LBZ: Injector hold down

[Josh2002cc]

Hey guys, I just completed a head gasket job on my 07 GMC LBZ truck and it now has a small tick. It is coming from the drivers side and from the balance rates it shows #6 being out of whack. Now it did not have any ticks or knocks before tear down and I know 100% the valves were adjusted to GM spec. Here is what I am thinking. I used the GM torque value to secure the injector hold downs but I spoke with someone and they claimed the GM spec isn't enough and I should torque them down more. I think compression is being leaked past the injector causing the faint tick and higher balance rate. FWIW I did use new sealing hardware, both oring and copper washer.

Anyone ever hear of this?

 

[x MadMAX DIESEL]

If the GM spec isn't enough how was it enough when it came from the factory

 

[Josh2002cc]

If the GM spec isn't enough how was it enough when it came from the factory

Perhaps I used the wrong spec, it was a few days ago but IIRC it was something like 18 or 22 ft lbs. Do you know what the proper spec is? I don't see how your post was of any help though....

 

[TrentNell]

Perhaps I used the wrong spec, it was a few days ago but IIRC it was something like 18 or 22 ft lbs. Do you know what the proper spec is? I don't see how your post was of any help though....

I have seen the same spec , the last LBZ head gasket job we did we decided we didn't trust it , so we went 37 ft lbs ( same as LB7 ) , the fastener , hold down, copper seal, and cylinder head are similar so we figured it would be OK and it was .

 

[IOWA LLY]

I have seen the same spec , the last LBZ head gasket job we did we decided we didn't trust it , so we went 37 ft lbs ( same as LB7 ) , the fastener , hold down, copper seal, and cylinder head are similar so we figured it would be OK and it was .

That's really tight. I'm pretty sure the LB7 uses a bigger bolt for the hold down.

I have never had a problem and I have never torqued them that tight.

 

[seth999]

22ft.lbs. is spec on the hold downs...thats all i know

 

[JoshH]

I've never had any problems getting the copper to seal using the factory spec of 22 lb ft, but I have had and seen some not seal up well if there is a little debris under the copper. Unfortunately, it usually deforms the copper and requires it to be replaced.

 

[TrentNell]

That's really tight. I'm pretty sure the LB7 uses a bigger bolt for the hold down.

I have never had a problem and I have never torqued them that tight.

I know it is quite a bit above spec but have heard from a few others of having the same problem , probably just as josh stated but we tried it out and it never gave that feeling you get when you exceed a fasteners max torque rating or the heads , usually when you cross the point you feel it in the torque wrench and don't recommend any one with out knowing that feeling trying it , hard to describe the feeling but have been wrenching long enough to trust my hand . the safest bet is always to stay with the stock spec .

 

[wes06dmax]

I used torque specs of the famous german goood-in-tight on mine and it has done fine

 

[Josh2002cc]

I used torque specs of the famous german goood-in-tight on mine and it has done fine

Yep, the time I don't trust my own internal torque o meter shit leaks.

Thanks for the info guys, I feel i can get the problem fixed using a touch of all the info above. I know the bores are clean but you never know, i'll take the injector out and triple check it.

 

[IOWA LLY]

I know it is quite a bit above spec but have heard from a few others of having the same problem , probably just as josh stated but we tried it out and it never gave that feeling you get when you exceed a fasteners max torque rating or the heads , usually when you cross the point you feel it in the torque wrench and don't recommend any one with out knowing that feeling trying it , hard to describe the feeling but have been wrenching long enough to trust my hand . the safest bet is always to stay with the stock spec .

Once you tighten a fastener to the point in which you exceed its maximum "yield", (stretch in layman's terms) its already to late and the fastener is junk.

 

[Josh2002cc]

Once you tighten a fastener to the point in which you exceed its maximum "yield", (stretch in layman's terms) its already to late and the fastener is junk.

But he said he didn't feel it go past that point. So in his case he is okay.

 

[schulte]

Check for exhaust leaks maybe? Did you remove the exhaust manifolds from the heads when you took the heads off? If so, did you replace the gaskets? Also check the up-pipe bolts and gaskets.

You could try shutting off that injector with DVT in EFILive if you have it, and seeing if the tick goes away. If it doesn't, it's probably not injector/copper washer related.

Either way, its pretty quick to pull the injector and replace the copper washer if that's the case, just make sure you clean the surface down the hole before putting in new. If there is, you can pull the glowplug out, rotate the engine to TDC for that cylinder, and push some compressed air in through the glowplug hole (make sure that's clean first of course) to try to blow some of the debris out of the injector hole.

 

[Pondsy]

When HG were done on my 06 LLY, it developed a ticking sound immediately after. It turned out to be one loose injector and one that had a "nick" in the oring. Replaced both rings and retorqued - all better.

Hope it's something that simple.

 

[schulte]

When HG were done on my 06 LLY, it developed a ticking sound immediately after. It turned out to be one loose injector and one that had a "nick" in the oring. Replaced both rings and retorqued - all better.

Hope it's something that simple.

Was there a nick in the o-ring or in the copper washer?

 

[2DMaxx]

hey when you guys ae talking about the injector holddown is that the clamp bolted to the valve cover ? I noticed fuel smell and found that it's coming from passager back far injector where can I get this ?

 

[ripmf666]

hey when you guys ae talking about the injector holddown is that the clamp bolted to the valve cover ? I noticed fuel smell and found that it's coming from passager back far injector where can I get this ?

check to see if yours came loose if not we might have a few extras.

 

[LBZ]

Check for exhaust leaks maybe? Did you remove the exhaust manifolds from the heads when you took the heads off? If so, did you replace the gaskets? Also check the up-pipe bolts and gaskets.

You could try shutting off that injector with DVT in EFILive if you have it, and seeing if the tick goes away. If it doesn't, it's probably not injector/copper washer related.

Either way, its pretty quick to pull the injector and replace the copper washer if that's the case, just make sure you clean the surface down the hole before putting in new. If there is, you can pull the glowplug out, rotate the engine to TDC for that cylinder, and push some compressed air in through the glowplug hole (make sure that's clean first of course) to try to blow some of the debris out of the injector hole.

x2. I was kind of wondering the same thing. My truck developed a slight tick on the PS after I replaced that manifold. I'm pretty sure it's leaking as I never replaced the gaskets and they looked a little rough.

OT but did anyone ever find out if the injector that you cutout in the DVT is the cylinder in the firing order or the physical cylinder the way they are numbered in the block itself?? Eg: If you cut out #3 is that cyl 3 or the third cyl in the firing order which would be cyl #7? I remember Ben questioning this way back.......