profuse007

You soudn curious. You should delete it and keep us updated. not being sarcastic either.

Uisge Beathe

I didn't feel you were being sarcastic but I appreciate the clarification. I think we all probably add or own "Tone Of Voice" to what we are reading, especially an online forum, and make even a sincere suggestion sound like a smart ass suggestion or vice versa...I know I am certainly guilty of it anyway.

I think I will do just that though...I clocked my balance shaft bearings to block off the oil holes and the guys at LCE let me order JUST the oil squirter, since I obviously didn't need additional bearings or their bearing driver.

I work funky hours and only have a few hours a week of free time let alone be able to dedicate all of those free time hours to being out in the garage ...but once I eventually get this bare block built up and running I will post my thoughts, experiences, pitfalls, etc.

Although, I doubt I can give you guys an honest assessment because it's not like I'm tearing into a perfectly good running 3RZ and just deleting the balance shafts to see what kind of HP it nets me. My existing engine is a very tired 3RZ that had a cracked exhaust manifold and suffers from a more than likely burnt or possibly stuck exhaust valve(s). With a strong headwind my truck won't even go over 65 miles per hour, completely floored. I have to downshift to 4th on a 10% grade if it's really long. I think I had 89 psi on one cylinder with both a dry and a wet compression test.

Soooo....I just so happen to have a long block I got for a steal. Once I tore into it I found out why (spun rod bearing), so I am doing a complete rebuild...new crank, pistons (.20 over), rods, master rebuild kit includes timing, water pump, oil pump, etc. essentially all new short block components. The head and valve train are all good and I had them mic'd by the machine shop anyway. Throwing on a Mean Green starter, new radiator, Marlin 1,200 lb clutch, Thorley headers, Magnaflow cats and muffler, ARB rear locker, misc. other goodies and debating on Marlin's 4.7 gears or just do it right and go dual transfers. All of this should keep me busy for a while.

MSR

i've deleted two, both are still running fine the vibration is hardly noticable and you dont need lc's kit

MSR

just press the new bearings in blocking off the oil holes and tap for plugs at the chain oil holes. Machinists have been doing this since the mitsubishi 2.6 from the 80's

increase in power and reliability

shumacpacha

Despite the romance out there with Toyota's engineers and engineering, after having suffered the wrath of a balance shaft design failure, balance shaft elimination is about correcting a major flaw in Toyota design, which the company subsequently eliminated.

At 40,000 miles of careful driving and regular oil maintenance, the bearing on one of my balance shafts failed and sent shards of metal into the engine, blocking the oil pump and nearly taking down the engine. According to the local engine shop, they have repaired a dozen such problems with the 3RZ-FE over the last few years. The bearing failure tends to happen in newer engines -- between 50-75,000 miles.

I am not a fan of balance shafts, and in my opinion, due to hundreds if not thousands of balance shaft bearing failures, Toyota should finance this modification.

By the way, the balance shafts is not designed to balance the engine. Instead, they mask off vibration in the crankcase. According to a Mitsubishi tech site, here are the pro's and cons of a BSE:

The good
• More HP to the wheels
• Zero chance the balance shaft belt will fail and kill the timing belt
• Zero chance the balance shaft bearings will fail and damage the rest of the motor
• More oil pressure to the rest of the motor

The bad
• More vibration is felt in side the car (no more is made, just more is felt)
• More oil pressure to the rest of the motor, which is usually too much. Extra work to get the oil pressure back in spec.

GV27

*Shrug* I had no idea the 3RZ was such an unreliable motor. Yeah, if you guys are getting less than 100k miles between rebuilds due to balance shaft failures, by all means, you couldn't do much worse.....

As usual on Internet forums, the engineering of an engine is well beyond people. And a comment like "wtf was toyota thinking? why didn't they just balance the motor internally?" is just a stupid comment. They DID balance it internally - they put two balance shafts inside the block to do that.

And yes, actually more vibration IS made without the shafts. If a potentially vibration-generating force is canceled out before it has a chance to cause a vibration then no vibration is made. The pistons motions of a "boxer" engine is probably the most obvious analog when imagining how a a balance shaft works. But a balance shaft is not a rubber motor mount. It does not damp out vibration, it counteracts vibration-causing forces before a vibration can be set up.

It CAN be used to make a smoother "feeling" engine but is more frequently used to cancel out destructive internal vibrations. The concept has been used in all sorts of racing motors, right up to Formula 1. I believe Renault's narrow-angle V-10 of the late 90's, early 2000s had them, I know that Honda's late-80s/early 90's all conquering narrow-angle V12 featured balancing shafts. And you can bet your life those weren't in there for comfort.

Now I wasn't on the design team for that engine so I don't know WHY they decided to use balancing shafts but I can guarantee they had a good reason. It's NOT a cheap design option at all, but sometimes might make for an overall cheaper engine by letting them use cheaper parts elsewhere. It may well be simply for comfort and if you don't care it doesn't matter. I do strongly suspect that removing them will decrease the life of the motor but to what degree, who knows? Remember though that "6 months with no problems" or 10k miles or 20 or 50 are all entirely different prospects to the 300k+ durability that Toyota seems to shoot for in their stock designs.

None of this is to say that YOU shouldn't pull your balance shafts, but to say they're in there for no reason at all is just silly.

Chris

space-junk

iTrader: (1)

all im gonna say is that i got rid of mine and now have 17K on my motor in 9 months... it runs fine... only time i feel vibrations is when its idling really low (think 700-750) and thats just in the steering wheel and stick... once it revs out it goes away...

something to mull over... if the 3RZ NEEDED balance shafts for longevity, then why did the 2RZ NOT need them? its because of the 3RZ's longer stroke and the fact that Toyota didnt want their customers to feel the slight vibration increase in the cab that the 3RZ provided...

for those thinking about doing this mod, im not going to say its the best or worst, just saying that i havent had any problems with mine... Yet...