Butcher knife edge vs Eagle forged?

[darren]

Absorb harmonics and change the frequency to safe frequencies that aren't common in normal operation.

I should do a project where I analyze 1st-4th order harmonics on the crankshaft and roughly where these are located.

I can guarantee Mitsubishi engineered these engines to place them low in the rpms where the forces from these harmonics would be lowest. From my understanding you raise the resonant frequencies by removing mass. Any time you are operating around one of these harmonics the stress on all the components in an engine are greatly raised. The lower order harmonics are usually the most violent too so extra care is taken to avoid them.

I'm not saying I completely understand it and can explain it, but millions of dollars worth of structures and machinery has been destroyed by operating at these dreaded frequencies.

Also, there is a reason why we have a harmonic balancer. It absorbs/cancels out much of these dreaded frequencies. I usually recommend Fluidampr for stroker applications since the ATI was created specifically to target specific harmonics of the 2.0 engine. Top race teams usually use ATI because they have the budget and knowledge to tune their harmonic balancer/dampener to combat troubled frequencies in their engine.

I second this. You're on the right track there buddy with the numerous orders of harmonics in a crankshaft and what they are for each crank design...as we've actually done this testing many years ago. I should try to dig that stuff up sometime since I've slept since then.

NO ONE should ever run a billet crank damper with their motor. I'm not here to recommend a brand, but I will say it's also hard to beat a new OEM unit. With ANY crank...especially the Butcher, it is always stressed to run a crank damper. Period.

 

[darren]

Darren... that goes for a box stock engine too!


I understand the theroy behind the butcher crank, just never used one.

What is a stock engine?

Never heard of it...

 

[agentorange313]

After reading all of this all I can say is

"The more you know"

thanks for the knowledge everyone.

EDIT: Can an eagle crank be "butchered"? I know in the beginning of this thread it Eagle was mentioned then dropped due to the oem being far stronger and balanced. 2.3 cranks are far and few and eagle seems to be the only available 2.3 cranks for 6 bolts.

 

[BogusSVO]

What is a stock engine?

Never heard of it...

Yeah you have.... Thats what you start with.. and junk most of whats in in it.!

I am sure if you go talk to your teardown guy, he could show you one.

 

[darren]

After reading all of this all I can say is

"The more you know"

thanks for the knowledge everyone.

EDIT: Can an eagle crank be "butchered"? I know in the beginning of this thread it Eagle was mentioned then dropped due to the oem being far stronger and balanced.

Check it...

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Finished off in our new "Vader" coating for heat dispersal.

 

[Calan]

^ work of art. I want one.

Since it was brought up...

Darren... out-of-the-box balancing aside, what are your thoughts on the strength of the Eagle 4130 cranks vs. the OEM ones? Do you have any data showing that they would be more prone to failure than an OEM crank, assuming they are both properly balanced and clearanced??

 

[Diamond Star Werks]

MJ, Yes its possiable. But Why?

Now you have to add weight to both the flywheel and the balancer. So more money is spent on custom one off parts or figuring where and how to install weight.

Like the Butcher crank, cut the weight, then balance the crank internally, that way off the shelf parts can still be used.

Now the old school machinist, may have started with an external balanced engine.

I would guess a chevy 235 or 250CI

Why would be to reduced rotational mass. Without the counter weights. Putting weights on the ends would take less than weights on the crank. At least thats my theory. His might have been completly diff. I'm sure it wouldn't be easy to perfect the balancing though.
I didn't get to ask all questions i wanted to though. So alot unanswered here.

But Im certain he told me he externally balanced an internally balanced engine.

 

[darren]

^ work of art. I want one.

Since it was brought up...

Darren... out-of-the-box balancing aside, what are your thoughts on the strength of the Eagle 4130 cranks vs. the OEM ones? Do you have any data showing that they would be more prone to failure than an OEM crank, assuming they are both properly balanced and clearanced??

None whatsoever since I haven't had that many step up to the plate and have us Butcher one...let alone been out in the field long enough to surmise a valid opinion on one. Remember..we have to be fair about things like that.

However, my gut tells me that the stocker is quite good to do the same thing...but if folks are wanting a stroker motor or stroked rotating assembly, I steer them towards the Eagle for simplicity reasons....and of course, availability.

I do like Eagle's fillets in the journals though...thought they were nice. Not too bad of oil flutes as well. The balance on them out of the box has been just as wonky as any other Eagle product out there. They're not "plug and play". But just fine once tweaked.

Now whether their metal comes from US or China, that I don't know. China has really started to get a solid grab hold of the US market for alloys. However, you won't see us selling out using cheaper alum for our rods I can grant you that.

 

[agentorange313]

...
Now whether their metal comes from US or China, that I don't know. China has really started to get a solid grab hold of the US market for alloys. However, you won't see us selling out using cheaper alum for our rods I can grant you that.

Stop teasing us:
FFWD Connection - Race Injuns That Will Freeze Your Brain

 

[hks-gst]

While we're on the subject of cranks, Darren or Jackson auto do either of you have experience working with the Magnus motorsports billet units?

Magnus Billet Crankshaft | Magnus Motorsports

 

[darren]

While we're on the subject of cranks, Darren or Jackson auto do either of you have experience working with the Magnus motorsports billet units?

Magnus Billet Crankshaft | Magnus Motorsports

None at all. Never had my greasy hands on one...never have even seen or heard of anyone running one for that matter.

But what I do know is that it's a very expensive piece. Maybe more than it needs to be.

Jackson, care to chime in? I'd be curious myself.

 

[spoonman]

All for butchered cranks.





But said above, are Eagles stronger/weaker than stock OEM crankshafts????

I agree on the balancing aspect.


But I find it very hard to believe that a stock crankshaft is stronger than an Eagle. The Eagle crankshafts are forged 4130 alloy steel. Better machining and as mentioned better fillets.

(Used) Stock cranks have the advantage of having thousands of stress relieving heat cycles and are nitride treated.

 

[Miakehl]

I'm paying real close attention to this thread as I'm deciding on what to do with my street/autocross motor build.

I want a 94 or 100mm crank but I also want it as light and free-revving as possible with a 9.5:1 86mm piston.

Subcrib'd.

 

[ceedawg]

Buddy, I wouldn't have you pay for something and use if I thought it wasn't going to work out for you! I've built many of the same motor you have in over 13 years with NO returns. Think about that! There is A LOT of liability with a motor. It aint no turbocharger.

You don't get that kind of record by recommending something that doesn't work.

Well Buddy sorry I mean Darren, if I felt differently I would not have commisioned you to build this motor,just like you I noticed the word "butcher" while browsing the forum, so I took interest and read this thread hence my first post in the thread yesterday. Based on the experience of others which have been posted in this thread,I felt lead to ask my questions. However due to your responses that's been cleared up! Greatly appreciated.
My questions were never meant to discredit your work. I have always heard you built strong motors and thats why I went with FFWD and I'm happy with that choice. So take it easy big guy!!!

 

[bcracecar]

I got sucked into this post! So much great info on here guys! Everyday I read, every day I learn.

 

[JacksonAuto]

None at all. Never had my greasy hands on one...never have even seen or heard of anyone running one for that matter.

But what I do know is that it's a very expensive piece. Maybe more than it needs to be.

Jackson, care to chime in? I'd be curious myself.

Same here. It's a reboxed crank from someone else. It's a horrible design, the weight was removed from all the wrong areas. It's probably light, but that doesn't mean diddly when it's laying on the ground in pieces. We're not big fans of using lightweight parts in turbocharged engines. Build 'em for strength.

We use OEM cranks up to around 700hp. For some reason they like to crack the #4 rod journal. I'd feel comfortable saying that around 40% of the OEM cranks that come through the shop are cracked. Not sure why, but that's the reason we don't use them in higher HP applications or when the customer plans to race the car freqeuntly. For 700-900hp hp or so we'll use a Manley or Eagle, depending on the application. Over that we go with a billet crank, usually a K1. Problem is Eagle and Manley don't make a billet 6 bolt crank. May need to explore the Butcher crank as an option

 

[white92talontsi]

That Magnus crank looks an awful lot like a Manley.

 

[JacksonAuto]

It does look very similar.

 

[dsmusmc]

Same here. It's a reboxed crank from someone else. It's a horrible design, the weight was removed from all the wrong areas. It's probably light, but that doesn't mean diddly when it's laying on the ground in pieces. We're not big fans of using lightweight parts in turbocharged engines. Build 'em for strength.
)

Well you could say most of the stuff they use is "reboxed". There pistons are Ross built to there spec and the rods are R&R which they clearly state so it's not like it's really a secret. As for the crank mines not much lighter then stock. Three pounds isn't all that much I really doubt your going to find one in pieces .

S We're not big fans of using lightweight parts in turbocharged engines. Build 'em for strength.

May need to explore the Butcher crank as an option

Those 2 sentences kind of go against each other.

That Magnus crank looks an awful lot like a Manley.

I don't think it's a Manley because where does the 92mm crank they use come from? Also I think they only use 7 bolt cranks where Magnus has the opinion for 6 and 7 bolt for all their crank options. Manley does a 94mm but I don't see a 92mm same with Eagle.

 

[JacksonAuto]

Those 2 sentences kind of go against each other.

Honestly I haven't even taken the time to look into what a Butcher crank is. I said we may explore it as an option.

 

[JacksonAuto]

Well you could say most of the stuff they use is "reboxed". There pistons are Ross built to there spec and the rods are R&R which they clearly state so it's not like it's really a secret. As for the crank mines not much lighter then stock. Three pounds isn't all that much I really doubt your going to find one in pieces .

I'm not really sure what your argument is here but sorry if I ruffled your feathers. The issue is that you don't know what you're getting. If he's using Ross pistons and R&R rods that's cool, you know the quality. If these were Manley cranks it seems that he'd disclose that as well. There aren't many companies around that are going to make cranks for a relatively small company which makes the most logical option being overseas production. IME That option isn't much better than an Eagle crank.

 

[bastarddsm]

We use OEM cranks up to around 700hp. For some reason they like to crack the #4 rod journal. I'd feel comfortable saying that around 40% of the OEM cranks that come through the shop are cracked. Not sure why, but that's the reason we don't use them in higher HP applications or when the customer plans to race the car freqeuntly. For 700-900hp hp or so we'll use a Manley or Eagle, depending on the application. Over that we go with a billet crank, usually a K1. Problem is Eagle and Manley don't make a billet 6 bolt crank. May need to explore the Butcher crank as an option

Which cranks are you finding cracked at the #4 journal?

 

[white92talontsi]

Which cranks are you finding cracked at the #4 journal?

I am not sure what Jackson is seeing but I mostly see it in 100mm OEM cranks.

 

[JacksonAuto]

Odds are the same with all OEM cranks IME. Both 6 and 7 bolt, DSM, Evo, 88mm or 100mm doesn't make much difference. Just something that causes a problem with the #4 rod. I'd tend to believe that it has more to do with fuel or air supply rather than an inherent flaw with the crankshaft design or construction.

 

[hks-gst]

I believe that the Magnus cranks are made by Australian manufacture called PAR engineering makers of PAR gearsets..very high end stuff.

Par-Engineering - Crankshafts