Dmaxstore Connecting Rods

[Bdsankey]

I'm not concerned about being 50-75 ft lbs low on torque on the race tune, it shreds the tires on tune 4 at anything under about 40mph even with a rear locker, let alone the race tune. I was just meaning if you stay in that 1250 ft lbs torque range you may randomely break a crank or even crack a lb7 piston before you bend a rod, it's anyone's guess. Some cranks break at stock power, and it's rare but lb7 pistons have randomely broke. Lots of people run 650+ on bone stock lbz's, and almost every single time it's the pistons that go, mine went at 575/1050. The rods are almost always just fine. If I'm gonna start throwing aftermarket rods and more than $6,000 at a motor it's going to be built to hold 1,000 hp+. Otherwise I'd stick with the keys and lbz/lb7 combo and keep it under 1250 tq and be happy with 650. For pistons, rods, springs, pushrods and a flexplate I would have right at doubled my build cost. Then I'm still stuck at 650 unless I go bigger fuel and air which is 1000's more. I decided to be content with 650 haha (MY FRIENDLY & HUMBLE OPINION ONLY)

As James said, you're adding parts that are not 100% needed to be considered reliable. The point is, on any stock rod motor lower rpm fueling/cylinder pressure is kept out of it to help the engine live. Your comment about at 1250ft-lbs you can randomly break a crank, that is true but you can also break them randomly at 550ft-lbs (OEM) or you could not have them fail to north of 2000ft-lbs. My truck is rods/pistons, stock crank, stock main caps, ARP main studs and has seen over 2200ft-lbs without failing. My point is the statement still stands, the crank failures are not a direct result of horsepower/torque. You will bend a LBZ rod from horsepower long before you break a crankshaft from horsepower IMO.


It's also not just 50 to 75 ft-lbs, I'm talking about area under the curve or average torque not the loss of peak torque. The average torque on a built motor truck at the same HP (lets say 675-700) is much higher, especially if it a truck equipped with lets say a set of compound turbos or a fast spooling VGT.


You don't need springs, pushrods, or a $700 billet flexplate to hold the power reliably. The sub $400 BD flexplate is a great option and will hold anything could ever make (I haven't seen one broken yet but I also haven't seen everything).

 

[OleBlackyLBZ]

I agree I would for sure run the bd flexplate, you made 2200 ft lbs on stock springs and pushrods?

 

[D_Ferrante801]

I agree I would for sure run the bd flexplate, you made 2200 ft lbs on stock springs and pushrods?

We have made 1100+ on Morey Louges truck with stock mains with no dowels, no main studs, no girdle, stock push rods, stock LLY pistons, stock balancer, no fancy billet flex plate etc.

Ended up with 36 cracks in the 8 pistons and motor still alive and health past the piston part ( bearings all fine and so on ). Not saying its the right way but that motor was alive for 50k miles and only pulled apart to refresh when we found the cracks.

 

[Bdsankey]

I agree I would for sure run the bd flexplate, you made 2200 ft lbs on stock springs and pushrods?

No, my truck is full SoCal valvetrain (their springs with steel retainers, their pushrods, their cam, and Merchant rocker pedestal bolts because I'm cheap). Head over to my build thread for a full overview. https://www.duramaxdiesels.com/forum/threads/05-lly-sleeper-build.81760/

 

[OleBlackyLBZ]

No, my truck is full SoCal valvetrain (their springs with steel retainers, their pushrods, their cam, and Merchant rocker pedestal bolts because I'm cheap). Head over to my build thread for a full overview. https://www.duramaxdiesels.com/forum/threads/05-lly-sleeper-build.81760/

Thanks, so the Billet main caps and girdle haven't been proven yet to help in 1,000 hp builds or they help but you just don't have to have them at that power level..?

 

[Bdsankey]

Thanks, so the Billet main caps and girdle haven't been proven yet to help in 1,000 hp builds or they help but you just don't have to have them at that power level..?

They do help, I just don't have them. My engine was not originally built for the power level I am taking it to and I have accepted the risks of pushing it to the 1400-1500hp area. My initial build was set out to build a 1000hp street truck that would pull in our local "street diesel" sled pulling class. I have since gone well past that goal.


Billet mains and girdles address issues with the bottom end main web stability as well as maintaining the main bore geometry but they do not solve the other issues that arise at extreme power levels that simply cannot be remedied at this point with an OEM block. After talking to those who have more knowledge in building extreme power engines can solve one problem but not the other.

 

[OleBlackyLBZ]

They do help, I just don't have them. My engine was not originally built for the power level I am taking it to and I have accepted the risks of pushing it to the 1400-1500hp area. My initial build was set out to build a 1000hp street truck that would pull in our local "street diesel" sled pulling class. I have since gone well past that goal.


Billet mains and girdles address issues with the bottom end main web stability as well as maintaining the main bore geometry but they do not solve the other issues that arise at extreme power levels that simply cannot be remedied at this point with an OEM block. After talking to those who have more knowledge in building extreme power engines can solve one problem but not the other.

So If I was going to build a 1,000 hp motor that may go north one day then running at least billet main caps and even possibly a girdle is not a bad idea unless I was trying to meet a budget or just didn't have the cash.

 

[Bdsankey]

So If I was going to build a 1,000 hp motor that may go north one day then running at least billet main caps and even possibly a girdle is not a bad idea unless I was trying to meet a budget or just didn't have the cash.

Like James and I have already said, you can get away with less. Is it a bad idea? No, but if you pick the right parts on a budget you DO NOT need everything you said "you'd be dumb not to have". You also haven't answered the question James asked you, why do you need billet main caps? What are they solving?



What we are all nicely trying to tell you is that you have a lot left to learn and it's probably time to sit back and soak up the information. I was once there and I am still learning more and more each day. I am definitely not above admitting I am wrong when someone who has been there and done that shows me why something does or doesn't work.

 

[OleBlackyLBZ]

They do help, I just don't have them. My engine was not originally built for the power level I am taking it to and I have accepted the risks of pushing it to the 1400-1500hp area. My initial build was set out to build a 1000hp street truck that would pull in our local "street diesel" sled pulling class. I have since gone well past that goal.


Billet mains and girdles address issues with the bottom end main web stability as well as maintaining the main bore geometry but they do not solve the other issues that arise at extreme power levels that simply cannot be remedied at this point with an OEM block. After talking to those who have more knowledge in building extreme power engines can solve one problem but not the other.

I do not know from personal experience exactly everything that billet main caps help with which is why I've been curious, but from your advice as well as what everyone else has told me and said on other threads I would STILL run at least arp studs and billet caps if I ever had a really really high hp build done, even though 1,000+ has been done on stock caps AND stock bolts many times .. Again I was not meaning to call ANYONE else stupid and even though I was speaking only of myself I will apologize to everyone the second time for what I said, I realize the wording was terrible but it was not meant the way it looked.

 

[OleBlackyLBZ]

When I said "you'd be dumb" I was 100% sarcastically talking about myself and laughing because it seems there never a good place to stop with the crave for more power.

 

[gmduramax]

Have billet main caps or girdle ever been proven to help, or is it just simply something else overpriced to sell to someone. Back when people first started building Duramaxs the consensus was to loosen the clearances and let the bottom end move around, because no matter what you cannot stop the block from moving around. What has changed? People making more power? At 1000hp you don’t need a girdle or billet caps, but shops sure are pushing them.

 

[OleBlackyLBZ]

That's really good food for thought, Andrew what's your thoughts and experience with arp main studs, how needed are they in big power builds?

 

[Chevy1925]

When you start pushing high rpm and 1200+ hp, billet mains and girdle are good food for thought, they don’t stop the issues though, they only slow it.

All the blocks still move around in the bottom end, the lml with caps/girdle is much less likely too but still will. Bearings then take the beating so you need to check main cap clearance against what the block was at during the original build and either replace just the bearings or hone again and drop bearings in (hopefully things didn’t get to out of place). Also need to see if the caps fit in the block extremely tight and a few other things.

You can dowel them, billet cap, girdle, fill the block, and sprinkle it with magical fairy dust but it’s still going to move around and cause crank walk. After 1400-1500rwhp, it’s anyone’s guess how long the block or bearings last. Just hope you got a Tuesday block. I like Tuesday, it seems to be a quality productive day in mfg