5140 rods?

[Krooser]

PDQ...

I'd use these... need to get the crank turned and nitrided but it would be hard to find a better rod at a better price.

http://www.ebay.com/sch/i.html?_nkw=pankl+rods

[Mark O'Neal]

It's all about the tune, not the parts.

Expensive parts / bad tune = broken.
Stock parts / good tune = cheap performance.

Best post in the thread.

At 8 grand I'r still rather see a rod with dowels locating the caps.

[user-23911]

There's a whole world out there that wants you to spend, spend, spend on aftermarket parts.
It's another case of mind control bullshit, shiney is better.


Rods might or might not be worth it, it all depends on the starting point.


Most other aftermarket parts, they're just total crap.
They don't perform, they don't survive the test of time and they can't even get the facts right as far as ratings go.

[user-23911]

I've seen a few stock factory conrods which have broken.

In every case they've bent before they broke.

Someone mentioned in another thread recently..........shot peening and polishing.
I think that one must be another internet myth too.
The idea behind blasting and polishing is to remove stress points where the cracks start.

But if they bend before they crack...........??????
(too much timing with E85 will do it.)
No, the tuner said it broke because it wasn't strong enough....lol




Then of course we get back on topic.
5140 (or 4340) rods.


You can get really cheap ones out of china.


Are they stronger than stock?
If so?
Prove it?
Just because the salesman says they are?


The only time I've ever seen a rod that shattered before it bent was a cheap china rod.
No doubt it was 5140. or maybe 4340?
Or just remelted scrap iron.


OK maybe it's like factory cranks that snap.
I've seen a few of those too.
They always shatter with no sign of bending.
Maybe it's just the luck of the draw and a small % of them are made with defects in them?...bubbles?
The broken cranks I've seen were all completely standard, jap diesels, different makes, different models.

[englertracing]

Those NASCAR rods would be PERFECT.
Grind the crank to sj, or Honda journal
Some of those rods have an edm oil hole which is really neat and cost serious $$$

[jeff swisher]

You talk of boost and got me to thinking how strong are the stock 4.8 LS rods that GM makes.

I have a friend that owns a dyno/ speed shop and they boost the snot out of these LS engines and The owner told me the 4.8 lives longest.
He said the fail point is the piston pin will get pulled through the piston.

The 4.8 can take more boost for longer than the others using stock parts..AND I mean stock parts.. the heads never been unbolted.
He has made just a tick under 1000 hp at the wheels with 29 psi through a turbo letting off 1000 rpm early. as he just wanted 24 PSI.


The tune is on the money.
Aren't those rods powder metal.. how strong are those? How strong are they compared to what you have.

Maybe it is the tune.
If they make 600 wheel HP from some used junk they are not even telling people because that saddens them to make so little power.

This is one little 4.8 never had the heads off before he really turned the wick up on it.
https://www.youtube.com/watch?v=62-VaoAw5qk
https://www.youtube.com/watch?v=Iyr41Srb4uY

[user-23911]

He said the fail point is the piston pin will get pulled through the piston.

Yes, I've seen that happen too, first hand (an import).

When there's insufficient piston to bore clearance AND the piston gets too hot due to a bad tune, the piston gets stuck in the bore and the crank pulls the pin out of the bottom of it.

But it's still not a fault with the conrod.


In my own case the rod broke but the bolts didn't.
So to me, that means that the bolts are sufficiently strong.
Therefore it's a waste of time and money swapping to something else.

[Krooser]

I'm using stock Mopar 340 bushed rods in my dirt car same as it had... Keeping the revs to 7K or so.

Saving the Pankls for the next generation build.

[cv67]

skip the SIRs....would cringe at the upgraded ones with 30 lbs of boost..

Just get the better ones put it together NA and go have some fun why risk the rest of the pieces going cheap on the rods?
Not giving you the answer you want to hear I know-

[Mark O'Neal]

30 pounds of boost on a SIR rod.

If someone would front the dough to do that on a motor with a clear (preferably Kevlar) oil pan.....I'd like to watch.

[novadude]

With 30 lbs of boost and high revs do you even need to worry about rods if you are running a stock GM 400 block? I would think that the block would be as much of a liability as the rods.

[pdq67]

OK!

Thanks and the SIR rods are out, so now does SCAT sell a LJ, 6.25" long I-Beam 4340 rod.

I think Big Joe 1 called them Pro Comp?

If so what is their part number and where can I buy them?

And thanks all for trying to keep me out of trouble, I appreciate it.

I am also just dreaming about the boost!

pdq67

[Racerrick]

6.2 is the longest Scat pro series I-beam rod so spend a bit more and buy 6.25 h beams rods

[pdq67]

6.2 is the longest Scat pro series I-beam rod so spend a bit more and buy 6.25 h beams rods

I do remember now, since SCAT didn't have a 6.25" I-Beam rod, I went with the SIR rod and flat missed their strength difference compared to the Eagle forged crank.
Oh, sorry, I just am not a fan of H-Beam rods and PM rods is all.

Thanks Racerrick for posting.

pdq67

[cgarb]

I did see the Eagle FSI part number you originally posted but only on eBay. Eagle didn't list that rod. It's either a typo on eBay or just not listed on Eagles website. I would call eagle and confirm from them direct. If the FSI is made in 6.25" that seems like your best option on a budget. Other than that be prepared to get your checkbook out.