, with other metallic elements added to improve machining.


    Its primary use is as a balance weight which is added to the crankshaft of an automotive engine, where the existing counterweight is not large enough to compensate for the weight of the reciprocating and rotating components attached to the crankshaft's connecting rod journals. Rather than add to the counterweight by welding or fabrication, holes are drilled in structurally safe positions in the counterweights, and "slugs" (cylindrical dowels) of Mallory metal are inserted and fastened securely.


    The difference in density between the replacement Mallory metal and the original steel is about 2:1, so the counterweight is heavier without changing its shape or size.
    [​IMG]
    OBVIOUSLY a machine shop doing balancing work on a rotating assembly's , and adding mallory metal slugs to counter weights,on the crank must do quality work or problems with durability usually result that get damn expensive or dangerous
     
    Last edited: Feb 2, 2016
  10. Grumpy

    Grumpy The Grumpy Grease Monkey mechanical engineer. Staff Member

  11. Grumpy

    Grumpy The Grumpy Grease Monkey mechanical engineer. Staff Member

    some rather interesting related videos









     
  12. Grumpy

    Grumpy The Grumpy Grease Monkey mechanical engineer. Staff Member

    ear.

    [​IMG]12/13
    All ’87-and-later Chevy blocks come with a one-piece rear-main seal. This requires the use of a late-model one-piece rear-main seal crank. Starting with the ’88s, most passenger-car engines converted to hydraulic roller cams that required a spider. This is a truck block where the spider mounting bosses are not drilled and tapped, because the truck engine used a flat-tappet cam. These can be easily drilled and tapped to mount the spider for a hydraulic roller cam.

    [​IMG]


    Number Details
    10106122 Category: Crankshafts
    Type: Small Block V8
    Date:
    Notes: 350, 3.66 inch stroke, 2.76 inch journal, forged steel, ZR1 - LT5
    10168568 Category: Crankshafts
    Type: Small Block V8
    Date:
    Notes: 265, 3.00 inch stroke, medium journal, cast iron, 1 piece rear main seal
    1130 Category: Crankshafts
    Type: Small Block V8
    Date:
    Notes: 327, 3.25 inch stroke, medium journal, forged steel, 2 piece rear main seal
    1178 Category: Crankshafts
    Type: Small Block V8
    Date:
    Notes: 302, 3.00 inch stroke, medium journal, forged steel, 2 piece rear main seal
    1181 Category: Crankshafts
    Type: Small Block V8
    Date:
    Notes: 305/350, 3.48 inch stroke, medium journal, cast iron, 2 piece rear main seal
    1182 Category: Crankshafts
    Type: Small Block V8
    Date:
    Notes: 350, 3.48 inch stroke, medium journal, forged steel, 2 piece rear main seal
    14088526 Category: Crankshafts
    Type: Small Block V8
    Date:
    Notes: 305/350, 3.48 inch stroke, medium journal, cast iron, 1 piece rear main seal
    14088532 Category: Crankshafts
    Type: Small Block V8
    Date:
    Notes: 350, 3.48 inch stroke, medium journal, forged steel, 1 piece rear main seal
    14088535 Category: Crankshafts
    Type: Small Block V8
    Date:
    Notes: 305/350, 3.48 inch stroke, medium journal, cast iron, 1 piece rear main seal
    14088552 Category: Crankshafts
    Type: Small Block V8
    Date:
    Notes: 350, 3.48 inch stroke, medium journal, forged steel, 1 piece rear main seal
    2680 Category: Crankshafts
    Type: Small Block V8
    Date:
    Notes: 327, 3.25 inch stroke, small journal, forged steel, 2 piece rear main seal
    2690 Category: Crankshafts
    Type: Small Block V8
    Date:
    Notes: 350, 3.48 inch stroke, medium journal, forged steel, 2 piece rear main seal
    310514 Category: Crankshafts
    Type: Small Block V8
    Date:
    Notes: 350, 3.48 inch stroke, medium journal, cast iron, 2 piece rear main seal
    3279 Category: Crankshafts
    Type: Small Block V8
    Date:
    Notes: 305/350, 3.00 inch stroke, medium journal, forged steel, 2 piece rear main seal
    330550 Category: Crankshafts
    Type: Small Block V8
    Date:
    Notes: 350, 3.48 inch stroke, medium journal, cast iron, 2 piece rear main seal
    354431 Category: Crankshafts
    Type: Small Block V8
    Date:
    Notes: 262, 3.10 inch stroke, medium journal, cast iron, 2 piece rear main seal
    3727449 Category: Crankshafts
    Type: Small Block V8
    Date:
    Notes: 283, 3.00 inch stroke, small journal, forged steel, 2 piece rear main seal
    3729449 Category: Crankshafts
    Type: Small Block V8
    Date:
    Notes: 265, 3.00 inch stroke, small journal, forged steel, 2 piece rear main seal
    3734627 Category: Crankshafts
    Type: Small Block V8
    Date:
    Notes: 327, 3.25 inch stroke, small journal, forged steel, 2 piece rear main seal
    3735236 Category: Crankshafts
    Type: Small Block V8
    Date:
    Notes: 265/283, 3.00 inch stroke, small journal, forged steel, 2 piece rear main seal
    3735263 Category: Crankshafts
    Type: Small Block V8
    Date:
    Notes: 283, 3.00 inch stroke, small journal, forged steel, 2 piece rear main seal
    3782680 Category: Crankshafts
    Type: Small Block V8
    Date:
    Notes: 327, 3.25 inch stroke, small journal, forged steel, 2 piece rear main seal
    3814671 Category: Crankshafts
    Type: Small Block V8
    Date:
    Notes: 327, 3.25 inch stroke, small journal, forged steel, 2 piece rear main seal
    3815822 Category: Crankshafts
    Type: Small Block V8
    Date:
    Notes: 265/283/302, 3.00 inch stroke, small journal, forged steel, 2 piece rear main seal
    3835236 Category: Crankshafts
    Type: Small Block V8
    Date:
    Notes: 283, 3.00 inch stroke, small journal, forged steel, 2 piece rear main seal

    Number
    Details
    3836266 Category: Crankshafts
    Type: Small Block V8
    Date:
    Notes: 283, 3.00 inch stroke, small journal, forged steel, 2 piece rear main seal
    3848847 Category: Crankshafts
    Type: Small Block V8
    Date:
    Notes: 283, 3.00 inch stroke, small journal, forged steel or cast iron, 2 piece rear main seal
    3849847 Category: Crankshafts
    Type: Small Block V8
    Date:
    Notes: 283, 3.00 inch stroke, small journal, forged steel, 2 piece rear main seal
    3876764 Category: Crankshafts
    Type: Small Block V8
    Date:
    Notes: 283, 3.00 inch stroke, small journal, forged steel or cast iron, 2 piece rear main seal
    3876768 Category: Crankshafts
    Type: Small Block V8
    Date:
    Notes: 283, 3.00 inch stroke, small journal, forged steel, 2 piece rear main seal
    3884577 Category: Crankshafts
    Type: Small Block V8
    Date:
    Notes: 327, 3.25 inch stroke, small journal, forged steel, 2 piece rear main seal
    3892690 Category: Crankshafts
    Type: Small Block V8
    Date:
    Notes: 350, 3.48 inch stroke, medium journal, forged steel, 2 piece rear main seal
    3911001 Category: Crankshafts
    Type: Small Block V8
    Date:
    Notes: 307/327, 3.25 inch stroke, medium journal, cast iron, 2 piece rear main seal
    3911011 Category: Crankshafts
    Type: Small Block V8
    Date:
    Notes: 307/327, 3.25 inch stroke, medium journal, cast iron, 2 piece rear main seal
    3914672 Category: Crankshafts
    Type: Small Block V8
    Date:
    Notes: 327, 3.25 inch stroke, medium journal, forged steel, 2 piece rear main seal
    3923279 Category: Crankshafts
    Type: Small Block V8
    Date:
    Notes: 302, 3.00 inch stroke, medium journal, forged steel, 2 piece rear main seal
    3932442 Category: Crankshafts
    Type: Small Block V8
    Date:
    Notes: 267/305/350, 3.48 inch stroke, medium journal, cast iron, 2 piece rear main seal
    3941174 Category: Crankshafts
    Type: Small Block V8
    Date:
    Notes: 307/327, 3.25 inch stroke, medium journal, cast iron, 2 piece rear main seal
    3941178 Category: Crankshafts
    Type: Small Block V8
    Date:
    Notes: 302, 3.00 inch stroke, medium journal, forged steel, 2 piece rear main seal
    3941182 Category: Crankshafts
    Type: Small Block V8
    Date:
    Notes: 350, 3.48 inch stroke, medium journal, forged steel, 2 piece rear main seal
    3941188 Category: Crankshafts
    Type: Small Block V8
    Date:
    Notes: 350, 3.48 inch stroke, medium journal, forged steel, 2 piece rear main seal
    3949847 Category: Crankshafts
    Type: Small Block V8
    Date:
    Notes: 283, 3.00 inch stroke, small journal, forged steel or cast iron, 2 piece rear main seal
    3951130 Category: Crankshafts
    Type: Small Block V8
    Date:
    Notes: 327, 3.25 inch stroke, medium journal, forged steel, 2 piece rear main seal
    3951529 Category: Crankshafts
    Type: Small Block V8
    Date:
    Notes: 400, 3.75 inch stroke, large journal, cast iron, 2 piece rear main seal
    4577 Category: Crankshafts
    Type: Small Block V8
    Date:
    Notes: 327, 3.25 inch stroke, small journal, forged steel, 2 piece rear main seal
    4672 Category: Crankshafts
    Type: Small Block V8
    Date:
    Notes: 327, 3.25 inch stroke, medium journal, forged steel, 2 piece rear main seal
     
    Last edited: Oct 31, 2016
  13. Grumpy

    Grumpy The Grumpy Grease Monkey mechanical engineer. Staff Member

  14. Grumpy

    Grumpy The Grumpy Grease Monkey mechanical engineer. Staff Member

  15. Grumpy

    Grumpy The Grumpy Grease Monkey mechanical engineer. Staff Member

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