Contour Enthusiasts Group Archives Forums Modifications Duratec Performance Just Nuts & Bolts but......

Just some random info you may all find useful.With many members working on engines/pulleys/dampers etc I thought it useful to add some info about what may only be understood as 'just nuts & bolts'.
A large number of the engine & vehicle parts on the Contour use 'yeld control' hardware.Yeld control methods of torquing replaced the conventional torque wrench on a lot of hardware on this car.I think you will find the crank damper pulley is one of them.Torque to yeld is a method where the amount of clamping load of the bolt/nut is maximised to the limit of the bolt/nut before it starts to stretch under excessive load,with me so far?Once a bolt/nut exceeds its elastic limit it starts to extend or stretch,as it does this the clamping load reduces.Some methods to tighten these bolts is based on angular movement,this is ok to a limited respect but does not tell you if the bolt has passed its 'yeld' point and is stretching.Most yeld control hardwre is tightented with a electronic 'SPS Wrench' which measures when the bolt when 'snug',then measures its torque Vs extension/stretch up to its maximum clamping load,a very exotic torque wrench.Please take care with yeld control harware,the conventional torque wrench or 'two grunts ' on a breker bar wont get it.If the bolt has gone into extension or stretch its clamping force will be reduced,the bolt is usless after it passes its elastic limit.Regards TAH

So for those of us lacking a NASA torque wrench, is there a physical effect that indicates you're about to induce plastic deformation? Perhaps a sudden increase/decrease in torque resistance, or a sound the bolt makes? Anything?

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Rob Weiss
'99 Mystique, 2.5L, MTX, Black, 20K miles
Build Date: Dec 98
Everything on it except factory CD player (good thing!)
Mods: Throttle Hang Fix, SVT Conical Intake
Future Mods: Ford Synthetic MTX fluid, Motor mount
Inserts
Far Future Mods: CD Changer in the glovebox
or good CD Radio

You could use the torque angle method but if you want to be 100% see if you can hire or rent the correct wrench or try your friendly tech at the dealer.My only concern and the reason I raised this is because a crank damper etc comming loose at 6,000 will make a bit of a mess of your engine compartment.

Terry-No disrespect but I think you mean "yield control" not yeld, don't you?

Same same!

Now that we've got that straightened out... I didn't replace the damper bolt when I installed my UD pulley. I've had the opportunity to check it at least half a dozen times and it has not backed off. Now I'm not disagreeing with Terry, but sometimes I think a little common sense is req'd for issues like this. When I replaced the clutch and had the flywheel resurfaced on my 5.0 Mustang I purchased and installed new flywheel to crank bolts. I figured that this was cheap insurance to keep both my feet attached to my legs next time I'm at the dragstrip. That or an aftermarket scatter shield/bellhousing. The Ford manual tells you to replace every freakin' fastener after removal. I think it's a bit of a ploy to keep the $$$ rolling in for service parts. If the customer questions this on the invoice, they can just show you the manual which of course says to replace with new fasteners!

Hey give the man a break, He is English and they slaughter the english language all the time . I should know, I work at a Ricardo facility and I can not understand them sometimes.
Just kiddin!!!!

Sorry,but I cant agree that 'this is just common sense' with some of the postings here re mods etc.As I said if the bolt has started to stretch its useless.Hey Onestep,do you know Bernard Ibrahim ? we worked on the Ford V12 project(ex manifold) when he was @ Ford and I was at Benteler.

I think the best way to handle this for a do-it-yourself (DIY) is to make sure you know the torque specs BEFORE you take it apart, replace with the exact same bolt (some can be re-used, like current mustang head bolts suposedly can be re-used like 5 times before replacing) but better safe than sorry, right. Anyway, then just use a quality torque wrench when reinstalling.

BTW, Terry, today we had a "farewell lunch" for a guy in my department who was moving to advanced engine and the Aston VO3 program (D&R for the V12)

Yep, know him. He works down in the Belleville office, only briefly met him.

[This message has been edited by onestep (edited October 09, 2000).]