Why do my header bolts keep coming lose?
#25
Here's the why the little bastards back out.
Most headers have a raised section around the tube to thelp the gaskets seal. Problem is when you tighten them, the flange bends towards the head. The pushing back, pushing on the bolts is what keeps them tight. Then the first heat cycle, heats up the flange, and the metal relaxes. Nothing is pushing out the bolt, keeping it tight anymore. If you don't catch it soon enough, this is when you will start to notice them back out. So you keep tightening them unitl the flanges are done stretching.
Our header stuff, we use .500 thick flanges. Weld the tubes on the inside and machine the headers flat. When you go to put them on, you use a little orange rtv, no gasket. Snug it up in any order. Come back once you did it once right after and do it again. Sometimes the rtv squishes, and only feels tight. If you come back, you can sometimes get another 1/16 of a turno out of them. Only need to be tighetened to 15-20 ft/lbs or so. Not much. They don't flex, so you don't need to retighten. Hope this long drawn out explaination helps.
Most headers have a raised section around the tube to thelp the gaskets seal. Problem is when you tighten them, the flange bends towards the head. The pushing back, pushing on the bolts is what keeps them tight. Then the first heat cycle, heats up the flange, and the metal relaxes. Nothing is pushing out the bolt, keeping it tight anymore. If you don't catch it soon enough, this is when you will start to notice them back out. So you keep tightening them unitl the flanges are done stretching.
Our header stuff, we use .500 thick flanges. Weld the tubes on the inside and machine the headers flat. When you go to put them on, you use a little orange rtv, no gasket. Snug it up in any order. Come back once you did it once right after and do it again. Sometimes the rtv squishes, and only feels tight. If you come back, you can sometimes get another 1/16 of a turno out of them. Only need to be tighetened to 15-20 ft/lbs or so. Not much. They don't flex, so you don't need to retighten. Hope this long drawn out explaination helps.
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08-20-2015 11:34 PM