Forged Crank

TexasT

Texas, Where are you from
Joined
Sep 10, 2002
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?
 

750H.P.V6

Brutal 6 Racing
Joined
Sep 4, 2001
The Eagle cranks work fine. They are priced right and everything you need for the build you're proposing. I'd put a few bucks into rods myself as you can buy a good aftermarket set that won't set you back a heap of $$. If you buy aftermarket pistons you'll be going with a full floating wrist pin. This being said you'd have to bush the small end of you stock rods and you will have to resize them and while you're there you'll probably put ARP bolts in them so just buy the aftermarket rods. I'd rather see you run a 109 block than a 4.1 as the block casting is better all round if you have access to one.

Neal
 

TexasT

Texas, Where are you from
Joined
Sep 10, 2002
I'd have to look for a 109 block and they just are out there like they used to be. Any recommendation on the rods I would or should look at? I'm not against buying stuff but I don't really want to but as you state they would come with good fasteners I guess and the small end ready to do the new pistons. I want to get the zero deck to ward off the detonation.
Good info. Anyone else?
 

TurboTGuy

Gray Beard Member
Joined
Sep 24, 2010
Nick Micale has done lots of 4.1's

Reach out to him. He's feeling better and taking calls now.
 

434nova

Active Member
Joined
Sep 30, 2013
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.
 

TurboTGuy

Gray Beard Member
Joined
Sep 24, 2010
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.
Holy crap!
 

434nova

Active Member
Joined
Sep 30, 2013
Yeah... holy crap... I thought they flex and crack... maybe I’ll just run my stock bottom end until it dies.... that’s a lot of power!
Fastest stock bottom end I know of goes 6.04 @ 114mph in the 1/8. Car gas no cage so he doesn’t run it out the back. But that’s a solid mid 9 sec car. He has over 100 1/8 mile passes. This is a true bone stock bottom end. Ironically he broke his forged girdle stroker and he had this stock shortblock laying around so he put in so the car wouldn’t be down. Now that’s impressive.
 

TireFryer

The New Kid
Joined
Dec 21, 2001
Man.. shows what can be done with really good tuning and a good engine management system... crazy a stock v6 from 30+ years ago can run mid 9’s
 

750H.P.V6

Brutal 6 Racing
Joined
Sep 4, 2001
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.
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
 

434nova

Active Member
Joined
Sep 30, 2013
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
I think they get broken more then they brake if you know what I mean. But I agree a eagle crank and rods aren’t that expensive. But you will also need to include a balancer or have you stock one modified since the cranks are internally balanced. Just another thing to include if your on a budget.
 

hemi8

Goin Sideways
Joined
Jun 6, 2001
Molner rods, Eagle or Scat crank
Yeah... holy crap... I thought they flex and crack... maybe I’ll just run my stock bottom end until it dies.... that’s a lot of power!
Do you have a expert dyno tune shop you can take it to for a tune? Getting the car tuned right is not easy unless your an expert.

Mike
 

Nigel

Well-Known Member
Joined
Jun 16, 2001
Eagle cank and rods are a good deal. I currently have them. Two small things, the snout was a little undersize, don't remeber by how much. I added an ATI balancer, which is setup to be honed to fit it is press on. If you try to use a stock balancer, may have fit up issues if the snout being a little small is typical for that crank. Did not need to hone the ATI to get the right press fit on the eagle crank. I thnk the balancer was supposed to be .007 to .01 undersize for the press fit, you have to double check that. The knurl is a little deep on the back and I get some oil out the rear main. Was a little disapointing on a new build, but I am not taking it a part for that, not sure how to address that on a new crank. Everything was round, and came out right around .002 on the mains and the rods.
 

Mike T

Well-Known Member
Joined
May 3, 2013
Eagle cank and rods are a good deal. I currently have them. Two small things, the snout was a little undersize, don't remeber by how much. I added an ATI balancer, which is setup to be honed to fit it is press on. If you try to use a stock balancer, may have fit up issues if the snout being a little small is typical for that crank. Did not need to hone the ATI to get the right press fit on the eagle crank. I thnk the balancer was supposed to be .007 to .01 undersize for the press fit, you have to double check that. The knurl is a little deep on the back and I get some oil out the rear main. Was a little disapointing on a new build, but I am not taking it a part for that, not sure how to address that on a new crank. Everything was round, and came out right around .002 on the mains and the rods.

I discussed this with them a couple of years ago and I don't know if any of it has been corrected yet.
 

Nigel

Well-Known Member
Joined
Jun 16, 2001
I discussed this with them a couple of years ago and I don't know if any of it has been corrected yet.
I did mine back in 2019. I also realized I was off a decimal. The press fit was in the range of .0007 to .001.
 

TexasT

Texas, Where are you from
Joined
Sep 10, 2002
All good info. I know a couple guys who are deep in the tens on the gnecu. One is on a stock bottom end. Though he sold that car and is putting together another one last I talked to him. So an aftermkt ecu would probably be used especially since e85 is definately in the plan.
I'll do some hunting on the molnar and eagle rods. Will also need a flex plate for internal ballance that will also add to the total. It stacks up in a hurry.
I think that is the reason I want to go to a forged crank and two billet caps. It is to keep the thing from getting squirrely and busting the block up. The stock stuff is pretty stought but it is old and the stuff I have hasn't been treated nicely. I do have a crank out of the 4.1 but even that I don't know the history of.
Lots of decisions.
I want to thank all who posted and I do appreciate the time and efforts as sharing isn't always how this stuff goes.
 

Jerryl

Tall Chinese Guy
Joined
Dec 14, 2004
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?
 

Mr.Spool

Well-Known Member
Joined
Nov 6, 2006
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?
The ability to see what's going on with the entire car.shocks, springs,bump boxs,better boost controllers,ability to control timing better and much better auto correction.
 
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