I am going to re torque my head bolts this weekend anything I should be ready for? I know I am supposed to take them to 125 ft lbs is there a sequence to follow? I know some of the bolts are under the valve covers is there anything else that I will need to remove?

 

I did my valve-springs and you have to take out some head-bolts. When re-installing them you do a torque sequence of 66ft/lbs then 89ft/lbs and finally 90* more rotation. I put my torque wrench on them after and kept testing to see how many ft/lbs it was and it was over 120. my untouched bolts were at 110ish. It makes me wonder if after time the 120ft/lb bolts will rest and get down to ~110 again.

After that thought, it made me wonder how worthwhile retorquing the head bolts is unless you go though and check them a couple of times.

 

Well I don't think that I have anything to lose and I am pushing 40psi so it may help some to save the head gasket for a little while anyway lol.

 

yeah i know what you're saying. i am at 40psi and it comes on instantly... and then add all of my timing into the equation and i am probably running on borrowed time.

 

Torque sequence is also in the FSM. There are like 3 or 4 headbolts that you have to get to, that are under the injector lines. I loosened all the injector lines @ the injector and was able to get to them all. I retorqued mine 3 times, but I never went over 100. IIRC, the FSM says 92, but I did mine @ 100.

I didnt have to bleed the lines either, just tighten them up and check the lines as soon as you start it up to make sure they are not leaking.

 

Thing is to not fiddle with them; set the wrench to 120lb-ft and try TIGHTENING them. If they don't move and the wrench snaps, move on to the next one. Don't loosen any unless you're doing valve work at the some time. The book shows a normal criss-cross tightening sequence, but for a retorque all you need to do is not miss any,

 

I re-torque mine once a year. Just did them last week and took them all to 130 ft lbs. I have been told the limit is 135.
As stated above, just remove the lines from the injectors and possibly the clamp brackets and you should be able to get the bolts under the lines.

My head gasket seems to be leaking a little for the last 4 years at #1 cylinder above the oil cooler. I'm sure I am running on borrowed time running 45 psi and turning 200,000 miles.

 

I guess I'm getting old because the only re-torque I do is the day after I install a head. This has been my method since 1965. Also, I saw the tech portion on Spike TV a few weeks back demonstrating the results of different thread lubricants and re-torquing bolts. They showed how to break a bolt using the wrong type of thread lubricant while re-torquing to the maximum torque. Personally I'd rather pop a head gasket than snap a head bolt off in the block. I guess this is one of those do whatever you feel best in doing deals?

 

I've thought about doin this too and goin to at least 125 lbs. I want to get studs but I may do this til the funds allow. The only thing that has kept me from doing this is the fear of breaking a head bolt...

I've heard that you can just re torque them with them already in and i've heard its better to take each one out one at a time, lube them, then retorque them a few times? Just retorquing them sounds easier but I guess it depends how lucky you are???

 

Ok now you all got me scared I think I will just leave it alone.

 

Don't be scared!

Make sure to read page 2.

http://www.dieselpowermag.com/tech/d..._to/index.html

 

JQmile is right, there's nothing to be scared of. Before I got in to bending wrenches, phrases like 'torqueing' and 'head jobs' sounded strange and mysterious, like some sort of voodoo. It is, but only if you don't know what you're doing. Once you know how it works, why it works the way it does etc, voila! enlightenment. No more scaredy cat.
125 ft.lb is nothing. You can do that with a 1/2" breaker bar. And if you snap a bolt, get it out and get another one. These are machines, and parts are replaceable, you're not amputating a leg. The only bad times come when you put too much lube on the bolt and cause hydrostatic lock. You can crack the block doing that.
You've got nothing to worry about Bill. Just make sure you follow the sequence they have in the FSM and you'll be fine.

 

Cummins B Series head bolts stretch during their normal life cycle. Cummins provides a thread length reference and a reference "use or don't use" gauge with a replacement head gasket. It's the torsional stress that will cause the failure because as the bolt stretches it thins and eventually reaches the breaking point. So as a particular point of discussion, how do you know the amount of stretch that your head bolts currently have while they are installed in your engine? Are they still within the specified length tolerance? I am a firm believer in referencing the Cummins Service Manual for even the most routine service procedures beyond oil and filter changes.

 

So maybe a better question what is the advantage of re torquing stock bolts. Who has done it and how was your luck in doing it?

 

I see it more as "How many times can you get away with it before you reach the end of the stretch limits caused by the re-torquing?" and how many times have they been re-torqued since the engine was new? This could also have the possibility of varying with age, the number of heat-cool cycles, and total run time. This could give variable results in different cases. A lot of folks on here have gotten away with doing it once without failure but to me it's a bandaid on putting off the real fix whenever a head gasket is starting to fail.