arp head stud torque setting

[insomniacshotrods]

Its me again sorry have alot of questions. I called arp and they told me to torque head studs to 85 lbs with 30wt oil.. then i read alot of other post of the internet that said that was too high and one guy had valves leaking with aluminum heads at that rating , the head manufacture told him to go to 65 and that solved his problem. I just called arp again and told em i was using aluminum heads and he told me 5 lbs less with them but that it called for 90 so 85 would be correct with oil as lube. I seem to recall the engine i built right before the blower motor and it called for 75 lbs and i stripped some of the block threads. So i sent this block off to have it built. If i strip a block thread or more on this block im gonna have a melt down and have a fiberglass bonfire in my backyard lol...Thanks again for helping me through this guys.

 

[GT63]

Its me again sorry have alot of questions. I called arp and they told me to torque head studs to 85 lbs with 30wt oil.. then i read alot of other post of the internet that said that was too high and one guy had valves leaking with aluminum heads at that rating , the head manufacture told him to go to 65 and that solved his problem. I just called arp again and told em i was using aluminum heads and he told me 5 lbs less with them but that it called for 90 so 85 would be correct with oil as lube. I seem to recall the engine i built right before the blower motor and it called for 75 lbs and i stripped some of the block threads. So i sent this block off to have it built. If i strip a block thread or more on this block im gonna have a melt down and have a fiberglass bonfire in my backyard lol...Thanks again for helping me through this guys.

Are you talking about head bolt studs? The ones that go into the block and hold the heads down? If you're using studs in the block, you only need to coat them with thread sealer and screw them in a little more than finger tight. Once you slide the heads down over the studs, and install the washer and nut, then you torque the nut down to the torque spec of the head manufacturer. Edelbrock recommends 65 ft lbs for their aluminum heads. Make sure you torque them in the correct sequence. I like to start at around 30 ft lbs, then go to 45 ft lbs, then 65 ft lbs.

Now if you're using regular head bolts, that's different.

 

[one finger john]

First thing I would do is have your torque wrench calibrated and certified. And if it is off too much, step up and buy or borrow a quality wrench. I kinda like my old SnapOn wrenches, clickers, certified within a pound. 25 years old or so. There has been a great debate on the internet about torque values and lubrication. That can be discussed at another time. The thing I would do is take my time, set the studs up with the threaded portion flush with the block, sealer applied, let it set for a day so that the sealer is completely dry (you used laquer thinner to clean the threads before installing the studs, right?) Did I mention I am in favor of pulling the heads. Since your "pro" builder isn't there any more, left the state, divorce, I'd call it good insurance. Cost you the price of a pair of head gaskets. For the cost of a pan gasket, check the bottom end. And cam gear bolts. Up to you. All can be done with the engine in the car.

I've used WD40 on immaculately clean stud threads, 30 wt. oil will be fine. Don't forget lubricant between the washer and head and between the nut and washer. Check with the cylinder head manufacturer for recommended torque specs with ARP studs in a blown application. On head studs I would go half the value, then half of what is left, then half again, then half again. 80 lbs final would be 40 lbs first (after seating the head and tightening all head nuts finger tight, making sure the head is not hung on the dowls), 20 lbs next (60 lbs total so far), 10 lbs next (70 lbs total), then 5lbs (75 lbs total)and 5 lbs final (total of 80lbs) Then come back the next day and check at 80 lbs (might have loosened, might not) After initial heating/cooling cycles, at least two or three re torque studs. NEW studs will stretch some, I know, people will say that's a lot of torquing around, but it has always worked for me. Also makes the final torquing less scary than from say 60 lbs (it seems you just keep tightening and tightening and tightening ... and the wrench isn't clicking). Then you COULD put the blower manifold on, torque as needed, fill with water, and pressure test before proceeding. Should hold 15 lbs for an hour. Look for seepage around studs. If no seepage ... :hooray: You have a sealed package. On to the cam setting and final assembly.

John

Forum, anything to add or debate?

 

[insomniacshotrods]

Thanks all , Dart web site said for aluminum heads go 70# with arp studs or bolts. Might split it and go 75

 

[Screaming Metal]

The head mfg'er knows what his heads are designed to torque down to. If you use 65 with the bolts you can use 65 with studs. The block, nor the head 'know' the difference, aslong as its held down with the correct amount.
Now, with studs you get a better 'feel' on the torque....its being applied better. When you torque a headbolt, your draging and twisting agianst a cast iron head. This affects torque. On aluminum heads, you don't have that drag. Matter of fact, when you drop on that washer, put a few drops oil oil onto the threads of that stud, put that nut on and start torque'ing, the threads being oiled and the drag agianst the head is eliminated because the twisting action is being applied to a slick washer coated with oil and the slick underneath surface of the nut being torqued down.

I wouldn't suggest you over torque'ing your heads....thats asking for trouble. If you got Edelbrock heads, Edelbrock will tell you what you need as far as torque. If itwere me, I'd got stock torque for that head +5 lbs., but thats me....

 

[Screaming Metal]

Listen to what OneFingerJohn told ya....he has some good points there. Since You've already run the motor some....They might stretch some and loosen up, but I doubt it.

Like Mike said, you go to you pull the threads then back off. Essentially, thats what they do when they're trying to figure out thier installation process. But...YOU don't need to do this...just torque them to where they need to be. 85 seems like a bit much. Alum can compress, and studs will stretch, but since these holes have been used some....80 is really close to pulling the threads out....then its really fun!

I can say if you pull one out, chances are that they will be more than one try it on ya. So...should you ever experience this, and you plan on keeping your car for a long time....go ahead and heli-coil them all. Then you don't have to worry. If any of my blocks get messed like that, I helicoil it and I know its good. They'r expensive, but worth it....