Factory crank shaft (F-Body 3.4)

[Doward]

BTW - 3.1 and 3.4 cranks are the same. 3.31" stroke. #981 forging is the strongest, as far as I know!

[SappySE107]

What I wanna know is why the DOHC crank costs more from GM. Same casting, but costs more.

[Guest]

Um no, a smallblock crank is MUCH stronger than ours. Even fire v6's use a split journal crank which is weaker by comparison to a shared journal crank. If you want mega torque and no chance of failure from a V6 crank a oddfire crank is MUCH stronger.

I know what you're trying to get at, but the 660 does not use a split journal crank, each rod is on it's own journal. A split journal looks like to cylinders mated together,but one is offset from the other.

[xxrollin]

Doward, you said something about a #981 forging, is this a forged crank and not a cast crank for the 60degree V6's?? I'm not aware of a forged crank other than what Jbody.com has to offer. We do need a high quality forged crank and I dont know why no big aftermarket suppliers are offering to make'em. Crower, eagle, ext.. Maybe if everyone sends about 5 e-mails a day to these guys they might get the picture, never know..

[SappySE107]

We do? 99.9% of 60V6 owners don't want/need a forged crank, and id say very few enthusiasts would need this crank as well. The 3.6 VVT has a forged crank, and I think even the new 3500/3900 engines are using forged steel cranks as well. No one in their right mind is gonna go after a forged steel crank. JBP is attempting and and aside from them I dont think there is gonna be a ready made supplier ever. You can always have a one off made, which is probably what anyone that really needs this crank will do anyway.

[xxrollin]

Yeah sure, why not. Your bottom end is the weakest link with the cast iron crank as far as I'm concerned. Sure the factory crank can probably and safely support up to 500hp and not twist bend or break. But there are a few I'm sure cause I'm one of them that'd like to see a forged crank and see how far you can go before the next part goes. And you seem to be speaking for 99.9% of 60V6 owners, your saying that no one in there right minds will look at a forged steel crank if the factory cast iron fails them, it can happen. I was just asking a question but I quess since your speaking for 99.9% of all 60V6 owners out there, your right we dont need a high quality forged crank's, cause our poor quality mexican built cast iron cranks are a dime a dozen anyway. And its not a want or need issue, its a wish issue right now, and I'm sure it was out there being offered in a variety of strokes, rod diminsions, there would be people wanting one to either stroke there engines out or have that piece of mind knowing there bottom end will take everything they can put on it. So I'm speaking for .01% plus a few people I know that WANT one.

[SappySE107]

You are clueless on the stock crank aren't you. Try grinding off the casting marks, polishing it up, shot peening/hardening it...and tell me what you get out of performance wise before it breaks on you. Im not speaking for anyone but if you wanna get an attitude over this thats your heart attack, not mine. As far as im concerned, the stock rods are the weakest link, or the pistons depending on what motor you have.

Tell me, how many times have you heard of a 981 cast crank failing? If its such an issue surely you can think of a few.

[bszopi]

You will explode many a tranny well before you have issues with the stock crank...

[Doward]

I'm not saying the #981 is a forged crank.. I'm just saying I've heard it's a better forging, lol! I don't think anyone really has to worry about the crank itself - it's actually pretty beefy, stock.

[DetroitsFinest]

I got the tranny covered I got a buddy who builds 4L60Es for LS1 cars that are making well over 450rwhp and they hold damn well. 4L60Es are the same in V6 ad V8 model cars, just a different bellhousing. My tranny will prolly out live everything else! haha.

nah, I didn't try to come off as stuck up, I just feel some people ride Tiagos nuts too hard Thats why I dont really post on most of the V6 F-Body forums anymore, they all tell me about how sweet Tiagos car is, and I've heard more than enough about his car. Kind of gets annoying

[RacerX11]

If you spend the money on a forged crank, you better spend money on some custom billet 4-bolt main caps as well. If you are making enough power to need the forged crank, you are going to blow the bottom end right out of the block, and your pretty new crankshaft will be sitting there on the ground

Marty

[xxrollin]

True, I know what you mean. I've already got a set from Callies that were custom made, 4340 billet steel. But how are you gonna stroke an otherwise stock cast iron crank for those of you that want to stroke your engines to gain displacement besides having it offset ground. I'm not pulling any attitude, just saying I for one would love to see a forged crank and I have seen one fail, but it was due to oiling issuse. Most companys that make forged cranks by the truck loads for all GM and Ford V8's are at a very low price of $400-$750 depending on material and weight issues, ex: lighting holes, balancing. I'm not arguing here but I'm just saying it will never happen for our engines unless alot more people want to start customizing these engine alittle more than a set or .040 over pistons. Which isnt going to give you alot. So I guess if I just make a suggestion about "itd be nice to see a high quality forged crank" everyone here and there mother must not think so, but if it was available, I know almost 50% of everyone here would probably get one to either stroke there engines or whatever..

[v6h.o.]

with a large stroke in a 3.1L or a 3400 there isnt much more room to fit in rods that keep the rod stroke ratio in the area where its optimum. as it sits the r/s ratio is on par in a 3.1L

Crower used to make forged cranks for the 2.8L (2.99 stroke) for the midget and baja racers that built up the 2.8's.

for my N/A application, a forged unit is just not worth the $$ i know the stock crank can take what i can throw at it. rather spend the $$ on the rest of the engine at this point in time.