Aluminum Rods, I've Never Seen Them Offered Or Talked About In Here? Curious

GNVYUS 1

Well-Known Member
In the import world they pop up often, even in street cars, but I don't see anything offered or even really mentioned for us?

I just got a set for my 2.0L Talon (156mm length at $900) since it's gonna be a stroker engine, less load on the crank at high rpm, better rod ratio vs stock length on crank and they're strong as hell (long term fatigue being the one downside).

I asked the shop what it would take to make a set for the 109 and it was pretty much cash and this...

"I would suggest changing the pin bore to something more "standard" such as a .927 or .990. The big end is also an odd size so it'll cost money there to make fixture changes."

It sounded like $1400 for 6 aluminum rods.

Comments and bombs 💣 away!!??
 

PSID6

Active Member
Personally, I don’t think your average Buick spins enough RPM to even consider an aluminum rod, especially being that it’s eventually a throwaway part. Also for $1400 a set you could get a good quality steel rod. Like Carillos, Oliver etc. that could potentially last through multiple builds.
 

GNVYUS 1

Well-Known Member
I figured the racers would want the
Rev faster, Rev higher, Handle big power part most and not care if they pitch the rods after X miles or X passes.

But price is always a factor for street guys, not usually for drag guys though. Hahaha
 

turbobuick

Well-Known Member
Staff member
My understanding is they pretty much wont physically fit in the block. I would like to know more or hear of someone who has run them.
 

TIMINATOR

Active Member
Above 6500-7000 there is HP to be had, below 6000 nothing to be gained for the cost, plus since they grow in length there is a small deck height change (tighter-more compression- less piston/valve clearance), but mostly as the big end grows, there is less bearing crush and heat transfer, the crush is important to keep the bearing from spinning, that's why alum rods are dowel pinned.
Mostly, there is a ton more HP available FOR THE COST, than alum rods provide at the RPM levels we run.
I have run a bunch of them in my BBC dragsters at above 7000 RPM and there was ET there, but much of the gain came from lightening the counterweights, as I usually cut the counterweights as much as .220" on the diameter to facilitate easier balancing.
Ya pays yer $$$$, and make yer choices.
TIMINATOR
 

GNVYUS 1

Well-Known Member
What would you estimate is the safe RPM GAIN by going to aluminum rods over the steel rods, 500rpm? Like 6500rpm max on steel but 7k aluminum?

The new V3 al rods I got for my Talon were a redesign to match F1 tech (I think he said) to gain strength and be a tad lighter. There's a guy with V2 rods and after 8+ years he has over 100 passes and 30k miles on them, damn. Modern Al rods don't appear to be as short lived as the 70-80s racers were running. These new ones sound like they're able to live in multiple big HP builds.

But if they don't fit because they're thicker than mute point for us.
 

TIMINATOR

Active Member
The point is moot. I say that sarcastically!
It's not about RPM gain. Power band of the combo is primarily determined by cam, induction, and head flow, not by rotating nor reciprocating mass. Lighter weight in rotating mass allows faster rpm gain and lighter reciprocating weight allows more HP due to the reciprocating weight having to start and stop twice per revolution. Lighter reciprocating also allows for a lighter counterweight, again allowing for faster RPM gain.
Once more, lighter weight parts shouldn't change the power band, but may change shift point slightly upward or downward, depending upon vehicle weight, and number of gears in the trans.
TIMINATOR
 

Mr.Spool

Well-Known Member
I figured the racers would want the
Rev faster, Rev higher, Handle big power part most and not care if they pitch the rods after X miles or X passes.

But price is always a factor for street guys, not usually for drag guys though. Hahaha
Your right
 

Mr.Spool

Well-Known Member
What would you estimate is the safe RPM GAIN by going to aluminum rods over the steel rods, 500rpm? Like 6500rpm max on steel but 7k aluminum?

The new V3 al rods I got for my Talon were a redesign to match F1 tech (I think he said) to gain strength and be a tad lighter. There's a guy with V2 rods and after 8+ years he has over 100 passes and 30k miles on them, damn. Modern Al rods don't appear to be as short lived as the 70-80s racers were running. These new ones sound like they're able to live in multiple big HP builds.

But if they don't fit because they're thicker than mute point for us.
The rod is not the limitation of the 109
 

rag231

Well-Known Member
I know of 2 motors that have Aluminum rods on 3.55 Weber cranks in 109's. Weber built both motors. One was ran heavily in TSM around 2012/13. One is still in service to this day. Both motors ran in the 5's in the 1/8. SBC journal GRP Rods on larger destroked cranks, 3.07 stroke crank used BBC rods, no real mods needed. When we had a rod / crank shortage creative thoughts were flowing!
 

Kip

Well-Known Member
If my memory is correct Billy Anderson built Sully an aluminum rodded engine back in the day that ended up being sold with his car to Ron Bailey.
 

Chuck Leeper

Toxic old bastard
Staff member
One could always step up to "unobtanium".
Had a set in a Buick headed 406SBC.
Old conversations by guys we no longer see here....
 

GNVYUS 1

Well-Known Member
unobtanium

The good news is Darren at FFWD is willing to make these rods for us, so they'll be an option for anyone interested. I have their 3.0 rod for my new stroker Talon, pic below.


I've read about import guys knife edging the crank to the point where the aluminum rods and kniving shaved off like 5-7lbs, WTH.

I'm gonna assume the limit with the 109, is the 109. Hahaha
 

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turbodave231

Moderator
A set of good Molinar rods:
  1. Won't break the bank
  2. Will far outlast the aluminum rods
  3. Support 700RWHP or more
Why go through the expense and hassle of having custom aluminum rods made for an engine that makes most of its power under 6000 RPM?

For a high dollar build like a TA blocked or S2 blocked/headed engine one might consider aluminum, But the true benefits come when the engine is designed for much higher RPM (above 7000 RPM). The practical limit for RPM in a titanium valved S2 headed engine is 8500 RPM. That limitation is due to Valvetrain and not reciprocating weight.......and yes I know the Indy engines turned more RPM than that. But Indy/Indy Light S2 engines used steel rods.

Cost/Benefit is the real issue as I see it.
 
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