Every time you loosen a bolt you take a chance on compromising the head gasket integrity, especially with the reputation of 6.0 heads to start with. It also gives the tech a chance to check the heads for flatness and correct any problems. Not to mention it's $200 cheaper where I sent him and the job will be done RIGHT.

 

I would prefer whoever that does the job not to do the job one bolt at a time and I will put in new gaskets to feel safer. I believe I'm going to put in black onyx gaskets, but I just found a oil leak coming from my oil pan or crank sensor. So I'm not sure if I'll have whoever fix my leak to put the studs in while the engine is out. I'm not having any problems with the studs, but would like to have it taken care of before I do have problems later. Thanks for everyone's opinions.

 

This is for information purposes only, I am not taking sides. The existing TTY bolts are torqued to 165 foot pounds. There are 16 bolts per head. 16 x 165 ft lbs = 2640 ft lbs of compressive force holding down the head. Taking out one bolt at a time and replacing it with a stud lowers the compressive force by 6.25% to 2475 ft lbs. Since there is no dynamic load on the head to lift it off the gasket, I see virtually no compromising of the gasket integrity. The added compressive force of the ARP studs when torqued to even the new figure of 210 ft lbs will squeeze the gasket an additional 21.5%. Not engineering, just simple math. I would like to see an engineers calculation of the forces I just described. It would be enlightening, good news or bad.

Regards

 

One, the procedure for torquing with bolts is 65 first in sequence, 85 next, then 3 times 90 degrees. This is done to bring down the head equally. The specs for max warpage is no more than .004. If you measure, the gasket with its multi-layer steel construction is .008 to .012. Removing a bolt completely can actually cause warpage. Many heads that have been replaced because of warpage were warped during the removal process. Has there been people that have done it with no problems, sure. In my opinion, its russian roulette to do it that way. The question for you to ask......are you prepared to take that chance?

 

The key to this is a tech that know how to do it properly --- that means using nearly the same (or close to) the torque of the removed bolt at first, replacing all the bolts in the same manner in the proper pattern using the same torque, then going back and retorquing them to the new torque.

In the hands of a skilled tech, the technique should work fine.

However, in the hands of many others, not precisely following the procedure for torquing right may distort the heads or otherwise stress the entire assembly.

 

I believe there are only 10 bolts per side.
So 10 x165 = 1650 ft lbs. of compressive force holding down the head. Taking out one bolt at a time and replacing it with a stud lowers the compressive force by 10% to 1485 ft lbs. The added compressive force of the ARP studs when torqued to even the new figure of 210 ft lbs will squeeze the gasket an additional 36.7%. Not engineering, just simple math. I would like to see an engineers calculation of the forces I just described. It would be enlightening, good news or bad.

I'm still nor convinced that this is the way we should be calculating the clamp force.

 

Headviking,

I agree, that is why I asked for an engineers calculations on something like this. I may see my Brother in law tonight. He is a metallurgical engineer for Ford. I may ask him for a simple formula that gets close at least. I did ask him about this before. His take on it then was where I formed my opinion. No dynamic lifting force and even 10% reduction in pressure would not let the head move enough to measure.

Regards

 

Oh, and you are right, 10 bolts per side. That's what I get for re-designing some handicapped restrooms and looking at FTE at the same time. I think I got the rest rooms right though

 

I think it is more like 165 lb/ft spread equally across the head. The torque does not multiply. But I could be wrong because adding 100 lb blocks into the box of my truck adds 100 lbs more weight to the tires each time I add another one.

 

One other thing that math can't compensate for is if you have a compromised gasket or head that has not blown yet. Does the unclamping/clamping seal its fate or help it? I am compelled to say that if you are not having a problem don't tempt fate. If you have a problem fix it right the 1st time. If I am going to get dirty it doesn't really matter if its for 1 day or 3.

 

How are you ever 100% certain there is not a problem if you can't see it? Like vlonely said you got 50/50 odds. Either it works or it breaks. I've learned that doing right 1time saves 2+ times half arseing it.

 

just how did we figure its only 165 ft lbs? I think its a little bit more then that.

65 ft lb, 85 lb, 90*,90*,90*.

 

Cheezit,

When I did put the Arp head studs in the new engine I checked the torque values on each head bolt before I loosened them. I started with my Snapon torque wrench set on 150 ft lbs. It clicked before the bolt moved so I stopped and reset to 155, then 160 and then 165. Still no bolt movement. At 170 ft lb setting thw bolt moved slightly before the wrench clicked. All did the same thing. I the surmised that the factory torque was between 165 and 170 ft lbs. If this method is not correct, let me know. Always looking to learn more.

Regards

 

I think I'm alittle confused now with all the math and I'm really glad that everyone has gotten so detailed. And I'll have so many questions for the tech. Isnt it better to replace the gasket while replacing the studs? I understand that its a big job, but I want to feel confrontable with my choice in how the studs are replaced and would feel better replacing the gasket also. Does anyone recommend a head gasket? Overall, should I replace the studs if I dont have a problem?

 

Since you are pulling the engine anyway and were planning head gaskets anyway the discussion is moot.