This is the opposite of a recent post. I have put the manifold back on, torqued and tested with no leaks. I used Nord Lock washers to hold the bolts in place, this may be the issue. The theory is they will bite into the manifold and the bolt and the wedge lock design is supposed to prevent them working themselves loose. The problem is the Nord Lock bolt combination is not holding, the bolts are working loose. I also used a small amount of anti - sieze on the bolts.
The vehicle is a Cat 3126, the manifold is cast iron, and the bolts are a black stainless steel. I re-torqued the bolts to spec thinking that was just the gasket setting in. I cycled it again up to about 150 degrees F and the bolts needed about 1/15 turn to be back in spec. I then drove the vehicle about 12 miles, this was a full heat cycle up to operating temp for 15 minutes or so. Today the bolts were way loose, I had to torque them over 1/6 turn to get back to spec.
Question: Is there something about the cast and stainless being too hard for the Nord Lock to sink into the manifold / bolts? The torque is only 30 ft lb, this may be too low for the washers to work?
I thought and thought the washers were bi directional, they were independent of which side was up. Did I over think this?
I can remove 11 of the 12 bolts one at a time am remove the Nord Locks. The original bolts were held fast. I am thinking that this may be required.
Again, thank you all in advance.
PS The engine runs great and is quiet with the new gaskets. With the bolts working loose this is only temporary.
The vehicle is a Cat 3126, the manifold is cast iron, and the bolts are a black stainless steel. I re-torqued the bolts to spec thinking that was just the gasket setting in. I cycled it again up to about 150 degrees F and the bolts needed about 1/15 turn to be back in spec. I then drove the vehicle about 12 miles, this was a full heat cycle up to operating temp for 15 minutes or so. Today the bolts were way loose, I had to torque them over 1/6 turn to get back to spec.
Question: Is there something about the cast and stainless being too hard for the Nord Lock to sink into the manifold / bolts? The torque is only 30 ft lb, this may be too low for the washers to work?
I thought and thought the washers were bi directional, they were independent of which side was up. Did I over think this?
I can remove 11 of the 12 bolts one at a time am remove the Nord Locks. The original bolts were held fast. I am thinking that this may be required.
Again, thank you all in advance.
PS The engine runs great and is quiet with the new gaskets. With the bolts working loose this is only temporary.