Butcher knife edge vs Eagle forged?

[DSM's 4 life]

I am looking at building my 6 bolt. After looking into crankshafts I ran across these two and was wondering what would be better since the price point is the same.



FFWD Connection - Race Components That Will Freeze Your Brain

Built4g63 :: 1G DSM 90-92 :: Engine :: Crankshafts :: Eagle 6 bolt DSM crankshaft

 

[viperlp01]

A balanced OEM is better than both of those cranks.

 

[DSM's 4 life]

So just a polished stock crank within specs?

 

[TSITurbo95]

Yes, you would save tons of money, and they have been proven to handle tons of power.

 

[2slow4now]

A good stock crank should be fine. If you get used go ahead and have it micro polished, magnafluxed, and have your assembly balanced.
I thought about the lightened "butcher" crank but was worried that on a quick throttle let off that the engine may have problems returning to idle without dying. Keep in mind I have a lightweight aluminum flywheel as well. It may not cause such a bad problem with a stock flywheel.
I went with an Eagle crank but only because I got such a good deal on it. The quality seemed to be very good because when I had it balanced it hardly took any drilling to get it balanced. They even spun balanced to 8k and they said it was spot on and wouldn't worry to spin it to 10k. All my rod assemblies are within a half gram of each other though so I'm sure that helps alot.

 

[viperlp01]

I have talked with multiple people making 800+ hp the factory crank balanced and polished is the way to go. In engine builds unless it is a 6 bolt stroker we recommend a factory crank over any aftermarket crank. We have a crank balancer in house so if you need someone to balance it and polish it we can do it. The weight of the crank is needed for more than just rotational energy but also harmonics and overall strength.

 

[95talongirl]

I have talked with multiple people making 800+ hp the factory crank balanced and polished is the way to go. In engine builds unless it is a 6 bolt stroker we recommend a factory crank over any aftermarket crank. We have a crank balancer in house so if you need someone to balance it and polish it we can do it. The weight of the crank is needed for more than just rotational energy but also harmonics and overall strength.

+1 It's worth going through and having the crank, pistons and rods balanced. Had that done on mine, and even without balance shafts, the car is so smooth. You'd be surprised how much harmonics effect strength! So yeah, stick with the stocker and have it balanced/polished!

 

[Calan]

I have talked with multiple people making 800+ hp the factory crank balanced and polished is the way to go.

FWIW, I have heard Shep say that the only thing he's never broken is a factory crank.

I think the Eagle 4340 crank is a good piece also though, at least up to 600whp. I've run mine in the stroker for 30-40k miles, and I haven't heard any reputable bad rap on them as far as I can recall.

 

[DSM's 4 life]

I had my 7 bolt crank polished and balanced the shop said it was within specs. But on this new build I wanted a quicker reving engine. From what I hear this can also be achieved from a lightweight flywheel.

 

[viperlp01]

What is "Balanced within spec"? Factory cranks that have been in engines for 100k are better balanced than an Eagle crank fresh out of the box and they are still 5+ grams off... If you want a faster revving engine use quaility light weight parts. Aluminum rods, light pistons, and high compression will make that engine rip.

 

[Fehrion_sit]

What is "Balanced within spec"? Factory cranks that have been in engines for 100k are better balanced than an Eagle crank fresh out of the box and they are still 5+ grams off... If you want a faster revving engine use quaility light weight parts. Aluminum rods, light pistons, and high compression will make that engine rip.

a higher compression ratio will make the engine spin up faster? kinda sounds counter productive ?

 

[viperlp01]

a higher compression ratio will make the engine spin up faster? kinda sounds counter productive ?

Higher compression makes the engine responsive which makes the engine move through the rev range faster.

 

[white92talontsi]

Darren's butcher crank is a good piece as long as you keep it below 750AWHP. After that the crank will start to bend and eventually break.

We run OEM cranks on our 2.0 Evo's and run 45-50psi and make 900+hp without issues.

The OEM crank's are very strong, If tuned properly a 1,000hp 4g63 will go a year if not more on a stock crank.



As stated higher compression will make the engine more responsive. Couple that with light pistons and aluminum rod's (R&R or BME) and you have a 4G63 that revs like a crotch rocket.

 

[biglady112]

One thing I see not mentioned here, is if you are looking for a faster revving engine, you cannot beat the loss in mass that a twin disc clutch with matching flywheel will achieve.

With an aftermarket piston, aluminum rods, a lightened crank and a twin disc, the car we had running was very rev happy like a motorcycle. The crank was done by a very talented machine shop, but is not always neccessary. But like I said, everyone seems to have overlooked the clutch.

 

[TSIflyer95]

Another thing to keep in mind, is knife edging is actually a bad idea. Most people don't realize that. But once you get into the physics of air movement in the crankcase you will understand.

A regular round nose crank does much better. I do some work with NASCAR engines and on the cup series motors which made over 900 hp this year are all round nose.

Knife edge has a bad habit of disrupting the way it flow through pan with oil and such.

Round nose is like an airplane wing. It gives air/oil something to stick to. Just my 2 cents though .

 

[twicks69]

The butcher crank was fun in my old motor, like stated above; it started having jump-roping issues pretty badlt at 750+AWHP. If I kept it around the 650AWHP/600TQ range it didn't have a problem for 3 years. Once I turned the power levels up to the 750+AWHP/700TQ range, then it was chewing out the inner main bearings. The crank literally bent around 0.016" out of round. It was junk. Granted, mine was also a steel rod 4G64 butchered crank setup, running very high boost and running up to 8600rpm.

I also had it with 550g Eagle H-beams and Ross pistons, with a race flywheel QM gear drive twin disk. It revved out VERY FAST, and was freaking awesome. Great motor, just killed the crank.

I would definitely do it again with a STOCK OEM Mitsubishi crank, checked and polished to get your bearing oiling specs, and couple it with R&R aluminum rods, Ross or CP X-Style ultra-light pistons with skirt coatings and 0.220"-wall tool steel wrist pins, L19 or H11 rod bolts, and run aluminum main and rod bearings with the OEM Mitsubishi thrust bearing for your application. Balance the rotating assembly and run it with a Quarter Master Gear-Drive 7.25" V-Drive Rally twin disk clutch assembly and a race-weight flywheel (6#) for cars below 2800#, and street flywheel (10#) for street cars or cars above 2800# as it will significantly help with rotational inertia for starting from dead stops, launching, or uphill stops. Having the heavier flywheel will help with reducing jerkiness of driving a multi-disk clutch, and is worth the tradeoff of extra weight on the assembly. It also helps having a higher rotational inertia with the twin disk as you are less likely to break the springs on the 3/4 and 5/R hub and sliders in the transmission.

Also, go with a Fluidampr or ATI crank harmonic damper. I run the Fluidampr, but people have good luck with the ATI as well. Stay as far away from aftermarket billet aluminum pulleys and OEM crank dampers when you start making real power as they like to seperate themselves. If you start having crank harmonic issues from flex you will also throw the counterweight straight off the OEM crank pulley. , you will also normally take out the crank position sensor on 97-99 motors. Ask me how I know !


OEM crank, light rods, and high quality wrist pins with the proper piston for the job.

 

[2slow4now]

The butcher crank from FFWD is made similar in design to an airplane wing. The leading edge is rounded and the tail is thin.

Good point Big lady. Any parasitic weight you can shed off the rotating assembly will help with making it faster reving.

 

[twicks69]

I didn't have any oiling issues with Darren's Butcher crank, just bent it at very high power levels.

It lasted 30,000+ miles for 3 years of abuse at 650AWHP/600TQ.

 

[Miakehl]

Another thing to keep in mind, is knife edging is actually a bad idea. Most people don't realize that. But once you get into the physics of air movement in the crankcase you will understand.

A regular round nose crank does much better. I do some work with NASCAR engines and on the cup series motors which made over 900 hp this year are all round nose.

Knife edge has a bad habit of disrupting the way it flow through pan with oil and such.

Round nose is like an airplane wing. It gives air/oil something to stick to. Just my 2 cents though .

FFWDconnection edges their butcher cranks like airplane wings, rounded on the cutting edge and tapered on the backside.
Read

Also, they use YOUR crank to cut on so if you send them an OEM unit they'll send you back a cut, balanced, and polished OEM unit, so I don't see what the problem is...

 

[TSIflyer95]

I probably should have read his link a little closer. My apologies. Lol

 

[spoonman]

The counter weights on a stock crank were spec'ed for heavier OEM rods and pistons.



I love FFWD's cranks. How much power can they hold? Twicks experience says a lot but I want to hear more imput from other high HP engines running these cranks.

 

[Diamond Star Werks]

This will glide through that oil faster than Lydia during oil wrestling night at the Pip.

Lol funny

 

[twicks69]

The counter weights on a stock crank were spec'ed for heavier OEM rods and pistons.



I love FFWD's cranks. How much power can they hold? Twicks experience says a lot but I want to hear more imput from other high HP engines running these cranks.

You probably won't find more than a handful of 7-bolt 4G64 2.3L strokers out there with this crank in it, let alone at my power levels. My GT4088R was in a different zip code on the compressor map.

You might find some 6-bolt 4G63 2.0L Butcher setups in the 600-700AWHP range with 600TQ or so.

 

[hubz91talontsi]

I think the butcher crank is a great option for those of us that push small turbos. Someone reving to 11k probably not so much.

 

[JacksonAuto]

The counter weights on a stock crank were spec'ed for heavier OEM rods and pistons.

The counterweights on a 4G63 crank do not match the weight of the rod/piston combo. This is the case on V engines, but not most inline 4 cylinder engines.

When balancing a 4G63 crank, each counterweight is made equal. Also, each rod and piston should be made equal but the counterweight is not matched to the rod/piston.

Bobweights are not used to balance a 4G63 engine.