I've decided that I'm going to do this project the right way and over-build the bottom end of the 454 (thanks to the advise from one of the forum members). I plan on spinning the engine up to 6500RPMs and I want to be able to do it without fear of breaking anything.

I need some advise as to what crank and rods to go with. First off, which of the two rods is better?

6.135" 5140 Forged Steel Eagle SIR Rods
OR
6.135" 4340 Forged Steel Eagle ESP Rods

What would be the advantage to going to a 6.535" rod? It would give me more displacement right? Would I have to worry about piston to valve clearance?

What crank would you suggest?

 

I think if you go with longer rods you will have to shorten the offset of your crank shaft. You may also be able to get a piston where the rod mounts higher in the piston. I don't know if that makes since, but basically ya, I would worry about clearance, expecally if your going to be going to 6500 RPM. I have heard stories of people who had NO problems at idle, and up to 3-4000 RPM, but once they tried to spin it to 5-6K, things started to hit, and they found out their clearances where to narrow. Try calling the rod manufacture for their advice.

Daniel

 

4340 is chrome-moly with nickel, very very strong (and very nice to machine), ie yeild of 180 ksi when properly heat treated. not familar with 5140, and i do not have my book with me, but i'd guess it is not as strong. which is more $?

aren't the +.400 rods intended for tall deck blocks?


[Modified by Turbo-Jet, 8:24 PM 11/2/2001]

 

The 6.535 rods are for a tall deck block whick is +.400" taller from the crank center line.

For the little extra $$ go with the 4340 material. The 5140 is good and is what GM uses for their high performance stuff, but why risk your engine by trying to save a few bucks on the rods.

Be careful when you buy the crank, and make sure it is balanced. I talked with an engine builder today who said he put an extra $250 into balancing an Eagle crank because the guy got one that wasn't balanced for his set up.

 

longer rods = more torque
shorter rods and larger bore = more horsepower

If i were you i would use arp bolts every where and maybe those miloden main caps talk about a high revin machine (capable )

ZD :jester

 

Bence, what this I see at the bottom of your signature? I thought you didn't ever plan on using slicks. Guess you really want to beat guys.

A longer rod pushes the wrist pin up higher into the piston. Some guys don't like doing that because then it interfears with rings. I dunno, i'm just going by the little I know about small blocks but I don't think it would be different on a BB. I'm not real keen on the long rod arguement but I think the piston travels less feet per second or something. There's some really good information about that on http://www.corvettefaq.com It helped me understand it alot better.


[Modified by Stingy74, 8:44 AM 11/3/2001]

 

hey bence with stingy 74's comment i would recomend that you try to make the tires the weekest link... where you get good enough traction but not enough that you start blowing up diff housings and such, but if you become an avid racer, make your car capable of doing so. It cost less in the long run to buy top notch heavy duty parts than cheep stuff that you'll break

ZD

 

I had originally thought about BF Goodrich Radial TAs, but I spin pretty good coming off of the line now. I still plan on babying it out of the hole (ie no clutch dumps) and I won't be power shifting it either.

I guess I'll spend a little extra and go with the 4340 ESP Rods. Thanks.

 

I think I've been bitten by the horsepower bug. I have decided to go with a forged stroker crank (4.300" Stroke), Matching Aluminum Rods & Flat Top Pistons. I believe that would put my engine somewhere around 495 cubic inches of displacement (with the +.030" Bore) :)

I'll probably have to step the cam down a notch to a 282 solid lifter cam. I'll have to call Comp Cams and see if I'll run into piston to valve clearance with the 294S @ 6500RPMs. I'm not sure I'll be able to run enough of a domed piston to get the desired 10:1 compression ratio for the 294 cam.

 

Aluminum rods? On the street? I can see the benifits of a lighter reciprocating mass, but don't aluminum rods stretch a certain amount after high rpm use?

 

Aluminum rods = race only!

They fatigue very quickly and must be changed out regularly.

 

I would skip the aluminum rods and spend the extra cash on the GM performance parts aluminum roval port heads. Since your car was
originally a small block car, the aluminum headed big block will weigh
closer to what a small block weighs. They also cc around 110 in the
combustion chamber so your c/r will still be around 10.5 to 1 and
because they are aluminum, you can get away with a that c/r without
having to run octane booster much of the time. I have them on my
1969 Camaro SS 396/375 and the lighter front end helps with a quicker
weight transfer to the rear end, thus better traction. Good quality heads
and I also went with the CNC matched intake. I bought mine here:

http://www.paceparts.com


:smash: :smash: :smash: :chevy :chevy :chevy

 

I JUST RECENTLY PULLED OUT MY 496" MOTOR. I HAD A LUNATI 4340 4.25" CRANK WITH MANLEY 6.535" H-BEAM RODS AND TRW #2399 RACING PISTONS IN A TALL DECK BLOCK. TO FIT LONG RODS AND A STROKER CRANK IN A SHORT DECK, YOU WOULD HAVE TO GO TO DIFFERENT STYLE OF PISTON AND DO SOME CUTTING, BUT IT CAN BE DONE. I RAN A COMP CAMS 288AR STREET ROLLER WITH ALUMINUM RECT. PORT HEADS. THIS COMBINATION HAD PEAK POWER AT 6300 RPM'S. LONG RODS DON'T SIDE LOAD THE CYLINDER WALLS AS MUCH AS THE SHORTER RODS, ESPECIALLY WITH A STROKER CRANK. THEY ALSO KEEP THE PISTON AT TDC LONGER. THE MOTOR WAS VERY STREETABLE.

ONE THING I WOULD LIKE TO POINT OUT IS THAT BIG BLOCKS ARE CAPABLE OF A LOT OF HORSEPOWER WITH STOCK PARTS. A PROPERLY PREPARED MOTOR DOESN'T REALLY NEED 4 BOLT BLOCKS, EXPENSIVE RODS AND FORGED PISTONS TO PUT OUT 500+ HP. TALK TO SOME OLDER GUYS AT REPUTABLE MACHINE SHOPS. THAT BEING SAID, IF YOU HAVE THE MONEY, BUY THE PARTS. THEY WON'T HURT AND ARE FUN TO TALK ABOUT.

 

I currently have an eagle cast steel crank and the 6.135 SIR rods for my big block build up. I went with this combo for money concerns. It will handle the big block power as long as you do not get wild. The rods and crank only cost me $500.

Mark B.

 

I'm of a recent convert to alum rods in a street engine. But since I'm not a professional, I depend on the experts for advice. Here is what I learned a couple weeks ago.

Called Childs & Albert to get the word on alum rods for a street engine. They have several sets of alum rods in street cars, some as high as 40,000 miles without a problem.

They said the most critical precaution with alum rods is to make sure the pistons do not hit the head or valves. To make alum rods work on the street you need .060" clearance between the piston and the valves. Takes careful assembly, but the weight saving and a faster revving engine is your reward.

Before calling C & A I had always avoided alum rods. Then I drove a friends Mustang with a new engine and alum rods. It is UNBELIEVABLE how fast that engine revs, and he has a stroker crank in it too, reminds me of the 1969 302 Z-28 engines!

I figure these rods are so over built for a street engine that it'll be very difficult to hurt one without trying to purposely to hurt it. If alum rods are built for blown nitro engines, my carbureted engine will be a walk in the park. And since I plan on running pump gas, the compression will be low enough that the piston to valve clearance will not be a problem.

 

So, what are you guys paying for aluminum rods? Sound expensive...