*BILLET* aluminum rods

AHall

AHall

Hobbyist
Inquiring about aluminum rods. Drag racing application mostly. Also preferably 5.9/6.7, but duramax info is also appreciated. Maybe save a little weight in rotating assem. Will they crumble if torque comes in quickly? Be better in high rpm? Waste of money? Once a year consumable parts?

Lets hear it....
 
Yes, if quickly means 2k ft/lb at 2500rpm.
Yes.
No.
Depends, the rod manufacturer will need to make a recommendation.
 
I wouldn't worry about it, as my understanding goes, most aluminum rods were developed mainly to reduce shock-load to the crank, but Cummins cranks hardly break, so I'd say you're fine.
 
Aluminum rods are made for one reason, to reduce weight. As far as shock load to the crank, they do absorb a little, but definitely not a reason to go to aluminum. I went to aluminum rods in the diesel for several reasons, weight reduction was a big factor, but I use different rod journals on the crank and smaller wrist pins to make the piston stronger. Aluminum rods are cheaper than steal and you can order a set of custom rods with any dimension and get them in a week for around a $1000. I use GRP rods and had these rods done up over 4 years ago for the Duramax. I did a set of Cummins rods about 7 years ago.

I have steel rods with the hemi rod and smaller wrist pins coming for stroker motors, in either 427 or 400 cid.

Here are a stock rods, a new steel rod and an aluminum rod.


IMAG1031.jpg



here is my motor going together , the rod piston and wriste pin saved 650 grams of weight

580885_409492512420619_1524249396_n.jpg
 
Seems to me the gains would be marginal at diesel rpms. Turn up the boost and forget about it.

Now the alky's or gassers really cranking the rev's it could be huge.
 
If you always do what you have always done, you will always get what you have always got.

That is the problem with diesel mind set, boost covers up all ills. Well that is the problem with trying to drag race the diesel engine in the mainstream world. Big boost makes power, but the motors are short lived make a lot of killer heat, and are sluggish. You can have the faster diesel on earth, and if it can’t win a round of drag racing because it’s sitting on the starting line waiting on the turbo to spool, what good is it. I’m building my dragster to go NHRA and IHRA mainstream racing, and have a reasonable chance of going rounds.

As to aluminum rods and weight making power, what does it take to sling and extra 11 lbs. of weight around? I have a mock up rotation assembly for a Cummins I did many years ago, and it seemed like it shaved 2 lbs. off each piston and rod.
 
The AL rod debate is really simple to understand. It take more room to make an AL rod be strong enough to handle what needs to be done. Cummins and Duramax engines do not have the room to fit them IF you want to keep things stock diameters. You will need to reduce the crank pin size and the wrist pin size to allow for enough material in the rod to hold up. You will be replacing the AL rods about every 40 runs or so, it is a disposable item. So if your building a dedicated race engine that's one thing but for a street/strip driver do not do it.
 
I have seen aluminum rods in Top Dragster applications 1200 hp 565 cid motors run for 250 passes. The life of a set of aluminum rods is dependent on several things, rpms and how silly light we try to make them. A few years back, even before the new billet rods Bill Miller Engineering put a set of aluminum rods in a 454 tow rig and ran then for over 100,000 miles without a problem. In my comp motors I put 70 to 75 laps on them, but that was at 10,500 rpms.


I will check bearings every 20 laps or so and cycle the rods out at 100 laps if I don’t see and bearing pinch.
 
Big difference between a 454 and a Cummins. How are they clearing the Cam with aluminum rods?

Sent from my DROID X2 using Xparent Blue Tapatalk 2
 
There is no problem with clearance; I use a much shorter stroke anyway. These rods are not for everyone. But they are for people that want to go to the extreme with a drag racing engine that will operate in a light weight car where the motor has to accelerate. I would not feel uncomfortable putting then in a 2,6 sled pulling engine either. I designed a steel rod that uses the smaller crank and wrist pin to reduce weight as well, I’ll have a few sets of those in a month.
 
The Aluminum rods are around a $1000 , the Steel rods are $2395 for either stock style Dmax or the light rods
 
I've not cut down a Cummins crankshaft pin size so not sure what that's going to do for life but in a Duramax it going to shorten it by about 1/2. I've done several cut to both Hemi pin size and Big Block Chevy pin size and while there are fine for doing testing and race only motors with a short life span I would not do it for a Street/Strip truck.

So for a Duramax it's buy a crankshaft custom made and rods made which runs the bill up pretty good, but it's only money right?
 
morkable said:
How much boost would be too much for these rods?
Click to expand...

its not about boost , its about power. they work really well at 50 psi in a top fuel motor that makes 8000 hp and 5000 lbs of torque.

the new block is on the way , and it will use a BBC 2.200 pin with BBC mains.
I would not use these in any aplacation other the drag racing or 2.6 pulling engines.
 
You must log in or register to reply here.
Back
Top