Contour Enthusiasts Group Archives Forums Modifications Duratec Performance crank????

how strong are our engines cranks?????

i know that the svt crank is forged which means that for the most part its a durable unit. however under high power situatuations how strong is it??

also does the stock 2.5 use the same crank as the svt, also with the stroke being the same, what about the 3.0's with all the talk about titanium rods, sho bearings, and custom pistons. will the crank last in the long term

also has anyone thought of cryogenically (spelling) treating our existing componets, from what i understand it reorganises the componets structure and makes it stronger

what im looking to do is make a bad @$$ 3.0 with an 7500 rpm redline 8000 fuel cutoff but since i will only be able to afford this only once (with lots of penny pinching) i want it to be dead reliable

Crank on 2.5 same as SVT,good for around 230hp.Not same as 3.0 crank.Cryo is 'en voge' at the moment,I've yet to see any firm test data (cryo Vs stock) that it gives benefits.

thanks for the quick reply terry i do aprriciate it... so the stock svt crank is good to about 230 hp, what about the 3.0 crank what id like to do is have a 250-260 hp naturally aspirated 3.0 with 100 shot just to "be sure" ill win. i dont mind spending the money if its done right the first time (the only time) so i was thinking 3.0 with sho bearings, titanium rods, arp studs/bolts with custom forged pistons.... will the stock 3.0 crank stand up to this combo at say 8000 rpm????

also are there any other known techniques to stregthen a crank

also is there a company that would make titanium valve retainers for our cars (our are these just over kill)

Terry, how is 3L crank different - if stronger will it work in the 2.5L?
The 230 HP limit - would the trimetal bearings increase this limit?

Stoc crank in 2.5 & 3.0 is too heavy for high rpm.

What do you mean by high rpm? I kinda thought 7K was high.

???

Shot peening and stress relief is probably a good way.

warmonger

Cryogenic treatments in steels or iron alloys is mainly done to get rid of retained austenite. Austenite is one of the forms that steel takes when it is heated up. Quenching is then performed to transform the austenite to other phases such as martensite, bainite, etc. The problem is if not all austenite is transformed to another structure, then it will continue to slowly transform to other phases at a slow rate, even phases that are less desireable. The kinetics require long times at room temperature and above ranges. If you go to too high a temp then you begin to transform back into austenite. The kinetics are much faster for liquid N2 temperatures when transforming the retained austenite. As with all engineering it is more complicated than first glance.
As far as cryo treating other metals? It's basically virgin territory. There is evidence that it does nothing at all for aluminum alloys, but that could change any day since its not positive.
for what its worth: if you want to get cryo treatments, then make sure its an iron alloy. Otherwise it may be a waste of money and you may not ever know a difference either way. For cranks however, it's not a bad idea for racers. I am skeptical for the street racer though. Shot peening is a proven way to improve durability so check it out, otherwise you could end up chasing a fad.

warmonger

i have a question about the rods and pistons, how much power can they handle before they shoot through the hood, and where can i get new, stronger ones?