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View Full Version : Head bolt torques. M50 2.5


whiskychaser
06-07-2007, 05:28 PM
No I'm not being a lazy person -search button doesnt work! :-) Standard instructions are 20nm first torque, then 90 degrees then another 90 degrees. My torque wrench is good but doesnt even start till 28. I'm sure I've seen 3 stages of torque in nm on here somewhere. I've got them at 120nm at the moment. That feels like more than enough for an ali head. Anybody put me right?
winfred
06-07-2007, 08:37 PM
i don't know about nm but it's 22 foot pounds and 90 degrees, then another 90 degrees, it's not good to over torque these bolts because they will break as they are designed to have a certain amount of elasticity to deal with the differences in expansion of the head and block
whiskychaser
06-11-2007, 09:12 AM
i don't know about nm but it's 22 foot pounds and 90 degrees, then another 90 degrees, it's not good to over torque these bolts because they will break as they are designed to have a certain amount of elasticity to deal with the differences in expansion of the head and block

Take your point. Wouldnt be a good move to wreck the head for the sake of a new set of bolts. Got a new set on way together with a torque wrench complete with accuracy cert. I'm sure the bolts that came out originally didnt have washers under them. But I just noticed real.oem do show them. Assume this is to spread the loading. Any advice on which is correct plse?
Dave M
06-11-2007, 11:01 AM
Take your point. Wouldnt be a good move to wreck the head for the sake of a new set of bolts. Got a new set on way together with a torque wrench complete with accuracy cert. I'm sure the bolts that came out originally didnt have washers under them. But I just noticed real.oem do show them. Assume this is to spread the loading. Any advice on which is correct plse?

If you're asking whether washers are supposed to be present, the answer is yes. Rather than the dealer (if its a PITA) you might try to get them at a fastener shop. Just make sure they aren't el' cheapos as they take quite the load.

Dave
whiskychaser
06-11-2007, 11:44 AM
If you're asking whether washers are supposed to be present, the answer is yes. Rather than the dealer (if its a PITA) you might try to get them at a fastener shop. Just make sure they aren't el' cheapos as they take quite the load.

Dave

Thanks Dave, Thats just what I wanted to know