Rod alignment

[blykins]

Well, to be honest, the Chevy rods do fit everything that's designed for them. Now, if the offset is something that needs to be adjusted to make peak hp, that's yet to be seen. I'd like to see an independent engine builder do the testing, with rods that are the same weight, same length, same bearings, etc. I'm not going to take the word of a connecting rod manufacturer who, to be frank, has been the only one to produce a test result. That's the same thing as a spark plug company stating, "Our testing has shown that our spark plug produces 20 hp more." We all know how that goes.

The way I see it, there are two arguments here:

1. Are all the rods in a SBF with a SBC rod offset like the diagram shows? I know for a fact that they're not.

2. Are you losing hp by not having the rod perfectly centered. Again, I'd like to see a third party test.

[blykins]

Some pictures of some SBF engines with SBC rods:

*Dart aluminum 9.500" block, Callies crankshaft, Callies Compstar SBC rods:



Cylinder #2 is about as centered as it gets.

*Dart SHP 9.500" block, Callies crankshaft, Oliver SBC rods:



Again, cylinders 1 & 2 are centered.

[Steve.k]

Ok for as many as you have aligned others say the opposite. I've seen them off and ran it that way as never had option. Now i do and will switch. And guess what no extra cost!

[blykins]

Ok for as many as you have aligned others say the opposite.

Then I'd like to know what the difference is and why Molnar is saying that this is a problem with every SBC on a SBF platform. It's obviously not. If I would have used one of those "Centralign" rods in one of the engines that I posted pictures of, then it WOULD have been offset and not centered. Not trying to be argumentative here, but I'm looking for answers because everything is not as they say it is, and I'm wondering why.

[Steve.k]

Brent they are saying it is a problem more often than not. So they addressed it, i don't knock them one bit. Least they have the balls to do it! Im willing to bet every high end nascar engine makes dam sure things are dead on. If its a sales gimmick at least it doesn't cost me a nickel. And no offset how nice!

[blykins]

Do you get my point though?

Look at those two pictures above. If I would have bought their rods, they WOULD have been offset and it wouldn't have corrected anything, but made it worse!

If it's a problem on some and not a problem on others, then how are you supposed to know ahead of time?

Someone show me some data, because I'm not buying into it.

[Steve.k]

After further investigation turns out my hp gains posted in this topic may have been conservative!

[modok]

Wait.....which way is supposed to be better?
when I read the first post i thought the off-center rod made more hp, which would be interesting.... but since everybody else assumes the opposite then I must be mistaken???
Re-reading it again, it is never stated which way is better

and are we talking H beam or I beam???

[af2]

Wait.....which way is supposed to be better?
when I read the first post i thought the off-center rod made more hp, which would be interesting.... but since everybody else assumes the opposite then I must be mistaken???
Re-reading it again, it is never stated which way is better

and are we talking H beam or I beam???

You had to go there didn't you?? I am running LS rods in a Gen1 block...... Hmm don't they just make the piston go up and down???? LOL

[modok]

H beam is some 3-4x more rigid than an I beam in that dimension.
Should be a significant difference.

[Mark O'Neal]

We've been buying Chevy rods and stuffing them 'in anything" for the past 50 years.

[bobalattie]

Well, I bought into the hype and got the molnar offset h-beam rods 6.200, 408 sbf, 4340 eagle crank (scat didn’t have a release date for the 4340 internal balance 3.85” crank, so I hand to change my plans), race-tec 2618 pistons.

[Steve.k]

Dead nuts on!!

[cjperformance]

Always run the offset toward to exhaust side! Cos its hotter!

[blykins]

Well, I bought into the hype and got the molnar offset h-beam rods 6.200, 408 sbf, 4340 eagle crank (scat didn’t have a release date for the 4340 internal balance 3.85” crank, so I hand to change my plans), race-tec 2618 pistons.

Not dead nuts on, but looks as close as the pictures that I posted above with other brands of rods.

Funny, I mentioned this to an engine builder buddy of mine who specializes in dirt track cars, mainly Chevy stuff. He said, "That's funny, because even a Chevy rod in a Chevy engine isn't perfectly centered between the pin bosses..."

So where are the "special" Chevy rods for Chevy engines?