Hey all,

just looking for some ideas here. My truck has one of the cast iron eyelets, the ones on the head that the intake horn bolts screw into, broken off. It hasn't been a big deal because I have an aftermarket horn that uses studs and nuts instead of bolts. So I just have a nut on the other end, inside the intake plenum, with loctite to make sure it doesn't come off and get sucked in. I am about to take the intake horn off again to replace my powesteering pump and reseal my vacuum pump and I was wondering if I would be better off with a lock nut and loctite just as an extra safety to make sure that nut doesn't come off, but I'm not sure if that would be safe either because I'm not sure if the nylon ring could get sucked or fall out. I'm also concerned about the heat from the grid heater weakening the loctite or melting the nylon in a locknut. What do you all think? What would you do? I know the right answer is replace the head, but that's just not an option right now, so what's the next best thing?

Edited June 14, 20168 yr by leathermaneod

 

8 minutes ago, leathermaneod said:

aren't there plenty of other places in an engine where it is just as critical, if not more, for a nut to not come off?

Yes, rod and main bearings, nuts on the rockers, bolts on the fly wheel, ect.  but cheap insurance, you can never have to much of it. 

10 minutes ago, notlimah said:

Could be over thinking a little bit but who cares! I think loctite, and a quick punch/pinch to the threads to keep it from backing off in a worse case scenario and your  good.

 

Just don't forget that you fudged the threads later on down the road when you're trying to take it off! 

Lol I know I've been thinking that too. Although if the loctite 272 paperwork is to be believed, it may take up to 600* and tools to get the loctite to break free anyway....

 

8 minutes ago, IBMobile said:

 

Yes, rod and main bearings, nuts on the rockers, bolts on the fly wheel, ect.  but cheap insurance, you can never have to much of it. 

Agreed, I just have to wait and see if I can get enough threads to really do any good. I think 2 threads max is probably gona be all I have to pinch or punch. Hopefully I can pinch because I'm a little leary of banging around in there, dont wanna risk breaking anything else or bend the plenum plate. Too bad its so difficult to weld cast Iron. 

i would seriously just get a used head, have it worked over and cleaned, slap it on with a new headgasket. will be much easier fix than a serious issue waiting to happen. you will forever be stressed about that nut if you dont get a good head.

9 hours ago, CUMMINSDIESELPWR said:

i would seriously just get a used head, have it worked over and cleaned, slap it on with a new headgasket. will be much easier fix than a serious issue waiting to happen. you will forever be stressed about that nut if you dont get a good head.

 

Absolutely... The all around safest solution is replace the entire head. I found a wonderful machine shop in Caldwell, ID that does CNC cobalt valve seats for Cummins head and has the tooling for doing fire rings.  That was half of my last trip was it interview this machine shop and see what kind of quality for the owner of the truck I'm working on.

 

I really appreciate the input guys, but getting another head just isn't an option right now. That's why I was asking for suggestions on the next best thing. If anything I'll just tack a weld spot on there to be 100% sure it can't come off next time I go home. But I'm pretty sure the loctite and lock nut are gona do the job until I can weld it and then eventually get another head. 

 

When I do get another head I wanna be in a position to do the others things I want to get done at the same time. For example, head studs and injectors. I don't even know enough about heads to know if I should get fire rings or o rings or valve seats or anything...I don't even know the difference between fire and o rings....id love to learn though, hint hint lol I have a lot to learn before i start looking for a used head. I need to know what to look for and how much to pay and what all to get done to it before putting it on my engine.

Looks like I could just get a new head from dap too....

Edited June 19, 20168 yr by leathermaneod

Head stud a recommended by most engine builders. As for fire ring or o-ring that is required for more of a racing setup like TFaoro with high boost and twin turbos to prevent gasket blow out. I'm sure Ron will answer all your questions.

 

You can call and talk to Ron he's the owner.

http://www.northwestmotormachine.com/about.html

 

 

Thanks for the info and for their contact info! I'd kinda hate to waste his time though, because its not something I'll be doing anytime soon and, much as I'd like to, I wouldn't go through him just because of having to ship the head that far. For now I'll just try to learn what I can online 

What to lose but some time spent, cost of Loctite®, a nut and stud.  The head is already damaged and if this fix holds together for a year or more you're that much ahead.  If it brakes then put a used/rebuilt head on.   

Just now, IBMobile said:

What to lose but some time spent, cost of Loctite®, a nut and stud.  The head is already damaged and if this fix holds together for a year or more you're that much ahead.  If it brakes then put a used/rebuilt head on.   

Agreed, plus its already held for a year. It was about a year ago that the shop put that nut on. Only thing is, if that nut were to come off and actually make it into a cylinder, I think I'd have a major rebuild on my hands. I really don't see why it would come off though with this loctite 272, plus the Klean an Prime, and the locknut, and deforming the threads if possible. 

Got another question related to this temporary fix with the nut on the stud. Supposed I tack weld the nut to the stud, then I'd have no more worries about it coming off. Do I need to do anything special to protect the trucks electronics while I'm welding that? Like disconnect the batts or something?

Also, if I were to buy a used head off c list or something, what should I look for or try to avoid? Should I look for one with similar miles to mine? What all do I need to have done to it before installing it? I found one on c list that came out of a freightliner school bus. Guy wants $250...this is the head number 245394362703 here's the link http://harrisburg.craigslist.org/pts/5629924402.html what do you guys think? Should I jump on it for that price?

Edited June 21, 20168 yr by leathermaneod

I think you're waaaaaaay over thinking this. How often do the nuts on the outside of the intake horn come loose? Never? That's how often that inside one is going to come loose. Loctite, locknut, and don't worry about it!  

6 hours ago, TFaoro said:

I think you're waaaaaaay over thinking this. How often do the nuts on the outside of the intake horn come loose? Never? That's how often that inside one is going to come loose. Loctite, locknut, and don't worry about it!  

until murphy decides to let it get loose and get sucked in, sticking a valve open trashing a piston, connecting rod, crank...

 

just sayin. i wouldnt run the truck with anything in it that could even in the most unlikely event come loose and trash an engine.

 

killer dowel pin come to mind? 

Edited June 21, 20168 yr by CUMMINSDIESELPWR

4 minutes ago, CUMMINSDIESELPWR said:

until murphy decides to let it get loose and get sucked in, sticking a valve open trashing a piston, connecting rod, crank...

 

just sayin. i wouldnt run the truck with anything in it that could even in the most unlikely event come loose and trash an engine.

 

killer dowel pin come to mind? 

Each to their own if course! 

The kdp wasn't loctited and didn't have a lock nut on it. 

We've all got rod and main bolts too.... one of those fall of your can kiss the motor goodbye. They are vibrated more and assembled with lube .... 

 

I'd trust my $7,000 motor with that nut there but not everyone shares my opinion

The only thing I would do is crush the last few threads of the bolt so nut just can rattle off. You can hit them with a thin punch or small chisel as long as the last few threads are damaged it won't just rattle off.

I appreciate everyone advice and opinions on this! I finally got the loctite Klean and prime but didn't get to do anything yet because I had a very long day at work. I'm not sure yet what I'm going to do, but if anything more than just loctite and nut, I will use a needle noose and try to Cush the threads as @IBMobile suggested. I don't really wanna go banging with a chisel in there. I also really want to agree with @TFaoro on this one. Between loctite and locknut I don't see how it could come off. But then I also do tend to think that Murphy will get me any way he can so I see where the rest of you are coming from lol The other thing that does worry me is the fact that Gravity is acting against the nut since it's upside down, and unlike the top nuts on the horn, it may not be tight against anything if the old threads hold the stud at all. My only other concern is the heat from the grid heater since it's right there, but the loctite is rated for up to 450°. I don't think the grids will get that hot. Anyway I will probably try the needle nose idea first and if that doesn't work maybe I'll try a punch. Thanks again everyone. Even though I really think we are all over paranoid lol after all the nut stayed on there for the last year and I don't think the shop used anything special on it. It came off way to easy for my liking. It felt about how a normal locknut feels, and it was also only into the nut about 3 turns...

Edited June 22, 20168 yr by leathermaneod

hey guys,

So I have sort of a new problem. I finally got all my stuff and loctited the nut on the stud. Problem is I was totally not thinking when I did it and this is what I ended up with. 

I had in my head that I had to use two nuts jammed together, like in the second pic, to tighten the nut on the bottom becuase thats what I had to do to take the old nut off. Never occured to me that I could just screw the nut all the way on to the end of the threads . Well becasue I was trying to tighten the locknut with the two nuts jammed together, thats all the tighter I could get it(first pic). I never thought the two nuts could turn on the stud if they were tight together. Well apparently they can when you get the nut on the other end tight enough and a top lock nut gets pretty tight. I had planned to have the nut on another two threads, thats why the loctite is up so high. That caused me to also not get as much loctite as I wanted. Gravity still pulled it down the stud in at least one spot, but its kinda thick stuff. So my dilema is, do I try to get this back apart and do it over, or leave it be? My concern is that I won't be able to get it apart now due to the loctite and having to use the two nuts to loosen it, and that ill just be weakening it by trying to get it apart....I know I know, get a new head. I cant right now so I have to do the next best thing. 

That will work. I don't see any problems there using studs like you've done. The locTite should work well with that self-locking nut.

Thanks for the vote of confidence Mike. I'm just really bummed that I was so blind and didn't see there was a better way to get that nut on further while I was doing it. The whole time I felt like I was missing something and then I showed my buddy this morning, first thing he says,"why didn't you just run the nut down to the end of the threads so it wouldn't turn?" And I felt like this  lol. And I didn't get as much loctite in there as I wanted because the nut didn't go on as far. Hopefully it's enough. It's definitely on there better than the last one was, so that's good at least. My aftermarket intake horn is such a pain too. It has those studs instead of bolts which in this case is kinda good, but the nuts on the right are almost impossible to get to. When I do get another head, I'll be getting a different intake horn, injectors, and maybe studs. And maybe if I'm rich at the time I'll get a new exhaust manifold too 

That lock nut bit into that stud and you can see the Loctite  on the threads between the stud and nut.  I don't think that nut is going anywhere.