LLY - Cracked piston

juddski88

Freedom Diesel
Jul 1, 2008
4,387
8
38
Chesterfield, Mass.
I recommend billet hold downs and new hardware much more often these days for lly + generations. I have stretched stock bolts, and stripped threads from the head and bent and snapped stock hold downs in a few LLYs. First was my own built truck, and it happened at the end of a truck pull on cylinder 7. Second was a twin turbo stock fuel lly and happened with spirited driving on cylinder 6. Third truck was a workstock vgt truck with 45% injectors and happened several times over a weekend of pulling on multiple cylinders. Fourth truck was my father's, just recently, stock injectors, 425hp tune for 150k miles, 268k miles on the hardware, stretched 4 bolts and bent 2 hold downs - cylinders 1 & 7. All of these trucks ran different tuning from different people and had pretty different power levels.

Just my observations...
 

JoshH

Daggum farm truck
Staff member
Vendor/Sponsor
Feb 14, 2007
13,091
101
63
Texas!!!
I haven't looked in awhile, do they offer high strength studs? The hard part, to me, will be the DIN washers.
I've never seen any washers with the injector hold down stud kits I've installed. The thing I would be concerned about is the tapered seat in the hold down for the bolt. The factory bolt somewhat centers itself in the hold down and has a good contact with the taper. The kits I've used have the same matching taper, but I don't know how easy it would be to find something to give the same taper off the shelf.
 

Bdsankey

Vendor
Vendor/Sponsor
Feb 1, 2018
2,359
105
63
Neenah, Wisconsin
I've never seen any washers with the injector hold down stud kits I've installed. The thing I would be concerned about is the tapered seat in the hold down for the bolt. The factory bolt somewhat centers itself in the hold down and has a good contact with the taper. The kits I've used have the same matching taper, but I don't know how easy it would be to find something to give the same taper off the shelf.
The hold downs a friend of mine made use a DIN 6319 spherical washer which can be had cheap (and I do have here). The hard part is getting good hardware. I've been looking at ARP 400-8018 but I don't think they have the yield strength I'm after.

 

juddski88

Freedom Diesel
Jul 1, 2008
4,387
8
38
Chesterfield, Mass.
I've never seen any washers with the injector hold down stud kits I've installed. The thing I would be concerned about is the tapered seat in the hold down for the bolt. The factory bolt somewhat centers itself in the hold down and has a good contact with the taper. The kits I've used have the same matching taper, but I don't know how easy it would be to find something to give the same taper off the shelf.
McMaster had the tapered washers available, I have bags of them, the studs, and the nuts. I haven't had time to sit down a research them again. I threw the packing slip away years ago and my order history isn't saved that far back. I now get must of my custom hardware from Atlantic Fasteners, and haven't had time to cross this stuff to their catalog either. Sorry.
 

Bdsankey

Vendor
Vendor/Sponsor
Feb 1, 2018
2,359
105
63
Neenah, Wisconsin
McMaster had the tapered washers available, I have bags of them, the studs, and the nuts. I haven't had time to sit down a research them again. I threw the packing slip away years ago and my order history isn't saved that far back. I now get must of my custom hardware from Atlantic Fasteners, and haven't had time to cross this stuff to their catalog either. Sorry.
Interested in selling one full set?
 

NevadaLLY

Adam B
Feb 24, 2019
145
3
18
Reno, NV
E6CFFAD7-A05A-42DB-B3A7-D034D985BEC8.jpeg
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2011 hydroboost is in. Simple job. Mine showed evidence of leaking so this should be a big improvement.

goal today is to get the rotating assy complete to short block. Long block if I’m lucky.
 

NevadaLLY

Adam B
Feb 24, 2019
145
3
18
Reno, NV
How awful was install? I’ve been wanting to run one of these for awhile since the OEM insulation likes to go up in smoke.
Well since I could basically sit in the engine bay, it was a piece of cake. If you’re reaching around the turbo and down pipe, it’ll be tough to get to the 10mm bolts you need to take out to install. The plastic clips can be spun off by hand and re-installed the same. Also, mine was torn out by a pack rat years ago so and I was putting it off because of that 😂
 

Bdsankey

Vendor
Vendor/Sponsor
Feb 1, 2018
2,359
105
63
Neenah, Wisconsin
Well since I could basically sit in the engine bay, it was a piece of cake. If you’re reaching around the turbo and down pipe, it’ll be tough to get to the 10mm bolts you need to take out to install. The plastic clips can be spun off by hand and re-installed the same. Also, mine was torn out by a pack rat years ago so and I was putting it off because of that 😂
Id be doing it when my engine is out as well. Good to know it’s not bad! Definitely looks far better than the OEM unit
 

NevadaLLY

Adam B
Feb 24, 2019
145
3
18
Reno, NV
3E159B8B-F324-44D4-86C4-5B01366E785D.jpeg
somehow I broke an oil ring using my compressor - ARP tapered type. Not sure how or why or what I did wrong - all was lined up nicely. Anyone know where I can get or if I can get just an oil ring? +.020 over.
 

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