[parish8]

[Turbo_RORO]

Originally Posted by Eldi Z

This is important news.
Would be good to verify the weight side-by-side to the OEM combo on a scale.

Word on the street is, that currently there is no aftermarket pistons/rods provider that is actually 100% on-spec Bob weight of the OEM material.

I think that it depends on spec. Some builders have much lower tolerances than others. I agree with you 100% a truly balanced engine is better. But It is my understanding that they are within 1% of each other, and factory. Now is that accurate enough for you? I'm not sure. I do not know how accurate they are truthfully , but I can say for a 100% fact that when I replaced my pistons and rods the carbon build up on some pistons vs others could create a difference greater than 1%. If I pull the main bolt to do studs I may pull the rods and pistons and check the weight. I should have done that before.

[Eldi Z]

Originally Posted by Turbo_RORO

I think that it depends on spec. Some builders have much lower tolerances than others. I agree with you 100% a truly balanced engine is better. But It is my understanding that they are within 1% of each other, and factory. Now is that accurate enough for you? I'm not sure. I do not know how accurate they are truthfully , but I can say for a 100% fact that when I replaced my pistons and rods the carbon build up on some pistons vs others could create a difference greater than 1%. If I pull the main bolt to do studs I may pull the rods and pistons and check the weight. I should have done that before.

I tend to believe that a 1% difference should not matter as long as you adhere to the rated RPM levels and not push it overboard.
But it would really be interesting to put the stock Rod-Piston combo on the scale, right next to the aftermarket one and see the difference.

[ShizzySupra]

We still had the motor balanced with my set-up. Everything was fine. Still kicking myself for not doing main studs right then and there. :(

[parish8]

Originally Posted by ShizzySupra

We still had the motor balanced with my set-up. Everything was fine. Still kicking myself for not doing main studs right then and there. :(

Me too if that is the only thing keeping me from another 200hp. I was told part of the issue was lack of a center balanced crank. Didn’t know what they were talking about until I looked at the crank and sure enough there are no counter balancers on the middle throw. (Not and engine guy)

[Eldi Z]

Well. since you had the motors balanced properly, this again probably proves that there is no true aftermarket "Drop in" solution for Pistons / Rods (separate or as a combo).
Otherwise, why bother taking out the engine and balancing it?
The whole idea of "Drop Ins" is to save this process.

Since the slightest discrepancy in Bob weight can lead to premature engine failure and this probably holds true the higher the power and the higher the RPM that is being run.

[Turbo_RORO]

Originally Posted by parish8

Me too if that is the only thing keeping me from another 200hp. I was told part of the issue was lack of a center balanced crank. Didn’t know what they were talking about until I looked at the crank and sure enough there are no counter balancers on the middle throw. (Not and engine guy)

Me three. I'm doing a cam soon. Defiantly going to do main studs. Maybe some port work on the heads, maybe some... Oh shit, this thing is never going to run again

[Turbo_RORO]

Originally Posted by Eldi Z

Well. since you had the motors balanced properly, this again probably proves that there is no true aftermarket "Drop in" solution for Pistons / Rods (separate or as a combo).
Otherwise, why bother taking out the engine and balancing it?
The whole idea of "Drop Ins" is to save this process.

Since the slightest discrepancy in Bob weight can lead to premature engine failure and this probably holds true the higher the power and the higher the RPM that is being run.

I wouldn't say that it proves anything. I have not weighed them, nor have you, and no one has stated any numbers that "prove" anything. Lets stay on track. I am again still saying I don't know the numbers, but neither does anyone else (or at least they have not posted them). I would like to know what the factory balance is. I know for a FACT that the ring gaps were not acceptable at all. Gaps were (top ring) .015-.02 off max spread. That's pretty bad.

[ShizzySupra]

Whoa whoa whoa. MANY people have dropped them in and been fine so far.

In all 3 of our cases our cars were larger builds. For mine it was stock and we did rods/pistons/cams/headstuds/maggie/headers/converter/etc etc etc.

It was FAR more economical to just remove the engine/trans at that time and since almost everything was removed from the block AT THE TIME we figured just check for balancing. It required ZERO changes. It was just a double check that we had access to that charged me nothing (the hone DID cost me slightly).

Stay on track lol.

[Turbo_RORO]

Originally Posted by ShizzySupra

Whoa whoa whoa. MANY people have dropped them in and been fine so far.

In all 3 of our cases our cars were larger builds. For mine it was stock and we did rods/pistons/cams/headstuds/maggie/headers/converter/etc etc etc.

It was FAR more economical to just remove the engine/trans at that time and since almost everything was removed from the block AT THE TIME we figured just check for balancing. It required ZERO changes. It was just a double check that we had access to that charged me nothing (the hone DID cost me slightly).

Stay on track lol.

Thanks Shizzy. That's the kind of response I think we all were looking for. I did not balance mine but will at least check when I do the main studs( just to have another data point). Not trying to be a dick but few people have done big builds like yours so the info is not out there yet. Did you do main studs?

[ShizzySupra]

I will this winter depending on what I want to do with my setup. I think I can get a 9.5 out of the maggie full weight. Might just do a small shot on top and call it good. Car is a riot and very streetable. Very simple.

Originally Posted by Turbo_RORO

Thanks Shizzy. That's the kind of response I think we all were looking for. I did not balance mine but will at least check when I do the main studs( just to have another data point). Not trying to be a dick but few people have done big builds like yours so the info is not out there yet. Did you do main studs?

[Turbo_RORO]

I think the next question we need to ask now is how much power can the block handle? Without 6 bolt heads, or sleeves etc. Has anyone had a block failure due to power production?

[ShizzySupra]

Originally Posted by Turbo_RORO

I think the next question we need to ask now is how much power can the block handle? Without 6 bolt heads, or sleeves etc. Has anyone had a block failure due to power production?

I think the blocks are fine. Even the LS1 blocks were fine. Its the heads lifting that will be the issue per usual

[jessrayo]

Originally Posted by Turbo_RORO

I think the next question we need to ask now is how much power can the block handle? Without 6 bolt heads, or sleeves etc. Has anyone had a block failure due to power production?

I had LME build me a complete forged motor for my 2016 on twin turbos after the stock piston rings broke. I spent a lot of time talking to Bryan about what limitations they have found with these engines. This is all after putting 5 different engines in my 2013 ZL1, 3 failures over 1000 whp....

I was assured that the design of the new LT engine block has eliminated the problems I had on my LS engines with blowing head gaskets and lifting heads. He said they have several motors out running over 1500 whp without a 6 bolt head or any O-rings or other stuff we had to do on the old LS. His comments reflect what others have said earlier in this post in that they are finding main bearing failures at super high power levels. My current engine has a LT4 block specifically because that block has larger main bearing supports. The other things that can be done on any LT to improve bearing life are better main bolts and upgrading the crankshaft. Many times crankshaft flex is what ultimately destroys the bearings. They say the stock crank is good for 1000whp, over that.... I upgraded mine.

Running a supercharger off the front of the engine puts a lot more load on crankshaft. It's just the way it works. It is ultimately why I gave up on running compound boost, if you put 5 pounds of turbo boosted air pressure into the supercharger and then compress that to 18 or 20 pounds it puts a huge load on that supercharger....heat, belt slip, bearing load......just doesn't work well.

But heads should be fine on the LT motors from what I've been told.