exhaust manifold studs

[**ICEMAN**]

anyone using studs instead of bolts in your exhaust manifold or know where to get them and the part number?

prefer ARP !!!

 

[TORQUE THIS]

I looked back in March and April when I was doing my head. Had no luck!

If I remember right, the problem was the metric thread.

 

[DAWG-1]

Exhaust Studs

I have come up with a kit. This kit will include studs, washers that expand and contract with the manifold and a custom made 2 piece locknut. I have them on my truck with the ATS manifold. I have not had any loosen. Let me know if you are interested. Sam

 

[**ICEMAN**]

yea,,i'm interested. what brand are they? price ??

got a pic ??

 

[RustyJC]

You might want to read THIS thread.



Rusty

 

[Bob Wagner]

Here ya go Sam



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hope this helps

 

[DAWG-1]

Bob thanks for posting the picture.



The stud kit includes: 2 piece machined lock nut assembly, 1 metric stud, 2 hardened washers 10mm and 3 belleville washers. This is one stud assembly. E-mail me if you would like more info at -- email address removed -- . Thanks, Sam.

 

[**ICEMAN**]

thanks for the info.



still don't understand why all the washers ??

 

[RustyJC]

still don't understand why all the washers ??

A Belleville washer is a conical spring. Three of the particular Belleville washer being used are required to give the correct clamping force while still allowing the manifold to expand and contract without overstressing the fasteners. The hardened washers on either side of the Belleville stack protect the manifold and nut from the "working" of the Belleville washers as the system heats and cools.



Rusty

 

[Dallass]

Will 10mm all threat work, cut to 47mm, instead of trying to find studs for putting the 3 piece ATS manifold on a second generation truck?



Dallass

 

[rweis]

I have 2 more sets from when I had the same problem and came up with basically the same solution. You need them in top#3 and top#4. I used the OEM bolts and sleeves and stainless steel TSB on all the rest. 2 * $45 or 12 * $45. Initially I did the 12 * $45 then realized I really only needed #3, #4 and therefore had 10 spare sets which I have sold off 8 sets over the past 2 years.



A set is a 52mm stud, washer to protect the manifold boss, 3 INCONEL Belleville washers, a washer to protect the lock nut, Drake Lock Nut.



You can have them (each set) for my cost ($45) + $5 total shipping. 2 sets = $95



Bob Weis

 

[Luke Warmwater]

I got one of those sets from Bob. So far so good!



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[Joe Mc]

OK - I'm having a hard time understanding why the need for studs? I check my Allen caps that came w/the ATS every oil change and I've been unable to budge them?

 

[rweis]

What the problem is - is



There is a physical property of metal called elasticity and plasticity. If you stretch a bolt within its elastic limit then when it is allowed to go back to its orgional length it will do so. If you go beyond its elastic limit then it will NOT return to its orgional length, that is called taking the bolt into its plastic limit.



To hold torque cold or hot you have to keep the bolt in its elastic limit. I am NOT a engineer, but as I understand it the amount of stretch a bolt can take depends on a lot of factors. Some of those factors is the material the bolt is made of, the length of the bolt, and other factors.



A short bolt does not have the same amount it can be stretched and stay within its elastic limit as a long bolt has. That is why DC put LONG bolts in the manifold. They can stretch the amount of growth the manifold does when it gets hot and expands and still go back to their orgional length when it cools. They did not forsee tht the bolts would eventually rotate and hence the TSB using the stainless dog bone bolt keepers.



A short bolt like the cap bolts that came with my ATS manifold can not stretch as far as the manifold will grow when it gets hot AND go back to their orgional length and therefore they will stretch to their plastic limit and not go back to their orgional length when they cool. What this really means is they lose torque as they cool. When they are stretched in their length as the manifold boss gets thicker from heat they will hold well, then when the manifold shrinks when it cools they can not return to their orgional length and they lose the holding they had orgionally because they can not go that far back and shrink in length because they have gone beyone their elastic limit. My cap bolts actually fell out, like out on the road, out onto the manifold casting, etc.



Now when we put on the ATS manifold we can use the orgional bolts on all but #3 top & #4 top because of the interferance of the ATS manifold tubes with the OEM long bolts.



I found out with a HUGE amount of help from RUSTYJC that I could use a stud (short 52mm in my case) that would normally be stretched well past its elastic limit IF I used a washer package called Belleville washers. These washers are a little cone shaped but ARE DESIGNED to go from cone shape to flat and back to cone shape over and over and over ... again. They are specifically made to flatten and return to their orgional shape time after time after time ... . However they only each will absorbe a certain amount of the flattening needed, hence why you need 3 of these things. With a 3 belleville package each one of them taking some of the flattening (manifold growth with heat) together as a package, they all can handle the amount needed.



So to keep the short stud from going plastic because it can not stretch enough to handle the growth of the manifold boss we use 3 of these cone washers. The cone washers are actually what flattens as the manifold boss thickens with heat. When the manifold boss cools and gets thinner the cone washers to back to cone shape. Therefore you never change the torque because the stud is not being stretched beyond its limits.



Because the belleville (cone) washers are moving ever so small amount if you do not put something between them and your manifold boss they will cut a ring in the softer metal of the manifold boss. Not good. So put a sacrificial washer (stainless is what I used) between the belleville stack and the manifold.



Now the same thing does the same thing on the other end of the belleville stack up toward the lock nut. I did not want the belleville cutting into my lock nut so I put a sacrificial washer up there as well.



Now you have to put some kind of nut on this stack that will not rotate. Some have satety wired the nut, I used a Drake Lock nut, others use different kinds of lock nuts, whatever works and does not loosen with cycles.



That is why the Belleville washers. They are an industry standard designed to flatten and return to their orgional cone shape cycle after cycle.



Bob Weis



Luke, I put the TSB on mine to insure the OEM bolts would NOT EVER rotate, EVER. The TSB is thin stainless steel metal strip with a hole in each end slightly smaller than the OEM bolt head. You drive the undersized hole over the bolt head and it tears the metal to the shape of the bolt head and is held on by the metal that was torn to form the bolt head shape. However because it is formed to each head of the bolt (#1 #2 top, #1 #2 bottom, #3 #4 bottom, #5 #6 top, #5 #6 bottom) it keeps the OEM bolt from rotating.

 

[SHobbs]

Got to ask. How did you get the exhaust man. silver? If it was a paint how well does it hold up and also the turbo housing? Any other colors?

 

[jwilliams3]

I always go to 45 ft lbs with the manifold bolts with anti-seize added to the threads and have not had problems.

 

[rweis]

When I did the stud thing the torque on the stud without lube was 25ft #, - % for lube (locktite) = 17 ft #. The torque for the Drake lock nut with lube (anti seize) was 17 ft #. The torque on the lock nut part of the lock nut was 10 ft #.



I think the OEM bolts with sleeves are 32 ft #.



Bob Weis

 

[Dallass]

What year did Cummins first start using bolts with sleeves to mount there manifold on the engine?

 

[biggy238]

That's a good question. . It seems to me that the sleeves would alleviate any of the issues at hand by allowing the lateral movement to occur without removing the elastic properties of the bolts.