50Trucking
Member
My main bolts are square and I can’t get 90 lbs of torque before the edges of the bolt head shear off with a 16 point socket.
Main bearing bolts
- Thread starter Geo.T
- Start date
oldspert
Senior Member
Buy a 9/16 square point socket.
Bruce of MN
Well-known member
I can’t remember, can you get a crowfoot wrench on it?
Flathead
Well-known member
The original bolts were a snug fit in the block. You would tighten up the nut, after positioning the cotter pin hole in the bolt for best installation. This snugness is what centers the main cap on the block, there are no dowel pins or other methods to keep the cap in position. The popular grade 8 bolts are looser in the block and do not center the cap. Just something to think about.
Bob Bidonde
Well-known member
Torque of a structural joint should be to 75% of the bolt / stud yield strength. This reduces the alternating stress range (varying tension) induced by the reciprocating parts in the engine. Reducing the alternating stress range significantly improves the joints fatigue life.
There should be nothing in the joint that compresses before the bolt / stud reaches its maximum loading. If there is, the joint looses its preload and the strength and fatigue life of the joint is threatened.
I strongly suggest that the original joint design should not be altered by the addition of any none stock parts.
Oil leakage from the exposed nuts is rare in my experience, but can be easily sealed by coating the nuts with an epoxy paint like POR15.
There should be nothing in the joint that compresses before the bolt / stud reaches its maximum loading. If there is, the joint looses its preload and the strength and fatigue life of the joint is threatened.
I strongly suggest that the original joint design should not be altered by the addition of any none stock parts.
Oil leakage from the exposed nuts is rare in my experience, but can be easily sealed by coating the nuts with an epoxy paint like POR15.
Last edited:
nkaminar
Well-known member
On my Burtz block I used some O rings that had a small (thin) cross section. They were completely compressed into the hole so that the fastening was metal to metal.
All steel has very much the same coefficient of elasticity up to the yield point. It is 30,000,000 psi. The grade 8 bolts have a higher yield point than grade 5 or lesser grade.
All steel has very much the same coefficient of elasticity up to the yield point. It is 30,000,000 psi. The grade 8 bolts have a higher yield point than grade 5 or lesser grade.
Dan McEachern
Senior Member
Are you guys really pulling main bolts to 100 ft-lbs ???????????
Gene F
Well-known member
What Bob said goes for me too. I have a center pressurized main in my engine, and the microscopic amount of oil that may get past the shank of the bolt is insignificant. In fact, I have never even noticed such a thing on my car. I used to fix things (and equipment) for a living. We used to say tinkeridus has ruined a lot of equipment.
Just put the engine together, do a good job, and go on. No magic washers needed.
Just put the engine together, do a good job, and go on. No magic washers needed.