Anyone use 440 Source Ultralight stroker crank yet?

I see they are offering this option for there 4.250 stroke cranks now. Anyone use one yet, or opinion on there strength/quality
http://store.440source.com/Ultralight-Crankshaft/productinfo/44042506800-6-LW/

I hadn't seen that before but I like the idea. I used a SCAT superlight crankshaft in my last 470 build. I really like the idea of taking unnecessary weight off the crankshaft if you can afford it.

From the pics it looks nice, Pendulum counter weights, Drilled thru the Mains, Scalloped bolt flange. Just missing knife edged counter weights.

Thanks for posting that.....I have a 400 block I was thinking of doing a low deck 512 for next year with....Not sure how much faster I really want to go though....My pump gas RB 512 has already been 6.13 in the 1/8th....And I am not sure what the safety requirements are for going faster.

i just got my std 400/512 Source crank back from being balanced. the machinist said he only had to take 40grams off the crank to match my rods n pistons. how do you go with a crank thats 3000 grams less to start with?

Was that a special order? They only show the RB mains and no 3.91" strokes on the website. Thanks, Steve

Just depends on WHERE the weight is and where it isnt..
I normally turn down the counter weight a considerable
amount so they spin quicker.. along with a sharper edge
on the leading edge.. I've want to do the same edge on
the trailing side to reduce windage

Andy... that Scat crank looks pretty nice..what did
it take to balance in on your set up

Well the crank came balanced for the stroker kit but the pistons ended up being lighter than advertised so we had to re-balance the crank. It took a little work to do the re-balance. Had the crank come un-balanced the job would've been easier.

Final bobweight on this crank was 2222 grams so it is fairly light for a big block.

Kind of a semi-custom order. SCAT has raw forgings on hand and they can machine up most anything. They make a lot of NHRA Super Stock cranks with Honda journals and stuff like that that isn't in the catalog. You just have to tell them what you want and wait a few weeks for it to show up.

SCAT has the CAD files on hand to produce fully machined lightweight Mopar cranks but they don't really advertise it. You just have to call them and talk it over with the engineer.

The nice thing about working with SCAT is they have the ability to do all of the machine work and heat treating and finish work in the USA. Some of the other crank vendors are just box movers. So if it isn't in the catalog they can't make it. SCAT imports raw forgings and then does the rest on shore so they can move things around if you want.

Nice! Thanks for the info. So....How much $$$?

440 source offered the lightened cranks about 10 or so years ago. Remember they blew them out at a really low price to get rid of them. Not sure if it was an issue with the cranks or just no demand. I wanted one at that time but they were sold out when I finally placed my order. But we ran their regular crank for many years with zero issues in a drag only motor.
Good luck with it.

Is pendulum cuting really worth anything or just good for advertising? Seems that as close to the centerline as that weight is they could remove smaller weight farther out and be just the same inertia to accelerate it? Seems like it would make the crank a tiny bit more flexible as well where turning down the outer diameter of the counter weight would remove unwanted stress.

Taking the weight off the crank is primarily to remove weight from the front of the car, not to reduce rotating inertia. My SCAT crank is 54 lbs which is 13 lbs lighter than a factory 383 crank. So that is 13 lbs off the nose of the car. My pistons and rods are also lighter than stock by roughly 1 lb each so that is another 8 lbs off the nose of the car.

It probably doesn't matter on a bracket car but on a competitive class car there is a huge advantage to taking 20 lbs off the nose of the car and putting it in the trunk.

You should see some of the circle track cranks, especially the sprint car stuff. They take a ton of weight off of those cranks, mostly to get the car as light as possible.

That is correct. We offered these lightweight crankshafts from 2006-2008, but discontinued them due to low demand. We never had any problems with them. Over the last year or two, we noticed that we had an increase in people asking for them again, so we decided to bring them back.

Also, on the question about 3000 grams being taken off the crank, bobweight is being confused with total weight of the crankshaft. The 3000 grams is being removed from the total weight of the crankshaft (as if it was being weighed on a standard scale.) The bobweight, which is related to how the crankshaft is balanced, (essentially the "difference" between the crankpin side of the crank and the counterweight side, if you were to split the crank in "half") remains unchanged.

I have one of the lightened 440 Source stroker cranks in my 493". It's swinging a set of max-lightened & coated Ross forged flat tops in a zero-decked block and fed by a set of ported Indy EZ's and an aluminum Eddy sixpack intake. It's a high quench motor with those little heart shaped chambers on the Indys. The crank was beautiful.

The motor spins up almost instantly, and even with a McLeod steel flywheel and street twin clutch hanging on the back of it, it takes a little extra attention to pull away from a stop from an idle without all the normal inertia. I can feel the difference in reciprocating weight when I drive my buddies 440 manual trans car. I forget what the bob weight came out to.

It's got around 6000 something miles on it, and is still going strong. Hopefully it will live a long healthy life. The car it's in puts people right in shock on a regular basis.

so are the SCAT cranks similar to 440 source cranks? I guess that means I could order a stock stroke super light by the sounds of it

I'd like to be able to get a forged hardened super light stock stroke crank for the rb 440

Call Scat they can make one.

Crower can do it as well. Don't have a picture of my Crower crank handy though

I have a regular 440Source crank in my car. It's been in three years and runs 150mph in the 1/8
I'd like to try a light weight in my next build.
Wonder how it would hold up to hi rpm.

If your racing where the engine rpm varies very little, like a Powerglide equipped drag car with 800-1000 rpm drop on a single shift, there won't be much advantage to a liteweight crankshaft / rotating assy. If you are racing where the engine rpm varies a lot, like a 4spd manual drag car losing 2000rpm on each of 3 shifts, weight of the rotating assy can make a big difference.

Here's a comparison of two engines that I installed a street/strip manual 4spd car, only significant difference between them was different component weights. Not Mopar, but the results are still relevant...

...Engine #1 was 4.04" x 3.48" w/ 5.7" i-beam rods, hypers with gas ported spacers and 1.2mm rings (12lb oil), 49lb crank and heavy 8" balancer, 1863g bobweight.

...Engine #2 is 4.03" x 3.48" w/ 6" aluminum rods, forged pistons with lateral gas ports and 1.5mm rings (14lb oil), 42lb crank with pendulum style counterweights, drilled rod journals, 6" balancer, 1492g bobweight .

Both had flat tops with nearly identical quench and compression. Exact same intake and carb, same carb calibration. Exact same cam installed on the exact same intake centerline. Exact same flywheel and pressure plate installed in exactly the same car, same weight, with exactly the same gearing and tires. Even though these tests were a couple weeks shy of 2 years apart, both tests are on the same location with zero tire spin and conditions were very close to the same. The car itself was basically a time capsule...I lost engine #1 a few weeks after the test, and i had other irons in the fire so the car sat until engine #2 was ready to install...just picking up where i had left off with regard to developing the car. Here's the average rates that each engine gained rpm WOT thru the gears...

1st gear 2000 to 4000 rpm- engine #1 1634 rpm/sec........engine #2 1910 rpm/sec (276 rpm/sec difference) = 18.8% gain
1st gear 4000 to 6000 rpm- engine #1 1975 rpm/sec........engine #2 2217 rpm/sec (242 rpm/sec difference) = 12.2% gain
2nd gear 4000 to 6000 rpm- engine #1 1070 rpm/sec.......engine #2 1116 rpm/sec (46 rpm/sec difference) = 4.2% gain
3rd gear 4000 to 6000 rpm- engine #1 535 rpm/sec.........engine #2 541 rpm/sec (6 rpm/sec difference) = 1.1% gain
No 4th gear data available for comparison.

As you can see, the quicker an engine sweeps thru a gear, the more you will gain from lightweight components. These two engines might both make around 500ft/lbs each running steady state NA, making engine #2's 12.2% gain in 1st gear from 4-6k roughly equal to around a 60hp advantage over engine #1.

Sometimes it helps to think about what happens in opposite extremes...

A given engine has a maximum acceleration rate that it can gain rpm without any external load at all...like a neutral free-rev. At that point all it's power is being used to accelerate itself, and no power is left over to do external work. The lighter an engine's rotating assembly, the easier/quicker it is to accelerate. Sweeping thru the heart of it's torque curve, engine #1 in my example above could gain rpm without a load at the average rate of 8500 rpm per second. Engine #2 could gain rpm without a load at the average rate of 11,515 rpm per second.

On the other end of the spectrum if a car accelerates and works it's way thru the gears, it eventually reaches a point where the engine can no longer accelerate the car. At that point all the engine's power is being used to overcome friction/drag, and there is no power left over for acceleration. This is also the point where the weight of the rotating assy no longer has any effect at all on the power output of the engine. All the torque the engine is making is reaching the transmission's input shaft, no power is being absorbed by the rotating assy as inertia. Operating WOT against maximum load, engine #1 and engine #2 both make the same power.

Looking at these two extremes makes it easier to understand how acceleration rate can have such a huge effect on dyno data. The two otherwise identical engines will make about the same torque when operating against maximum load at a constant rpm, but if engine #1 were dynoed at an acceleration rate of 8500 rpm per second, it would make zero torque on the dyno. Engine #2 still has power left over to move the needle.

If you are running wide open across the ocean, less crankshaft weight will probably hurt you more than help you. If you are a dirt track sprint car on the pole during a re-start, less crankshaft weight is going to be a “BFD”! Most of us here will fall somewhere in between.

Grant

No interest?
OK!

I have an ultralight in my low deck 512. It's going in front of a 4-speed. It wraps up really quick on the test stand. I'll hopefully see how it does in the car this year.

Mine is done, and we have a few passes on it...Hits the convertor hard! I love the way it revs...We are expecting 9.60's out of my combo this year...

Another thing to consider is total rotational weight on how it affects traction, stick shift car with small C.I. normally will use a heavier flywheel and clutch assembly than a larger motor will due to the difference in the ability of the car to spin the tires, like how a converter stall can affect traction
Lightweight is right, big (C.I., carb, exhaust, tires) is best

Andy, I choose one of 440 Source's Ultra-light cranks for my RB when they were first offered thinking the reduced weight of the reciprocating assembly would be easier on the stock block's mains. I don't have the bob weight handy, but the replacement pistons came in at 524 grams to match the old ones.

I had the motor apart to change pistons to lower the compression 2 points and resolve some valve train harmonics issues that resulted from insufficient of spring pressure/ hydraulic rollers being spun to high. There was no sign of cap walk on the parting line or on the caps.

How much do you suspect the lighter weight crank and reciprocating assembly actually helps the stock blocks live?

I'm glad to hear that your not seeing cap walk
Are you running the stock caps in your motor? If not what type did you use, steel, aluminum or ductile iron?
Thanks for this information

I don't know if a lighter crank helps or hurts the block. A person can make a good argument either way and without some really expensive testing nobody knows.

I do know that taking weight off the nose of the car is good for drag racing though.

So while accelerating, the heavier rotating assembly takes more power to accelerate (makes sense), but would it still not use more power (although considerably less than when getting up to speed) at a static RPM since you are still having to spin a heavier weight? Even at a static velocity, there's always acceleration when dealing with circular motion, is there not?.

Theoretically the entire rotating assy is just an energy storage device, basically one big flywheel. It soaks up energy as it accelerates, then gives that same energy back as it slows down. If that give/take were actually averaging out, there shouldn't be much difference overall in a heavy vs lite crankshaft/flywheel/clutch comparison. But there is a difference that I believe shows up on the time slip for two basic reasons...

1- lower launch rpm compared to the trap rpm. Basically if you were to launch a car at 6000 and trap at 8000, the engine will be burdened with creating enough additional energy during the run to make up that overall 2000rpm difference. Keep in mind the exponential effect that comes with rpm, it takes 16x more energy to accelerate that rotating assy from 6000 to 8000 as it did to accelerate it from 0 to 2000. In this case a lighter rotating assy is an advantage because it will absorb less energy while making up that 2000rpm difference between launch and trap.

2- less energy wasted during a post shift wheelspeed spike. The return of energy after the shift can be so intense that some of the energy released during fallback can be spent in non-productive ways, like knocking the tires loose for an instant. Because a lighter rotating assy releases less energy during fallback, that also reduces the amount of energy wasted as wheelspin after the shift.


Grant

I remember seeing one of the first pendulum cut ultra lightweight NASCAR cranks at ABS years ago, it was very pretty and super lightweight. I'm remembering 35 Lbs. being the number for the SB Chevy and similar for both the Mopar and Ford SB racing cranks
I've always been concerned on the additional cost and longevity factors on using one
Maybe soon

Al, the Crower price might scare a few of them however.....lol

But also remember it's only one of the rotating components before the power gets to the ground.....so you really need to add in the sum of all the other (assume they are the same as before for comparison) rotating masses (the converter/flywheel, the trans, the driveshaft, the rear axle, the tires and wheels.

Yes the mass is less but you really need the sum of the old sums/sum of the new sums and you see the overall percentage of reduced total mass is far lower than you may perceive.

Herb Adam's book "Chassis Dynamics" explains this in much more detail....but even though the motor "free Rev's" much easier with a lighter crank.....remember you still have to hook the load to it.

The example in my post on page 3 was basically a direct heavy vs lite crankshaft/pistons/rods comparison, in a real world 4spd manual trans application. The first part did include ALL of the other rotating components. The difference during the 1st gear WOT pull was equal to about a 60hp gain. By 3rd gear, that gain was down to about 5hp.

If one were performing that same comparison on an engine dyno, testing at a single acceleration rate would not tell the whole story.

Grant

What was the ET difference between the two combos?

Well I'm not gonna say you are wrong for sure They do make a nice product. But it certainly is another level of expense to be sure. But worth the money and less then Bryant or Winberg

I didn't know you could even say "440 Source" and "Crower" / "Callies" / "Winberg" in the same sentence on a Mopar forum. ==>

Thanks for the insight guys. I'm running the stock caps, ARP studs and a Hughes girdle.


Interestingly, the engine runs soooo much smoother throughout the RPM range with the new valve train parts and Mike at B3's geometry kit that it is astonishing.

I'm thinking that the harmonics that ate up my last valve train is what is missing from this build and likely why the motor feels like it runs so much smoother now. It's a night and day difference.