ls1 rod bolts
 

I have a LQ4 out of a silverado HD thats going in my car. im converting it to a carb setup with a 2216 cam and springs. i also plan on putting a 100hp shot of nitrous on the motor for straights. i keep hearing that i should go ahead and replace the rod bolts while i have the pan off. ive always resized rods when changing bolts but i hear that i dont have to resize these because of the fact that they are powder metal rods. can anyone verify this or give me their insight on this topic?

I would never swap bolts without re-sizing. But that's me, as it's a big deal if you have to repair it later.

I've heard some do it with success, but not worth the chance to me.

Jody

rod bolts
 

Agreed... you SHOULD resize them, as most aftermarket bolts have a slightly larger knurl or shank area. Do this as a test- if you cant lightly tap the bolt in all the way, it needs resizing, as the bolt will push material toward the rod pin, which will slightly squeeze the bearing ends.

Honestly, have you called ARP yet? I had heard that they make a replacement bolt that you don't have to resize, but I have yet to install any. I like to use the Wave bolts, or Katech rod bolts- and true the rods at the same time.

Either way you smoke it, replacing the rod bolts is cheap insurance, as the factor LS pieces are not the best.

It is very common practice on LS motors. With traditional rods don't get the cap in the exact right place when you press in the bolts so you always need to resize. With LS motors the caps go back in the same place. Just make sure to do one at a time so you don't mix up the caps.

LS motors use bolts only no nuts

Here's the skinny on ls rods. Rod bolts are torque to yield so they are not reusable. The PM rods are cracked cap so they can't be resized. Measure your rods, replace any that are out of spec. Get a set of ARP bolts and get it back together!!

well i am NOT taking the motor apart. i was just planning on replacing the bolts while i had the pan off to put the new one on. i hear they are the weak link. just verifying that this is neccessary..

Absolutely positively replace the rod bolts with ARPs. It's a $75 insurance policy that will help save your motor, heads, valvetrain, block....everything that gets messed up when a rod lets go. With LSx motors, you DO NOT have to resize, just follow ARP's torque instructions and you'll be fine.

What he said, we have put the ARP rod bolts in 4 different engines, following ARP's torque directions. No issues with at 6800 rpm .

thanks for the info guys, had no idea they used bolts instead of the normal small block bolt and nut pressed in setup.

Jody

i swapped them and it was very simple. i just held the motor with a cherry picker and put jackstands under the mounts. no issues..:thumbsup: thanks guys

No problem!

I have an 08 L92, is it true the factory rod bolts were upgraded and less susceptable to breaking? Would changing the bolts still be recommended?

I would suggest leaving them alone "if" you know the motor was healthy when pulled.

For the power level you are after, they will be fine in stock form.

Removing them, resizing...etc, etc, will throw some money after something that isn't broken - imho.

Then...if you do break them, you get a great excuse to put the stroker crank in there! :thumbsup:

the LS rod bolts do not require re-sizing of the rods, so they're pretty cheap and easy to do. With that said, I did them on my LQ9 because I plan on making over 500 hp and felt it was cheap insurance.

Jody

So I pulled the pan today and spoke with ARP. They said there is no way of telling if replacing them would throw the rod end out of round. ( cracked cap rods are not resized ) I have the bolts, but I'm vacillating on if I should proceed. The engine is an 08 6.2 with SPS 12.9 bolts from the factory. I read somewhere that GM had upgraded the rod bolts sometime in the last few years. I have 5k on the engine and she put down 420 at the rear wheels, I do plan on making more power in the future.

Opinions?

What level of power is safe with a stock short block?

Edit:

Here is what I found, stock 12.9 bolts have an equivalent strength of 156,600 yield & 174,000 Tensile.

Arp 234-6301 bolts are 180,000 yield & 215 - 220 Tensile.

Increased rpm redline is the main cause of rod bolt failure.

I have decided to go ahead and replace the bolts. I will be using a stretch gauge, ( most accurate method ), and only loosen one bolt at a time.

I think either way you are okay. The reason I mentioned what I did, is there are many companies building super chargers, turbo chargers...and other head/cam packages that push LS power way up, and none of them "REQUIRE" a rod bolt swap.

We are working on a 700 rwhp single turbo 1999 Trans Am right now that has been flogged by the owner and is still sitting on the stock bottom end that has 140K miles.

If I had the engine out in parts and was assembling it...this is a no-brainer question. However...I too would be hesitant to disturb the apple cart if there isn't currently a problem knowing that there are plenty of motors putting down tons of power that have full stock bottom ends.

I wish I spent less time reading. Had I never read anything about the rod bolts, I would be fat, dumb and happy. :lol:

It is my understanding that the early LS1s were the problematic rod bolt engines. I have read and been told that anything after 2000 is upgraded from the factory and that ALL of the 6.0 and 6.2 LS engines are not a problem in regards to the rod bolt failures. However, any time an engine is pushing much over the stock horse power levels they should be replaced. So for the 08 L92 6.2 the stock bolts are fine if the engine will not be spun to the moon and the power level is kept reasonable.

But as stated above. They are cheap insurance any time the engine is apart.