JSHTech Posted June 23, 2011 Share Posted June 23, 2011 I'm sure this discussion has been held on this forum before. I tried searching through old posts but didn't really find much. I made a similar topic on the Ford message boards before, and about 40% of the responses were useful and the rest were a waste of my time spent reading them. Which way do you guys prefer when you do head gaskets, bolts or studs? And which way seems to yield better results. I'm asking because the customer is asking me, and unfortunately (or fortunately, depending on how you look at it) I don't have the experience to give him a good response. I've done a few of each when I was working with my mentor, but I've haven't done the job on my own yet. Quote Link to comment Share on other sites More sharing options...
mchan68 Posted June 23, 2011 Share Posted June 23, 2011 I've already installed 100s of studs on these beasts, so far with a 100% success rate if that means anything. I also prefer the installation procedure of studs versus the factory head bolts (no back breaking 90 degree final tighten steps). Hope this answers some of your questions. Quote Link to comment Share on other sites More sharing options...
Brad Clayton Posted June 23, 2011 Share Posted June 23, 2011 I think head stud installation sucks, I would much rather tighten a torque to yield bolt. The factory bolts are tit to tighten with a cheater bar and you can start and stop as many times as you want before reaching the desired turning degree. With the studs, you have to use that nasty lubricant shit and once you start turning you absolutely cannot stop till you reach the desired torque. As far as longevity, if the owner is working the truck with in it's limits the studs will work as intended, but if the truck is pushed too far beyond that, they will give it up just like the bolts do. Quote Link to comment Share on other sites More sharing options...
Keith Browning Posted June 23, 2011 Share Posted June 23, 2011 From what I have come to understand the studs are stronger and will take more abuse than the stock bolts. But I have heard of head gasket failures after stud installations. I imagine some of that could be abuse, some could be improper installation and others due to other problems that were not detected during tear-down and inspection. Regardless, you need to examine what lead to the failure if that is why you are installing studs. It is common knowledge that overboosting these engines is detrimental to cylinder sealing. If you modify the engine or tune it, you are asking for it. If you don't identify the reason for overboosting you are likely to eventually have a repeat failure in my opinion. Sticking turbochargers coupled with outdated engine calibrations are a recipe for blown head gaskets. Quote Link to comment Share on other sites More sharing options...
Matt Saunoras Posted June 24, 2011 Share Posted June 24, 2011 If you modify the engine or tune it, you are asking for it. Agree 100% I can't understand why these guys pay untold amounts of money for these trucks and feel the need to fuck with them, for a lack of better terminology Granted I tinker around more than anyone and I wouldn't give up my 4" straight pipe for the world but you've gotta be crazy to tune a 6.0, they're already loaded hot from the factory any more and like you said, you're asking for it Quote Link to comment Share on other sites More sharing options...
Jim Warman Posted June 24, 2011 Share Posted June 24, 2011 Points to ponder.... when tightening a bolt - especially a fucking long bolt (let's remember that these bolts appear to extend into the main bearing web region), there is a lot of difference between the major point of friction (the threads) and the head of the bolt. I have no idea how much "wrap" a head bolt endures when being tightened. I have no idea how much torsional stress exists between the friction apparent at the flange of the bolt and the threads... I do firmly believe that there is some torsional stress that is imparted into the bolt and stays resident and that, after thermo-cycling, that the bolt is more likely to loosen (even if only a few degrees) than tighten until the torsional stress is disappated to the point it can no longer release itself. Picture a torsion bar spring - twisting one end of the bar to overcome friction at the other end. With a stud, most of the torsional displacement or loading is concentrated at the end with the wrench. The wrench directly overcomes the friction at the flange of the nut. And only a portion of the twisting motion or force is transmitted down the length of the stud (attention to proper assmbly lubrication is essential). FWIW, except for engines with the head integral to the cylinder casting (a la Offy), cylinder head studs have been part of race winning engines for many, many years. Quote Link to comment Share on other sites More sharing options...
Brad Clayton Posted June 24, 2011 Share Posted June 24, 2011 The 6.0l was doomed from the beginning. The 7.3l had 6 head bolts per cylinder. The 6.0l cut it back to 4 and then used them to hold the rockers in as well. Quote Link to comment Share on other sites More sharing options...
Jim Warman Posted June 24, 2011 Share Posted June 24, 2011 Isn't it odd that (you are so very nearly right) the 6.0 was walking the edge with the 4 per cylinder/2 sharing layout but the VT365 wasn't? Stepping into the WAYBAK machine (Sherman, set the timer for 2002) I recall stories about ITEC having concerns about Fords demands for increased power levels. I have not a clue about "normal" boost for a VT365... I imagine it to be about a half atmosphere less than a 6.0PSD. The 6.0 is walking closer to the edge of the cliff than the VT.... I will assume that ITEC was faced with "suck it up princess or we cancel the order" or at least a variation on the theme. And we can't discuss some of this without mentioning wet stacking. Nobody buys a Cornbinder because it is "sexy". If you buy a Navistar truck, you will paint a name on the side of it and you will make it work for its living. All manner of people buy a SuperDuty... even people with small penises. So - now we have a truck pretending to be a Honda Civic and exhaust paraphenalia starts to gum up. Unison ring sticks and we get overboost - EGR can't open and we get overboost.... and, of course, cylinder pressures get way out of hand.... We wont blame the guy that tries to make his truck act like a car... we wont blame some aggressive marketting crap but we will call the motor a POS.... I still love the tag line "customer expectations exceed design limits"... I think there is more truth in that statement than most of us are willing to acknowledge. Quote Link to comment Share on other sites More sharing options...
Mikill Posted June 24, 2011 Share Posted June 24, 2011 I have done both and haven't had the same truck come back in for another headgasket job. Quote Link to comment Share on other sites More sharing options...
GregH Posted June 24, 2011 Share Posted June 24, 2011 I've put in a few sets of studs - maybe a couple dozen over the years. I've had one fail on an absurdly hopped up truck. The rest held just fine. As for stock jobs, I've had two fail. One was on a transit bus 30,000 miles later, and the other was a 250 15,000 miles later. I found that the 250 was running a 120 horse tune while towing a 19K travel trailer over highway 441 through the smoky mountains when it popped. Both setups will fail if pushed too hard. Quote Link to comment Share on other sites More sharing options...
Bruce Amacker Posted June 24, 2011 Share Posted June 24, 2011 I have not a clue about "normal" boost for a VT365... I imagine it to be about a half atmosphere less than a 6.0PSD. The highest HP I see in ISIS is 215hp with a spec of 17.5 ± 1.5 psi boost at rated speed. Quote Link to comment Share on other sites More sharing options...
cbriggs Posted June 25, 2011 Share Posted June 25, 2011 I have seen replaced head gaskets fail twice. One had a banks 6 gunn kit, and got studs at first gasket replace, around 60,000kms, redone at 120,000kms.(scattered the motor at 140,000kms) Second had an edge juice, got stock head bolts on original gasket job, around 100,000kms and was redone at 240,000kms. Quote Link to comment Share on other sites More sharing options...
Jim Warman Posted June 25, 2011 Share Posted June 25, 2011 Thanks, Bruce... pretty much about what I guessed... A theoretical 180 cubic inches of unreacted air. The 6.0 wasn't so much a bad engine as it was a victim of circumstance. That's my story and I'm sticking to it. FWIW, I do not own a diesel... I cannot justify owning one. I would spend less than 3 weeks a year driving it as intended and 49 weeks a year trying to kill it. Firggin' tyops!!! Quote Link to comment Share on other sites More sharing options...
Bruce Amacker Posted June 25, 2011 Share Posted June 25, 2011 The 6.0 wasn't so much a bad engine as it was a victim of circumstance. I agree. IH doesn't seem to have nearly the problems that FMC does with this engine. That's my story and I'm sticking to it. FWIW, I do not own a diesel... I cannot justify owning one. I would spend less than 3 weeks a year driving it as intended and 49 weeks a year trying to kill it. I would LOVE to own a diesel but the selection of models in this country is so lean that I can't buy what I want. I would never own a newer one without a warranty, that's for sure. I'm still wanting to do a repower, though..... Quote Link to comment Share on other sites More sharing options...
Keith Browning Posted June 25, 2011 Share Posted June 25, 2011 Firggin' tyops!!! Quote Link to comment Share on other sites More sharing options...
jimmy57 Posted June 26, 2011 Share Posted June 26, 2011 The argument I see for studs is the fact the stock tune of motor with a stuck unison ring or vanes can create combustion pressures that will overhwlem the head bolts' ability to hold. I have a stock 2006 F450, 4:30 gears 4x2. I haul hay and my tractor with it. One day when hauling hay and with no prior driveability problems, I pulled onto highway and had a moment of VERY sluggish acceleration followed by a couple of seconds of OMG where did that come from power. Immediately smelled coolant. I had idled the truck as it was a 100F day and I wanted the a/c cold after I got the round bales loaded and that was the only contributing factor, if that even can be considered that. TTY bolts fit in with robotic assembly or at least machine assisted assembly. Those bolts work well with a multi socket impact wrench head that uses torque bars for the torque step and then a sleeve drops and enagages splines on outside of socket and a high gear reduction drive turns the bolts through the angle. Going to high measured torque repeatedly is expensive too- wise. Even if a human does it, the torque wrenches need frequent service and calibration. I do not know for a fact that IH used that type tool on 6.0's but the other engine factories I've been in used those tools. They also use them for subframe bolts on unibody cars and I would imagine the body bolts on most body on frame. My point is the TTY bolts are not necessarily the engine designer's first choice but is the fastener that works given cost and assembly speed targets. Quote Link to comment Share on other sites More sharing options...
BrunoWilimek Posted September 2, 2011 Share Posted September 2, 2011 Just a little note as reported to one of our techs from an engineer at FOMOCO that looked at the studs vs bolts issue on the 6.0 when they started to have gasket issues. Seems they investigated the use of studs and determined that the threaded area in the block was not strong enough for the extra torque arrived at when using studs, leading to block distortion. This is why FOMOCO does not endorse or suggest using studs in this engine. Quote Link to comment Share on other sites More sharing options...
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