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Valve Cover Bolt Sizes


10cjennings

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This thread was originally asking what to torque the Valve cover bolts down to, but I was able to find out the FSM recommends 7-12 Ft lbs. Well somehow with my torque wrench at 11.5 ft lbs one of the bolts snapped. It's getting dark so I'm going to start the extraction process (I think there's enough threads there that I can grab with a pair of plyers). But now I've got to find replacements for the valve cover bolts. I have no idea how that bolt managed to snap besides the possibility that it's an extremely crappy quality bolt, so I'm going to replace all 6 with something of high quality. What dimensions are those bolts? My car is a 78 280z with the original L28.

 

Thanks,

 

Chris J.

 

EDIT: Does 6x1.0mm Thread pitch and about 2 inches long sound right?

Edited by 10cjennings
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Was 11.5 ft-lbs at the bottom end of the range on your torque wrench? Torque wrenches can be very inaccurate at the end of their range. I think this is more likely than poor quality bolts.

 

The torque range is 5-80 ft lbs, it's a relatively new (Had it for about 8 months but it doesn't get all that much usage) Craftsman "Digitork Torque Wrench" (IMO A very high quality tool). I've never had any reason to suspect it of being in accurate. I'll run it by my local Sears and have them re-calibrate it for me just to be sure.

 

Luckily upon removing the valve cover I was able to easily unscrew the rest of the bolt, but I am wondering what could have caused this. Could have been a much more annoying situation if I was going to have to weld/solder on an extension to grip the bolt and turn it out or drill out and re tap the threads.

Edited by 10cjennings
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Those break all the time. Your specs seem correct. What I do is just take one with me to the hardware store. They usually have the thread checkers and comparing lengths is as easy as it gets.

 

Yeah, I'll be doing that tomorrow, as well as sourcing a new VC gasket (It got a little beat up in the process of removing the VC and I'd rather just replace it.

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