Engine blue printing/balancing
 

This seems to be one of the few things not talked about on here. So who has had their entire rotating assembly balanced? On a boosted junkyard lq4 would it be worth it to do? Oh and I'm not talking about the "pre balanced" rotating assemblies that are usually way off spec :cody: Would it help the stock internals hold up under more power? I know it will help the bearings last longer but does it help overall performance for every application? I would think it would free up some power to have it done correctly.

Would be curious if it would.

Though it seems most people bend the rods or blow up a piston on stock motors before anything haha. I know you can't get around the fact that early LQ4's have weak rods and will bend at a much lower power level than a later LQ4/LQ9.

It'll be an 05 or 06 engine for that exact reason then whenever I get another one built or that one gives out I'll put some good rods and Pistons in it :burnout:

You are asking the right questions and props to you for not falling into that catagory of guys who think the balanced rotating assemblies are good to go. I can tell you from a ton of experience 99% of them need work to be balanced properly.

Is it worth it? I think it really depends on what you are trying to accomplish. Most everyone is familiar with the SBE 5.3 mustang that has run 4.60's at over 154 mph in the 1/8 mile. That SBE, while using stock components, was a blue printed and balanced setup. It wasn't just taken from the junkyard and bolted in.

Well that just about sums it up then I'd say it's a must if you wanna put down big numbers. I'm assuming the bottom end was studded as well as the heads on that 5.3?

That combo was run and blown up quite a while ago so I really don't remember fastener specifics. I do know it had ARP rod bolts in it but can't comment on the main fasteners or the head fasteners.

It should be noted though that the motor was run dry (no water) on methanol fuel. While they where pushing boost numbers around 40+ psi, it's survival was largely due to the fact that the car was only run in the 1/8 mile. Most times when you start really hammering on these things, the damage comes in the last half of the track when running a 1/4 mile.

^ 100% true on that. Amazing how much that last 3-4 seconds hurts the engine.

If you are interested in building an engine that will last any decent amount of time at 6000+rpm or with a lot of power then I would certainly have it balanced. Even if your tuneup is perfect when the crankshaft turns into rubber at high rpm because its not balanced well enough it will destroy bearings in a hurry.

If you are a "well if it blows up ill just put in another one from the junkyard and let it eat!" type of guy then don't bother.

I agree.

Haha I'm definitely not a fan of pulling all the shit off to swap a motor back in. Good info on here though and pretty much confirmed what I was thinking about balancing, etc. just wanted to get yall's opinion on it that have the really fast trucks on here and have actually done it and not the "well shoeless Joe down the road did it" Type of guys lol

I balance pretty much everything I build... in fact everything. A balanced engine just runs so much better.. eliminating harmonics is never a bad thing. This one engine I am putting together is just a stock bottom end LQ4 for a turbo build. It was one I got screwed over on really as it was nowhere near as good of shape as it should have been. In fact 4 out of the 8 original rods were so out of round you couldn't even fix them with the 2 thou overbore. I had a set of Gen 4 5.3 rods ( this is an LQ4 with floating pins) and when I measured them they were lighter than the originals by a few grams anyways. I could have have put it together and tried it.... but screw that. I had it balanced like anything else and they did their fair share of work on it. It's a stock bottom LQ4 with ARP rod bolts only ( and they don't distort the caps... I tried them... hell the stock bolt torque wise is a lot tighter than the ARP is.... but I didn't measure stretch and I imagine the stockers stretch a lot more too.

Honestly I think balance and setup is all that keeps the one dirt track 355 I built alive... a 2 bolt 1 piece rear seal small block with the stock crank and rods ( ARP hardware) that sees 8000+ rpm all the time on the track.... and is on it's fifth season now.

Balance and setup... keeps them alive! Within reason of course lol.