spectre6000
Well-known member
I'm asking here, because in my experience the GJ crowd on average seems to be the most technically savvy across the board and doesn't suffer quite as badly from tribal thought and weird inexplicable or overly irrational biases. If it weren't Sunday afternoon, I'd call the manufacturer, but here we are...
I'm doing a head gasket job on my truck, and it's the newest engine I've ever worked on (YMM is immaterial, but it's an '04 Dodge Dakota with a 4.7L V8). As such, it uses TTY head bolts, and it's my first time dealing with them.
I went through the torque sequence stated in the manual, and one of the final bolts in the series felt like it went plastic or started to shear for the last 2-3 degrees of the final step... To clarify, it's giving me resistance at, say 60 lb. ft. (who knows what it really was since it was the degree stage, but assume for the sake of clarification), then the torque required to turn the last few degrees felt like much less; maybe 15 lb. ft. or something arbitrarily and noticeably lower. Since it is one of the very last bolts in the sequence and fairly accessible, I could conceivably pull it and replace it with a new fastener, but I'd loose however long waiting for it to ship, never mind the cost of what would undoubtedly be a whole new set (about $50). This only happened on 1 of the 20 bolts. The rest behaved pretty much as any other head bolt I've ever used. For all I know, given the type of fastener and the theory behind it, it's supposed to do that, and the rest just didn't quite get there for some reason.
Obviously, I don't want to push it any further to see if I did actually feel it start to shear, but also, plastic yield is pretty much in the name of the type of fastener (and makes it super difficult to search for)... The manual clearly states (though I wouldn't do this personally) that a bolt can be reused if it doesn't appear "necked", so one assumes these things are coming OUT necked and it would have been functional in that state...
Who out there has a lot of experience with these fasteners in these applications that can tell me if it's acceptable for one to feel like it was starting to shear/give/go plastic/however you want to call it right at the end? If not, can I pull and replace that single fastener, or do I need to pull the whole set (and even replace the MLS head gasket) to avoid warping the head or something?
I'm doing a head gasket job on my truck, and it's the newest engine I've ever worked on (YMM is immaterial, but it's an '04 Dodge Dakota with a 4.7L V8). As such, it uses TTY head bolts, and it's my first time dealing with them.
I went through the torque sequence stated in the manual, and one of the final bolts in the series felt like it went plastic or started to shear for the last 2-3 degrees of the final step... To clarify, it's giving me resistance at, say 60 lb. ft. (who knows what it really was since it was the degree stage, but assume for the sake of clarification), then the torque required to turn the last few degrees felt like much less; maybe 15 lb. ft. or something arbitrarily and noticeably lower. Since it is one of the very last bolts in the sequence and fairly accessible, I could conceivably pull it and replace it with a new fastener, but I'd loose however long waiting for it to ship, never mind the cost of what would undoubtedly be a whole new set (about $50). This only happened on 1 of the 20 bolts. The rest behaved pretty much as any other head bolt I've ever used. For all I know, given the type of fastener and the theory behind it, it's supposed to do that, and the rest just didn't quite get there for some reason.
Obviously, I don't want to push it any further to see if I did actually feel it start to shear, but also, plastic yield is pretty much in the name of the type of fastener (and makes it super difficult to search for)... The manual clearly states (though I wouldn't do this personally) that a bolt can be reused if it doesn't appear "necked", so one assumes these things are coming OUT necked and it would have been functional in that state...
Who out there has a lot of experience with these fasteners in these applications that can tell me if it's acceptable for one to feel like it was starting to shear/give/go plastic/however you want to call it right at the end? If not, can I pull and replace that single fastener, or do I need to pull the whole set (and even replace the MLS head gasket) to avoid warping the head or something?
