Cranks: Billet vs. Forged?
Cranks: Billet vs. Forged? I was wondering for a street applicable, but high horsepower FI engine, would a E-4340 billet crank be better than a forged crank. Furthermore, would it weigh less and would it be worth an extra $600 over a forged piece? Also anyone explain the benefits of the billet vs. forged. Thanks
Chris
<small>[ January 28, 2003, 05:01 PM: Message edited by: Trojan T/A ]</small>
Chris
<small>[ January 28, 2003, 05:01 PM: Message edited by: Trojan T/A ]</small>
TECH Fanatic
Joined: Nov 2002
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From: metro st louis
Re: Cranks: Billet vs. Forged? I'm a little out of my league here but some of the mills I've seen are putting about 700hp to the ground with a stock crank that is polished. I've always been told that the billet cranks are for 1000hp monsters. Remember when the price difference between those two cranks could have bought you a forged 350 crank?
Anyway check out Harlan's (y2khawk) set up. I think he is still running a stock crank.
Anyway check out Harlan's (y2khawk) set up. I think he is still running a stock crank.
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From: Upstate NY
Re: Cranks: Billet vs. Forged? Marlan Davis wrote a good article in Feb 03 Hot Rod Magazine about metallurgy. Cranks are well covered.
Billet, as in machined from a 8-9 inch diameter slug of barstock, are often the only alternative to stock crank if forgings are not available. LS1 was in that boat initially, but I'm not sure if good 4340 LS1 forgings are economical yet.
A good cast steel crank is often better than a low-grade forging.
Define "high hp FI" street engine. Below about 500 hp, good cast crank is ok. If 4340 non-twist forged crank is available from a major crank supplier, it will be more than adequate. Billet and forged cranks can both be machined to the same weight.
The reason good billets are available for reasonable(?) prices now is because of good CNC lathes which can machine a 385 lb billet into a 45-50 lb crank in a reasonable time.
FWIW, even though a forging may have good 'grain flow' in the crank which is generally thought to be superior, an aircraft quality (AQ) bar of 4340 is probably a better piece of metal, and in the end stronger. Top Winston Cup teams use a lot of billet cranks, and not just because they can make them faster than they can get a forging machined.
Don't bother with an expensive billet if you can get a good 4340 forging.
Billet, as in machined from a 8-9 inch diameter slug of barstock, are often the only alternative to stock crank if forgings are not available. LS1 was in that boat initially, but I'm not sure if good 4340 LS1 forgings are economical yet.
A good cast steel crank is often better than a low-grade forging.
Define "high hp FI" street engine. Below about 500 hp, good cast crank is ok. If 4340 non-twist forged crank is available from a major crank supplier, it will be more than adequate. Billet and forged cranks can both be machined to the same weight.
The reason good billets are available for reasonable(?) prices now is because of good CNC lathes which can machine a 385 lb billet into a 45-50 lb crank in a reasonable time.
FWIW, even though a forging may have good 'grain flow' in the crank which is generally thought to be superior, an aircraft quality (AQ) bar of 4340 is probably a better piece of metal, and in the end stronger. Top Winston Cup teams use a lot of billet cranks, and not just because they can make them faster than they can get a forging machined.
Don't bother with an expensive billet if you can get a good 4340 forging.
4340, billet, billeted, billets, crank, crankshaft, difference, forged, forgings, horsepower, hp, ls1, recommendations, sbc, versus, vs
