head bolts vortech
- Thread starter schoffs4
- Start date
run the studs in hand tight. they have a little allen head on top to snug them in. using locite on the block portion is personal preference, i personally dont us it, just the ARP thread lube on the top end.
for head gaskets, use your favorite brand. Comtec, Fel-Pro, OEM, just use one that is a Multi Layer, and make for damn sure the machine shop did a perfect surface job on the block and heads.
for head gaskets, use your favorite brand. Comtec, Fel-Pro, OEM, just use one that is a Multi Layer, and make for damn sure the machine shop did a perfect surface job on the block and heads.
CobraRed_96_GT
Active Member
Saw this thread and had to throw my 2 cents in. Any time you are going to go boosted you need to use strengthened head studs, whether you get the ARP units or some other brand.
The stock head bolts are torqued to yield using published torque specs. What this means is you are tightening the bolt to the point where you are physically twisting the bolt....which is doing two things.
1. It is stretching the bolt, physically lengthening it.
2. You are physically changing the crystalline structure of the metal at a molecular level, this is called metal working.
Point number two will actually make the bolt stronger...initially. But in a boosted application you will quickly fatigue the bolt due to the much higher pressure oscillations.
Point number one will start you down a slippery slope, once the bolt is stretched, it is easier to stretch further. In fact it can stretch so much that under any serious level of boost it can actually stretch enough to lift the heads off the deck. Imagine the kind of problems this leads to....blown head gaskets, fluids mixing, destroyed bearings and pistons. That is assuming your rig doesn't try to compress water at some point. In other words, it will take down your mill real fast.
I had a built shortblock put in my rig that was supposed to have head studs....turns out that the builder decided to cut a corner or two and used factory bolts. Guess what happened to my motor?
If you want proof on a mass scale, look no further than the massive warranty claims that Ford and Navistar are dealing with in the 6.4 powerstroke. Navistar wanted to use head studs and Ford told them to use bolts. As a result, nearly 30% of these motors have lifted their heads off the deck.
So I guess my point is to never, ever, build your engine for boost without strenthening your fasteners. The $165 buck you spend on them is a drop in the bucket during the build-up, and can prevent some serious repair bills in the future.
Hope this saves you some money at some point.
The stock head bolts are torqued to yield using published torque specs. What this means is you are tightening the bolt to the point where you are physically twisting the bolt....which is doing two things.
1. It is stretching the bolt, physically lengthening it.
2. You are physically changing the crystalline structure of the metal at a molecular level, this is called metal working.
Point number two will actually make the bolt stronger...initially. But in a boosted application you will quickly fatigue the bolt due to the much higher pressure oscillations.
Point number one will start you down a slippery slope, once the bolt is stretched, it is easier to stretch further. In fact it can stretch so much that under any serious level of boost it can actually stretch enough to lift the heads off the deck. Imagine the kind of problems this leads to....blown head gaskets, fluids mixing, destroyed bearings and pistons. That is assuming your rig doesn't try to compress water at some point. In other words, it will take down your mill real fast.
I had a built shortblock put in my rig that was supposed to have head studs....turns out that the builder decided to cut a corner or two and used factory bolts. Guess what happened to my motor?
If you want proof on a mass scale, look no further than the massive warranty claims that Ford and Navistar are dealing with in the 6.4 powerstroke. Navistar wanted to use head studs and Ford told them to use bolts. As a result, nearly 30% of these motors have lifted their heads off the deck.
So I guess my point is to never, ever, build your engine for boost without strenthening your fasteners. The $165 buck you spend on them is a drop in the bucket during the build-up, and can prevent some serious repair bills in the future.
Hope this saves you some money at some point.
CobraRed_96_GT
Active Member
While he's right, these physics factors become a problem at higher boost, like he described on his built shortblock. Point to the person with stock internals running 400-440rwhp that is having problems related to their head bolt please.
Thank lots of good info i will use studs but arp head bolts are over 300 bucks where can i get them for 165? I want the best of everything i hate doing anything twice, but my pocket book giving me a hard time if ayone got sugestions of places to get what i need for a good price please let me know.
billfisher
Active Member
im using stock bolts. 525rwhp 03 cobra's use them. and im not going above 500rwhp.
edit: probably
edit: probably
Schoffs4, you are seeminly correct on the price. I guess I am just living in the good old days when materials were much cheaper (just 2 years ago).
I just did a new search and the best i could find was $345. I will keep looking around and if I find a good deal hear in the next 48 hours, I will PM you.
I just did a new search and the best i could find was $345. I will keep looking around and if I find a good deal hear in the next 48 hours, I will PM you.
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