Alloy rods in a 440 street engine?

[LR1970]

Hi, I am after anyones opinion and experiences with using alloy rods in a street engine. I am building a street 440 that will be driven hard at times but not thrashed. Just a weekend driver that will last. The rods I had were discoloured and I was advised maybe look for others. After talking to a few guys I decided to build an engine that will rev quickly and have good throttle respose. So a lighter bottom end was suggested at the possibility of loosing a little torque. Hypereutectic pistons and alloy rods is what I plan do add to the build. i still need to decide on cam and induction. Any suggestions? I would like to run a 509 cam and 6 pack set up, but i don't think it will work so well.

Here is my set up

72 Roadrunner
15 inch Rally wheels with 60 height tires
727 with 2500-3000 stall
440 + 30
factory forged crank
alloy rods
Hypereutectic pistons
906 heads with os valves and mild porting
hedman headers and 3 inch exhaust
509 cam? maybe milder to suit induction
6 pack/dual quad 600s/RPM Performer with 750 performance holley vac sec?

 

[67 B-body]

The 509 hyd cam will want more converter than that.... It's a lopey no bottom end camshaft! I used it in my 69 RR years and years ago....... Boy that was a long time ago!!!!
Anyhow,,, I ran 4.11 gears with a locker setup and 4200rpm converter.... It did OK, but no real street racer and ran mid 12's in the 1/4. What compression will you be making and with what cyl heads? These bigger hyd Mopar performance cams will want about all the compression you can dish out to them. Flow is very important too,,, in other words cyl head choice is VERY important for building good horsepower... You'll get a ton of advice on the "best" way to build an engine,,, but the end result is always going to be that : the more air and fuel you can get into the cyl and provide good ignition, the more power you'll make.... Turbos, blowers, nitrous are all means of providing more of this than the atmosphere can do on its own....
Happy Moparing!

 

[Meep-Meep]

Interesting read on the aluminum rods. I guess it makes sense if you pound on them like a full race engine then they will work harden to the point of failure. It's also interesting to note that no production cars are using aluminum rods (none that I know of anyway) but some high end cars have Ti rods. Personally I'd think about using a lighter flywheel or even an aluminum wheel before using aluminum rods. Seems that would give a similar effect and may cost less. One other note is the crank counterweights will have to be cut down a lot to balance the assembly with aluminum rods and that's machine shop time.

Regarding cams, my concern is the .509" may not like the divided plenum dual plane intake as much as a single plane, but I never tried a high overlap cam with a 6 BBL. One cam I do like is the MoPar .528 solid. It's on a 112 lobe separation and has great streetability but also makes plenty of power. Deep gears are recommended.

 

[RustyRatRod]

Aluminum rods aint for street motors.

 

[HT413]

Aluminum has a fatigue limit, unlike steel. The only gaurantee with Al rods is they WILL fail... eventually. They use em on race motors because they know they'll be replacing them soon enough. Thats why most aluminum parts are big hunks of metal like heads, intakes, even pistons, where the loads are spread over a much larger area than the small neck of a rod.

Besides, Factory rods are plentiful - and cheap. Spend the money on a better port and valve job.

 

[IQ52]

Hi, I am after anyones opinion and experiences with using alloy rods in a street engine. I am building a street 440 that will be driven hard at times but not thrashed. Just a weekend driver that will last. The rods I had were discoloured and I was advised maybe look for others. After talking to a few guys I decided to build an engine that will rev quickly and have good throttle respose. So a lighter bottom end was suggested at the possibility of loosing a little torque. Hypereutectic pistons and alloy rods is what I plan do add to the build. i still need to decide on cam and induction. Any suggestions? I would like to run a 509 cam and 6 pack set up, but i don't think it will work so well.

Here is my set up

72 Roadrunner
15 inch Rally wheels with 60 height tires
727 with 2500-3000 stall
440 + 30
factory forged crank
alloy rods
Hypereutectic pistons
906 heads with os valves and mild porting
hedman headers and 3 inch exhaust
509 cam? maybe milder to suit induction
6 pack/dual quad 600s/RPM Performer with 750 performance holley vac sec?

Aluminum alloy or steel alloy?

 

[HT413]

Lol, that's an awesome question and so true, so many people think "alloy" means aluminum. Technically all steels are alloys of iron.

 

[RustyRatRod]

Generally, when people go out of their way to use the word "alloy" they mean aluminum.

 

[Cranky]

http://en.wikipedia.org/wiki/Aluminium_alloy

 

[IQ52]

I still want to know what the guy from QUEENSLAND thinks an alloy rod is.

 

[383man]

Bottom line is I would not use aluminum rods on a street eng. Race engines use them but as was stated they get replaced alot. Steel rods is the way to go on a street eng. Just make sure the "alloy" rods you use are not aluminum. Ron

 

[Sixer]

Aluminum rods use a "pinned" bearing, that should tell ya something. They also require more valve to crown clearance, yet another indication their life expectancy is expected to be less than optimum. I do know of a couple guys that have run them on street motors (Chevs however) and had good results. They were, however, very well constructed motors.

 

[RustyRatRod]

I still want to know what the guy from QUEENSLAND thinks an alloy rod is.

White pine. :blob1:

 

[mopar367]

Speaking of connecting Rods made of other materials, I read a hot rod magazine from the 70s. It had plastic connecting rods in it! They were black looked like dense pvc or something. They were comparable to aluminums I think it said.

 

[HT413]

Man, i'd worry about torquing the bolts, let alone using em. In the 90's i worked on a project to replace steel plates for broken bones w reinforced composites. That way MRI 's could work. There are some remarkably strong/tough/light composites out there but dang, rods live a tough life.

Speaking of connecting Rods made of other materials, I read a hot rod magazine from the 70s. It had plastic connecting rods in it! They were black looked like dense pvc or something. They were comparable to aluminums I think it said.

 

[lewtot184]

i can tell by the comments that nobody here has ever built an aluminum rod engine.

 

[Sixer]

i can tell by the comments that nobody here has ever built an aluminum rod engine.

And you would be wrong. But I won't hold that agin' ya.

 

[Cranky]

i can tell by the comments that nobody here has ever built an aluminum rod engine.

Why don't you enlighten the ones that you feel have no experience in building one? :blob1:

 

[RustyRatRod]

And you would be wrong. But I won't hold that agin' ya.

Yeah, he's wrong more than once. lol

 

[RustyRatRod]

Why don't you enlighten the ones that you feel have no experience in building one? :blob1:

Yes by all means. I am waiting anxiously. lol