11mm Head Bolt Torque Spec/Procedure

[ArizonaBOSS]

Rob:

You mentioned in another post that you could get the head off in less than an hour, which leads me to believe you know how to re-assemble them as well.

I just got an Aluminator NA short block and I'm probably going to start putting my stock heads on it by Friday.
It is a 2014 block that uses the newer (and shorter) 11mm head bolts (compared to the longer ones that came in 2011-2012 engines).

Do you know the correct torque spec/procedure for tightening these 11mm TTY bolts?

I will be using the FSM procedures found here to re-assemble the heads onto the new short block (save for any difference in head bolt torque specs). http://iihs.net/fsm/?dir=823&viewfile=Engine.pdf

And WOW the stock bolts were scary to remove. Needed a breaker bar w/ a big cheater pipe to get em broken.

Thanks!

--Drew

 

[blacksheep-1]

Yes, as I recall they are torque-yield bolts, basically you torque them to a spec then go a specific amount of degrees past that. The bolts are used only one time for that reason. It takes a special tool to measure that, it fits on the end of the torque wrench. IMO a much better way to go is with ARP studs, I personally prefer a "clamping" method rather than simply bolting them on, the caveat with that is that it makes it a serious PITA to remove the heads in the car past the accessories because you have to have the room to pull the heads straight up for about 6 inches. So far no one that I know of makes the tool to keep the timing chains lined up so you can remove the heads without pulling the timing cover. They make them for the 2 and 3 valve engines but not for the 4 valvers.
BTW once you have the heads off go back and counter sink the bolt holes in the block, it doesn't take much but when you tighten things up it pulls the aluminum around the bolt hole up just a bit. Take a flat piece of metal and using some 220 grit sandpaper pull it across the block deck and you'll probably see what I'm talking about. This is another reason I like studs, they seem to pull from the bottom of the threads as well as the top.

 

[ArizonaBOSS]

Thanks for the quick reply!

Sounds like I need to call the FRPP tech line

 

[steveespo]

Thanks for the quick reply!

Sounds like I need to call the FRPP tech line

This is a good question, I bet the 4 stage , 30 ft/lb then 90 degree, 90 degree sequence is still correct but you never know. That does seem like a lot of torque, must be close to 200 ft/lbs. be careful you don't pull the engine stand over
Let me know the answer, I will most likely be doing this sometime in 2015.
Steve

 

[ArizonaBOSS]

The revision of the procedure is 2/2014 so I'm now guessing that what is shown is correct for the application.

 

[blacksheep-1]

This may hold some value for you and why I like studs over bolts

http://arpinstructions.com/instructions/256-4702.pdf

Do I need head bolts or studs for my engine?
It depends on the installation. On many street-driven vehicles, where the master cylinders for example might protrude into the engine compartment, it’s probably necessary to use head bolts so that the cylinder heads can be removed with the engine in the car. For most applications however, studs are recommended. Using studs will make it much easier to assemble an engine, as the stud will act as a guide, ensuring proper alignment for the head and gasket. Studs also provide more accurate and consistent torque loading. See page 38 of our catalog for more discussion on the topic. For help in deciding what is best for your application, please call our Technical Support desk at 800.826.3045.

http://arp-bolts.com/p/contact.php

Also...
The Torque Angle Method
Since the amount that a bolt or nut advances on the thread per degree of rotation is determined by the thread pitch, it would appear that any amount of stretch in a given bolt or stud can be accurately predicted be measuring the degrees of turn from the point where the underside of the bolt head or nut face contacts the work surface. Termed the "torque angle" method, this procedure has long been the standard of civil engineering. It has been suggested that torque angle is a relatively simple and valid procedure to use in "blind" installations—where it is not possible to physically measure the actual bolt stretch.

ARP has conducted extensive evaluations of the torque angle method, and concluded that – for high performance engine applications – it is suitable only when calibrated for each installation.

Our investigation has proven that installed stretch is dependent not only on the pitch of the thread and the degree of rotation, but also on the amount of compression of the clamped components, the type of lubrication, the length of the male fastener, and the amount of engaged thread. It's important to note that for the same degree of rotation, the amount of bolt stretch will be critically different between an aluminum or cast iron cylinder head, or when installing a steel main cap on a cast iron or aluminum block. Furthermore, there is a significant difference in stretch between the long and short cylinder head bolts or studs on the same head. The torque angle method can be accurate – but only if each individual application has been previously calibrated by direct measurement of bolt stretch. If you do employ the torque angle method, it's best to begin calibrating rotation from some small measured torque rather than the first point of contact with the work face. To achieve optimum accuracy, always use ARP Ultra-Torque® fastener assembly lubricant whenever possible.
http://arp-bolts.com/p/technical.php#p7TPMc1_3

 

[ArizonaBOSS]

That makes sense, they are referring to the inherent "spring" force of the two bodies being clamped.