Aluminum rods

[gearhead409]

Any thoughts on using aluminum rods in a W engine. last summer i was talking to one of our members at Bowling Green about a crank i had that was drilled for alum. rods (Alcohol dragster crank) and it would be hard to add enough weight back to it for steel rods. he said that would be a great time to build an alum rod W engine. i've been thinking about what he said ever sense and today i said to myself, will, why not.

 

[Ronnie Russell]

I attempted to use aluminum rods earlier this year on out new race motor. New Bill Miller rods, 7/16 bolts. These rods were 10 yrs old but new, still in original packaging. Crank was 454, steel, cross=drilled. As I was wiping pan rails for pan installation, I noticed what appeared to be a crack in one of the rod caps. Kept trying to wipe it off, couldnt be a crack. Took it out and it was indeed a crack. Right in the area you would suspect over-tightened. But it was not over tightened. Barry, my partner, called Bill Miller and described the problem. Miller said that this was not unusual, said shelf life was short on aluminum rods. That makes no sense to me, so we ordered a set of Eagles and re-balanced. Im not saying aluminum rods are bad, but not worth the gamble to me. Hope you have better luck, motor ought to spin good with them.

 

[gearhead409]

Ronnie, you're scaring me already! did you have alot of trouble rebalancing the crank as i thought it would be with mine?

 

[Ronnie Russell]

Kim Barr Racing Engines of Garland, Tx rebalanced and had no problems. I would have to check with him to find out the material he had to remove or add. Barry is an old high school buddy of his, so Barry takes care of that and then brings to me for assembly. The Miller rods were 6.125 Took .030 off pistons to achieve .020 in the hole. Needed a minimum of 060 , piston to head for aluminum rods. Had to re-order pistons too. Got a nice set of "low compression pistons now". Will use them sometime in a street motor and use .022 gaskets. Barry got the Miller rods in a batch of parts he bought from a an old racer who quit the sport. Those rods sure were beautiful, but sure caused us a lot of problems and expense. Again, just because we had a bad experiance, doesnt mean the next guy would. But scared me enough so as not to take a chance.

 

[gearhead409]

Ronnie

about ten years ago my buddy and i built a 468 big block blower motor for a prostreet guy. my buddy built the block using Bill Miller rods per the request of the customer and i built the blower and drive. it's in a Monte carlo, the guy plays with it on the street, it aint fell apart yet! that was 10 years ago. i would say he is pushing his luck.

 

[Ronnie Russell]

Bill Miller rods are quality parts. I was really looking forward to using them, cant explain the crack, but uncomfortable with explaination. Leave it to me to get the one bad one . I will stay with steel for the peace of mind. Good luck

 

[gearhead409]

Ronnie

i balance the pistons and rods here but send the cranks to midwest balancing in Col. they do alot of sprint car stuff. i just didn't want to spend a small fortune on heavy metal. lately i have been using a guy in Springfield O. but his health is getting bad.

 

[Tom Kochtanek]

Advantages of aluminum?

Other than reducing the rotating mass, are there other advantages in using aluminum for the con rods?

Best,
TomK

 

[Ronnie Russell]

Tom, If you were to see these rods , you would think that these are the strongest rods in the world. Huge! but light. The 7/16 bolts present more clearance issues. We wanted to use them because " we had 'em". Thought about ordering 1 replacment rod, but I was concerned that if 1 had a crack, was there another that was on the verge of cracking? But to answere you question, as far as Iknow, Rod weight is the advantage of an aluminum rod. Cant explain why one would crack at 65 lbs. of torque. Maybe 50 lbs would have saved the rod, but my research said 65 lbs. 7/16 rod bolts!! Everyone knows of aluminum rods reputation of stretching and the need for more quench, sounds like more disadvantages that advantages. Im sure there are many that have had good results with aluminum rods, but unless someone is trying to turn 8,000 rpms, I think steel makes more sense.

 

[JimKwiatkowski]

I ran Manley Aluminum rods in my 409 stroker without a rod breaking,but a mallory weight came loose and destroyed that 409 I ran Manley Aluminum rods in my Big Block that was in my Camaro,after 2 years of running the rod broke in the middle of the rod and destroyed the Big Block .They say the rod broke is because the engine was not warmed up to operating temp before racing .I now run Eagle Steel H-beam rods in my 468,I just don't trust Aluminum rods Just my opinion

 

[gearhead409]

Thanks everyone for sharing your opinions on alum. rods. you pretty much have talked me out of the idea. thanks

 

[DIV1RACER-2]

alum rods

Ronnie

Some how i missed this thread, i have the same situation as you had . Bought a motor & a bunch of parts. The motor had BMR alum rods w/ it along with all the other parts to assemble. I have never used alum rods before but had no concerns till i read this!!!!!! I don't buy the explantion of " short shelf life " !!

Did you show the rod to any body that is an engine builder or machinist??

Think i need to call Bill Miller !!

I can't just change rods in this combination , Some really unusual parts & ideas in this one !! How about a 4.090 stroke w/ a 6.200 long rod !!!!!!!!!

 

[Ronnie Russell]

Denny, Im sure there must be a way to check new aluminum rods. Maybe some sort of X-ray process. Bill Miller could answer that. To avoid confusion, my race partner, Barry Taylor , is the person who actually talked to Bill Miller. I mention this so that when you talk to Miller, he will remember the call. I showed our problem rod to several. But what could they say? It is cracked center at the big end, on the outside of the rod. It appears to anybody and everybody (including me) that the rod was over torqued. It is a classic stress crack. If it belonged to someone else, I would say , "well , you just overtightened it". But it was my hands and my torque wrench, so I know better. This rod was probably the one bad one in a 1,000. We wanted to use those rods real bad, but just wasnt comfortable with the other 7. "Good luck with the 4.090 stroke engine, that sounds like an interesting project. Hope we dont have to line up next to it in the future.

 

[DIV1RACER-2]

Ronnie


Hopefully we can line up @ this years gathering , where ever it is , Talked to Fred [ ss425 ] lately & is still working on having something @ Clay City Ky.


Won,t miss this year ! Truck boned me last year or would have been there.


I think the process for cking alum is called zyglo , Aircraft people probably know this ???

 

[gearhead409]

Denny

Zyglo is correct. it's used here locally at an aircraft lighting company i used to work at. i would think Bill Miller would be using a process like this. i don't buy the shelf life thing. alum rods and aircraft parts fail after so many cycles and need to be replaced. the goverment would warehouse parts for years before using them.

 

[Skip FIx]

I've run some BME rods in my Pontiac 45 for 4 years now spinning the cast 4.21 stroke to 7000 a few times. No problems. One thing I do not like though is you are supposed to run them 0.020 down deck per BME for stretch, growth. But where do they really end up? No one really klnows so it may be too fat down and kill some of your quench. You also need to let the motor come to good temperature before hammering it.

They may be replaced when I build the 4.350 bore 4.21 Pontiac motor.

 

[tmracing62]

If you were building something for which parts are readily available and twisting it up to high rpm's quickly was the plan and you didn't mind the expense/maintenance then alumnium rods would be in order. And if every hundredth was hugely important too. I know lots of guys that went to aluminum rods and went back because of the hassle and worry factors. You can buy plenty of bang for the same bucks somewhere else in the engine, chassis (hook) and body weight.

I don't know if I am over it myself, but most of the exotic parts are really just mostly mental and for the serious specialized racer types that have the big bucks. Build a really solid combination that works as perfectly as you can design/afford and be happy. Much happier than a pool of oil and chunks of rare metal on the starting line anyway.

 

[Ronnie Russell]

"Build a really solid combination that works as perfectly as you can design/afford and be happy." Possibly the best one sentence piece of advice I have ever seen in print. Thanks, Michael

 

[gearhead409]

tmracing62

well written, thank you. and thanks to everyone for helping me get my feet back on the ground.