TB2

iTrader: (1)

First of all, I would never consider a stock cast crank. GM's forged crank is not a bad piece. Before aftermarket cranks were readily available stock forged cranks were totaly acceptable and they got the job done.
look, alot of how any crank lasts depends on the setup and how much abuse it will see. I would never consider any stock crank for a heavy nitrous motor. Its the instant hit that snaps cranks. But for an NA motor they will handle pretty much what a stock block will handle. A transbrake shouldnt have much affect as the motor is already preloaded when its released. As we all know, good rods and a good balance job is critical.
E85 is irelevent. If I left my motor completly the same and switched from E85 back to race gas, with a proper tune the motor would see similar abuse with either fuel.
And Gary, I dont know what you do and dont know. And not to slam you, but if you want anybody to take you serious having an avatar of a minivan is not going to cut it.

1BADRZ28

iTrader: (2)

this.

1gary

TB2.Point well taken.All I'll say is like always,you can't judge a book by it's cover.LOL

There a dozens of members here that at first I didn't think they knew much.But since been around for awhile I found how wrong I was and gained my respect.

DIGGLER

iTrader: (1)

my stock cast crank has been fine running mid 9's or quicker the past couple of years. with nitrous.

1gary

Diggler-tick,tick,tick,goes the clock on that.............

TB2

iTrader: (1)

Diggler, if you can get away with it. More power to you. I know other guys doing the same thing. My buddy ran a 3rd gen camaro 400 sbc with a cast crank and nitrous in the low 10's and his never failed. If you can do it, it allows you to put that money in other places to go faster. But that would put me out of my comfort zone for sure. My concern is not for the crank, thats cheap, but if it does fail the other expensive components that it takes with it.

DIGGLER

iTrader: (1)

whatever your are comfortable with is what you should do. i think most people overbuild their engines, though. then they dont have any money left for the car.
i would estimate my ticking time bomb has around 100 passes on it.

1BADRZ28

iTrader: (2)

I had no issues with a stock cast piston 400 dart heads with a 300 shot back in 2000. I got a good amount of hits until the rings broke. It was good time but was a known time bomb. I had several cast cranks nitrated that had the sauce added and never boke one. I'd say they were around 600-700 hp with the nos. The cast pistons/rings were another story.

project89

iTrader: (1)

wow i ask if a factory forged crank is going to hold up and this turns into a bitch fest.

im going to kepe the crank, and my speedpro pistons granted they arent srp's or some other high dollar forged slug but they will work.

when i switch to the afrs and vic jr efi ill pull the rods and swap them out for a better piece and swap the 224/224 cam for something a lil larger

my car will see the track 2-4 times a year and one trip to the salt flats a year

the way i look at it the car will make the same power with the afrs vs the stock heads it will just take alot less boost presure to do it.

even though i could crank the boost back up with the afrs and make a ton more power im going to sit this car in the mid 9's and be done with it with either set of heads

1gary

I think I made my point clear enough at this point in the thread for you to understand how I feel you should go.I apologize to you for any part in taking your thread in a misdirection.Please do post a build thread with pix's.

project89

iTrader: (1)

there is already a build thread inthe power adder section, though i started it after i swaped pistons and rods in the motor.

ive also been neglecting to update it at times so some parts of the build arent posted there, one of these days ill go back and update it

right now ive been forced to halt the build.

i just opened up a small business and without warning the building i live in was sold which was totally unexpected so im currently looking for a place to move, once i get moved ill get my sponsorship set up here and at ls1tech and get back to working on the car

Mystyk_Wynds

Ok so how about this thread:
http://speedtalk.com/forum/viewtopic.php?f=1&t=21462

I understand the debate here. But if most of our cranks are allegedly nodular iron and not cast, I would think the cranks can take some serious abuse.
Now you can get a forged steel crank for about $200.
I say check your stock crank and rods for cracks, then remove the flashing, shot peen the rods and crank. If you wish, go as far as nitriding and maybe Cryo.

The guys in the above link, are turning stock cast iron 350 cranks in excess of 7k. So you do your thing.

Oh yeah, and most forged cranks, reguardless of material composition, usually respond well and the same as cast or nodular cranks to shot peening and cryoing. Nitriding is dependent on the material composition, the other two are not.

1gary

Gawl you guys drive me nuts.You want to go faster,but don't want to buy the equipment to do it. Now you of course have two choices. Either you can invest in treating a pc of junk so the first spun bearing confirms that it is a pc of junk or you can go belly up and buy a(that you need) crank that is salvageable. Oh those two choices are take a oldtime drag racers advise or not.

ZONES89RS

iTrader: (2)

Since I swapped to then gen III and IV platform, I do not have to spend money on so many go fast parts. I have seen expensive parts break as well, but stock sbc cranks have lived through quite a bit.

DIGGLER

iTrader: (1)

ironic this thread pops up now... i am in process of pulling my "ticking time bomb" out of my car and selling it to a guy who is putting it in his street car. i never had any trouble out of it. still has 60+psi oil pressusre, runs good, and doesnt have any leaks. instead of investing a couple grand extra in forged engine parts, i put that money into the chassis/converter. worked great.

1gary

That is why from yrs ago guys used to have the fuzzy dice hang off the rear mirror. LOL...........

InfernalVortex

iTrader: (4)

Does anyone have any proof of this "cryo" crap working? People with the ability to put liquid nitrogen on things have been charging other people for the privelege of freezing their things for decades.

Ive even seen guitarists pay more for vacuum tubes (component in guitar amplifiers) that have been "cryo-treated" because it makes it "sound better". There's hardly a singly industry out there that doesnt have its own "cryo-treat" scam connected to it somewhere.

I need some cryo-treated cheeseburgers.

ZONES89RS

iTrader: (2)

Good question. Snake oil and snake freezing?

project89

iTrader: (1)

actually cyro treating does have some merits in a few aplications, i can recall a few parts in the top alky dragster that were treated and would last an extra 2-4 passes. and for anyone who knows the tad class being able to get 2-4 extra passes out of some parts could mean the savings of alot of money each race season

1gary

But to spend money to treat a stock forged crank doesn't make sense when that extra costs could be applied to a much better unit overall in a aftermarket quality crank.No,no,not a Scat or Eagle.

A.Delaney

A GM sbc engine block can handle 900hp? I was assuming 600hp was about the limit. My 2 bolt 400 block im afraid would crack like an egg at even 800hp. I think Dart said the SHP blocks were good for 650hp. Im sure there pretty reserved on that number. I figured I would go with an SHP if I ever wanted to slap a blower on my 400.

A.Delaney

I have an Eagle 4340 crank and Eagle H-beam rods all balanced in mine. Its held up fine for me at 13.1 with some spray.

DIGGLER

iTrader: (1)

900 is about the limit for a STOCK 4 bolt block. by that point the main caps will be walking around some.

project89

iTrader: (1)

this is correct, i wa sjust stating that we cryo treating does have some merits but for street/strip guys they shouldnt have to have anything cryoed.there should be the correct part for what most street street/strip guys are doing thats strong enough

the only reason we did is with the tad we were buying the top top of the line strongest parts out there and was still pushing the limits on them,and or breaking them,and it would help them last just a few passes longer.
the money saved from them lasting a few extra passes was much much more then the cost of having the stuff treated

1gary

We run a 632 Alky BBC on the bottle.Best time in the 1/8th is 4.56@150.None of the parts are treated.Just the appropriate parts to get the job done.

ZONES89RS

iTrader: (2)

Well, comparing to a top fuel engine that runs on the edge of hydro locking, there is surely a benefit.

project89

iTrader: (1)

im talking about sub 500 ci cars that are going 5.2-5.4 in the 1/4, we get certain drive line related parts cryoed and we buy the best parts available

project89

iTrader: (1)

thats exactly what i was getting at, cyro treating does have its benifits in the right places, and ur average street /strip car is not one of them

1gary

I surely miss the time when guys decided to build a car,(and no we at that time didn't make alot of money),bought the best you could understanding it was just apart of the deal. It was a cornerstone of hot rodding and drag racing. Not the current thing going on putting a assortment of the cheapest pc's of junk they can find.

1gary

My advise is for you on the next teardown have the crank mag'ed right behind number 2 main journal and have it measure on all journals for taper from side to side. Those have a history of cracks behind number two and breaking in the same area. The taper allows you to torque the bearing,but they don't make good contact. If you have a machine shop that can measure the cranks index,it is another thing those are not very good.

DIGGLER

iTrader: (1)

there is guys running 14's with fully forged engines, and there is guys running much faster than that with a stock engine. i would rather be the guy running much faster.

1gary

Trying not to get too far off topic.Thing is those guys going faster without the required investment put all of us at risk when that plan fails ending up with a oil down........

I think I am pretty constant advising people what to buy given their goals. I don't think I am a person who is bench racing in my posts trying to push them into over spending. I do think I am a guy who thinks alot about how the amount of money spent in the long run and the reliability is effected. And with a good aftermarket crank rebuild ability I think has a greater opportunity and no less better overall quality.

Shagwell

Stock 4-bolt 350 block.

In the 400 blocks, the "509" 2-bolt is actually considered the "best" stock block. The 4-bolt blocks are all techincally weaker than the 2-bolts in the 400's because the main caps are too thin where they're machined down for the outside row of bolts; they're known to crack the caps between the bolts.

I've seen several high-mid 5 sec 3000-3200 lb n2o cars running the stock "509" 400 block as well as 350 4-bolt blocks, beyond that they don't tend to live well. - A buddy hurt a couple worked 509 castings when getting into the lower 5's, he's now been 5.0x's and is pushing for high 4's in X275 on a Dart SHP w/o any issues.



As for the BBC's, we've went 4.70's @ 3000lbs on a stock block for several seasons w/o any issues. In fact, that block now has a bracket combo in it and is still running just fine.

ZONES89RS

iTrader: (2)

Have been enjoying beating the gen III and IV engines with cam only, I will never go back to the gen I. I replace nothing but the valve train and that does. It include rockers. The sbc was a fun learning experience though and I have fond memories. Call it luck, but several of my junkyard gen III/IV swaps have yet to break. My sbc engines gave me issues here and there.

Wish I could aford a bbc though, always wanted to do a 496.

DIGGLER

iTrader: (1)

thats why people have such good luck with the ls engines... they arent messing with anything really, just putting a cam in it. (not saying thats why you've had good luck with yours) gm put them together well.

ZONES89RS

iTrader: (2)

Yep, just comes with the times, I would hope a 2000+ engine would work out better than 1970-1995 tech. Although I can tell the vortec sbc and lt1 stuff bridges the gap with the ability to take abuse from the old stuff to the LS. At least my experience.

DIGGLER

iTrader: (1)

my experience is there isnt as much of a difference between the 2 gens of engines as everyone makes it out to be. you've got tons and tons of people that really arent that good of a mechanic working on sbc's/LT1s and they just can't keep them together or whatever. they go to a bone stock LS engine and don't mess with it..... and bam they have no more trouble. musta been that crappy old sbc that was causing all the trouble.

ZONES89RS

iTrader: (2)

I mean stock for stock. The capability aside, the pre vortec engines seem to give up more than the powdered metal lower ends. Just my experience. Slapping a cam and nailing 7200 has been a blast, but I have a couple sbc engines I built 3-5 years ago that are still beating the streets and chewin tires, no doubt what the can do!

Mystyk_Wynds

hey, If anything I was just putting out appliable options of what you can do. Isn't that one of the points? I mean if you drop $600 into mangfluxing, shot peening, possibly nitriding and lightening/balancing a stock crank...Generally your still farther ahead.
I understand doing it right, but by who's standard is this? Magazines that are owned by those after market companies?
I figure by dollar amount, forged crank=$400+ forged rods=$200-$1000+ pistons lightweight=$300-$1000+ Rotating assemblies can be had for average of $800.
Out here, Nitriding=$150, Shotpeening=$150, Magnaflux=$75, Lightening=Starts $75 and balancing is $75-$300
All in all its a matter of perception and personal interest.

ZONES89RS

iTrader: (2)

I am just addicted to what we call "grenades", see how far the stock stuff can go.

project89

iTrader: (1)

lol i quess u could call my motor a grenade.
i say i split the block before i break anything else though.unless i get carried away with the tune and get to agressive with my timing or lean it out to much then its going to be a piston/rod

ZONES89RS

iTrader: (2)

Well, it is a blast pushing stock parts to the limit. I love the ability of the LS, but for boost, the ol sbc 5 bolt per cylinder hold tons of boost.

Mystyk_Wynds

Yep thats my goal, see what the stock can handle. Besides 305s' are a dime piece and I want to experiment a little at a time. But ya know, it seems so damn hard to get an ls/lt cam for this engine for under a $100. It would be nice but my cam is the stock one for the 305-350 vette. So everything I find is less duration but more lift.
Just gonna see what the stock crank and rods can take.

1gary

No-no,it's not perception.Sorry man,to sink your boat,it's experience.I do hate those shiny comic book ads in rag magazines like Hot Rod.There isn't any valuable info in any of them.

TB2

iTrader: (1)

So if a stock 350 4 bolt block is good to 900hp. Is that completly/partially filled with hardblock? How much does it help? And at what hp should this be done at? Ive been considering filling mine up to the freeze plugs before I start spraying.

Or is it the main caps that give up? How much extra will billet caps help?

ZONES89RS

iTrader: (2)

Jesus, have you seen what the dime a dozen 4.8 builds do with a ls6 used cam? Very impressive. They damn near give those away. Seen one make 770 rwhp with a s480 turbo.

DIGGLER

iTrader: (1)

ya 4.8/5.3's are almost impossible to beat for performance on the dollar. if you can get one into the car for cheap, that is the way to go nowadays.

as for the stock block, i know a mid 70's 4 bolt main with arp studs is good to 900 with no fill. plenty of people have done that, and some have gone well beyond that but its a gamble at that point. and the mains will scoot around and do some crazy stuff.
factory forged crankshaft is good to about the same point. they are really good cranks, but not 4340 alloy.

1gary

Diggler. I have been looking at the LS's. Seems the consensus the stock iron blocks are ok to F/W HP of 800. Then a aftermarket block is heavily suggested.

Guys you if you like can bookmark my user name. Why??. Well I think this whole thread is at the end of the day about money. I'm the best buddy you can find anywhere. I promise I will never suggest you take that chance to lose everything and at the end of a use of anything you will have something to sell. Been there done that.

Orr89RocZ

iTrader: (20)

Interesting thread... Lots of varying opinions. Everyone knows someone who breaks parts either stock or aftermarket and also know a guy who cant break a stock motor at ridiculous power levels. Just seems to me not everyone is able to make stock or cast parts live when pushed to high power and rpm levels...else youd hear about it often. Not many can do it that way due to many reasons. Machine work quality, tune up, faulty parts etc

Whatever the case build to your budget. Most forged cranks and h beams with good bolts will last longer than the block they are in. A factory 350 block at 900 hp is a touchy subject. It depends on the casting used for the block, the machine work done and how that power is made. Nitrous high rpm motor is gonna stress mains alot harder than lower rpm turbo will. My research led me to a dart block when doin my turbo build. Just too many stories of blocks cracking or caps walking on factory blocks at the power levels i wanted

I know 87_ta says his dart shp block caps are starting to walk alittle and thats a nitrous 7200 rpm motor with splayed 4 bolt caps. That should be stronger block than any factory 350 done 50 yrs ago....or id hope so with todays metallurgy and foundrys.

I get crap for my build all the time from my budget jy lsx friends who are making big power on stock truck motors for thousands less $$ than i have in mine haha but i feel confident in my internals and block to handle everything i could want and to do it for a long time. I was able to afford it and i dont regret it. Just wish i did it right the first time instead of throwin small heads and cam in it first build. I knew id want more and had to rebuild

But if machine work is good and tune is good and safe, and rpms are kept in check, i dont see why a stock crank cant be used for moderate goals. Circle track guys have broke them but they may see 7000-8000 rpm alot and thats more stress than what most drag racers go thru or street strip guys

Mystyk_Wynds

Well most of the time before the stock crank goes the rods will bend or break. One of the discusions I had with a machine shop was me explaining concepts. One is well if shot peening can improve the cranks rigidity from 7-18% then that means it can handle that much more. Flex is what kills the crank, rigidity is resistance to that.
Now this convo was on my 35pd tech iv crank. Which breaks around 5-6k. So I applied the math to him like this now that should be the breaking point.(5350-5900)--(6440-7080). I also added in that if I nitrided in addition, I should be able to hold it at 5500-6k all day.
but most common failure with gm is rod failure.