Ls main caps

[bssmith11]

I am reassembling my 5.3 lh6 and I am keep breaking main cap bolts. I've bought new bolts still same result. I'm using the correct torque specs and sequence. Any help would be appreciated!

[user-17438]

Where are they breaking? Is there debris in the threads? Are you using the wrong lube?

[DaveMcLain]

I am reassembling my 5.3 lh6 and I am keep breaking main cap bolts. I've bought new bolts still same result. I'm using the correct torque specs and sequence. Any help would be appreciated!

What are the torque specs that you're using?

[bssmith11]

15ft lbs + degree

[bssmith11]

15ft lbs + degree

[bssmith11]

Where are they breaking? Is there debris in the threads? Are you using the wrong lube?

The threads are clean . I thought I've read not to lube the bolts? They are twisting off into the block.

[user-17438]

With my digital torque wrench they are usually torqued about 60-63ft/lbs at the correct angle. They shouldn't come close to snapping at that torque. Check your torque wrench. Try torquing them to 15 then re-set torque wrench to 60 and see how close it clicks at the angle you need.

[peejay]

I bought a torque wrench from Summit and it's prety far off in the forward direction, with the lowest error at the 80lb range where it's only 10% high. At 25lb it actually torques to 37 or so.

Now that I know that, I can adjust for that. And check it frequently against the load cell to monitor calibration drift.

[MadBill]

I regularly verify my clicker TW against my beam wrench. The latter, as long as it is zeroed, the needle doesn't bind in the slot and the handle is swiveling freely can't be out of calibration.

[Newold1]

Why fight with a break the factory bolts. Make sure the threads in the block are clean and properly lubed. Buy and use a good set of ARP main stud kit and torque with a calibrated torque wrench to the specified torque settings from ARP.

[ProPower engines]

GM supplied bolts or cheap aftermarket replacements??

[bssmith11]

Gm bolts. I'm using a craftsman digital torque wrench.

[pamotorman]

I had this happen one time. I switched from oil to moly kote as a lube and the first main stud i torqued snapped off. after drilling it out I went back to oil

[bssmith11]

Everything I have read was to install them dry.

[Warp Speed]

Everything I have read was to install them dry.

That would be your problem. Unless the bolts come coated. Even then, you are using a light initial torque, followed by an angle schedule. Pretty tough to over lube (too slippery) it, as it will have little effect. No lube could cause your problem for sure.