Forged Crank

Mr.Spool

Well-Known Member
Joined
Nov 6, 2006
So, I'm in the market to assemble an engine. Looking at a forged crank and maybe a pair of billet center caps to keep it in there. We all know the production block is weak or at least not real suitable for high boost and lots of rpm. It will be a street strip type setup. Probably on e85 and possibly an ecugn or holley. Haven't really planned that far yet.
Anyway, I get looking at cranks and the unit summit sells seems like it would work. Do I really need to spend the coin on a 4340 one or is this 4140 one plenty. Sez it is good for 1k hp.
Will probably just do a set of two dot stock rods resized and fitted with arp hardware. Not planning to spin it over 6k rpm and may never see the high side of 5500rpm. Though I will say it should see north of 30-35 psi boost . Not real sure on heads yet would like some ta units but will probably just clean up a pair of the 8445 units and get a valve job and run em. Budget build for sure but I really don't want to have to pull it back out or drive over the crank. And from what I've seen guys doing with the new engine management and e85 I'm pretty sure it will run just fine.
Next becomes the question of a block. I have a couple 4.1L units. One is already .040 over and one came out of the wrecking yard and might be standard bore, not sure. With the advent of relatively cheap custom pistons I am leaning towards getting up with earl brown and ordering up a set to fit the .040 over block and sending that to see what it will do.
We have a machine shop the locals use so I will have them do the machine work. And handle assembly at home.
Street car , drive to the track, run it and drive it home and it will see several if not many trips to work and out to the local car meet ups.
Anyone have thoughts or experience they would like to share?
Port the iron head, 109 block,any crank you choose,there is no need to go wild with the right builder and tune any crank will stay in there
 

Mr.Spool

Well-Known Member
Joined
Nov 6, 2006
You've done very well with your combo but for every story like yours there are 10 guys that didn't fare as well. An Eagle crank and rods aren't going to break the bank and are cheap insurance.

Neal
If there breaking a stock crank then they need to look into other areas like the tune or the build itself.ive hammered on several 109s with a stock crank and have yet to break one,900+horsepower.
 

TexasT

Texas, Where are you from
Joined
Sep 10, 2002
I think about it this way;
30 years ago, using the same stock short block we use today, 10.9x was considered almost impossible. Nowadays we consider it very doable if not a walk in the park for some. So what changed?
X2 on the engine mgmt. Light yrs ahead of what the original stuff does. Even the gm 411 stuff the ls guys run does wild things compared to the original sfi stuff we used back then. The thought of a knock gauge is rudimentary cc ompared to o2 in each exhaust and tuning by cylinder. Injectors that reliably out flow originals. And the fuel pumps to do it. An 044 bosch is pretty rudimentary too compared to the pumps guys put in the tank these days.
 

phil_jordan

Active Member
Joined
Aug 22, 2012
I run stock crank, stock rods, with trw forged pistons and 2 center billet caps. I been a best of 10.06 @ 135 mph. The stock crank can take a thrashing. I run 29psi now but am planning on going to 35 psi or more with the new 6466 turbo.
Sheesh!!!!
 

750H.P.V6

Brutal 6 Racing
Joined
Sep 4, 2001
If there breaking a stock crank then they need to look into other areas like the tune or the build itself.ive hammered on several 109s with a stock crank and have yet to break one,900+horsepower.
Your combo is the exception not the rule. It true to say your results far exceed anyone I have dealt with in the last 30+ years. It's also true to say I've seen lots of broken stock parts in the same timeframe. There is nothing magic in the stock short block its just all cheap OEM junk, actually its cheap OEM junk that is 35 years old.

What I find funny about these threads is that when people offer up legitimate information based on decades of first had experience they get drowned out by the Bigger Better Most stories you find all over the car forums. You know the ones "My buddy pulled a engine out of a '85 Regal in the wrecking yard and we've been running 9 flat for 6 seasons"

You'd think I told the guy to buy a TA block with a Crower billet crank and rods. It's funny how people will spend $1500 on a turbo or $3k on a set of heads but won't pony up an extra grand for a decent short block.

Neal
 

TexasT

Texas, Where are you from
Joined
Sep 10, 2002
Your combo is the exception not the rule. It true to say your results far exceed anyone I have dealt with in the last 30+ years. It's also true to say I've seen lots of broken stock parts in the same timeframe. There is nothing magic in the stock short block its just all cheap OEM junk, actually its cheap OEM junk that is 35 years old.

What I find funny about these threads is that when people offer up legitimate information based on decades of first had experience they get drowned out by the Bigger Better Most stories you find all over the car forums. You know the ones "My buddy pulled a engine out of a '85 Regal in the wrecking yard and we've been running 9 flat for 6 seasons"

You'd think I told the guy to buy a TA block with a Crower billet crank and rods. It's funny how people will spend $1500 on a turbo or $3k on a set of heads but won't pony up an extra grand for a decent short block.

Neal
As far as turbo goes, I'll likely have a ta60 or ta62 on it as I have one of each to try out. I never really thought I got the most out of the stock one so I never bolted either on. Intercooler will probably be a custom unit. I've been studying up on cores and hunting a torn up stocker to cut the endtanks off of so I can make my own slic. Nothing fancy just something with less pressure drop.
I'm not against running the stock crank but I figured if I was going to hunt one down and summit being a few exits down i20 from the house I might want to go that route. But it does seem to spiral up in a hurry. Flex plate, balancer, pistons, rods then we get to the top end with injectors, fuel rails, maybe heads, rockers, lifters , pushrods. It gets to five figures in a hurry . Then there is the ecu and harness for that. And the fact that the wife might not be near as excited to build an engine as I am.
 

Mr.Spool

Well-Known Member
Joined
Nov 6, 2006
Your combo is the exception not the rule. It true to say your results far exceed anyone I have dealt with in the last 30+ years. It's also true to say I've seen lots of broken stock parts in the same timeframe. There is nothing magic in the stock short block its just all cheap OEM junk, actually its cheap OEM junk that is 35 years old.

What I find funny about these threads is that when people offer up legitimate information based on decades of first had experience they get drowned out by the Bigger Better Most stories you find all over the car forums. You know the ones "My buddy pulled a engine out of a '85 Regal in the wrecking yard and we've been running 9 flat for 6 seasons"

You'd think I told the guy to buy a TA block with a Crower billet crank and rods. It's funny how people will spend $1500 on a turbo or $3k on a set of heads but won't pony up an extra grand for a decent short block.

Neal
neal hope i didnt offend you,wasnt my intention.nothing wrong with a forged crank,but remember its still going in that cheap oem block designed for 400hp ;)
 

Mr.Spool

Well-Known Member
Joined
Nov 6, 2006
I run stock crank, stock rods, with trw forged pistons and 2 center billet caps. I been a best of 10.06 @ 135 mph. The stock crank can take a thrashing. I run 29psi now but am planning on going to 35 psi or more with the new 6466 turbo.
And it's not a lightweight
 

626gn

Well-Known Member
Joined
Feb 15, 2009
But it does seem to spiral up in a hurry. Flex plate, balancer, pistons, rods then we get to the top end with injectors, fuel rails, maybe heads, rockers, lifters , pushrods. It gets to five figures in a hurry . Then there is the ecu and harness for that. And the fact that the wife might not be near as excited to build an engine as I am.
No expert advice to give you (cuz I'm not one of them) but having just gone through all of this myself, I can relate. Things certainly do add up very quickly. Determining where to draw the line was a big struggle for me. In the end, for my simple needs and purposes I probably did overbuild and overspend but I feel better erring on that end then the other. Having an understanding wife, even though not a car enthusiast herself, definitely helped :) Good luck with your build man!
 

87GN_Bart

Active Member
Joined
Jul 12, 2016
I can't believe anyone would gamble on a 30 year old crank on a new build. There are forged cranks for $500 that don't have metal fatigue. The choice is yours however most builders would recommend a forged crank..Penny wise and pound foolish.
 

TexasT

Texas, Where are you from
Joined
Sep 10, 2002
I understand the lure of a $500 forged crank but as above that is just the starting point. Then comes the balancer and flex plate to balance that internal unit so we are closer to a grand than not with tax and shipping . Then comes the actual balance job. As the while we are there gets going with forged pistons and new rods. So there we get it to two grand or $2500 and we haven't bought any crank or rod bearings, had the block vatted and checked, and some cam bearings and freeze plugs installed.
Gasket set, hg, and a valley pan for another hunski or two. Then a cam. Roller you say? There is another grand. Where are we? Five large or so and we haven't even seen that the block has the thickness in the cylinder walls with a sonic check.
And it spirals on.
 

434nova

Active Member
Joined
Sep 30, 2013
I can't believe anyone would gamble on a 30 year old crank on a new build. There are forged cranks for $500 that don't have metal fatigue. The choice is yours however most builders would recommend a forged crank..Penny wise and pound foolish.
Your still using a 30 year old stock block. For a 10 sec car a stock crank isn’t really a issue.
 

87GN_Bart

Active Member
Joined
Jul 12, 2016
There is nothing cheap about owning a old performance car where parts are hard to get, i love these cars but be prepared to open the wallet.
I believe most of the buick guys have faced the same problem.
 

TexasT

Texas, Where are you from
Joined
Sep 10, 2002
Makes me really reconsider the forged crank and just go with a couple billet center caps, have it align bored and go with the stock stuff. 30yrs old stuff is still plenty tough as evidenced by some of the numbers guys are putting down. I'm not on a over the top on he edge unit. I'm not in my twenties out on the street every weekend or at the track like I was back then . Mostly I just want to be able to drive it and have it be reliable . I'm not out coyote or hellcat hunting. Just want to cruise and be able to make some passes when I feel like it. But it will get some boost and the e85 to support it. Which means fuel system so there is that expense too.
 
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