Rod alignment

[blykins]

You’ll have to take my word for it then.

Not that it matters, but they are as centered as the pics the others have posted.

[n2xlr8n]

I do not have experience in this area (SBF), but couldn't it be possible that the bore centers are more consistent in the blocks that some professionals (Blykins, for one) use?

[groberts101]

This is more of a commonality for me than an oddball situation. You have to remember that I specialize in building SBF engines. These are not the only two that I have built.........

It’s going to be a 50/50 shot on whether the Centralign rods fix anything at all. So do I order a set of regular rods and a set of Centraligns at the same time?

This is getting ridiculous.

IMO, if it’s such an important thing to have a perfectly centered rod on the pin, then you need to go to a piston guided rod. Otherwise, the little end will never be centered in a running engine. To me, it’s not even that important and no one has been able to prove otherwise. The true benefit of a piston guided rod is to reduce friction at the big end.

I didn't read it all.. but I agree with this. How the hell can a center design rod without a pin guided bushing ever really maintain a true centered position?

If the rods big end never moved around on the crankpin in use?.. then we would see PERFECT wear patterns on crank pins in the EXACT same width as the bearing. Dunno, maybe they/that exists but I've never witnessed or heard of such a thing. Tolerance stacking is just too great and it ain't a perfect world, to say the least. Then add wider thrust bearing clearances along with larger rod side clearances and that crank pins wear pattern will NEVER be the same exact width as the bearings contact patch.

But.. from a purely idealized architectural standpoint I could never see it(rod centered on the pin) hurting a pistons location consistency within the bore though. So if splitting atoms, as so many around here like to do in their spare time, then I do actually think it's a better design in and unto itself. Still needs pin bushings to get the best of all worlds though. LOL

PS. also curious to what happens to crank flex and overall durability(for those already on the edge of tossing parts) when you move the big ends offset to "fix" the piston pins "incorrect offset"? Is it purely about the piston and rings.. or do we need to consider what may happen at the crank pins/fillets/margin area based on moving the rods offset?

[Steve.k]

If you read LSP's findings he said the rod oscillates quite abit from their findings from side to side taking up your rod side clearance and then some. If the rod is not as close to center as it should be then it can move further over than normal maybe as far as pin boss. So what this does is create more side loading. The idea of these rods is to keep it as close to center as possible to prevent that. Your right centering on piston is even better but maybe not cost effective for alot of builds. Lykins posts pictures of alignment and thats fine but all strokers for small fords are not created equal. So all this does is eliminate that. I just looked at a few rotating asssembles of stock engines i have in shop and they are dead on from Ford. Those are press fit pins so they will move the distance of rod clearance.

[elwood]

exactly, the question is, Where would you rather start, centered or all shoved over crooked?

BTW, i googled "blykins has proof"

0 hits

[blykins]

So my pictures showed rods that were shoved over? Hmm. Maybe you need to look again....

I googled “Don’t drink the Koolaid” and the first result was Jim Jones.

The second result was a link to this thread.....

[elwood]

no, your pix for the most part didn't show anything

[blykins]

Then zoom in.

It’s not that hard to see equal amount of wrist pin showing on each side.

Unless you don’t want to see it, which I think is the case with several members here.

We might as well be talking about abortion, the Bible, or Donald Trump.

[cjperformance]

Then zoom in.

It’s not that hard to see equal amount of wrist pin showing on each side.

Unless you don’t want to see it, which I think is the case with several members here.

We might as well be talking about abortion, the Bible, or Donald Trump.

[blykins]

Hey elwood, can you see this one buddy? This one ain't even one of mine.



That's a Dart 351W block, with a Lunati crank and Lunati rods. If you're looking for dead-on center, there ya go.....and it doesn't take a Centralign rod to do it.

I've got a BBF to finish, then I have to start on (2) 408C's and a 460 Windsor. All 3 of those small blocks get Molnar rods (non-Centralign of course) and I'll be sure to post up some pics for you all to ogle.

[elwood]

i guess there's some redemption of your non sequitur random examples of various engines and components

that is that i've been curious about the Lunati products, any specific part numbers or doesn't that matter either? because there's no guarantee that the Windsor spec crank or the rods for my application will be machined the same as those in your once again angled and distant pic. BBC's, BBF's, Pontiacs, Windsors, various manufacturers rods, Harleys, Triumphs, Zundapps and i don't know what else are not apples to apples to the sbc rods in a Cleveland example the thread is based on but maybe that counts a proof these days

thanks for the Lunati pix though, good to see they aren't all bound up to one side

[blykins]

According to Molnar, this is “supposed to happen” any time you use a sbc rod in a sbf application. That’s why I posted pics of Cleveland’s, Windsor’s, you name it.

Admittedly, I’ve seen the occasional kicked over rod, but for the most part, I don’t see it.

Again, what am I supposed to do when I have one that’s kicked over? Order one single centralign rod? Rofl....

And most importantly, what happens if I swap my centered Scat/Oliver/Compstar rods to Centralign rods with an offset? Will it make them non-centered? Lol

Snake oil....

[groberts101]

Got curious and just looked at my scat rodded/eagle cranked Windsor block. Molner must think I was born yesterday too cause I don't need no stinkin' centric rod design on mine either. Must be a Chevy thing. Lol

Edit.. i guess it IS a Chevy thing! Wanted to use a Chevy 6" rod in this little 8.2" block.. so glad I didn't but at least I now know Molner will straighten me out if I go that route in the future.

[digger]

So if the non offset rod is in the middle and you used a offset rod then it would no longer be in the middle. So we also have offsets rods also being in the middle and thus with non offset rod they would not be in the middle anymore presumably due to the particular crank?

In that case if you had a crank that needed an offset rod to sit in the middle what's wrong with using it? It seems pretty reasonable to want to minimise secondary motions of the piston by havering the rod nominally in the middle even though it moved around a bit it's limited to being in the middle on average

[blykins]

Got curious and just looked at my scat rodded/eagle cranked Windsor block. Molner must think I was born yesterday too cause I don't need no stinkin' centric rod design on mine either. Must be a Chevy thing. Lol

Edit.. i guess it IS a Chevy thing! Wanted to use a Chevy 6" rod in this little 8.2" block.. so glad I didn't but at least I now know Molner will straighten me out if I go that route in the future.

I used a Molnar 5.700 Chevy rod on a 289 ford road race engine. No issues.