I know this has been covered a million times but I suck at search and cant find it. I am bolting together my bottom end on a lq4 6.0. I cant find reliable info and torque settings. I am reusing the original bolts witch I read is fine. But torque values are all over the place. I have a angle gauge but folks say it can only be used with new bolts. Help?

 

Picture for reference

 

I use angle values when I reuse the OEM bolts. They’re not TTY bolts so you can reuse them. You do want to find out which rod bolts you have though. There were two different designs each with their own angle value.

https://help.summitracing.com/app/an...k-torque-specs

 

Can you please explain how "angle torque" is any different than TTY?

They BOTH use an angle value, but somehow, one is okay to reuse, but the other is instantly garbage afterwards.

For the record, I think TTY fasteners are a scam.

 

The TTY bolts are tightened to the point of plastic deformation, where they will not return to the original length once loosened. This plastic deformation point is like the tipping point before the bolt starts to “coke bottle” if you keep tightening it. Its also where you will get the maximum clamping force out of that grade and size of bolt.

The main and rod bolts torque to an angle, but the angle value is not enough to reach plastic deformation, so the bolt returns to its original length and can be reused with the same angle value. Bolts that tighten to a torque value (such as ARP) typically stretch to about 70% of what it takes to reach plastic deformation, so they can be reused over and over as well.

 

VERY well put! As clear an explanation as I've ever seen on this. Thank you!

 

Sorry, but how is this any different from TTY, which only gives angle specifications? How can you tell the difference?

 

In my apprenticeship, metallurgy referred to this as the elastic limit, beyond which a material cannot return to its original dimensions......

 

Well, in this case, OE bolts that are TTY do not return to their original size. So this is why they are supposed to be replaced, especially after being run for umpteen thousands of miles.
OP, FYI, this just may cost you more in the end. Best of luck.

 

TTY means Torque To Yield, and the yield point is pretty much synonymous with the point of plastic deformation. It can get a lot more technical, but it’s not really necessary to get too deep into it. TTA just torques to an angle, because it’s more accurate, but it doesn’t go all the way to the yield point.

I don’t think you can truly tell a difference other than what the manufacturer recommends, but I’ve noticed the TTY fasteners (headbolts) on an LS are all a lighter color than the TTA fasteners (rods, mains, rockers).

 

Yes sir. In my line of work, I got to see it tested in labs all over the world to make sure it’s done correctly. The testing rig will literally pull apart a piece of steel roughly .500” in diameter to find the ultimate tensile strength and then calculate the yield point from the stress/strain curve.

Someone posted awhile back and had test results on the different tensile strengths of LS headbolts, from the cheap ebay studs to the OEM bolts, and even the ARP. Really good info.

 

It was Jason from Texas Speed. They Did a Comparison with a 3rd party lab and posted the findings.

https://ls1tech.com/forums/generatio...ngth-test.html

It would be interesting to revisit as a few "New companies" have popped up. Xotic comes to mind

 

Yea, well, I have 2 ARP head bolts, from 2 different sets that broke before 65 lbs-ft and a few others from each set that are stretched almost to breaking point. These are brand new sets. So I put zero faith in the 200,000psi rating. I have yet to see a stock GM bolt break at all and the final torque yield on them aft the final 70* is roughly 85 lbs-ft

 

I posted this in the Gen V section today---

Got a surprise today. After seeing a lot of different torque values for ARP 2000 rod bolts and none of them were the same as the supplier that I bought the rods from, I decided to call Wiseco and see what they said. I have the LS Boostline rods with 7/16" ARP 2000 bolts. however, found out that they are not the same as the standard ARP rod bolt. The torque value is 30 ft# plus 50 degrees. They are good for 3 uses. I have a digital torque wrench that measures angle as well as providing a torque number when you hit the specified angle and the torque was a lot more that I would have expected for a rod bolt. Numbers were consistent, so I guess it's good. The Wiseco rep refused to give me a final torque number and said to use the angle method and a stretch gauge. You can only buy these bolts from Wiseco. More throwaway bolts!!

 

This is common in the race world. Some guys say they can reuse their bolts over and over. But how many times do they tear down their engines? Usually they grenade before they get to their 3rd tear down. Which in turn they have to buy all new parts.

But also when it comes to specific aftermarket bolts like rod bolts, the stretch method is the most accurate. Investing in a rod bolt stretch gauge is a good investment, not really that expensive and totally worth it in the end. That why it's always recommended to use that method first vs a torque value.
Forewarning, once guys know you have a stretch gauge, you'll be their new best friend.

 

Yep. Stretch was between .0048 and .0052

 

I'm not trying to be difficult here, but I still don't understand how the cylinder head bolts are TTY (using an angle method), and the main and rod bolts are totally good using an angle method as well.
I've been hearing for years that any fastener that uses an angle measurement for the final tightening sequence is TTY, and thus not reusable.

The only difference I see is that the cylinder head bolts have TWO angle specs, and the mains/ rods only have one.

For the record, if you look at the torque specs for GenV engines, there are a LOT of bolts that have angle measurements, and the first step is "remove and discard the bolt", and it's a 10mm bolt that couldn't be seeing more than 35-40 lb/ft of torque... Thus my assumption that TTY fasteners are a scam.

That, and I, and many other people have reused them with no ill effects.

 

Rods and mains are angle-torqued, BUT not beyond the elastic limit. They keep their original length when not torqued
Head bolts ARE angle-torqued beyond the limit, making them one-time use. After first use, they are longer than before torquing, making them nominally altered from new.

 

Sorry if I'm a dumbass, but then why don't we just angle-torque the head bolts and reuse them?

 

Re-read Post 6

TTY= Torque to the Yield point of the Fastener before Failure
TTA= Torque to a specified Angle to achieve a a specified Clamp Load but NOT to the limit of the fasteners Yield point before failure.