Engine Balance Options

[Syaoran]

If you're thinking about building your engine to work past the stock limits, you might want to take into consideration balancing the rotating assembly at a good, reputable place, preferably specialized in balancing engines.

First, the tables of my rotating assembly (before and after balancing). Important information on what I brought to the shop:

1. 98+ Camry crankshaft with the gear for the balance shaft still installed.
2. Crankshaft was only polished, not ground down for undersized bearings nor 3SGTE rods, and it hadn't been previously balanced aside from the (crappy) factory balance.
3. OEM like-new flywheel (seems to have been replaced by PO, so it's likely it's not a Toyota flywheel, but it's not a lightweight replacement either)
4. XTD "heavy-duty" pressure plate
5. OEM flywheel bolts
6. 98+ Camry timing gear with crank sensor trigger wheel and its washer
7. My OEM harmonic balancer/accessory pulley

With that said, here are the pictures:





The engine came balanced from the factory to what it seems +/- 2 grams of tolerance. 2 grams, not a fraction of a gram. This is very bad for a performance engine, but OK for a daily use engine. Here's an explanation as to why I say this based on my limited knowledge on the topic and the explanation given to me by the engine builder who balanced my rotating assembly.

Note the first table of the first picture: on there you'll see that 2.2oz-in will cause 35.20 lbs of force on the bearings at 3000 RPM. That's OK and not that much for that RPM. It won't kill your engine and it'll last for pretty long seeing that kind of strain. However notice the strain it's susceptible to at 7000RPM: 198.62lbs; that's a lot. As you go higher even, you'll see more and more.

On the right side table it's the same story.

After balancing, nearly the same ~30lbs are seen by the bearings at 10,000RPM instead of the previous 3,000RPM.

It's pretty easy to see how important engine balance is. It'll help your bearings last a lot longer, as well as your engine.

[Box]

Being these engine last well over 200,000 miles as it is, just makes you wonder how low long they could last with a proper balancing.

[Syaoran]

Yeah, but there is a reason as to why I posted this in the FI section. I told the engine builder my plans and he said that my engine would've probably lasted 1 year at most seeing the added strain introduced by the turbocharger. He said that unlike the high performance engines such as B series, K series, Yamaha engines, Nissan DE engines and the such, the 5SFE doesn't come balanced to a tighter tolerance simply because its intended purpose is not performance (we already knew that though) and that because of that reason it NEEDS to be balanced before making it see any kind of serious strain. It will last a lot daily driving it, it will last a lot less stepping on it and keeping it at high RPM for long periods of time and it will last even less turbocharged.

[PolliS_5S-FE]

Surely would you see performance gains by balancing the assembly? Or is it mainly a durability thing.

[Syaoran]

Surely would you see performance gains by balancing the assembly? Or is it mainly a durability thing.

It won't net you any gains in whp or wtq, but it'll surely rev easier and be much more reliable.

[Box]

In theory it would free up some power by reducing rotational mass, but how much is probably negligible.

[delusionz]

A few questions

1. When doing a cambelt job later on, the harmonic balancer can only go back on the same way right? (ie, the mechanic wont be able to put the drilled part on the opposite side)

and 2. what happens when you need a new clutch kit?

[Syaoran]

A few questions

1. When doing a cambelt job later on, the harmonic balancer can only go back on the same way right? (ie, the mechanic wont be able to put the drilled part on the opposite side)

and 2. what happens when you need a new clutch kit?

The parts are all balanced individually, and then as an assembly. The clutch pressure plate was balanced. If I were to change the pressure plate or turn the flywheel, I'd need to take them in to have them balanced again.

The harmonic balancer only goes on in 1 position.

[delusionz]

i have little markings on everything, including my pressure plate and flywheel need to go together with the markings lined up aswell as where it bolts to the crank i guess??


so on a normal engine, when you do a flywheel skim and a new pressure plate, that throws off all factory balancing or what? like does that mean the drill mark on the harmonic balancer doesnt mean **** anymore?

[Syaoran]

i have little markings on everything, including my pressure plate and flywheel need to go together with the markings lined up aswell as where it bolts to the crank i guess??


so on a normal engine, when you do a flywheel skim and a new pressure plate, that throws off all factory balancing or what? like does that mean the drill mark on the harmonic balancer doesnt mean **** anymore?

A fraction of a gram in change doesn't matter as much in an engine that's balanced to a 3gram tolerance, like stock, compared to an engine that is balanced to a 0.3gram tolerance, like mine.

This post has been edited by Syaoran: Jul 30, 2013 - 11:03 AM

[H8TRAIN]

Really appreciate the data in the pics Syaoran! Thank you for posting that up. I had been considering the need to balance a 5sfe for hard use. Your results show that balancing is key.