preload
Marine/Ocean
- Apr 12, 2007
- 176
Hi
I am new to this forum, but used to be in ROM (Read only mode). I am new to the fastening field but have quite a bit knowledge. My problem is we are yielding some bearing bolts right after installation on the cylinder block and crank case joint. I will provide you guys the info on bolt and joint parts and environment.
Bolt – carbon and low alloy steel flanged head 3/8-16 grade 8 bolt.
Joint – both cyclinder head and crankcase are made of Aluminum – copper alloy casting (soft joint compare to the bolt)
We also use a bead of gel seal in between the mating parts (cylinder head and crank case), when in contact, the gel seal uniformaly gets distributed on the mating surfaces. (making the joint even more soft?)
We make two engines V4 and V6. for v4 we have 6 bearing bolts and for v6 we have 8 bearing bolts. The tool used is two spindle dc electric torque angle monitor. For v6 We do bolts 1-2 then 3-4 then 5-6 then 7-8 and again do 1-2 (re torque due to elastic interaction) (I will try to upload a picture for better understanding)
Torque used is 31-15 lbs-ft on each bolt.Min proof load of the bolt is 9300 lbs.
Do you guys know why we are yielding bolts on a soft joint (if it is?)
I am new to this forum, but used to be in ROM (Read only mode). I am new to the fastening field but have quite a bit knowledge. My problem is we are yielding some bearing bolts right after installation on the cylinder block and crank case joint. I will provide you guys the info on bolt and joint parts and environment.
Bolt – carbon and low alloy steel flanged head 3/8-16 grade 8 bolt.
Joint – both cyclinder head and crankcase are made of Aluminum – copper alloy casting (soft joint compare to the bolt)
We also use a bead of gel seal in between the mating parts (cylinder head and crank case), when in contact, the gel seal uniformaly gets distributed on the mating surfaces. (making the joint even more soft?)
We make two engines V4 and V6. for v4 we have 6 bearing bolts and for v6 we have 8 bearing bolts. The tool used is two spindle dc electric torque angle monitor. For v6 We do bolts 1-2 then 3-4 then 5-6 then 7-8 and again do 1-2 (re torque due to elastic interaction) (I will try to upload a picture for better understanding)
Torque used is 31-15 lbs-ft on each bolt.Min proof load of the bolt is 9300 lbs.
Do you guys know why we are yielding bolts on a soft joint (if it is?)