LLY: Swapping to LBZ rods worth anything?

[thunder550]

Going to pull the LLY out of my 1500 for head gaskets and oil pan gaskets. Wondering if I should consider swapping rods since that seems to be the weak internal part on the LLYs. I'd be willing to pop the pistons out and swap rods but I am not interested in re-ringing the pistons or pulling the crank, so if those are necessary I'll skip it. Interested in everyone's thoughts or opinions. Aftermarket internals are not in the budget.

 

[clrussell]

Subd

 

[thunder550]

FWIW I'd love to run mid 11's in the truck, but not beyond 11.50 since I am not interested in caging it. Twin turbos are in the future (S475 over stock most likely), maybe some 30 or 40 over injectors, but that's about it. No plans for dual fuelers or modded CP3 or anything like that.

Ran a 12.40 @ 108 in warm weather with a trans that was still learning the 4-5 shift. I think the truck is capable of a 12.0-12.1 in current form with cooler weather, better shifting, and a little better 60'.

 

[Evan@InglewoodTrans]

To do it right you would have to have the rotating assembly balanced

 

[gmduramax]

What about LML rods

 

[thunder550]

I haven't been able to pinpoint whether or not they will fit, or if they are stronger. I'd consider them if both of those are true.

 

[clrussell]

To do it right you would have to have the rotating assembly balanced

Was planning on that and delip / cut pistons.

Worth the time and money?

 

[blue09dmaxx]

Should be able to hit your goal while staying stock air and fuel Charles meaux ran a 11.7 I believe

 

[thunder550]

I really can't see cutting another .7 seconds or more off my time without air and/or fuel upgrades. Stock turbo is already making 38psi.

 

[JoshH]

How much does your truck weigh?

 

[thunder550]

5300 race weight with me in it.

 

[duramaxzak]

I haven't been able to pinpoint whether or not they will fit, or if they are stronger. I'd consider them if both of those are true.

LML rod's will work if you use LML piston's. I don't think the LML rods have proved to be any stronger than LBZ rods though.

I wouldn't waste my time on LBZ rod's. The money you will have into bearing's, fasteners, balancing and gaskets I would at least do Manley rod's.

 

[thunder550]

Ok. I don't see any reason to replace the LLY pistons, so LML rods are out.

Still on the fence about the LBZ rods.

 

[Chevy1925]

ive always wanted to see someone throw just a set of LBZ rods or carrillos or something like that in without doing anything else (maybe delipped pistons). i just couldnt see the motor lasting as long as it could doing that.

you can certainly do it. the issues you may see is a bit more blow by or oil consumption due to reusing rings as they will no longer be in the same place they were prior in the cyl (this is what ive been told, im 50/50 whether its true), your crank wont like you as there is more rotating weight on a unbalanced setup as the stock stuff was not balanced to begin with, and you will still be on stock pistons and while they are strong, you still have the weak point of the lip left and from what ive seen, its a crap shoot on if they last above 650-700hp or not.

 

[SilveradoTwins02]

To do it right you would have to have the rotating assembly balanced

I am with Evan on his comment, rebalance should be done.

If you are putting rods in it then you should pull the crank , cam and have them keyed, throw in some P clevites and balance it. This would make it more reliable to around the 650 700HP range for around $700.
De lip the pistons for a couple more dollars "i charge 175 set" and some NPR rings for like 180 -190 ish.
$1100 and you have a freshened up and more reliable motor down the road.
Of course youll need the gasket kit and Head studs if you doont already have them

 

[thunder550]

Anyone know the weight difference between a LLY and LBZ rod?

As for ring position, I have read before that they rotate in the bore as the engine runs, wouldn't that make ring "clocking" or position unimportant?

 

[Chevy1925]

Anyone know the weight difference between a LLY and LBZ rod?

As for ring position, I have read before that they rotate in the bore as the engine runs, is that not true?

if that were so, i dont see the point in clocking ring gaps lol. i know in the samurai motors ive done and the last two honda motorcycles i rebuilt the ring gaps were really close to where the "spec" says to put them

LBZ rod = 1253 grams
LB7/LLY = 1160 grams

for comparison, Carrillos are under 1100 grams

 

[thunder550]

http://www.eng-tips.com/viewthread.cfm?qid=338363

http://en.wikipedia.org/wiki/Piston_ring

It is considered good practice to build a new engine with the ring gaps staggered around the circumference of the bore. This means that any escaping gas must negotiate a labyrinth before escaping past the rings. However, while the engine is running, the rings will tend to rotate around the piston and not remain in the position as fitted. Many rings will then stick in one spot at random and remain there for the life of the engine. For this reason, ring position during build cannot be considered to be important although most engine builders would feel uncomfortable assembling an engine with the gaps aligned.

If this is true, sounds like sometimes they do and sometimes they don't.

 

[Chevy1925]

wiki will never be a creditable site to me lol

 

[thunder550]

Thanks for the weights BTW.