I purchased a shortblock 3 years ago and put 12K on the engine as of this month. I have a paxton sn2000 on the unit also. Well, my luck, the snout on the end of the crank shaft broke I could not beleive it! I did not have that much tourqe on the shaftand after looking at the break, right behind the timming gear, it looks like there was a flaw in teh casting material.

Now I have to rebuild the engin again. My question is; Which forged material should I use? There is a very good local machine shop that has a chevy forged steel crank made of 1049 chevy steel. OR, I can purchase a brand new forged steel crank mad of 5140 for 100 bucks more off of ebay. I have a few concerns purchasing a crank off of ebay, then haveing some postal worker throwing the box around not knowing what is in the box........


Any thoughs or direction of what will work best for me?

I have AFR heads, 9psi boost, 50-75 NOS shot (have not used yet), tes headers/flowmaster exhaust. and pretty much anything else you can imagine.

Thank you for your help!

 

My only recomendations would be don't skimp or you are going to be doing the same thing you are doing now.

 

I'm going wiht the 4340 peroid! I DO NOT want to do this again!

 

Which crank are you buying? I've been watching this thread since it started since I'll be running a cog belt and 10+ pounds and I for damn sure do not want my snout breaking off like many here have had happen. When it comes to this $$$$$ is not a consideration IMO. I want to buy what is flat out the absolute strongest crank made for a SBC...

 

I'm going with the Eagle 4340. Now, you can purchase one of the billet crankshafts, but they are very expensive!

 

the eagle 4340 cranks can handle 1k plus horse. I am going with one of them for my car.

 

I'm using an Eagle 4340.I read somewhere they have been tested at 1200hp with no problems,plus they are very reasonably priced.

 

I run the eagle 4340 and so does blownss

 

What are the cast eagle cranks good to?? I have one and I want a procharger next year....would it be OK for say 6psi??

Sorry for swithching the subject, but I can't find much info on their cast cranks anywhere.

 

put the good crank in and forget the blower if you can't afford to do it right.

 

That's what I thought,If you can afford a 4 grand blower set-up then a $400 crank is hardly in the equation.

 

i had the same problem broke the stock crank behind the timing spocket put a forged crank in broke it,problem was supercharger belt i had to tight. have cast one in for two years still working belt alittle looser now.

 

I guess I will change the crank at that time, thanks guys.

 

i have had the same callies crank in my 388 for the past 3 years with no probs

 

With a supercharger? I thought your sig had a turbo on it.

 

i dont think i said i had a supercharger did i?

 

but on my wifeys car i have had a stock ls1 crank in it for two years of daily driving with a vortec on it with 10-12 lbs of boost no problems so i dont know, it sounds like this crank shaft had a flaw from the factory,also i forgot but did anybody check the har. balancer to make sure it is in balance. i have had a couple crank snouts tore up by that issue before

 

Raiden, I'm in the process of building a balanced forged 383 motor using Eagles components. 4340 crank, 3DH-beam rods and JE forged -16cc pistons. With the heads I'm using (hopefully Santa brings me my AFR's) and the 14# pulley I ordered I'll make 550+ rwhp. I was d*mn near convinced by summit and eagle's techs that the components I bought wouldn't even break a sweat @ 6000 rpms.