LBZ: Injector hold down studs [Archive] - Duramax Diesels Forum

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BALBZ
01-08-2012, 07:08 PM
Ok i have been looking and can not find any stud kits fir the LBZ injector hold downs. I have been having trouble keeping my injectors sealed to the head. Just had the motor built and after putting it back in the truck had some problems (very long story) so i pulled and tore the motor down to reasemble it so i know everything is right (do not trust anything my builder did).

When i pulled the injectors i had three that the o-ring was cut and one with obvious carbon on the injector body so it has to be from compression blowby around the injector. When they were installed all injector bores were cleaned before the injectors went in with new copper washers. A small amount of grease was put on the o-ring to allow it to slide in easier. All were torqued to 37lb/ft which is a bit tighter then GM spec but are still not sealing.

I was wondering if there is a stud kit out there (i have searched and found nothing) Or if i could possably make my own so i can put more torqe to the hold downs (50-55lb/ft) a little safer. Would it be possable to get a high tinstle strenght all-thread and make my own?

adeso
01-08-2012, 07:16 PM
Guy at SoCal makes a set of billet hold downs for the LB7, IDK who else does.

quadracer37
01-08-2012, 07:31 PM
Guy at SoCal makes a set of billet hold downs for the LB7, IDK who else does.

This is an Lbz. As far as I know, know one makes billet hold downs for the Lbz but I am pretty Sure you can get a hold of arp and they can get you what you need.

JoshH
01-08-2012, 07:35 PM
Do you have the little steel inserts in the valve covers that the end of the hold down pushes against?

Evan@LimitlessDiesel
01-08-2012, 07:42 PM
It sounds like you have an issue you need to find Chad.

BALBZ
01-08-2012, 07:47 PM
As far as I know, know one makes billet hold downs for the Lbz but I am pretty Sure you can get a hold of arp and they can get you what you need.

I thought about that but before i paid them who knows what for a set i might try and find a pice of all-thread that is rated for 50-60lb/ft and try that. I would think that much torque would hold them and im scared to go that much with the OE bolts.

Do you have the little steel inserts in the valve covers that the end of the hold down pushes against?

Yes the hold down pins are in the valve covers

JoshH
01-08-2012, 08:34 PM
I would not torque anything down that tight no matter what grade bolt you are using. You're already pushing it at 37, IMO. It's just going into aluminum. I've never had a problem using factory torque spec. Are you using new GM copper washers or did you just find some copper washers that are about the same size. Also, I know you said you cleaned the bores, but did you get all the crap out of the bottom, or did you just clean off the sides of the bore? The only time I ever had a problem with a copper not sealing was when there was some junk in the bottom of the injector hole, and it didn't let the copper get a good seal.

fishsmith
01-08-2012, 09:02 PM
The bolts will also shear off. We have a lmm in the shop right now that the guys in our shop tightened down a little too much and it sheared the bolt off.


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LBZrcks
01-08-2012, 10:22 PM
Talk to Guy, last time I was there he mentioned that he had some that were almost done.

ripmf666
01-08-2012, 10:52 PM
I would not torque anything down that tight no matter what grade bolt you are using. You're already pushing it at 37, IMO. It's just going into aluminum. I've never had a problem using factory torque spec. Are you using new GM copper washers or did you just find some copper washers that are about the same size. Also, I know you said you cleaned the bores, but did you get all the crap out of the bottom, or did you just clean off the sides of the bore? The only time I ever had a problem with a copper not sealing was when there was some junk in the bottom of the injector hole, and it didn't let the copper get a good seal.

He had good washers and o rings and heads were clean. All the gaskets and those parts came from me. His build jerked him around and housed out a lot of stuff on him and ran him around. Guy is doing a set of pistons and a cam for him now to be safe were thinking the builder might of rushed the build and one thought is never even backed valve lash off and just tqed the shaft back on not knowing what side they came off of. Chad I will send a new injector seal kit out with the head gasket for you. Call me if I can help you anymore if its after 3:30 pm your time text me I will be in the plant working and its easier to get back with people that way. Also were the injector tips clean before the coppers were installed or did they do that also ?

Slammed2007Lbz
01-08-2012, 11:42 PM
I had this problem bigtime with my old lly, i had to keep taking the injector out clean it new washer etc... and then keep retourqing the bolts and the next day they would be leaking again. So i assumed that the stock bolt must be stretching??? I tryed a grade 8 bolt from the local parts store and after 30 seconds of the truck running they would leak. So i bought NEW oem injector bolts and that fixed the issue. I guess after alot of heat cycles and 100k miles the factory bolts stretch and then will not hold tight anymore. I say just buy a new oem set and you would be good to go or go the route of ARP like said above

LBZ
03-29-2015, 07:42 AM
Bringing this back up.
Does anyone know if there is a stud kit from ARP for this and a P/N if so or is the only option to buy the billet hold down's from Guy or Industrial or somebody? I don't need the billet stuff, but I would like the studs.

mike diesel
03-29-2015, 07:59 AM
Interested as well. I've heard some guys say the stock hold down physically bends also. Not sure if that is true or not. I was tempted to try some 12.9 socket head bolts but was told to just buy the billet hold down kit.

LBZ
03-29-2015, 08:51 AM
Straight socket head bolts or regular studs won't work as the stock hold downs have a bevel in them where the head of the bolt seats. If I can't get just studs for a reasonable price I will just go with stock bolts again. As mentioned above they have been upgraded from the original design so maybe they are better now. I never had any issues but mine are rusted so I will be replacing them regardless.

mike diesel
03-29-2015, 03:06 PM
I have a buddy, built motor, triple turbo, almost 1100hp, 80 psi boost on stock hold downs for 3 years now and never once had an issue. Have another buddy, s475/stock twins making 650hp 55 psi boost and it lifted an injector. I'm running stock hold downs and almost have my compounds built...we will see what happens.

LBZ
04-06-2015, 01:43 PM
Bump

POWER Freak
04-11-2015, 08:46 AM
I won't be running big HP or anything but I went back together with new coppers, obviously, and new OEM bolts. I think i went to 25 lb-ft because I had a small extension on. I probably didn't need to but reading these threads from all of you crazies makes me paranoid :D

LBZ
04-11-2015, 01:57 PM
Well I give up the search for now.
Going with new stock bolts again.

x MadMAX DIESEL
04-11-2015, 07:23 PM
I've been so busy maybe I can check when I get home tomorrow. They studs SoCal uses are Arp, I might have some with the part number on the bag


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LBZ
04-11-2015, 07:29 PM
Do they have a beveled head though like the stock bolts?

x MadMAX DIESEL
04-11-2015, 07:36 PM
The nuts in the SoCal kit are beveled yes. I don't remember if the stock hardware is like that or not? But 100% yes on bevel on after market... To be clear, the studs are arp forsure. I'm gonna go and guess the nut is aswell. But it could be some other brand


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LBZ
04-11-2015, 07:42 PM
Ya the factory bolt has a bevel so it centers in the holdown. If aftermarket is the same it should work fine.

x MadMAX DIESEL
04-11-2015, 07:42 PM
The studs cost 20 bucks


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LBZ
04-11-2015, 07:44 PM
With the beveled nuts?

x MadMAX DIESEL
04-11-2015, 07:52 PM
No, idk about the price on those. Those will prolly be 300 bucks lol


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kjp800
05-29-2015, 08:38 AM
anybody have any luck with just the studs/nuts from ARP?

LBZ
05-29-2015, 08:54 AM
I gave up and just bought new GM bolts. When someone starts selling studs and nuts seperate I might look into them next injector swap.

kjp800
06-02-2015, 08:58 AM
Dirty hooker can get just the stud and nut kit for those interested.

x MadMAX DIESEL
09-14-2016, 07:45 PM
I have some studs I would like to use at home. Has anyone got a arp number for the nut only ?

CarolinaHD
04-11-2018, 02:04 PM
Bumping this back up, anybdy have the part number for just the arp studs and nuts?

ikeG
04-11-2018, 04:57 PM
Kevin said DHD can get them two posts up. We have ran 1500+ hp @ 70 psi for couple seasons on GM(new) hold downs and bolts. Always fresh washers and never a problem. Had an injector sealing issue at the end of season last year, so i ordered billet hold downs and studs but later found out it was a head issue anyway....