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Post Title: Are my bolts supposed to break?
Posted by: TheKryptKeeper at 10:01 PM 5/8/2008

So I'm changing my head on my ka24de. I tried to do it with my original head and when putting on my head bolts, 3 of them snapped when I was tightening to 75 ft-lbs. It ends up that that head was incorrectly checked and didn't hold pressure, so I got a new one and while checking my valve clearances, a camshaft bolt broke while going to 17 nm! What the hell? Am I supposed to change all of my bolts when doing the head gasket? Also won't the aluminum head break before the steel bolts?

Krypt



Post Title: Re: Are my bolts supposed to break? (TheKryptKeeper)
Posted by: wagzilla260rs at 10:06 PM 5/8/2008



ARP that's all you need to know...go buy some



Post Title: Re: Are my bolts supposed to break? (TheKryptKeeper)
Posted by: S13xCrazy at 10:06 PM 5/8/2008

thats a terrible situation.

Are you sure your torque wrench is accurate? Have you dropped it? Are you using the right conversion? (foot pounds, inch pounds, nM)



Post Title: Re: Are my bolts supposed to break? (TheKryptKeeper)
Posted by: darens13 at 10:11 PM 5/8/2008



you should replace the bolts. they are sort of a one time use sort of thing, because they stretch a little when you torque them.



Post Title: Re: Are my bolts supposed to break? (S13xCrazy)
Posted by: sebazztard at 10:12 PM 5/8/2008

Quote, originally posted by S13xCrazy »
thats a terrible situation.

Are you sure your torque wrench is accurate? Have you dropped it? Are you using the right conversion? (foot pounds, inch pounds, nM)

very very very easy to mix up when not paying attention, we all do it. but this was the very first thing that came to mind (correct lbs). and no your bolts shouldnt break, they were designed for the torque! hope you get everything straightened out, sounds like a nightmare.



Post Title: Re: Are my bolts supposed to break? (TheKryptKeeper)
Posted by: h.240 at 10:21 PM 5/8/2008



The aluminum head shouldn't break before the bolts do. It is a good idea to replace the head bolts since they are designed to stretch under tension, I actually just read that in a Popular Mechanics magazine an hour ago. Here is the tightening procedure for the head bolts as per the FSM if you don't already have it -

I would also get your tourque wrench calibrated to make sure you are torquing to the correct specs.



Post Title: Re: Are my bolts supposed to break? (h.240)
Posted by: TheKryptKeeper at 11:00 PM 5/8/2008

I juat bought a new torque wrench after the head bolts broke. Nissan insists that the bolts do NOT stretch and are to be reused.



Post Title: Re: Are my bolts supposed to break? (TheKryptKeeper)
Posted by: offroadbob at 11:03 PM 5/8/2008

it was 75 N/m not 75 ft/lbs
look at the FSM pic
Quote, originally posted by h.240 »


I was having the same problem when I was tightening down my cam cap bolts. 25 in/lbs or something like that and I kept snapping them at 25 ft/lbs.



Post Title: Re: Are my bolts supposed to break? (TheKryptKeeper)
Posted by: sebazztard at 11:05 PM 5/8/2008



its a good idea to get new bolts, but you broke way too many to be just an accident. i think it was your torque wrench causing the breakage. personally after all the work i would get new bolts just for some insurance. live and learn right?



Post Title: Re: Are my bolts supposed to break? (sebazztard)
Posted by: TheKryptKeeper at 11:22 PM 5/8/2008

The head bolts broke at 75 ft-lb. I just got a new torque wrench. I just checked and I confused in-lbs with ft-lbs. So, that is that. However, I just checked my injectors, and one was 25 ohms and another was 45 ohms. :-( Do I have to replace them or can I fix them?



Post Title:
Posted by: e1_griego at 2:25 AM 5/9/2008

You're not supposed to go past ~60 ft/lb for the head bolts....

Alex



Post Title: Re: (e1_griego)
Posted by: lrb_2000 at 5:18 AM 5/9/2008



yeah.. I torqued my arp's to like 59ft/lbs.... the FSM says 55-63ft/lbs

you were looking at 75 to 84 nM



Post Title: Re: (lrb_2000)
Posted by: S13xCrazy at 5:46 AM 5/9/2008



^^ yeah,

I think you made some mistakes haha. you aren't in the right units. These bolts don't just break.



Post Title: Re: Are my bolts supposed to break? (TheKryptKeeper)
Posted by: OutToWinPAHC at 6:37 AM 5/9/2008



Too much torque and they are torque to yield bolts so they must be replaced after one use.



Post Title: Re: Are my bolts supposed to break? (TheKryptKeeper)
Posted by: nissanman04 at 8:47 AM 5/9/2008

Quote, originally posted by TheKryptKeeper »
The head bolts broke at 75 ft-lb. I just got a new torque wrench. I just checked and I confused in-lbs with ft-lbs.

Yeah, you might break some bolts if you are using 12x the designed torque.



Post Title: Re: Are my bolts supposed to break? (nissanman04)
Posted by: TheKryptKeeper at 4:55 PM 5/9/2008



Hmm.... Well, damn.




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