can i run aluminum rods on the street????

i have a 392 blown hemi going into a 1960 dodge dart 2drht - have MT pistons with a set of Howard #393 aluminum rods - can i run these rods on the street ???....yes, i want to drive this car...this is NOT a quarter miler either....

 

i know someone that had a stroked ford big block with aluminum rods and the car was street driven, never had a problem.

 

According to the Tex Smith Hemi book Jr. Thompson used them on street hemis w/o a problem.

 

In a word no. I sold two sets of the same rods. Of course you could and live life on the edge. You gotta ask yourself is the cost of a good set of rods worth what the aluminum ones will take out when they fail.

 

what fails?...do they disinegrate after driving for a while on a trip?....man, these things are BEEFY ....the local 'guy' at our speed shop said the same thing....damn, don't want to spend on another set!

 

Sure you can, why would you want to? Do you already have them? Are they better than a set of forged steel for street use?, no. Will they last a while for street use?, yes. As long at steel ?, no. What will they destroy when they go?, block, crank, pistons, same things steel ones destroy when they go. Will they give notice before they go?, sure same as steel ones they will start to knock first, and given that you are not trying to drive them to California from New York, then 1/4 mile them, then sure they will tell you they are atarting to knock before they go out.
They are better reserved for race type use than a DD though.

 

I'll let the Hemi guru's on here chime in. All I'll say is they are great for racing, for the long haul on the street their not stable enough material for me. Hey the choice is all yours.

 

yes, i already have them - got them with the pistons - probably from some guy that had the same scenerio as i have now - only trouble was, he also said the pistons were .020 over - NOT - he lied - they are std 4.0000 pistons - so much for boring my block to clean it up...i got screwwed all around.....just trying to save my a$$ anyone want to trade for good steel rods?....

 

Sleeve it to standard?

 

Yes you can I had a small block chevy 283 spare motor for an old early modified dirt car.It had aluminum rods, I dont have a clue who made them! I put the motor in my old work truck and ran it for ten years trouble free.
Tony

 

Not the street. But the tech man from Howards told me to change mine on a circle track engine between 500 to 600 laps. I quit using them and went to a lighter flywheel/clutch and a lighter crank shaft. I then gave the aluminum con rods to my street rod [not hot rod] friends for muffler hangers. If you don't turn a lot of RPM the might last forever.

 

used or new? i would not even consider used aluminum rods as an option.

 

Those rods will stretch over time.... No thanks!

 

Tex must have been quite, I only see 3 red X's.

 

Nothing wrong with using them on the street. I have several customers that use them and have had no problems. One is a big time local street racer. Motor is five years old, freshened once. Sees race conditions, on "the hose", every weekend in the summer.

 

I know it's verbotten, but those O/T guys from Japan have aluminum rods in their stock Hondas ( cars and bikes). A friend twists his bike over 10,000 all the time with stock rods. I understand that these are engines that are engineered to do this. The thing with aluminum is there are many types of alloys

 

They wear out. Look at it this way, you can run an old 392 with 60 50+ year old steel rods and never worry about it but no one has ever run a set of 50 year old alumuminum rods.

Can you run them sure, will they be 100 mile rods, nope.

 

Interesting thread. I have been wondering more details on this myself. I guess there would be a ton of variables all the way from how the parts are made, to what previous life they had, to how they were assembled into your street engine and how they get used in their future miles. Keep us posted with what you end up doing.

When you think about what a rod goes through during day to day use, much less a 6-8K rpm blast through the gears, it is amazing that ANY of them hold up!

 

Tell you a funny story about aluminum rods, and just race parts in general. I was in the pits once and a fellow racer was sweating a TRW decal off of his car and replacing it with a Kieth black decal. I asked if he had replaced his pistons and he said "Nope." So I asked why the decal change, he just smiled and said, "Keith pays more."

No one at the local cruise is going to ask anyone else to get up out of their lawn chair and tear an engine down. Just tell people that you have aluminum rods and no one will be any the wiser.

 

In my TAFC we ran 8 hard pass's and changed rods. for what ever thats worth.
Rods were almost $100.00 each. motor $35'000.00 .

 

800.00 isn't much when you are talking 35,000 for the motor is it.

I actually had a flat track limey bike that I converted for street riding that I ran aluminum rods in it. I had access to sets at the shop I was working for. I probably put all of 7 or 8 thoudsand miles on that bike before I freshened it and sold it, it got new rods. On my long mile bike I ran steel rods, I had a set of aluminum rods for it but they hung on a wall.

 

i had a 327 back in the day with al. rods.built that sob for runnin hard. nobody told me i couldnt run them on the street. glad they didnt ran thet engine in my 55 for around 10 yrs. and ran it hard. never a problem.

 

Used no history NO. New OK but bring engine up to temp before pushing it.

 

Triumph, norton, BSA, and other brit bikes run aluminum rods with a steel cap stock. Not just one or two models, pretty much all of them. One of the triumphs that I have has probably had the top end replaced at least 5 times and has the original rods in it.

 

I wouldn't worry too much, with the price of gas today,( and you can't afford other rods) you won't be driving that Blown Hemi very far anyway!

 

A lot less internal pressures on a Trumpet or a beezer.

 

Aluminum rods will stretch and fatigue over time. The real killer of an aluminum rod is deceleration where they see a lot of stretch load. They handle compression good but not so much the other way. I have a handful of aluminum peices that Look like they were sent through a tree limb chipper, that I picked up off the street while waiting for a trailer to come pick me up. I knew the risks and figured I'd give it a shot, didn't work out so well for me. Mabey you'll get 10,000 miles out of em, mabey you'll get 1000. Is it worth it?

 

They aren't blown, but the ones I have are all 9.5:1 or higher compression ratio. Early models mostly were low compression (into the mid 60's).

If you used to run flat track then I'm sure you know how hard it is to kick over a TT special.

 

Trying to compare motorcycle short aluminum rods to v8 car rods is ridiculous. No comparison. Yes you can run them on the street but they will fail. Aluminum rods have a definite metal fatigue life and when that's reached they are going to come apart. Why risk it? What's the point? There are any number of quality, relatively light weight inexpensive steel rods on the market.

 

I couple of thoughts on aluminum in general. It is 1/3 the weight of steel but also 1/3 the stiffness of steel. To get the same deflection at a given load with aluminum versus steel, you need three times the volumn of aluminum. Think piston hitting the head. Aluminum also expands with temperture much more than steel. Get the aluminum hot and you increase the bearing clearance. It also decreases the piston to head clearance. Steel does not have a fatigue limit. Aluminm does. That is why aircraft have design lifespans.
Because of the weight to stiffness ratio is the same, I see no advantage to them. The large volumn of them increases windage loss and the temeperture dimension changes make them a a shot in the dark. Aircraft engines that are shaved of every ounce of extra weight use steel rods.