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Discussion Starter #1
Hey there can someone tell me the torque wrench setting for head bolts on my EA Falcon CFI.
I have been told its 40Nm , but my torque wrench is in pounds.
And is 40Nm correct?
Thanks for any help
 

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BA'o'Matic 100% working.
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40 Newton Meters = 29.50 Pound Feet

No idea on the torque setting for the head bolts though. but the conversion is correct
 

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Discussion Starter #3
Thanks for the conversion Dellboy.
Now just need to find out what the settings are?
Cheers!!!
 

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By memory it's 75 Nm.....checking....OK the book says 40 Nm then 90 dgrees tighter. huh. Never done a head like THAT before, usually I just do what it says on the packet.
Doesn't it say on the head gasket packet?
 

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A few places now are giving just a specific one off torque (ie. JMM specify a one off figure) - not sure but I think it's something like 120 ft/lb - or that could be 120 Nm - check for sure because there's a BIG difference!.
 

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The book says 40Nm then 90 degrees......odd, couldn't they just get the final figure?
 

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They don't give a final figure because the head bolts are Torque To Yield (TTY) head bolts. They are NOT supposed to be reused and basically all new cars use this type of head bolt. It gives greater clamping and the torque setting is used as a start value and the bolt is then stretched by the angle rotation past its elastic point.

Replacements cost around $30-40 a set.

Also the given settings are correct.
 

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Two SC 61's = trouble
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Exactly::: It also takes away any friction between each bolt. So they are hopefully the same ..
 

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not ford said:
They don't give a final figure because the head bolts are Torque To Yield (TTY) head bolts.
AHHHH silly me forget they aren't reusable, thanks.
 

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Discussion Starter #10
Thanks Guys!!
 

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Yes - the manual specified procedure (with the 90 degree further past a basic setting) is a stretch torque type of deal, and as ebxr8240 says - it makes for very accurate final result. Don't forget that is a "wet" torque - ie. put some oil on the threads and also under the bolt heads - but make sure the holes in the block are pretty much clear of oil and/or water before putting the head in place.

When my original head (gasket) started to leak, I discovered when I removed it that the head bolts had been put in absolutely dry at the factory - both on the threads and under the heads - which is probably why the damned thing leaked (ie. the bolts couldn't have been at correct final torque because of the friction).
 

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TTY head bolts are supposed to be less affected by lack of lubrication. The factory normally uses a preset air powered torque wrench. It torques it to the specified value +- some tolerance. I believe it tends to be on the high side because mine were bloody tight and one was broken flush with the head deck.
 

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Yes, stretch tensioning (the +90 degree part of the specified tensioning process) is virtually totally unaffected by friction - which is exactly why it's used - but any error in the basic (40Nm) setting will cause a much greater error after the stretch process than the original percentage of deviation was. The basic setting is specified as a lube torque precisely because it's pretty important for it to be accurate - if it's done dry it almost certainly won't be correct.

When I undid those original factory bolts they definitely felt harder to turn than I've subsequently experienced with bolts that had evidently been lubricated - but interestingly enough, those dry bolts came loose with much less rotation than the lubricated ones did - they most certainly didn't feel to have had as much stretch (over a period of 18 months I did 3 I6 head changes).
 

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The original threads are coated with a sealer and I guess it dries somewhat...

Any way imo its the "expantion of alloy" at every start or heat cycle that over time weakn's the bolts elasticity..Then clamping force is so low that gasget leaks then eventually blows..
 

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Discussion Starter #15

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I and others have found through experience, that the 30ft/pounds and then 90 degrees, does equal to somewhere around 75 ft/pounds, but i have for a long time started tightening mine to 100ft/pounds, and have never had a problem, i always use better quality bolts thou, not the ford ones as they have been known to break.

I discovered this after blowing many a head gasket when i first turbocharged my motor, i then started tightening it to 100ft/pounds and have never since had the problem.

The bolts are touque to yeld and strech when normally on a motor with the heads expansion as it gets hotter, i personally believe that the orginal 90 degree isn't enough pressure after the bolts have strecthed and that is why the 100ft/pound method seems to work.

If you go by the book, and tension them to what it says you won't have any problems if you retension your head, twice. first after two weeks second after about 20,000km's or 6 months. and even maybe again for the people getting up to the 150,000km area to do it again wont hurt.
 

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not ford said:
They don't give a final figure because the head bolts are Torque To Yield (TTY) head bolts. They are NOT supposed to be reused and basically all new cars use this type of head bolt. It gives greater clamping and the torque setting is used as a start value and the bolt is then stretched by the angle rotation past its elastic point.
You're basically right but it's more for an even force clamping throughout the life of the gasket - so you don't need to re-torque the bolts after the gasket settles to maintain the pressure.

You can usually get away with re-using the TTY's but for $40 a set why bother? Could be buying a whole heap of trouble! I just wish you could get the old non-TTY's for that price - here in NZ Ford want $12 for EACH of the 13 fekin bolts! Needless to say I only replaced the ones that didn't look mint.... and kept the rest of the cash for beer...mmmmm
 
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