Steel or Aluminum Rods?

Newbie here. I'm building my first blown alcohol engine. It's going into a full tube '68 Biscayne. I currently have a 12-71 Littlefield with an Enderle Bird and am in the process of building the shortblock. I'm shooting for 1100-1500 hp in a 468 or 496 BBC. Looking at other sites, I've noticed some debate on the necessity of aluminum rods at this power level. Since you guys run this stuff all the time, I'd like a professional opinion on the matter.
Thanks,
Rick

 

i have ran several bbc with blowers i used brooks alum. rods never one problem

 

As I see it we need to look at 2 things. First of all, 1100 horsepower or 1500? Then the next thing is an rpm range. If the thing is 1100 and your are going to keep things under say- 7500 or so, go with a good steel rod. If you are going to spin big RPM's or pushing (Actually) 1500, then you are looking at steel rods lasting no longer than an aluminum would. And at that point, the aluminum rods give a shock absorber feel to the bearings and bottom end, and you get that advantage. Also, other parts of a standard block deal at a true 1500 number will need to be taken apart and looked at about the same time the rods do, so why not?

 

Were gonna make no more than 1500 hp with this combo. I thought that increasing the stroke to 4.25 would bring down the redline to 7500 or under. This isn't an all-out deal - filled, studded and o-ringed Mark IV block, moderate boost, etc. Others have noted the absorbing qualities of aluminum. I am assuming that you would need to check the rod bearings more frequently with steel rods.

Thanks for all the help!

 

if your going to run this thing on the street use steel rods I wouldn't use a steel rod no more than I can fly to the moon..Dave
www.myspace.com/daveloweswr

 

Hello Rick,

Good steel rods cost more than good aluminum rods and the better steel rods are the harder they beat on the bottom end.

In addition, you said its your first blower motor so even though your expected HP levels are fairly low the likelyhood of making a mistake on the tuning and needing the cushion of the aluminum rods is greater.

Aluminum rods are the way to go.

Just my 2 cents,

Richard Gavle

 

I run Crower steel rods and crank in my 496 blown bbc altered 28 lbs of boost, shift at 8,000 rpm, 40 + degrees of timing. I check the bearings when I am playing with the tuneup but have yet to have any failures. Rod bearings easily last me 1 year and mains at least 2 years. The same rods have been in the motor for 4 years and never been changed. I run 4.20's in the 1/8 and 6.70's 1/4. I have been extremely happy with my choice but it is your car.

 

Alcohol Altered,

Just curious what kind of heads you run on your combo?

Richard Gavle

 

Aluminum rods are not the only deal for blower motors as some believe. Jsut ask the guys that run the offshore racing boats. they make 1500 hp ALL day with steel rods and they are in and out of the water which is pretty hard on parts. just be right on the tune up as it will not be as forgiving as an aluminum rod.

 

If you are going steel, go with Oliver, they are THE best

 

ok... i'll throw a few pennies in here too. i run blown chevy stuff... both blown alcohol and a 90% nitro deal with stock mark IV block (billet capped)

i AM NOT a fan of big stroke chevy motors... if you were pulling shit with it (a house?) or pushing a 40ft boat i'd say go for it. but i wouldn't do it on a dragstrip... in my experience it makes blown chevy's 'unhappy'

as for rods... i agree with a few comments that it's more tune-up related. the off-shore boat-boys make some crazy HP and no doubt punish them... little different demand. i would say clearances, tune-up, AND OILING SYSTEM are more crucial to consider

 

Thanks for all the info guys. This blown alcohol stuff is new to me. It's a whole different world from nitrous!

 

LOL, you're ruined now. You'll never touch another n2o motor again.

 

Ya. Going from a 600 hp nitrous SBC to an 1100+ hp blown, injected BBC. A little adjustment for the driver

 

I run Pro Topline 360x heads ported by Jim Oddy. I also run his camshaft.

 

I run an A-Team Rob Adler cam. So far, it's making tons of power, and it even came with a cam card! ;p

 

but on steel rods should you run a small stroke or can you run a 4.5 stroke bbc for blown. what would if any be the diss advantage of running a 4.00 or 4.25 to a 4.5 stroke. I know alot of people dont like big strokes, but my rpm will be low around 7000 through the traps.would the big stroke be better for torque. and worst for the rods and block? just want to make 1000 to 1200 in a altered for 7.50 class. have a tall bbc block.

 

My build is a 4.5 bore x 4.5 stroke Ford, 10.32 deck block. I went with aluminum rods and still don't plan on shifting more than 7300 if that. One thing that I ran into was the wrist pin, I had to use the .990 pin instead of the larger one because of the lower ring pack location on my blower pistons. I dont think it will be a problem though. I chose aluminum rods based on what people said about cracking the crank. I went with a billet crank also that has Chrysler rod journals. When I get it up and running I'll post how it does, picking it up from the machine shop tomorrow! Chris

 

No, the blower is better for torque.