What you guys running for rods in the LLY engines?

M

Mike Holmen

the Diesel dude
I going to build-up a decent street LLY engine. Been curious is the stock rod and crank set-up can handle a 1000rwhp, or you have to get aftermarket rods and crank?

Anybody making a gridle or a device to reforce the mains for the crank. I plan on using some spray.

This is my first duramax engine build, so I would like to make sure its a decent build.
 
Mike Holmen said:
I going to build-up a decent street LLY engine. Been curious is the stock rod and crank set-up can handle a 1000rwhp, or you have to get aftermarket rods and crank?

Anybody making a gridle or a device to reforce the mains for the crank. I plan on using some spray.

This is my first duramax engine build, so I would like to make sure its a decent build.
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Like previously stated, Carrilo, Howards, Crowers, or TTS (R&R) Rods are all capable of holding 1000+ WHP.. I choose Carrilo's for mine.. Factory Crank is hit or miss what it will hold but there are quite a few guys running 1000+ WHP on stock cranks. Some Crank options are to have your factory crank internally balanced or if you got a extra 6k or so laying around you can buy a internally balanced Billtet Crank. A properly built and balanced lower end with factory crank seems to be the most common build since most people are on some sort of budget.. SoCal Diesel offers Billet mains, girdles, studs, Rods and pretty much everything you could need or want for your D-max. I have also heard good things about Randy's Girdle and machine work....
 
Socal could probably make you a crank if you really wanted it. IIRC they offered it for a bit when they started selling there 7.1L kit, but since nobody bought it they discontinued it. Most will just use the stock crank like said above. Cryo treating is an option too but idk how much that would help. Ofcourse it would be a piece of mind, but for what dollar amount? Who knows. Best bet is to just use the stock crank, keyed. Along with a keyed cam and waterpump. Also I would not buy into heads from a big name place like Socal.. If you really really wanted a ported head I'm sure a local machine shop could do it fine for much cheaper. Thats another four grand that could be spent on turbos, this aint a Dodge. Our heads flow just fine from the factory. Valves would be a good investment though. But to answer the question, no they will never hold that horsepower on stock bottom end. If they did, well everyone would have a 10 second duramax..
 
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x MadMAX DIESEL said:
Socal could probably make you a crank if you really wanted it. IIRC they offered it for a bit when they started selling there 7.1L kit, but since nobody bought it they discontinued it. Most will just use the stock crank like said above. Cryo treating is an option too but idk how much that would help. Ofcourse it would be a piece of mind, but for what dollar amount? Who knows. Best bet is to just use the stock crank, keyed. Along with a keyed cam and waterpump. Also I would not buy into heads from a big name place like Socal.. If you really really wanted a ported head I'm sure a local machine shop could do it fine for much cheaper. Thats another four grand that could be spent on turbos, this aint a Dodge. Our heads flow just fine from the factory. Valves would be a good investment though. But to answer the question, no they will never hold that horsepower on stock bottom end. If they did, well everyone would have a 10 second duramax..
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SoCal still makes Billet cranks for sure and carries good stock cores and can modify either to be internally balanced...
 
I'm guessing that the stock rod will not last at that power level very long by your guys posts. What you guys running for pistons?
 
Thanks guys, great answers. Hate to ask this, but what breaks in the bottom end? How does the rod break? Could you run ARP bolts for the rods? I'm probably going to polish/debeam the rods, do the cyro/shotpeen. Pretty easy to spend big cash on this project. I got this engine so I can build-up a twin turbo build for a buddy. My brother just gave me two complete LLY engines, would like to at least get one running again. Might have to lower my power level expectations.
 
Normally the rod doesn't break ,it bends.lbz,lmm rods seem to be a slight bit stronger than the previous models but still not strong enough for big power.
 
I was planning on just getting the heads ports cleaned up/massaged some. Throw in an aftermarket cam, mains studs, homemade mains gridle, ARP rod bolts. Balanced/blueprinted.Nothing too fancy.

Anybody try using orings in the head? I plan to run 625 ARP's for head studs.

Thanks guys, sorry for all the newbie chevy questions. Just like to get a decent engine done up right this first time.
 
If you want it done right the first time you shouldn't skip getting some good rods.Because you will be tearing it down again if not.
 
Yep, for sure plan on getting rods, period. The stock ones just won't last.

I don't know of anyone personally that's o-ringed their Dmax head. With studs, they tend to stay pretty well planted up to & above 100psi. You might consider the bigger diam. arp bolts instead of the 625. I think they're similar price but hold much more IIRC.

Good luck with the build, sounds cool.
 
Our block is o'ringed and holds up great to 110lbs of boost, never had a head gasket failure.

We've broken a block/crank on one engine and beat the crank bearings out on a couple more, but the TTS rods and forged pistons continue to be perfect and keep going into the refreshed engine.
 
we bent every rod in our lly about a year and a half ago and the pistons were fine we fire-ringed the heads but we are running carrillos and forged pistons and as of right now we have broken one crank but they say that happens when u turn 5300 rpms running down the track as of last time we were on the dyno with a single charger we were 927 hp on stock crank and stock cam
 
TTS rods are not re-badged anything, we designed them here as we do all of our products. If your planning to make power your best bet would be to install aftermarket billet rods, have the factory crankshaft key'ed and make your mind up how much power you want to run as that will dictate which pistons you will require. Using a stock piston and delip'ing it is good for about 700 Hp at the crank max. Forged pistons will go much higher but the unknown on them is how long they will last if you plan to make it a daily driver. We have several with over 25,000 on them so far but we do not want you to get mislead about how long they will last.

With our forged pistons and rods we have made over 1600 Hp and things hold up well with a stock crankshaft that has been key'ed and the assembly balanced. Internal balance only goes to weaken the stock crankshaft as you must remove to much of the parent material and replace it with heavy metal, so do not waste your money on that one.
 
joehill said:
we bent every rod in our lly about a year and a half ago and the pistons were fine we fire-ringed the heads but we are running carrillos and forged pistons and as of right now we have broken one crank but they say that happens when u turn 5300 rpms running down the track as of last time we were on the dyno with a single charger we were 927 hp on stock crank and stock cam
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Stock rods or carrilo that you bent?

I bent all 8 of my billet rods last season.
 
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