head bolt retorque question.

[typ4]

The bunny died, I know what its for but not how it was done.
I am guessing the refinery is the place for the answer.

 

[CaptTom]

Hey fellas,

In your torquing sequences, do you normally step up your torques or just torque each bolt in sequence? Example, torque to 40lbs, then to 60lbs, then to 80lb final torque.

THX

 

[RLDSL]

REtorquing was a fine requirement for the gaskets that were coming out of the factory ... at the time, but even the replacement factory gaskets that you purchase now that are made by VR , are not built to the same spec as the ones that were made when the 6.9 first came out. The original gaskets in the early 80s would have been a composit gasket that had much more physical compression to it than a modern diesel head gasket .
I have run into this on a number of other engine makes as well, where the gaskets have been upgraded over the years, some drastically ( I'm actually quite surprised that they havn't upgraded the gaskets on these things to MLS like they do with much lighter duty diesels of the same compression rating , but it's probably because they know it would just generate more leakage problems due to machine shops being unable to provide properly smooth mating surfaces on the whole)
but a modern gasket should be rigid enough to where it does not require retorquing. If the thing is on it's original factory gasket then it's a crap shoot as to weather you really want to disturb anything after this long, but the factory gaskets would have been designed for a retorque.

 

[Dieselamour]

My understanding about head bolts is the stretch bolt (torque to yield) was designed to prevent the need to re-torque the heads and the stretch bolt MUST be replaced whenever the head is removed. Non-stretch bolts are reused and must be re-torqued at a certain interval due to loosening.

My experience with import and domestic from the 80's showed that GM had stretch bolts; imports like Toyota had standard bolts. The standard bolts were reused if the head gasket was replaced but the bolt could be finger tight at 30k miles and needed to be checked and re-torque.

My understanding from the 6.9l manual is you reuse your head bolts, therefore the head bolts must not be the stretch type, therefore, requiring re-torque at some repeated interval in order to prevent leakage and warping.

 

[icanfixall]

We don't re-torque any head bolt on any 7.3 or 6.9 because its not warranted. A reused head bolt is not needing to be retorqued. This topic has come back once again and we need to recall that our newer head gaskets do not require a re torque no matter if the head bolts are new, used or studs. No a disclaimer. If you choose to re torque them your doing whats not proven to be necessary but it is your engine. I understand the wanting to do what right but determining whats right sometimes takes on a new meaning depending on who you talk to or listen too. We do not have torque to yeild bolts in any part of the idi engines. I know a shop that does plenty of work on idi engines and they never re torque or replace head bolts. Never have had a come back either. No I have learned something about oil leaks from valve covers and heads. Once the path of oil has made it under the gasket really no amount to new gasket pressure will completely stop the leak. It being the oil will wick thru the now retorqued gasket no matter what you do. Its built a pathway and nothing can or will stop it. I understand those that and felt they stopped an oil leak by tightening up on the gasket but its still weeping. Its just not a large flow like when you discovered it. You want to re torque.. fine. Just do it but to know its not needed is what this post is all about. Nobody can make you do what you don't want to do. No offence taken either or sent out either.

 

[Dieselamour]

@ icanfixall- I am not offended. Thanks for the information. I agree with the point you make about a leak and trying to re-torque. Admittedly, I have been out of the loop as far as the technology goes. I just don't see how it is not necessary to check the torque on standard head bolts, as the answer to this standard head bolt/gasket loosening problem was the stretch bolt. I just need perform some research and see the technical data on it- then believe.

 

[Dieselamour]

I bought a compact diesel tractor and several of the owners of identical/similar models within the same brand were experiencing blown head gaskets and cracked heads after a couple to several years of operation. I called my dealer and asked if the bolts were TTY bolts, which he replied no. The manual makes no mention of re-torqueing the head, but as a preventative measure I checked my head bolts and half of them were substantially below the required torque, without breaking them free first (tractor was about 5 years old). This effort cost me a couple hours and a valve cover gasket. Did this effort save me a blown gasket or cracked head down the road? I think so.

 

[icanfixall]

I completely agree with the notion of this tracter requiring a retorque but attempting a comparison of the tractor and our known idi is not a fair comparison. To say they are alike is kind of saying they are completely different. We understand they both have heads. bolts and gaskets but thats where it ends. a fair comparison is not possible. Neither is timing our id engines like any gasser. We need to time both but try to adjust the timing on a running idi and see how many pieces your pump ends up in compared to a gasser . there just is no comparison. Once a member takes this idea.. No matter what it is. They tend to run with it. I'm in that boat but I choose the boat I'm in. As do others. Can we hurt things by retorquing our head bolts. Yes is the short answer. Can we get away with removing a torqued head bolt and installing a stud. Yes. Is there the potencial of damaging the head.. Sure is. To remove a head bolt and install a stud is an invatation of damage but we will try this no matter what if we are intent on doing it.. Its our engine and nobody can dictate to us what we will do with our parts. I just feel based on what I have seen and know from many years of working in big high end "stuff" I can't recommend retorquing our heads. But I agree if thats what a person wants I wont stand in the road blocking that nor am I going to say.. I told you so.. Thats not what many if not most of the topics here are all about.

 

[OLDBULL8]

Not to get in the middle of this discussion, I have no opinion as to what is right, wrong or unnecessary. This how the assemble line at the manufacturer does it, at least at Ford Mtr.Co. LEP. The block travels on an overhead conveyor line hung on a carrier like an upside down question mark ?, it can be rotated 360*, The head gaskets are slapped on, next station the heads are put on, next station all head bolts are inserted and engine rotated, next station one man with a hugh bolt driver torques down half the bolts, next station, same operation, next station head bolts are sample checked manually for proper torque, then the engine is rotated for the same operation in the next two stations. If any bolt found not torqued to specs, it is switched off line to a repair conveyor. The bolt drivers are air driven, if too many bolts are not torqued to spec, then the defective driver is exchanged for a spare driver. On the off/next shift all bolt drivers on the assembly line are checked and the torque set for the next day. If there is two shifts on the same assembly line, the bolt drivers, all of them on the line are exchanged. Each station has 20 seconds to perform it's function. The man doing the head bolt rundown, has to walk sideways the speed that the line is running, then return to his previous location to catch the next engine. The engines are spaced about 4-5 ft apart on the conveyor.

 

[79jasper]

I see both sides.
I would for sure do it, especially if putting a turbo on a na engine.

Sent from my USCC-C6721 using Tapatalk

 

[icanfixall]

I can agree with members that have a differing opinion on the topic. This is why this forum is so well accepted across this country and around the world.

 

[Dieselcrawler]

I wouldn't touch it. I have snapped headbolts off just trying to remove them......

 

[riotwarrior]

If it aint broke, don't fix it.....cause fixing something that aint broke often leads to it being broke which it wasn't to begin with and needing fixing which wouldn't have happened if it wasn't fixed in the first place.

 

[Agnem]

Always a good topic to discuss to raise awareness. As was stated we do not re-torque. There are a few reasons for that. First, our torque spec calls for the threads and bolt head and washer to be lubricated with engine oil, in order to achieve a proper torque. Obviously this cannot be accomplished without removing the bolt, and because our heads have a required torque pattern, there is no way to properly address a single bolt at a time without compromising the integrity of a head. Ask anyone who has done it, and they will tell you removing and installing ONE bolt is damn scary! Also the rear bolts cannot be removed without removing the engine or cab, UNLESS you are removing the head, in which case they can remain captured and its not an issue. Lastly, our head bolts are pretty long. Some on the outboard side of the engine are actually exposed to atmosphere, where they rust. Due to the bolt lenght, it takes a large amount of torsional stress to break them loose, as well as tighten them. This is why the oil is so important. Our used bolts actually call for a different torque according to the book, that is higher than the standard torque. As most will attest, torquing these makes you feel like you are going to snap them off. They are definitely getting pushed to their limit!

 

[icanfixall]

I tested a brand new head bolt to failure and that psi was 153,000 lbs when it broke. This is why I like using ARP studs. They test out at 200,000 lbs before they break. Just a little added clamping insurance when a turbo is added. Although my 89 with many hundred thousand miles on it never lifted the passenger side head. But the drivers side was replaced because of cavitation on number 8 cylinder...