RayG1988;940108 said:Here's some advice a friend gave me (not that I can actually take it due to lack of funds.)
"the block to have-70s C/K series 4 bolt main high nickle 3970010. This casting is also in camaros/vettes as 2 bolt mains.
thats fine but chevy rates those, and current production, 4 bolt blocks as good for 350hp
http://www.sallee-chevrolet.com/ChevyBareBlockProductionBlockSmallBlockV8s/10105123.html
http://www.sallee-chevrolet.com/ChevyBareBlockProductionBlockSmallBlockV8s/10066034.html
even the chevy strait 4 bolt bowtie blocks only rated at 450hp
http://www.sallee-chevrolet.com/ChevyBareBlockBowTieBlockSmallBlockV8s/10185047.html
you need to get into the splayed 4 bolt main cap blocks before the hp rating exceeds 450hp
you get ahold of one of these bad boys, theres no worries of block cracking or grenading at 500+hp.
we all know guys who have built engines exceeding 450hp with stock blocks but the blocks not designed for that stress and the main caps tend to walk at 450 plus, yes you may get away for years before something fails, but the blocks not nearly as strong as a BOWTIE,DART,BRODIX etc designed for racing, keep in mind an engine that makes 450 peak hp is making much less at lower rpms, any engine held at max rpms will far more quickly show its flaws than one thats only occasionally run hard, thats why the dyno hero gets to show the proof his engine peaks at 450 plus hp, and still gets to drive the car on the street for months or even years, its very seldom run at full stress levels
the heads that flow are any double hump pretty much. 461 461X 462 292 291 186 187. Make sure they have 202 intake 160 exhaust valves. (they have bigger ports to begin with) any X code head=factory high flow. (some aftermarket heads dont even flow as much as X codes) Angle plug heads are typically over the counter back in the day aftermarket GMPP. those are worth BIG bucks. I know im not mentioning the power pack 283s, or LT1 350 (1970) heads. Those are a needle in a pile of needles to find. I have a set of power packs on stand by but too much compression due to small chambers id need to run 112 race gas with -12cc dished pistons.
all pretty much 30 year old and tottally out of date info
you really need top read thru this first)
http://www.alaniztechnologies.com/headterms.html
http://www.rbracing-rsr.com/runnertorquecalc.html
http://www.dw1977.cz28.com/photo2.html
http://home.earthlink.net/~hennad/results.html
http://www.malcams.com/legacy/misc/headflow.htm
http://users.erols.com/srweiss/tablehdc.htm
http://www.purplesagetradingpost.com/sumner/techinfo/heads1.html#GM LT4
http://www.kendrick-auto.com/head_flow_figures.htm
decent DART,AFR,BRODIX, or TRICKFLOW heads make, ported stock or even bowtie heads look like a joke
If you cant come across those heads, Bowtie Phase 2 or Phase 3 heads.
If you do come across those heads, take them to a machine shop to have the rocker arm studs removed. Theyre factory pressed in and a bitch to get out. Have them removed and tapped so you can have screw in studs. Pressed in ones can from high rpm and vibrations caused, back out and ♥♥♥♥ up your valve train quick. rounding off cam lobes, bending valves etc.
crankshaft. You want to find C30 C40 C50 C60 trucks, dumptrucks, tow trucks. Some were equipped with 327s and 283s. Youll want the 327 crank. And if your racing, and regulations are 2bbl, youll want the intake (2bbl high rise) These cranks are steel, and nitrded. Take the crank and rotating assembly to a machine shop, have them lighten it, knife edge the counter weights, chamfer the oil holes. When you knife edge it, you are going to reduce the turbulance in the crank case which means less oppsing force on the crank at higher rpm. Your going to need your entire rotating assembly balanced. Pistons rods crank balancer and flywheel.
chamfering your oil holes will increase oiling to the bearings.
again 30 year old out of date tech info, theres far stronger and better cranks, rods,pistons, available
heres a post covering some of that info
I was recently asked if the differance between a cast crank and rods at $1200, vs FORGED at $1600 was worth the differance in cost by a guy who fully intends to race the car and has a high probability of useing nitrous...
"
Originally Posted by grumpyvette
think of it this way if you buy the cast/hyper deal youve WASTED $1200 PLUS, AND youll need to spend an additional $1700,-1900 PLUS, the gaskets and machine shop costs if you ever want to upgrade, if you buy the forged set up you spent about $400 more than you wanted to but youll never need to upgrade
spend $450 or $3000????
So Grumpy, just to make sure I understand, you think I should buy the better kit? You're kinda ridin the fence.
Just kidding, I get the feeling that if you could reach thru the computer you would be vigurously shaking me back and forth yelling "spend the freaking money"
"I get the feeling that if you could reach thru the computer you would be vigurously shaking me back and forth yelling "spend the freaking money"
thats .......what I get for useing a cheap VOODOO DOLL,........... NEVER TRY TO USE LOW PRICE PARTS ON CRITICAL COMPONENTS
your NOT getting the measage full strength if your only getting a (FEELING)......
by now you should be having SEVERAL REALLY NASTY 9 foot tall demons boncing you off the wall and ceiling and having the
"spend the freaking money"
in flames on the wall, if the stupid VOODOO DOLL was working correctly
I posted this before
""5140 or 4340 ? Get the Facts and End the Confusion."
Before we can answer the question "which metal do I need in my crankshaft". I think we need to take a moment and review just what each metal is made of and what are the best applications for each. In the following discussion we will see the strengths and weaknesses of each and with this information we will be able to decide which Crankshaft material will best fit our needs.
Starting with the basics, metals containing primarily iron are classified as "ferrous metals". They range from pure iron through exotic high-alloy steels. Stock Crankshafts are made from cast iron, a metallic iron with more than 2 percent dissolved carbon. One preferred variation, ductile or nodular iron has all its carbon contained in the form of tiny spherical graphite nodules uniformly dispersed throughout the metal's matrix. This makes the material more ductile (deformable rather than brittle) and eases casting and machining.
Even the best cast iron has only limited tensile strength. Increasing ductility, hardness, malleability and fatigue resistance requires removing most carbon and at the high end, alloying iron with other elements, creating "steel" an iron with less than 2 percent carbon
The most basic form of this is carbon steel, which contains up to 1.7 percent carbon and minimal additional alloying elements. Carbon steels are designated by a four digit number. The first two digits indicate the basic type, and the last two digits indicate the approximate midpoint of the carbon content. The "10" ID's these alloys as non-resulfurized carbon steel with some manganese (popularly called medium-carbon or mild steel). The second two digits the "45" or "53" means the steel contains about 0.45 or 0.53 percent carbon respectively. Stock forged OEM cranks are usually made from 1045 or 1053 steel. There are exceptions to this, some 350 high performance steel cranks in the sixties were made from 5140 and some manufactures offer 5140 or 4340 in their high performance aftermarket catalogs.
From these mild OEM steels the next step up is Alloy steel. Alloy steels allow for more variations depending on the alloying materials. Over time as manufacturing techniques improved and chemical knowledge grew., metallurgist developed whole families of alloy steels, custom-tailored to make metals stronger, lighter, more durable, more ductile, and harder. Alloy steels are also identified by a four-digit number, with the first two digits indicating the major alloying element or elements, with the last two digits indicating the approximate midpoint of the carbon range.
We will now examine the four most common groups of steel, we will examine their best uses and hopefully come up with a buying criteria for making a decision on our crankshaft purchase. We want our purchase to be based on knowledge of the product and its intended use.
4130 The best known chrome-moly steel. It is a high-strength/high-stress alloy when produced in thin sections (sheet metal and tubing). But 4130 possesses very poor deep heat-treating characteristics which make it a bad choice for machined or forged parts.
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4140 A deep-hardening chrome-moly steel , it forges well and has good impact resistance, fatigue strength and general all around toughness.
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4340 A nickel-chrome-moly steel, this alloy is used to make premium cranks.4340 has good tensile strength, toughness, and fatigue resistance. Modified 4340 alloys with vanadium and more silicon can make this already good alloy even tougher and more fatigue-resistant. The main drawback is cost.
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5140 This chromium alloy increases tensile strength, hardness, toughness, and wear-resistance over carbon steel. It has the same basic elements of 4340 and is made with the same process but is more affordable.
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So what can we conclude from this short primer. Our first conclusion is that we don't want to purchase a crank made from 4130. The lack of deep heat treating properties makes it unacceptable for most performance applications. That leaves us with 5140 and 4340. Of the two we feel 5140 is the crankshaft material that suits most clients needs. Reason #1, based on feedback from clients using our cranks the 5140 crankshaft lasts as long as the 4340 when used in all but the most extreme racing conditions. For applications where the engine is putting out 800hp or less and turning 8,000rpm or less, 5140 is the right choice. Reason #2, in engine building you save money where ever you can, if it doesn't effect the performance or durability of the engine and our 5140 crankshafts are priced 30-40% below 4340 crankshafts in cost.
short answer,forged is best, cast steel is significantly stronger than plain cast iron and can be slightly more flexable, unfortunately, as the quality gets better the cost gets higher, and your connecting rods are FAR more likely to fail than the crank in most engine combos below about 6500rpm
http://machinistinfo.com/types_of_cast_iron.htm
http://www.key-to-steel.com/Articles/Art1.htm
http://www.seaportsteel.com/TechHeat.htm
http://crankshaftspecialist.net/cryogenics.html
http://carcraft.com/techarticles/116_03 ... ndex1.html"
"Cast cranks weight less so the engine will rev quicker (like a light flywheel)"
thats a very comon MYTH!
keep in mind each crank casting or forging can be a totally differant design, and that the machine work done,and the weight of the total rotating assembly must be taken into account.
forged cranks can and frequently ARE lighter in weight , mosty of the weight is located in counter weights, a forged crank is generally used with FORGED rods and pistons and forged pistons and rods can be made both stronger and lighter at any given strength level, lighter rods/pistons allow for lighter counter weights.
example
http://www.scatcrankshafts.com/PDFs/ScatCrank07.pdf
if you compare carefully youll see the BETTER forged cranks are LIGHTER than the BETTER cast cranks and the weights of both cast and forged craks vary with the stroke and extent and quality of the machine work
the engine with the lighter rotating assembly only reves quicker in neutral, when its doing work (IE THE TRANS IS GETTING THE POWER TO THE REAR ) the car can only accellerate as fast as the CAR and tires,ETC will allow it to,
So true.
thats really all you have to know. That and what cam you should use. depending on the application, there is a such thing as TOO much and it can hinder performance."
agreed
Does this seem reasonable? Sounds too good to be true, help me almighty Chevy god.
hope that helps a bit