I'm in the process of assembling my engine, and I'm having trouble with the 5/16 girdle studs breaking. I'm using an RJC girdle. The first stud broke off and fell out while I was rolling the motor over on the stand. The second started pulling apart while I was reassembling the bottom end (after removing the other broken stud). I'm trying to figure out why their breaking before I install the engine. Here's the process I used to install the girdle. Installed the main studs, main caps, shims, and girdle. Installed the oil pan rail studs finger tight, and then loosely installed all the washers and nuts. Then torqued the main stud nuts to 95 ft/lbs. After the mains, I tightened the oil pan rail nuts to 28 ft/lbs, per the installation instructions that came with the girdle. My torque wrench was calibrated a year ago and I use it on a daily basis and have never had problems with other stuff. I had a local machine shop do the machine work to fit the girdle. Anything seem wrong here? Do I need to get stronger studs? Are these going to keep breaking once I get the engine running?
Girdle studs breaking?
- Thread starter Kansas T
- Start date
Buickz
New Member
- Joined
- May 27, 2001
Torque the studs on the oil pan less than the recommended value in the instructions. I think I did mine to 25 ft/lbs. This was the recommendation of my local engine builder/machinist as they snapped off on him while performing the line boring. The studs are just too weak for that kind of torque. Also, many 1/2 and even 3/8 torque wrenches are very inaccurate at the bottom of their scale (usually around 25 ft/lbs) from what I have seen. So if you know anyone with a 1/4 inch torque wrench see if they will let you borrow it to do those studs. This torque spec has worked so far for me as no more broken studs and the motor seems to be staying together. If you can find them get stronger studs that will take the torque, but that is a lot of torque for a fastener that small no matter what material it is. Another thing, are you using any lube on the threads as this can change the amount of stretch on the fastener? ARP lube and even oil will necessitate a change to lower torque values as you will get the same stretch for a lower torque with lube over none. I had RTV all over mine in hopes to make a good seal and nothing else so... Hope this helps.
