Are ARP Head Studs Overrated for our stock engines with stock boost???

[cheap bronco]

I apologize in advance for it, but read my question to the end before raising your blood pressure. I also have ARP head studs on my 7.3 idi, but do we really need them if we do not race or run stock boost on our engines? I also have a 2002 7.3 powerstroke and it boosts between 20-25 psi stock depending on load and incline, now it has headbolts from the factory with 125k. our engines run what a lousy 6-8 psi stock and I guess the thing to do is get studs for a lot of people as well as myself but now looking back I should've kept the $500, since I still developed a headgasket coolant leak with a stock psi turbo. Im not stating its because of the studs, but I was under the impression that studs have a tighter clamp on heads. now it could be just a bad gasket but I will report back after I tear into it this weekend. Im not knocking ARP studs, sure use them if you race and tow a train, but if you are the average joe like myself that use the vehicle for light tows and hunting I think regular head bolts will suffice. speaking of head bolts you guys say do not reuse them, if not where should I get news ones from that are not made in Eggroll land. I have 2 sets used, but im putting a spare motor together and need new ones if its not ok to reuse the old ones. Thanks in advance for everyones input

 

[icanfixall]

The decision to reuse head bolts or use neww ones or upgrade to ARP studs is completely a personal choice. This is what your looking at. A stock new head bolt breaks at 154,000 lbs as per the Stork Engineering testing shop I had run the test on. they are a nationally know lab that does plenty of testing for NASA too. The breaking psi on a used bolt is not known for good reason. What condition is the used bolt in and. Has it been over torqued. The ARP studs break at 200,000 or 220,000 lbs. Depends on when you bought a set. Is it worth it to increase the clamping force by 460 to 66 thousand pounds.. I feel it is. When we increase the clamping force on the head gaskets we are adding some insurance they stay sealed. Now to add one more item. My original engine had nearly 300,00 plus miles on it with one original head gasket and no leaks.. Ever. I cavatated cylinder 8 so it was sleeved there. The shop would not replace the passenger side head gasket no matter what. I believe they hoped I was coming back for the passenger side and charge me big labor for it too. Well f..u... I never went back because that side never failed. They took a chance on big labor but failed to get it. With the engine out they had a chance to increase the labor but choose not ro. So they lost big time.. Should you use studs or new bolts or even used bolts... Personal choice...

 

[88 Ford]

To be honest its somewhat odd that you popped the gasket at such low boost. The the head and block surfaces for flatness. Other than that you just might have been unlucky and got a bad gasket.

 

[typ4]

If I had a ****** engine I would and did reuse stock bolts, ran them 5000miles at 12 -18 psi of intercooled boost, collapsed a piston ,when I fixed that I researched the studs , installed them and never looked back.
I would do a very good inspection on the used bolts, and if you want a set with 500 miles on them pm me Ill make you a deal, and they are not crap bolts.
Get your spare engine lightly decked and the heads also then sink the valves a bit, I think all these blocks and heads need a light skim by now to hold a gasket.

 

[FORDF250HDXLT]

I apologize in advance for it, but read my question to the end before raising your blood pressure. I also have ARP head studs on my 7.3 idi, but do we really need them if we do not race or run stock boost on our engines?

no.this has been proven via multiple combined millions of miles that have been put on turbocharged 6.9/7.3l idi's since the 80's with no common head gasket failures related to boost pressure.this fact will never change.

 

[NTOLERANCE]

I also have ARP head studs on my 7.3 idi, but do we really need them if we do not race or run stock boost on our engines? I also have a 2002 7.3 powerstroke and it boosts between 20-25 psi stock depending on load and incline, now it has headbolts from the factory with 125k.

IDIs to power strokes is like apples to tomatoes.


Both round and red, but the insides.....whoowee.

Even when you take away the electronics, its a completely different animal.

But, I digress, your original question seems to have been answered.

edit: what head gaskets did you use?

 

[PwrSmoke]

There is no "stock boost" on a 6.9L IDI, and also not on a 7.3L except for the '93-94 factory IDIT which had 1/2" head bolts, used a better head gasket, pistons, rods, exhaust valves, etc. And all that to run only 2/3s the boost of an aftermarket bolt-on turbo system.

IMO, running a 6.9L with a turbo and no studs is problematic due to the small head bolts. If you drive easy, yada, yada, you could scrape by. Head gasket issues are common enough with these engines to make a wise person think ahead and get the best setup possible. If the budget doesn't support ARPs or another stud brand, then at least go with new OE style. IH intended them to be replaced this way.

I've had a Banks kit on my truck since '87 and it makes from 10-14 psi boost. The truck is well maintained. About 80K of it's 140K total miles were towing/hauling and when a head gasket blew spectacularly in '08, the heads were a mess. You could see they had lifted many times and when I measured the head bolt lengths, some were lots longer than the others, indicating stretch. I had replaced the head gaskets in the mid '90s due to an external oil leak. I recently found my receipts for that and was surprise to see I had the heads surfaced then and the valves touched up. I didn't remember that (must be getting senile ( : < ) but once I saw the parts (I used new bolts then, following the recommendations of many at the time) and machine shop receipts, I remembered seeing the head surface was fretted and eroded, again an indication of head lifting under boost. THE ENGINE ONLY HAD ABOUT 50K ON IT THEN, about 43K of those with the turbo and almost all of those were towing miles. That is an indicator to me that running 10+ psi boost with a 21.5:1 CR and working the truck like it was designed to be worked puts a lot of stress on the head gaskets and wimpy little 7/16" 6.9L head bolts. This story has been played out many times, here and elsewhere.

A 7.3L... a little more beef on the 1/2" head bolts, maybe they are "more OK" to keep. I don't have a strong opinion here because I have very little experience with the 7.3L but if I had a 7.3L, I would still budget the money for studs or at least new head bolts.

I'll go into old guy mode here and proffer the advice that when it comes to working on engines (and I did it professionally for 20 years before changing careers), I have always regretted most what I DIDN'T do when I tried to scrape by.

The thing you need to bear in mind here is combustion pressure. You compress a load of air and fuel 21.5 times in that combustion chamber. At sea level, you have around 14.7 psi atmospheric pressure filling the cylinder to around 85 percent capacity. Add 10 psi boost and you have filled the cylinder to 150% and if you add the appropriate amount of extra fuel, you have a much bigger "boom." You can calculate combustion pressure but my head hurts just thinking about it. Wallace Racing (http://www.wallaceracing.com/dynamic-cr.php) has a great dynamic compression ratio calculator, which will show you the dynamic compression/pressure (engine running it's cycle but not firing and the effective compression ratio factoring in cam timing). On a stock 21.5:1 NA engine it's 19.44:1. If you factor in 10 psi boost, you get a 32.66:1 ratio. And that doesn't factor in the effect of the extra pressure of the increased air/fuel charge and I submit that a turbocharged 6.9L is running right at the design limits. If you run easy, no trouble is likely. Run hard, you are reducing long tern reliability.

 

[ToughOldFord]

The IDI did not use 'torque to yield' head bolts, there is no issue with reusing cleaned and oiled head bolts:

http://freeasestudyguides.com/a1_4.html

 

[icanfixall]

The IDI did not use 'torque to yield' head bolts, there is no issue with reusing cleaned and oiled head bolts:

http://freeasestudyguides.com/a1_4.html

This statement needs some clearification. Clean threads where.. Better be both the bolt and in the block but do not chase the threads with a die nut on the bolts. those threads are rolled and not a cut thread. What condition are the used blts in. Check them for stretch and look over the shanks for rust and pits. Any pit found will compromise the integrety of the bolt. Oil on the threads is very important but so is under the head of the bolt and against the washer to head surface too. Oil is breaking down the friction created by the torque. Now who really does all this.. Not many I'm sure. Its really too bad International didn't use 9/16 inch diameter bolts in the 7.3 and 1/2 inch in the 6.9. I feel then studs would not be a need but a desire. I am glad our studs can be removed easily too. Trying to clean the block head gasket surface would be terrible if they were not easy to remove. I know a private shop that "claims" to have never had an idi come back for a blown or leaking head gasket and they reuse the head bolts on both size engines. Thats what the owner tells me but he might be flying the BS flag too. I just can't prove it one way or the other...

 

[Knuckledragger]

To add my own two cents, I will focus only on the bolts versus studs. There are several reasons not to reuse head bolts, although you can do so safely if you choose. One is that the bolts were designed to stretch on the first torque and that stretch is not repeatable. Kind of like pulling a plastic bag apart. You can get it to stretch to a certain point, then it just tears. An if you don't tear it apart, it stays stretched out. Same with the bolts. They are stretched out after one use, but can be reused if you are careful and don't go crazy with torque.

Another item is the length of the bolts compared to their diameter. I am really disappointed that IH used 7/16 bolts that are so freaking long. 5 1/4 inches? Really? Anyway, over that length, you have to overcome a lot of friction (on the threads) while torquing them down, and that creates a twisting effect on the bolts that does not ever occur with studs. This is yet another failure point that could occur when reusing bolts.

A third, as I was reminded by Gary's (icanfixall) post, is that unlike almost any other engines, some of our head bolts are exposed to the atmosphere all of their running life and will definitely encounter oxidation. If you decide to reuse your head bolts, you should at least replace the lower bolts that have been compromised.

The main advantages to using studs, even if you never put on a turbo, is that they are stable and create a much better clamping force than bolts ever could.

The automakers will eventually use studs again (remember flat head engines? All studs) to hold heads on engines, but they have to be presented with a financial advantage that bolts currently hold because studs take more time and steps to install, and cost more to produce (with a separate nut and twice the threads). So, we are left with buying aftermarket studs to get the best performance and clamping power, but bolts will do the job - just at a slightly lower performance point.

 

[PwrSmoke]

The IDI did not use 'torque to yield' head bolts, there is no issue with reusing cleaned and oiled head bolts:

http://freeasestudyguides.com/a1_4.html

Nobody said they are TTY bolts, just that they are small, weak bolts and there are too few of them for a turbocharged engine. OK for an NA engine but they may stretch when you put the engine under boost, release the clamping pressure, allow for combustion leakage and the head gaskets are more prone to completely fail. In a way, it's a similar problem that Ford had with the 6.0L. Fine for stock applications but when modified, not quite enough bolts to hold the heads down tight.

PS- And I agree with the above, they tend to stretch even when used normally, and that weakens already weak bolts.

 

[jaluhn83]

Depends - how lucky do you feel?

With fresh head gaskets and good bolts on a 7.3 I'd say you'd be okay up to about 10 psi. Wouldn't want to go over that, though I think some have and had no issues - just a personal comfort thing to me.

With an older engine it's anyone's guess.... head gaskets don't have an infinite life span, and the more pressure they're subject to the more likely they are the fail.

I wouldn't be too comfortable doing it on a stock 6.9 - look at the size of the stock bolts.... the studs are such a huge improvement over the bolts on a 6.9 that it's can't really be understood until you put them next to each other.

 

[riotwarrior]

Interesting thread...PUN intended...

 

[OLDBULL8]

Well now, you guys have got me scared to death. Put an old 88 7.3 engine in my 92 that supposedly has 80K miles on it. Only thing I did to it was check compression, all around 400 to 420. Now I stuck a Banks Sidewinder on it, top boosting is at 19 -20 PSI, I must say it runs like a ***** Ape. Those head gaskets must really must be stuck on from old age. Exhaust is 3". Don't tell me the boost gauge is off, which one of the three different ones is it?

 

[cheap bronco]

Well now, you guys have got me scared to death. Put an old 88 7.3 engine in my 92 that supposedly has 80K miles on it. Only thing I did to it was check compression, all around 400 to 420. Now I stuck a Banks Sidewinder on it, top boosting is at 19 -20 PSI, I must say it runs like a ***** Ape. Those head gaskets must really must be stuck on from old age. Exhaust is 3". Don't tell me the boost gauge is off, which one of the three different ones is it?

If I were to buy new headbolts, which manufacturer should I buy from. I dont want china crap