Injector Hold Downs?

[Ironworker15]

I put Antiseize or blue lock tight on EVERY bolt on my truck. It's saved me a ton of headaches. You just have to reduce the torque spec. The only place that kind of bit me in the ass was the injector hold downs. I was really scared about over torqueing those and went too loose. I ended up pushing a injector.

Yes, I do that on everything I install as well. The injector bolt was installed from the factory 150,000 miles ago. I chased the holes out with a thread chaser(not a tap) and torqued to factory spec with a little 30wt oil. I check torque on them every so often and haven't had one loosen up yet. I was contemplating billet hold downs until I saw a thread where the Socal ones broke and that made me leary of them. I am looking to make a set of M8x1.25 grade 12.9 studs at work to use instead of the OEM bolts. Thinking if I buy a long enough full thread bolt and cut it to length, chamfer the ends and use conical washers with 12 point alloy nuts , it'll be close to what Socal offers with their kits. I can't find a place to buy just the studs they offer.

 

[1FastBrick]

SoCal just has an issue with there vendor... there are other companies that offer similar kits.

 

[Ironworker15]

Yeah I've seen a few out there. To me it's not worth the 6/700 they cost. Not for the power I'll be making anyway. If I were running 100psi boost or more id consider it. But I'd rather save that money and put it towards something else more cost effective. Just my personal take on them.

 

[Ironworker15]

Seeing that whole billet hold down fiasco makes me wonder how my billet main caps from them will hold up. I haven't seen any failures of them , and I'm not sure if they're heat treated or anything like the hold downs. But I'd hate to ruin my build because of a material flaw. But then again, that's the price we pay for going aftermarket.

 

[1FastBrick]

I don't think those are heat treated.

 

[Bdsankey]

Seeing that whole billet hold down fiasco makes me wonder how my billet main caps from them will hold up. I haven't seen any failures of them , and I'm not sure if they're heat treated or anything like the hold downs. But I'd hate to ruin my build because of a material flaw. But then again, that's the price we pay for going aftermarket.

The issue was heat treatment, this is not a problem on the main caps.

As for your post about not running 100psi of boost, they fail well before that. I've seen stock trucks break a hold down and I've personally made 1340/2200 on new stock hold downs/bolts in my LLY. It's a cylinder pressure thing as well as luck of the draw IMO. Personally I like running them but I also like the peace of mind. If it's an 04.5+ truck then as long as it doesn't happen under full load (IE doesn't torch a head or hurt an injector itself) then it's not a long process to replace that one seal/hold down/bolt.

Being that my personal truck is an LB7 I didn't want to mess with it again hence why I went billet hold downs and threaded cups. Overkill for 800-1000whp? Absolutely. Do I want to do the injector job again? God no.

 

[Ironworker15]

I just threw a number out there. I haven't seen any break under any amount of power personally. Just what I have heard of on here. I guess $700 is cheaper than an injector or cylinder head. Do the hold downs themselves (the stock ones that is) actually break? Or is it the bolts? I've been looking into a set of studs over the factory bolts with new OEM hold downs. If money allows , I may go with a set of PDM hold downs. There's another machine shop MMRP I found that makes them as well with stainless ARP hardware for $550 or so. Haven't seen anyone run them yet though. Once I get the engine assembled I'll decide which route to take. Thanks for your input

 

[Bdsankey]

I just threw a number out there. I haven't seen any break under any amount of power personally. Just what I have heard of on here. I guess $700 is cheaper than an injector or cylinder head. Do the hold downs themselves (the stock ones that is) actually break? Or is it the bolts? I've been looking into a set of studs over the factory bolts with new OEM hold downs. If money allows , I may go with a set of PDM hold downs. There's another machine shop MMRP I found that makes them as well with stainless ARP hardware for $550 or so. Haven't seen anyone run them yet though. Once I get the engine assembled I'll decide which route to take. Thanks for your input

I've seen them break the bolt and I've seen others break or bend the hold down so it goes either way.

 

[1FastBrick]

With the LB7 being under the valve cover, I wouldn't want to do that injector job a second time either...

 

[Ironworker15]

Any idea on the steel they're made out of? Billet is a pretty generic term. I have a friend with a machine shop who I was thinking could 3d scan an OEM one and have a prototype made. I wouldn't mind testing them on my stock engine truck with just a tune. Just to see how they hold up. He does a lot of government parts so he's definitely more than capable of machining them. I'd be curious to know the grade of steel used and the Rockwell hardness on them. The OEM look like a cast piece. And obviously Socal's vendor had issues with their tempering process on a batch. I wonder what PDM does differently? You seem to quite knowledgeable about these parts. Any ideas?

 

[1FastBrick]

Given they claim "Built from Heat Treated High Alloy Billet Steel" I would say it's like 4140 or 4340 Chromoly or some variation of it. But I honestly have no Idea.

I don't like the Steps in the MMRP ones where it tapers down. That's the lazy way of machining and the sharp steps would be a point where a Stress riser would form.

 

[Ironworker15]

Agree with yeah on the MMRP ones for sure. I thought the same thing when I saw them. I'm sure they would say it's all part of the design, but anyone who has run a machine knows it's just skipping a few steps to save time. I know the billet main caps are 1045 carbon steel and Billet Speed Works( formerly Pro-gram engineering) makes or used to make them for Socal. Honestly I'm most likely going to run new OEM ones with OEM bolts. Unless my money tree takes root and starts budding soon!

 

[TheBac]

I split off the injector hold down discussion from IronWorker's Piston Ring discussion. Gotta love it.....the old DD "thread derail" is alive and well!!!!

 

[Ironworker15]

Yeah my mistake on that one. Thanks for starting the new thread.

 

[TheBac]

No worries! Trust me, it used to happen ALL the time here. When creative minds get going, you never know where it'll lead.

 

[Ironworker15]

Oh yeah I've read a few on here that I had to laugh at. You guys on here definitely don't take any bullshit and call it out immediately. Some of the older threads I read had me cracking up for sure. Great group of guys ya got on here.

 

[2004LB7]

I'd guess they are made out of 4140 or 4340 too. I would guess that 1080/1084 or even 5160 would work well too. Cheap and easy to heat treat. 8670 might even be better then all of the above.

If you want to spare no expense then a maraging steel, perhaps grade 350, but you would have to discuss this with the supplier to see which grade might work. Probably cost 100x the amount of any of the previously mentioned steels would.

If I was making them myself and doing my own heat treatment then I'd probably choose 5160 or 8670. Excellent yield and tensile strength with a very forgiving heat treatment process

 

[Ironworker15]

I did message the seller of the MMRP hold downs on ebay. According to him , they are his own design that he has manufactured for him. I asked about the steel grade and he told me he will find out. They have been run in several 1000 HP plus engines with zero failures he said. The ARP stainless hardware are 170,000 psi tensile strength similar to a grade 12.9 bolt. The conical washers are manufactured in house. No website for this company but he was willing to discuss the product with me and answered any questions I had. I'm leary of them having not known anyone who has run them. For the extra $100 I would go with the Industrial (PDM) set as I haven't heard of any failing. But it is good to see other people stepping up to the plate and starting to manufacture parts for these trucks as the limited number of aftermarket manufacturers keeps pricing very high. As long as they can maintain quality parts that is.

 

[2004LB7]

Mc master carr might have the studes you are looking for. Might be more economical to purchase a rod and cut it to your required length

McMaster-Carr

McMaster-Carr is the complete source for your plant with over 595,000 products. 98% of products ordered ship from stock and deliver same or next day.

www.mcmaster.com

 

[Ironworker15]

That would work better for sure. I'd just have to make sure the concave washers are the right dimensions. After talking with a few guys, running stock hold downs with studs doesn't make much of any difference since the OEM hold down can still bend or break. It's a crapshoot either way. Just like crankshafts and LBZ pistons. Some live some don't.