Forged rods and balancing of the V6 ...

[Audi_S4]

I have been thinking alot on the above and heared several different opinions and have also been told it's NOT easy to balance an S4 V6 engine !

It comes down to this : I have a crate bottom end (new AGB short block) that I want rods in. So I went to the machine shop where alot of my friends had engine work done and the dude is 60yrs old and had the shop since the 70's and does alot of rally and race engines

So I say , I have an S4 2.7 Biturbo V6 crate engine blablabla.... And I wanna put aftermarket rods in there with ARP bolts. He says no problem I can do that. Then I ask him can you balance the whole rotation assembly too ?
He says I can't do that V6 engine cause I don't have the contraweights (don't know what it's called in US) to balance a V6 cause this get's asked maybe once in 10 yrs and I can't make molds just for one engine but since your engine is brand new and tolerances from Audi are very good from the factory I can just balance the rods and pistons on their own and you will be perfectly fine we have done this a dozen times and it will be ok.

What's everyones opinion this ???

(please no opinion if you don't know what your talking about let's keep this an informative thread, thanks!)

[force fed]

Maybe explain to the guy what kind of horsepower your looking to achieve, and what kind of rpm the engine is goin to see, then maybe he'll have an idea of if balancing just the rods and pistons will work. Im sure someone with a little more in-depth knowledge of this will chime in...

[A62TURBO]

Just find another machine shop. This guy is obviously not tooled for your type of motor, but if you did only new rods you could get away without balancing.

[Audi_S4]

I told him 7500rpm rev limiter and 500whp
He said since it's only 250-300rpm more then a stocker and OEM tolerances are pretty damn good on these engines I would be more then fine.

To be honest it's not buying the parts and spending the € on these cars that makes my brain hurt but it's all the shit like this , he says this ,he says that .... in the end who is right ?

[Audi_S4]

Just find another machine shop. This guy is obviously not tooled for your type of motor.

I allready went to another shop that said it is indeed needed and also Loba motorsport confirmed it was needed but there also lot's of guys putting rods in these engines in their own garages at home and are perfectly fine so I ask myself if they are waiting for the granade to go pop?

[A62TURBO]

If you were doing rods and pistons I would say balance, but you'll be fine without a balance if your only doing rods.

[Audi_S4]

If you were doing rods and pistons I would say balance, but you'll be fine without a balance if your only doing rods.

That's what I've been told by many but I have no first hand experience with this so I want to be sure I do it right

[IgofastS4]

It does not have counter weights on the outside side of the motor, due to the fact it is internaly balnced not externaly, Externaly balanced motors have conter weights on the flywheel and balancer. the s4 2.7 is all Internal. the diffrence in rod weight will throw off the ballance from going to aftermarket rods from stock due to the grams in weight (of the rods). when they ballance it they calulate the (Bob) weight and make the diffrences to change the balance.

[Audi_S4]

It does not have counter weights on the outside side of the motor, due to the fact it is internaly balnced not externaly, Externaly balanced motors have conter weights on the flywheel and balancer. the s4 2.7 is all Internal. the diffrence in rod weight will throw off the ballance from going to aftermarket rods from stock due to the grams in weight (of the rods). when they ballance it they calulate the (Bob) weight and make the diffrences to change the balance.

That's some nice info. So what your saying is that he doesn't have a clue about the V6 TT

[IgofastS4]

That's some nice info. So what your saying is that he doesn't have a clue about the V6 TT

To put it nicely yes

[jibberjive]

I had to call around to like 4 shops (even the ones with the best reputations in the area) before finding a referral to a machine shop that had the bob weights for the V6. You might have to make some calls.

[IgofastS4]

I had to call around to like 4 shops (even the ones with the best reputations in the area) before finding a referral to a machine shop that had the bob weights for the V6. You might have to make some calls.

Who did you end up having do the balance for you ? My Machinest right? I just remeber seeing your IE rods, stock Pistons, crank
(Basicly your whole rotationg assembly) at his shop at one time long ago.

[julex]

You have to balance V motors since they are not "symmetrical" as I engines are where pistons/rods move in on plane. Changing weight of piston/rod assembly throws everything off in V engine. The rotating assembly needs to be balanced outside of engine with bob weights. Expect new welds/holes on you crank weights after said and done!

[fshowcars]

I allready went to another shop that said it is indeed needed and also Loba motorsport confirmed it was needed but there also lot's of guys putting rods in these engines in their own garages at home and are perfectly fine so I ask myself if they are waiting for the granade to go pop?

also keep in mind that when people like me 'throw in' pistons or rods, they are typically already balanced builds and replacements... at that, we plastigauge the installs to check bearings and if we aren't within thousands, something is up. If it's anything beyond replacing pistons or rods... it goes to a machine shop no question... so throwing rods in a car will work fine... issue is that most guys that throw stuff together never have cars that last years to see the outcome of their decisions. People that take shortcuts are rebuilding motors 2:1 than guys that do not.

in the end, i would never ever go to a machinist that doesnt' know the most elementary design of said motor... not knowing that S4's are internally balanced is really crazy for a machinist... I would not take his suggestions as gold seals.

[jibberjive]

Who did you end up having do the balance for you ? My Machinest right? I just remeber seeing your IE rods, stock Pistons, crank
(Basicly your whole rotationg assembly) at his shop at one time long ago.

Yeah, I had Jarl balance the rotating assembly. He was literally the only one in the valley with the bob-weights (that's not to necessarily say that he was my last choice.)

[IgofastS4]

Yeah, I had Jarl balance the rotating assembly. He was literally the only one in the valley with the bob-weights (that's not to necessarily say that he was my last choice.)

I am so glad he was able to do your with your balancing job.(Your trust is worth alot.) I have been doing buiness with him for 17 plus years and he has always been good. too bad we could not do anything to help the OP. (Due to the fact he is another country.)

[slow ride]

Geez guys, bob weights are weights you build up to mimic the weight of the rod/piston on each journal since you can't spin the crank on the balancer with those parts attached. They are installed on the rod journals, crank spun, and counterweights either drilled to reduce weight or Mallory metal (heavy metal) added to balance out the crank.

[IgofastS4]

Really

[bondar1989]

I heard that the stock rods can hold up around 500hp.

[Audi_S4]

Geez guys, bob weights are weights you build up to mimic the weight of the rod/piston on each journal since you can't spin the crank on the balancer with those parts attached. They are installed on the rod journals, crank spun, and counterweights either drilled to reduce weight or Mallory metal (heavy metal) added to balance out the crank.

Well this was something we allready knew but thanks for the tip

[slow ride]

Just making sure :) Some didn't seem to have it down or I figured it would help others not up on this stuff.

I'd measure the new rods big and small end and compare to the stockers. If it's sort of close it might be just fine or you can remove enough weight to make them close, etc. Just wouldn't want any crazy differences. It's crazy what they want for aftermarket china rods for these engines thougth. Price you pay for not dealing in large volume I guess.

[Audi_S4]

The balancing thing is quite a PITA as NOBODY around here can do it. I'm getting quite frustrated about it. There's LOBA in Germany and one place in Holland that does it. Loba is good but downside is , it's 500€ for balancing rotation parts only and sending my block is 200€ and getting it back is another 200€ so around 900€ for ONLY balancing the engine without assembling anything back together. Nothing wrong with there price offcourse it is what it is but the fact that they are over 600km's away and a short block weighs 81kg is quite a downside as I can't/won't assemble it myself I want the short block returned to me fully put together and balanced.

[JDM EJ1 95]

mine in the process of balancing.. not sure why any engine builder WOULDNT have the skills/knowledge

[jibberjive]

I think it's more that they don't have the hardware/weights than they don't have the knowledge. The machine shop with the literal best reputation in the valley simply didn't have the bob weights for my engine, as it's probably not worth the investment to do one engine every couple of years or whatever.

[Scotty@Advanced]

The balancing thing is quite a PITA as NOBODY around here can do it. I'm getting quite frustrated about it. There's LOBA in Germany and one place in Holland that does it. Loba is good but downside is , it's 500€ for balancing rotation parts only and sending my block is 200€ and getting it back is another 200€ so around 900€ for ONLY balancing the engine without assembling anything back together. Nothing wrong with there price offcourse it is what it is but the fact that they are over 600km's away and a short block weighs 81kg is quite a downside as I can't/won't assemble it myself I want the short block returned to me fully put together and balanced.

Wow that's a chunk of change.. There is one shop local I trust with my machine work and it's $310.00 for balancing a V8.. About $250.00 for a V6.

[julex]

You guys need to keep in mind that while US is the land of V6/V8 engines and as such with option for shops that do know what they are doing and have the equipment, europe is not. That's a land of I4 engines and finding a shop that can balance V6 could be problematic, at best.

[Audi_S4]

Wow that's a chunk of change.. There is one shop local I trust with my machine work and it's $310.00 for balancing a V8.. About $250.00 for a V6.

The shop in Holland quoted me 386€ ex btw (+21%) so around the same and that shop is also a good trip away from me so costs will rise with sending the block there + I have NO idea if they can be trusted so.... I'm not keen on having the most critical parts of my engine balanced by a place that I don't know if they are really up to the task concidering your build stands or falls because of this and if they should F up I'm seriously fooked