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-   -   Aluminum Con Rods (https://www.miataturbo.net/engine-performance-56/aluminum-con-rods-41430/)

hustler Nov 21, 2009 11:54 AM

Aluminum Con Rods
 
NOTE: I have divorced this discussion about aluminum rods from this thread: https://www.miataturbo.net/forum/t40553/
-Perez

http://img.photobucket.com/albums/v4..._3572JPG-1.jpg

chance91 Nov 21, 2009 03:06 PM


Originally Posted by hustler (Post 485344)

Chinese, right? That's the problems with the Ingot I'm talking about, I think.
Bad heat treating from the get-go, perhaps.

curly Nov 21, 2009 03:27 PM

That doesn't appear to be heat treated at all, solid billet pieces, you can still see tool marks in the center.

y8s Nov 21, 2009 04:07 PM

machined aluminum rods? not even polished/blasted to remove the maching marks? smells like a rebuild waiting to happen.

cueball1 Nov 21, 2009 04:46 PM

That split rod might make a good model for the MT.net t-shirts!

Joe Perez Nov 21, 2009 05:02 PM


Originally Posted by y8s (Post 485414)
machined aluminum rods? not even polished/blasted to remove the maching marks? smells like a rebuild waiting to happen.

They're somewhat popular with the guys running 500 hp / liter. Lighter weight than steel = less inertial strain at high RPM.

You can see tooling marks on some of these American-made units, for example: Aluminum Connecting Rods

sixshooter Nov 21, 2009 07:08 PM


Originally Posted by Joe Perez (Post 485428)
They're somewhat popular with the guys running 500 hp / liter. Lighter weight than steel = less inertial strain at high RPM.

You can see tooling marks on some of these American-made units, for example: Aluminum Connecting Rods

Aw, come on! Those in your link are obviously a significantly higher grade of machining and finishing. The one in Hustler's pic looks like someone did it on a cnc for a static display and somebody f'd up and actually used it. I bet there are some for sale on ebay somewhere just like them, though.

y8s Nov 21, 2009 08:39 PM

^ what he said. rounded corners and I can't see machining marks very well.

hustler Nov 21, 2009 09:03 PM

I believe that's a BME rod from an evo actually.

Joe Perez Nov 21, 2009 11:34 PM


Originally Posted by Halcyon (Post 485531)
I'm waiting for the post to say a specific "made is China" rod is as good as or close to belfab or the like.

A specific "made in China" rod is not as good as (or close to) an M-tuned rod.

:D


Originally Posted by y8s (Post 485489)
^ what he said. rounded corners and I can't see machining marks very well.

Yeah, I'm looking at the BME website right now, and that one in Hustler's pic does look a lot like 'em. Same chamfer around the rod journal, same shape on the shaft, only difference is that the ones on the website appear to have been polished so you can't see the tool marks from the milling operation.

http://www.bmeltd.com/a_images/rodcover.jpg

Thing is, and I admit that I'm no ME, but that sucker split right down the middle, through the most perfectly rounded parts of the assembly. To me, that screams "materials defect".


But we're threadjacking.

IHI Nov 22, 2009 07:57 AM

Wow... Those billet rods look cool! For $600 they are more expensive but they do offer a lot of weight savings.. The split one isn't what I'd like to see. No one can put a bend eagle or chinese rod in here (cheap H-beam).

Would somebody considder those billet rods?

chance91 Nov 22, 2009 03:27 PM


Originally Posted by curly (Post 485404)
That doesn't appear to be heat treated at all, solid billet pieces, you can still see tool marks in the center.


I was referring to Heat treating before the CNC process.

You have to heat treat the material at least once, sometimes several times, just to get it up to par for use. Of course, it's hard to say what caused the failure like that, but, to me, it looks like a flaw in the grain of the metal.

y8s Nov 23, 2009 02:17 PM

i think it's high time the aluminum cnc rods BS ended. nobody here will ever buy them. and if they do, I'll make a hat out of fruit roll-ups and eat it.

miata2fast Nov 23, 2009 04:14 PM

(Someone F'ed up there.

JE's are good stuff. They will spec out different grades of hardness to be used for different applications and power adders. When I told them that I was using nitrous, they speced an alloy specific to the demands that nitrous creates. Which is actually a little softer to have some "give" if I recall.

Edit. This post was originally in the JE vs Wisco vs Eagle vs Carrillo thread.)

BTW, back to the aluminum rods. Hustler's pic is not a BME rod. I have used them, and all of them have "BME" in the casting just like the photo in Joe Perez's pic.

y8s Nov 23, 2009 04:46 PM


Originally Posted by miata2fast (Post 486131)
BTW, back to the aluminum rods. Hustler's pic is not a BME rod. I have used them, and all of them have "BME" in the casting just like the photo in Joe Perez's pic.


I think I found the problem.

sixshooter Nov 23, 2009 06:18 PM


Originally Posted by y8s (Post 486148)
I think I found the problem.

"Hark! Hark!" harkened he.

Full_Tilt_Boogie Nov 23, 2009 06:28 PM

Fuck aluminum, its all about that titanium yo!

http://www.desmoworks.com/images/085015620331A.jpg


Now where's that money tree...

Joe Perez Nov 23, 2009 06:57 PM


Originally Posted by miata2fast (Post 486131)
I have used them, and all of them have "BME" in the casting


Originally Posted by y8s (Post 486148)
I think I found the problem.

Can not a forging process be made to leave a raised marking such as this?

neogenesis2004 Nov 23, 2009 07:25 PM


Originally Posted by y8s (Post 486105)
and if they do, I'll make a hat out of fruit roll-ups and eat it.

I will buy a set just to see this, but it has to be a real hat. Prepare for youtube video!

miata2fast Nov 23, 2009 09:14 PM

There is an advantage to aluminum rods. They are certainly not used in road racing or street use, at least not much, but if you are drag racing, and have a huge turbo or shot of nitrous, they are spongy enough to soften the hit to the crankshaft and main caps. The only real downfall to them, is there is no way of knowing when they fail. X-raying them will not show fatigue areas in aluminum (unless something new is out there to test them). That is why you have to change them every so often (What I was told any way).

Also you are not supposed to downshift a motor with them, because they have very little tensile strength. Downshifting is not done in drag racing.


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