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Discussion Starter #1
Hi Guys

I'm helping a friend doing an engine valve replacement on a 2005 Focus II 1.4L and would like to hear some expert opinions re. the following -

i) Do you put in the new cylinder head bolts dry or would it be better to apply a bit of lubrication ? Haynes and the online Ford Workshop manual do not mention lubrication and I was wondering whether this is done deliberately to ensure the correct tightening torque.

http://workshop-manuals.com/ford/fo...dures/removal_and_installation/cylinder_head/

ii) According to Haynes, the new crankshaft pulley bolt (M12 x 29mm) needs to be torqued to 40Nm + 90deg. Reading some terrible stories about the bolt coming loose, I am having cold feet about this as I'm not sure if the recommended torque setting will produce enough clamp force to hold everything in place. As you know, the crankshaft / pulley assembly has no key so the bolt clamp force is your only grace here. The bolt itself is a 10.9 grade (and I think with a pitch of 1.75) which is supposed to withstand up to 126Nm of tightening torque. In addition, Ford's online manual gives a tightening torque of 45Nm + 90 deg which is confusing things even further. I'm also assuming that this bolt should be installed with dry thread and without any thread lock compound.

iii) My final question is about the new coolant pump that we just installed. Is it normal for it to be quite stiff to turn as the old one can rotate quite easily. The new pump is still dry so could it be that once it gets in contact with the OAT coolant, it will ease off ? I'm concerned that the resistance of the new pump would put additional load on the crankshaft pulley and therefore the pulley bolt.

Many thanks guys and as I said, would really appreciate your feedback.

Cheers
 

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Welcome to FF!

I'm sure you'll be fine not lubricating the bolts before installation. The torque plus angle system is planned to result in the correct clamping force with less chance of errors that can be induced by variations in torque procedure on one hand - and the imprecision of torque specs. when using head bolts of the "torque to yield" type on the other.

Without trying to get TOO deep into it, the initial torque steps for either of the bolts you mention are planned to snug up the parts securely before the final angle turn that applies the planned clamping force. Thread pitch plus the angle of the turn combines to stretch the bolt a calculated amount as it clamps parts together, and for the head bolts compresses the gasket.

New water pump will be stiff out of the package, water seal does turn easier once lubed by coolant. It's something you wouldn't want to run dry before adding coolant to the system, not for the extra drag but to prevent damage to the seal.
 

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Discussion Starter #3
Thanks sailor for the kind greetings and the very useful input. As you well point out, I was also inclined to install the bolts with dry threads but with so many divergent opinions on this topic, one's head start to spin really fast. For instance, reputable vendors of head bolts such as Victor Reinz and Elring seem to insist that you slightly lubricate the stretch bolts to control friction. Maybe these are only generic guidelines and are not meant to be specific to every application. I'll go with the dry thread and hopefully things will work out well.

I note also your comments re. the crank pulley bolt and the coolant pump. I referred to various online sites where you can calculate the clamping force in relation to the applied torque and 40Nm + 90deg seem to produce some very significant clamping. Theory aside, I still cannot understand how some of these bolts are reported to come loose when renewed and torqued properly. I also couldn't find any advisories from Ford in this regard so it looks like the 40Nm + 90 deg setting still holds.

Well, that seems to be all for now.

Thanks once again sailor.

Cheers
 

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Ah yes, it does become a sticky wicket with conflicting info..

I wouldn't disagree with the sources you mention, "light lubrication" isn't really in the same category as well lubricated/greased/never seized. Even the light film to prevent corrosion you find on many bolts & is likely to remain in case holes may be adequate, degreasing to create an absolutely dry contact surface wouldn't be appropriate when screwing into the case in particular (steel on aluminum).

I'd wonder at stories of the crank bolt coming loose when renewed & torqued properly myself. Haven't seen those here, in fact the stories we see most often (including from the UK) are of bolts extremely difficult to remove.

Cheers
 

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Discussion Starter #5
Both Reinz and Elring recommend LIGHT lubrication only - I think a little bit of 10W/30 engine oil will do. Reinz shows a clever way to do it in order to keep the coating even and at a bare minimum - put some oil on a rag and roll the bolts in the rag. That should suffice I should think to overcome the friction coefficient of the threads and contact surfaces. You made a good point actually about degreasing the bolt holes, which I did with solvent and air gun. Hmmm, that will probably change things a little bit for me now 'cause I'm sure that I removed any traces of lubricant in there. And as you say, we're talking about steel on aluminium. The Reinz method is gonna be then, using clean engine oil. There's a good write up here on the subject matter and it seems to say that engine oil does not have a noticeable effect on the bolt tension unlike products like anti-seize compounds - http://benmlee.com/4Runner/threads/threads.htm

Speaking of aluminium, I remember I read somewhere that with some minor exceptions, all the Focus engine internals are made of aluminium. Haynes certainly makes this claim. Would that also include the crankshaft ? I only have access to the crank nose but I can swear that it's made from polished steel. Would that be correct or is it some kind of hardened aluminium alloy ?

Cheers
 

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Wiping with a rag sounds perfect, good way to get that light coating.

ALL internals is a bit excessive, crank is definitely NOT aluminum! Cast iron like most AFAIK, there are very few exceptions to that.
 
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