**** this thread.

 

dip hat.

 

... R U SERIAL?

so by that logic you also cannot rev the engine while it is in neutral.

 

Bitch, that's a Salsa Sombrero.

 

Sure you can.

I meant engine breaking. Down shifting to slow the car down in a corner can pull an aluminum rod apart, and is not recommended.

 

I went to the BME website, and now I am starting to think that the downshift thing about aluminum rods is a myth. Apparently you have to have different clearences, because the rod stretches and changes size more than steel rods from changes in heat.

Oops.

 

And to give you an idea what size money tree you'll need... we have a sports racer at work with a BMW M12/7 engine (2 liter, about 300hp NA), and it has titanium rods AND titanium rod bolts. When I redid the bottom end a couple years back we didn't know the history of the engine nor did we have any stretch figures for the bolts so we got new ones.

$100ea... for the bolts.

 

hell before mtuned came along rods were 800 bucks a set all over the miata world. If titanium rods where made stronger and saved a good bit on the recipricating mass, then it would be worth the extra cash imo.

 

for the honda B-series...

 

They are stronger and lighter... just no one wants to pay $2000-3000 a set for a Miata.

 

You'd be surprised.

 

and i'd eat a fruit-roll-up hat.

 

what brand of rod was that, we use GRP aluminum rods in alot of very high strung v8s with great success. aluminum rods do not have the life span of a steel rod. due to the constant expanding and contracting and the propertys of aluminuim. they tend to wear out. the aluminum used is genraly forged prior to machining, and i cant see why they wouldnt be heat treated. last time i checked heat doesnt remove the machining marks

 

aluminum doesn't have anywhere near the fatigue life of steel.

also, machining marks on a cyclically stressed part are basically like having a map of failure points for surface fractures. you want that **** SMOOTH and POLISHED.

some companies learn the hard way. in one of my ME classes, the prof brought in a pedal crank from a bicycle that was broken in half (aluminum). closer inspection showed that the break propogated from embossed lettering on the surface of the crank.

 

i totaly understand that machine marks create stress points. im just saying that heat treating wont remove them, i think i saw earlier in the thread someone bringing it up that there were machine marks in the rod and that means it wasnt heat treated or something like that.

what this thread all comes down to is that aluminum rods are a strict race only application. i dont see to many people on here with an engine setup that really needs the benifits of an aluminum rod. they are normaly used in drag racing where the engines run time is very short. the engines are rebuilt multiple times per season and the rods are constantly checked for stretch and cracks.

 

If you go to the BME website, it says that they are safe to use on street cars. At least there products. It might not be cheap, but if you want to go baller, why not?

BME's are probably used more widely than any other aluminum rod. They are very high quality, and used in Top Fuel dragsters. All Top Fuel cars use aluminum rods. You know how much power they make!

 

For a street car, what's the advantage vs. an H-beam steel rod costing half as much?

 

More horsepower.

It is not the cheap way to get it, but in an all out, budget doesn't matter motor, it will have an advantage over a heavier rod.

For the person who has the capability of fully developing the entire car, aluminum rods seems like a viable option. Assuming that it is in fact a myth that aluminum rods can not be downshifted, or that they need to be changed too often.

I am ordering some right now, damn it!

 

i work in a race engine shop, i see aluminum rods all the time. you do not want these on the street. not to mention the insane amount of clearencing needed to make room for there massive size.

 

That would be me. I meant it didn't look heat treated, AND it still had machining marks, which to me (a machinist) is sort of a sign of cheapness. Even if surface quality isn't important, unlike a seal or bearing surface, you'd still want it to be "pretty" for the customer. At least prettier than that. The part about it not looking heat treated was a separate comment, and I believe made before I knew it was aluminum.