Stock injector hold downs breaking point vs billet

[Hot COCOAL]

Well crap guys, I've had them in there for a couple months now....

Could over tightening the stock bolts when I reinstalled them do any damage at this point after being on there and ran like that?

Did I already possibly "pull" the threads a bit? if I backed the bolts out and torqued them down to the proper/lessor torque spec, do you guys think that would be best, or is the damage already done and I should leave them since I've not had any issue thus far....

Sometimes the net is not so great, right, lol. I just did another search and got the same myriad of answers... It seems to me like the LBZ hold downs were supposed to be torqued to 36ft lbs, I get the same answer from several places, even here when performing a google search...I'm gonna call the dealer today and see what they say, just for grins and giggles

 

[Harbin_22]

Bookmark this page CoCo
http://www.socaldiesel.com/LBZ Torque Specs.htm

 

[Hot COCOAL]

Bookmark this page CoCo
http://www.socaldiesel.com/LBZ Torque Specs.htm

You got it :thumb:

Thank you

I'm guessing what I'm looking for is the fuel injector bracket bolt?? And it says 22ft lbs...

Chit

 

[Harbin_22]

Yes

 

[Hot COCOAL]

Is there anything I should be looking for, in regards to over-tightening those injector bracket bolts?

Kyle, If it were you, well you probably wouldn't make this mistake so if you were me, would you loosen the bolts and re-torque them to the right spec, or just run it...

 

[Harbin_22]

I would leave them alone. If it did hurt anything, it is already done. Don't worry about it til they come out again. I would probably buy new bolts if you take then old ones out for some reason

 

[Evan@InglewoodTrans]

Out of curiosity, how much did you torque them down to? Did i read 55ft lbs?

I didn't think the recommended 28 or 36ft lbs was enough, so I took them to 42-44ft lbs for a lil added "safety" but wondered at what point would I pull the threads in the aluminum head? I didn't even think about the possibility of cracking or bending the hold down....

All you did was stretch the bolt. There is a reason for torque specs. Over torquing a bolt doesn't mean it's going to hold better. I'm surprised you didn't snap them off.

 

[Hot COCOAL]

How about those threads in the aluminum head??? Maybe chase them with a tap and call it good when the time comes, yeah?

And I will definitely be getting new bolts, probably before they need to come out just cuz I'm friggin worried about it now...

Funny thing is, I found and read that they needed 36ft lbs and I also read 22 numerous times, 22seemed like to little, the injectors had been out recently, I wonder if the guys that did the work torqued them down to 36ft lbs too???

To be honest that's about where the bolts started to feel snug, was around 32-36ft lbs, but not home, I mean they still felt "loose" @ 36ft lbs, so I gave a lil bit extra, like what felt right and got 40ft lbs off my wrench gauge, so I went with a target of 40ft lbs across all of them....and got about 42 out of most of them when I finished

Now here I am, 2mo or so later wondering WTF did I do now:spit:

:doh:

 

[Porno Joe]

you're lucky you didnt break a bolt or strip the threads at 40.

Hell I snapped a stock bolt the first time i did injectors at like 30. The second time i did them i was a p*ssy afraid i would break one, and only torqued them to 22. I pushed 2 out a week later. Torqued them to 26 or 28 and never had an issue since

 

[hondarider552]

Out of curiosity, how much did you torque them down to? Did i read 55ft lbs?

No, 55psi.


I have stock lb7 hold downs and arp studs from the billet kits. Torqued them to 45ft lbs. SoCal told me 55 for billet, and to split the difference from stock to billet for turque number. No issues so far.

 

[sickdiesel]

i torque stock ones to around 28-30ft lbs and i torque by billet ones with billet hold downs to around 35ft lbs.

no issues yet.

on stock bolts i ALWAYS use new bolts and coppers regardless what they "look" like.

 

[x MadMAX DIESEL]

Shouldn't need new bolts. You mostly definitely need copper washers everytime they are removed though. Lb7 must be different the external injector holddown as far as torque goes if you were told 55. Which is weird I'm sure it's the same bolt size. I'm pretty sure mine weren't spec'd to that, but I threw out the paper the other night

 

[Evan@InglewoodTrans]

Shouldn't need new bolts. You mostly definitely need copper washers everytime they are removed though. Lb7 must be different the external injector holddown as far as torque goes if you were told 55. Which is weird I'm sure it's the same bolt size. I'm pretty sure mine weren't spec'd to that, but I threw out the paper the other night

Lb7's have a bigger bolt.

 

[x MadMAX DIESEL]

Tin fur

 

[sickdiesel]

Shouldn't need new bolts. You mostly definitely need copper washers everytime they are removed though. Lb7 must be different the external injector holddown as far as torque goes if you were told 55. Which is weird I'm sure it's the same bolt size. I'm pretty sure mine weren't spec'd to that, but I threw out the paper the other night

for the $1.50 they cost, i think it is well worth it. just my $.02 tho

 

[Cknight199]

Just came across this thread and figured I better chime in. Was working one day doing an injector job on an LBZ and my boss told me the torque spec was 37 ft lbs, I torqued them all down, and on the last one I was torquing, the bolt snapped flush in the head. I looked up the correct specs and saw 22ft lbs, and told my boss. Anyways, the quick 4 hour injector job turned into a 14 hour helicoil mess. It was cylinder 6 that it snapped in, so we had to remove the brake booster to fit a drill in.

Anyways, at what power level do most stock hold downs break/bend?

 

[x MadMAX DIESEL]

No power level. Cylinder pressures seen from advanced timing and stuff like that


Sent from my iPhone using Tapatalk

 

[BLACKMAX1]

I reused my stock bolts and hold downs, two bolts lasted 4 runs and were then spitting fuel out everywhere. I replaced all bolts and measured the two that pushed out and they were longer than the new ones. Everything tq'd to factory and they've been good so far, over torqueing is only going to gal the bolts and make them weaker.

 

[LBZ]

I reused my stock bolts and hold downs, two bolts lasted 4 runs and were then spitting fuel out everywhere. I replaced all bolts and measured the two that pushed out and they were longer than the new ones. Everything tq'd to factory and they've been good so far, over torqueing is only going to gal the bolts and make them weaker.

Good to know. I will be replacing mine.

 

[DMAX497]

I lifted an injector...

Then bought billet hold downs.

I guess I coulda just bought a stock new bolt. Smoked my injector.