boosted94gsr

This!

Dark_Teg

How are B-series not internally balanced? There is no imbalance to the stock dampener or flywheel!

LightningTeg

Those are not internal components...

Dark_Teg

You missed my point, externally balanced motors run flywheels and harmonic balancers with an imbalance specific to the engine.

OneBadTurboCRV

LOL, it just shows who actually does stuff and who doesn't. No big deal, I don't have a build thread but...

Technically Honda engines (as almost all inline engines) are what is considered "zero balance" engines. This can be a version of internally balanced. The crankshaft is balanced on it's own and all external components are balanced separately on their own. Parts can be swapped as needed to no ill affect, even the rods and pistons as long as weight tolerances are maintained.

An external balance engine assembly must have the harmonic balancer and flywheel / flexplate balanced as one. You can't change out parts without rebalancing the three components together again (if you are doing it right).

Now of course, when you are building for performance using different parts than stock and revving higher than factory set rev limits, you want to balance the entire setup as one be it internally or externally balanced. Hondas usually are pretty close to zero balanced still when quality parts are selected, but it is good practice when building an engine.

wantboost

iTrader: (2)

I had a derp moment lol. However every stock B series engine I've taken apart never had components with matching weights. Every rod and piston weighed differently at the gram level. Plus last time I checked honda only zero balanced the crank after they were machined, not balanced with bob weights for the weights of the internals

Combine that together and you see why not having a harmonic dampener means bearing death. Honda B engines are some of the best engines around but they were still mass produced by an OEM and built by robot/human means.

With the standard version of the Zetec focus engine it too could be considered "zero balance" but again they don't do individual engine balancing. Whereas the SVT version was entirely hand built and each engine was blueprinted and balanced both as individual components specific to each engine and as a whole. Hell SVT even hand engraves the number of each cam cap and main cap by hand.

m4xwellmurd3r

I think for the stock application the piston and rods are at a "good enough" level to their eyes back in the 90s-2000s. The cranks are zero balanced though.

Regardless, even a perfectly balanced b series has secondary harmonics just from being an inline 4 banger and need a good damper to keep those from damaging the engine. Iirc its because the force exerted on the crank by the pistons at tdc is greater than the force exerted by the pistons at bdc, so it causes an ocillation that creates harmonic resonance. Without a damper, the harmonic resonance builds up in the internal components until something gives out. From what it seems from failures resulting from the ctr pulley, the oil pump drive gear shatters first since its the weakest against resonance im guessing (probably due to it being sintered steel)

wantboost

iTrader: (2)

Yes basically. Also that resonance increases as rpm levels increase, same thing goes for flat plane v8 cranks. You're constantly chasing those harmonics throughout the rev range.

OneBadTurboCRV

I split my response into three separate paragraphs for a reason. I said in the first paragraph that the components are balanced on their own; i.e. - when they were made at whatever factory and not when they were even near the other components. A stock reving, stock horsepower, and stock component engine is definitely "good enough". This is been proven with the longevity of every zero-balance inline motor ever made (i.e. - i4, i6, and flat crank V8). That's the whole reason I took the time to make a third paragraph and separate things out.

When we go to the third paragraph, I turned to non-stock components; i.e. - performance, CTR pulley, aftermarket pulleys etc... There is only one engine that came factory with the CTR pulley. This engine has a lot more work put into it so people shouldn't get the idea they can just slap a non-dampened pulley onto a engine that wasn't designed for it in the first place. If you did want to, the third paragraph applies - balance as an assembly. Same with aftermarket components... refer back to "non-stock".

To reply to your bob weight statement - The counterweights are exactly opposite of each other this eliminating the whole point of what bob weights are even for. I will reiterate, everything should be balanced at least on its own (aside from external balance obviously), if all together - even better! I think it is time for some reading:

Weighing in on Balancing Work - Engine Builder Magazine

OneBadTurboCRV

I just noticed my phone keeps auto-correcting bobweight... oh well. Anyways here is another link to read:

Eagle Specialty Products, Inc.

wantboost

iTrader: (2)

My phone does it too lol.

I can see your point. I grew up with old hot rod guys where nothing was ever balanced and I was always taught bob weight errrthang.

I wish I could remember how off my last LS crank was before the counterweight re profiling and balancing. It was fairly off from what I remember

OneBadTurboCRV

That's a possibility for sure, but for the RPM use it was intended for it was probably just fine. Everything is done and increments when cranks, driveshafts, whatever has rotation... I don't balance things for a living so I will keep the specifics to a minimum, but they have groups.

**** Just using RANDOM numbers here.**** But lets say they balance something at 3,000 RPM it will be good for 6,000 and 9,000 RPM. If they only went to 2,000 it would be good for 4,000 and 6,000 RPM or whatever the multiple is for each example. Harmonic waveforms are a more than I care to talk about because I am no expert on the subject matter. Need those dudes from ATI and Fluidamper in here battling it out.

Jack of all trades, master of none.

wantboost

iTrader: (2)

Yea I won't even think about harmonics. It makes me dizzy and a bit angry lol.

m4xwellmurd3r

The only thing i care to think about with harmonics is:
Harmonics bad, dampers good.

wantboost

iTrader: (2)

But it is much more complex than that. I'm by no means stupid (I even have letters from the President proving it lol) and I get the 1st and 2nd order harmonics, even a bit of 3rd order but from that point forward it's fairly difficult.

NotARaCist

iTrader: (1)

Y'all are making me wish I finished my Aerospace Engineering degree. Fluid dynamics I can do, kind of. Mechanical resonance was second year, though

m4xwellmurd3r

I understand about as much, but thinking about it too much hurts my head so i fall back on the basic understanding that harmonics are bad, and running a proper damper is good for the engine.

wantboost

iTrader: (2)

Typically if you've matched each internal component to the nearest gram and done a high tolerance balancing on the crankshaft it greatly reduces "bad" harmonics.

In the SVT Focus world we've got guys running 400hp or so on stock internals with lightweight crank pulleys. However given the differences between the engines it's not exactly an even comparison. The weak link with the SVT Zetec is the oil pump gear. Bumping the rev limit any higher than stock guarantees the gear shatters. A more durable gear from the aftermarket is like 400 dollars... For about double that you can buy a dry sump system minus the tank and lines and eliminate the problem entirely lol

Only thing that sucks is because they were such a low volume car (a little over 14k units from 02-04) that the aftermarket is pricey. As an example 1k buys you a basic tubular mini ram but the company does no prep to the weld els so they look like **** and every weld I've seen is extremely hot and undercut. The company charges more from there with change in quality. I can order a tubular manifold to fit the Mk1 RS (same platform and engine) for around 800 which has been back purged with amazing weld quality and penetration but it's like 100 to ship it or you can get a cast SPA manifold for like 350 lol.

Luckily there are still a lot of WRC spares floating around Europe so when I have to do a timing belt in the next 25k miles I'm replacing every timing component with WRC parts for a minimal extra cost.

m4xwellmurd3r

Wrc surplus, that sounds awesome.

I know my engine everything was within half a gram when i brought the components in to the machine shop for balancing. My crank didnt need balancing as well when they checked it.

Next time though im going to use a scale and mix/match parts around to see if i can get them to balance out better. Like, a slightly heavier rod small end with a slightly lighter piston, that sort of stuff.

LightningTeg

Mine definitely was not balanced, especially after I had the 3rd cylinder rod worked on after I spun a rod bearing years back. ATI pulley gives peace of mind...

wantboost

iTrader: (2)

Generally half a gram is fine. You normally find the lightest of each component and get the others to match.

However when seriously balancing you even take the weight of the oil film into account, generally 2 grams is what is accepted.

Yea WRC stuff floats around. Everything from the water pumps and timing parts to blocks, ITBS and plenums, even the turbo manifolds. A lot of people have started copying some of the WRC stuff as well.

It still kills me how much they will pay for parts.

wantboost

iTrader: (2)

875 gets you this from the US



855 gets you this from the UK



1300 gets you this from the US



1300 gets you this from the UK



Kind of a no brainer right? Considering the rest of the world got the Mk1 RS which was the factory turbo (same engine as the SVT) widebody rocket ship. Sad thing is almost no one realizes the RS manifolds fit our chassis and everyone nutrides the US company lol. They don't do any weld el prep and don't back purge. Every UK company back purges their manifolds...

LightningTeg

That CNC cut collector though...

Dark_Teg

My machinist used to build engines for indy cars so he knows a thing or two about high revving engines.

He balanced my rotating assembly and said it was easy cause I bought good parts. (CP pistons, Manley TT rods, ITR crank)

I am running an ATI dampner for peace of mind.

I wonder how many people that shatter the oil pump gear have had a previous align-hone done on the mains. Since the oil pump has alignment dowels it seems like the gear would be miss-aligned following an align-hone of the mains.

OneBadTurboCRV

That's why you check it with feeler gauges and adjust accordingly. Really it's engine building 101... check your clearances. Heck, even Evans Tuning did a how-to video on it years ago... It's unfortunate that the foolish few are the reason soo many misnomers are born.

Experience > Internet