ATS manifold cap screws keep backing out

[rweis]

ATS manifold. Love it. Cap screws keep backing out. I retorque them. They back out in about 6 weeks. I retorque them... ... .



2 questions



Can I change the cap screws to hex head bolts of the same length and diameter? Are Manifold bolts a special hardness or material to withstand the heat and thermal expansion? Hex head bolts would be easier to torque with a crows foot and a torque wrench (yep, calculate the difference of the length added by the crows foot)



What can I put on the threads to keep them from backing out every 6 weeks or so?



Thanks,



Bob Weis

 

[bmoeller]

Originally posted by rweis

What can I put on the threads to keep them from backing out every 6 weeks or so?

Loc-tite. Make sure you get the stuff that will let you remove the bolts, if neccessary, with hand tools and not require a torch (medium strength, I think would be OK). Just read the package.

 

[24V-DSL]

How the heck do you get to the bottom ones. I can't even see them.

 

[catoiler]

Threw the bolts away and put studs and lock nuts on and no problems!Lock Tight didn't work,header lock washers n/g! ATS don't leak no more or loosen up in 30,000 miles so far.

 

[rweis]

Catoiler - do you remember the length and thread pitch of the studs? I can measure the cap bolts to the shoulder and add 1/2" if you do not recall the length.



Locknuts?, obviously not the ones with the nylon insert. I'll ask at my local machine shop about the locknuts, but if you could give me a little more info on what to look for. Sounds like a better solution.



With a lock nut at least you can wrench them even if you can't see them.



Thanks,



Bob Weis

 

[catoiler]

Bob,don't remember the length but if you add 1/2" you should be good. The nuts that i used had a washer built in and on the washer were serrations. You could use a pinch nut with just as good results.







Mike



P/S The nuts were much easer to get at!!

 

[Shovelhead]

Did you try Safety Wire?

 

[illflem]

Use studs and prevailing torque locknuts like these

http://www.pacificfastenersinc.com/torque.htm

 

[aharrow]

Are you sure that the length of the socket head cap screws that came for ats were not to long because I had to cut about . 250" of the length they would bottom out in the head just a thought I have not had a problem with mine in 6 months Aaron

 

[John]

Bill (illflem), two things...



1) those nuts in your link are pretty much my favorite locking nuts... that and the same thing in a flange head configuration. They would definitely stay locked onto a stud. However, if removed they would probably remove the stud from the head (unless the proper Loctite Threadlocker was utilized on the studs prior to installing the studs. That would arguably be: Loctite 272).



2) those particular nuts are not very fastener friendly. By that I mean, they tend to tear up the corresponding male fasteners (the smaller the fastener diameter is, the worse it is). In other words, they are primarily used in applications where removal is not generally factored into the equation. Then again, they hold extremely well!



Another alternative to Nyloc locking nuts (nylon locking ring... which do not work in high heat applications), is SPS brand Flex Lock (sp?) nuts. They can be purchased at high quality, diverse fastener outlets. They are rather expensive however, they do not tear up their male counterpart.

 

[rweis]

I did not consider that the cap bolts would be too long. I will measure the depth of my particular block and compare the length.



I have already lost (vibrated totally out) one of the cap bolts from ATS. Are these special cap bolts? or can I find an equivalent at a machine shop for replacement? Are they a specific grade?, are they a special heat treated? What would I ask for as a replacement? If I go this route.



I do like the stud / nut concept as that would be much easier to tighten with solid surface contact of a wrench. I was going to work on this approach this weekend, measuring the depth, finding what stud size that would work best.



I do not have a stud wrench, but should be able to find one fairly easily that would fit the diameter of the stud.



I assume Loctite 272 would be able to perform in this high heat application?



As an aside: On the 2002 the water lines to the water heat exchanger for the transmission are formed hard side tubular pipes and of course are directly in the manifold nut access path. Do you see any problems with changing the hard side tubes to lengths of rubber high temp hose so they can be pushed out of the way for manifold nut installation and subsequent periodic checking?



Thanks for all input. TDR is a terrific group with knowledge that is unbelievable!



Bob Weis

 

[catoiler]

Don't know left mine on and just used a wobble socket,much easer to get tight!Just double nut the studs if you don't have a Stud socket.

 

[RustyJC]

Another option that won't tear up the threads of a stud and has excellent retention qualities is the Drake locknut.



Rusty

 

[rweis]

Ok, went to my local "real" auto parts shop. Went over and got the machinist from next door, added the race mechanic from the counter. Here's what we came up with.



Use a stud. A stud distributes half the gripping to the stud threads in the block and the other half to the nut on the stud. Sounds reasonable. Maybe someone here will be able to confirm this. The stud screws completely into the block with at least 6 full threads and seats the shaft of the stud into the threaded block bore. The stud is short enough to accomodate the thick ATS manifold boss, a thick manifold washer, a lock washer, and a nut without interfearance to the manifold body contours. The stud is a 10 x 1. 5 and I will get the length tommorrow.



I asked about loctite 272. They agreed that 272 would handle the heat of the exhaust area and hold fine. Just do the loctite, put in the stud, double nut for the torque, and let it sit for a couple of hours so the resins can "loc" it in "tite".



Then next comes a MANIFOLD washer. The washer that came on the ATS cap bolts are about 1/16", the manifold washer was about 3/16". Way thicker. Theory is that if the washer deforms concave or convex at all you lose the bolt contact to the manifold machine surface and therefore the torque and the nut can now loosen. The thicker washer is not suppose to be able to deform and therefore not lose surface contact (ie torque).



Then comes a split lock washer to maintain the torque loading. (Not too totally convenced about this. A locknut like Bill's Torque lock, or John's Flex lock or Rusty's Drake lock seems a better choice).



Then comes the nut. A pinch nut that is suppose to not be as succeptable to losing torque.



Sounds like a good plan to me, but what about to you?



Ideas before tommorrow afternoon when I start the job would be GREATLY appreciated.



Thanks for all your input.



Bob Weis

 

[QRTRHRS]

I put aside the steel cap screws that came with the manifold and used stainless instead. I torqued to what 40-45 lbs? I forget which but I know Evan Beck has posted that value. I use antisieze on them. They stay put and are pretty tight if I have to remove one.

 

[Extreme1]

If your bolt aren't too long, here's a fix from the old days when real cars had v-8's and you had to install headers to get the exhaust to flow.



Double washers. That's it, nothing else. I did this to my 454 powered '69 Camaro that I couldn't keep the Hedman Header bolts tight on. It worked. It's worth a try.

 

[illflem]

Several high end Italian diesel engines I've worked on have had stainless studs with brass nuts and two washers. You never break a stud removing them. Didn't know why there were two washers till just now.

 

[John]

Rusty, the "Drake locknut" looks extremely close to an SPA Flexlock nut.



Any of the mechanical type locking nuts should perform the task you mentioned very well.



Another idea...



I can't remember the name of the washers I'm going to describe although, I do know their retention abilities are at a minimum, excellent. Actually, it takes two of the same washer to work correctly. On one side of the washer are serrations while the other has a series of ramps (all peaking at the same height). The two washers are placed with the ramped sides together. The fastener can be easily tightened as the ramps are tight to and interlocked with each other. However, reversal is extremely hard because of the outboard serrations biting into the two pieces being bolted together and the ramps working against each other in a cam-like fashion. BTW, these washers are hardened. They will hold in the most difficult of conditions... i. e. , thermal cycling, vibration etc. I have successfully used these in several problematic applications.



These washers could be purchased at any of the finer industrial fastener companies in your area.



On another note, an idea that was already mentioned. Purchase specially modified or modify your present bolts by drilling for safety wire. As there is a specific (i. e. , correct) way of safety wiring bolts, that information should be sought prior to initiating this method. Although I pretty much know what I'm doing in this respect, it's very hard to convey this information without illustrations... ... kind of like teaching someone how to sail from a book. LOL



I try to use other methods of fastener retention prior to going the safety wire route however, I do have one thing safety wired on my Ram... my Mallory 4140M electric fuel pump. As it has a 1/4" piece of reasonably low durometer urethane isolating it from my frame, I felt the safety wire was the most viable and reliable option in this particular case as the four stainless steel socket head cap screws are not torqued anywhere close to yield.

 

[John]

QTRHRS...not to rain on your parade...

but...



using anti-seize on bolts that are to be torqued to a specific value will dangerously skew the actual torque applied to said fastener! In other words, the actual torque applied will be substantially greater than spec. Torque specs are generally given with the following prerequisite criteria as a basic rule of thumb: the bolts are assumed unplated and lightly oiled with a mineral oil (30 weight), with the excess oil removed. Plated hardware is generally torqued at 25% less than spec. By plating they mean, zinc, cad or even nickel. Galvanized plating will also skew torque values.



I generally do not reduce the torque on my own plated fasteners the full 25%... it's something I pretty much have experimented with through many, many years of using/learning about fasteners, from basic to trick to absolute state-of-the-art trick.



On my own ATS exhaust manifold which I installed around three years ago, I was fortunate to have a friend that was installing his around the same time. He and I researched our fastener needs for the installation and he ordered the required chrome plated, heat treated socket head cap screws and A/N washers from Gardner & Wescott. They still look like a million and have held very, very well.



... it will almost be a shame to cover them up when I add my ATS exhaust manifold/turbine housing blanket

 

[QRTRHRS]

Re: QTRHRS...not to rain on your parade...

Originally posted by John

but...



using anti-seize on bolts that are to be torqued to a specific value will dangerously skew the actual torque applied to said fastener! In other words, the actual torque applied will be substantially greater than spec. Torque specs are generally given with the following prerequisite criteria as a basic rule of thumb: the bolts are assumed unplated and lightly oiled with a mineral oil (30 weight), with the excess oil removed. Plated hardware is generally torqued at 25% less than spec. By plating they mean, zinc, cad or even nickel. Galvanized plating will also skew torque values.



[/I]

Thanks John. So, that's why the bolts were so tight when I pulled some out while doing some other mods.