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Building forged vq35de. Rotating assembly balancing?


Ortega_9

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I'm looking to up the power in my tt350z so looking into building a new powerplant.

 

Have any of you, with build vq's, had the rotation assembly balanced?

 

i'm planning on having parts weighed out and balanced that Way. I have done this a few times, and having no issues what so ever.

 

But having trouble finding information on the necessety of having the entire rotating assembly balanced together?

 

My reason for asking is if you buy a build short/long block that States it's been balanced, what does that include?

 

they can't really balance it without your flywheel/clutch etc.?

 

i have had my block honed, and my heads decked, and that is about the machining I normally do before building.

 

Any input other than what the interweb claims to be the truth.?

 

 

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10 hours ago, Ortega_9 said:

My reason for asking is if you buy a build short/long block that States it's been balanced, what does that include?

 

they can't really balance it without your flywheel/clutch etc.?

 

 

Hello, you need to ask the tuner/builder of the engine. Most of the time balancing means weighing everything and then put together. The good tuners/builders do this also, but also balance everything rotating. Including the flywheel and clutch offcourse. 

 

So the only thing to say to you is: contact the builder and ask what exactly is being done to the engine to balance it and how.

 

Hope this helps.

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Thanks. 

I'm the one building it.

 

iw'e heard about it but never seen it done here in Denmark.

 

i'we build plenty engines, but never had it done on the 4bangers i build in the past, but the V6 is another kind of monster, so might try to get it done somewhere.

 

i guess they will need the complete setup minus block and heads...

 

 

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I think they substitute the rods,pistons,rings with weights they bolt onto the crank so they can spin the crank,flywheel,crank pulley,clutch  and see where the imbalance is with computers. It’s still not ideal IMO as it doesn’t take into account the weight of each piston at different stroke lengths which will change the forces acting on the crankshaft.

Most places I had talked to in Scotland can’t do it either :-(

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10 hours ago, evilscorp said:

I think they substitute the rods,pistons,rings with weights they bolt onto the crank so they can spin the crank,flywheel,crank pulley,clutch  and see where the imbalance is with computers. It’s still not ideal IMO as it doesn’t take into account the weight of each piston at different stroke lengths which will change the forces acting on the crankshaft.

Most places I had talked to in Scotland can’t do it either :-(

Yehh, i'we seen some youtube stuf with the V8 guys on the other side of the pond, but never seen it done here.

 

i'm also asking wether it's nessesery? Or it's overkill. If anyone building vq's do it. Or it's "just" weighing out the piston,rods, rings etc, and putting it on a balanced krank?. 

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On 13/10/2018 at 11:31, ZMANALEX said:

These guys, local to me should be able to carry out what you require.

 

I have been associated with them for over 40 years and they are a well established, experienced machine shop.

 

http://www.agra-eng.co.uk/services/competition-departmnent

I think I tried contacting them previously and got a decent response, sadly neither myself or them contacted each other and my engine build went on the back burner.

**

Not sure if we will be able to carry out the bottom end balance in house at a reasonable cost . 
V-configured engines require either different types of machines or very intricate balancing techniques. 
If we are to do this type of dynamic balance in-house we would need to design, manufacture & fit special counter weights to your big-end journals. 
In order for us to do this we would need to know the correct balance factor specific to your crankshaft, which unfortunately is not information OEM's generally give out. 
Alternatively if you send your old OEM con-rod & piston assembly inc. bearings & rings, along with your new rods & pistons, it may be possible to calculate the balance factor but it's a pretty tricky job and will involve a lot of work.  
If we manage to calculate the balance factor we would have to manufacturing a set of counterweights to prove our sums are correct and then make up another set of counterweights to simulate the difference in weight of your replacement piston & con rods assemblies. 
As you can imagine it's extremely difficult to even hazard a guess at what this might cost.  
However, I have a couple of contacts who might be able to help with this at a reasonably attractive price, so don't despair, I'm just waiting to hear back from them...
**

But that was 2014 so things have probably moved on and Agra might be able to do it easier now.

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I've just sourced an HR engine for the reason to rebuild it next year and as all previous builds I've done I'll be getting the rotating assembly balanced to inc crankshaft, front pulley, flywheel and clutch cover. Pistons balanced and con-rods balanced end to end also.

 

Given my build is going down the n/a route revs may be higher than you're targeting going down the TT route but I still think it's essential to get this carried out as a small imbalance at low revs will multiply exponentially at hi revs! Leading to a rougher run and increased wear on your bearings etc! Not what you want when you're building from scratch!

 

There is a lot of maths and working out for the machinist where making the counter balancers required for V6 balancing is involved to actually make all this work so they need to be top end. These counter balancers need to be worked out from the piston/rods you're using so if this stage is skipped then just having piston/rod weights matched and crank balanced on its own once all assembled will not give you a rotational assembly that's balanced.

 

Although all this will dynamically balance the engine, V6's will always have an imbalance due to uneven firing order. Luckily Nissan have done a great job of the VQ 60degree V6 for us to start with!!

 

If you'd consider sending your parts to the UK for the work to be carried out I'll send you the details of the machine shop I've used for 14years and they have done VQ DE before too.

 

 

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8 hours ago, 350Butcher said:

I've just sourced an HR engine for the reason to rebuild it next year and as all previous builds I've done I'll be getting the rotating assembly balanced to inc crankshaft, front pulley, flywheel and clutch cover. Pistons balanced and con-rods balanced end to end also.

 

Given my build is going down the n/a route revs may be higher than you're targeting going down the TT route but I still think it's essential to get this carried out as a small imbalance at low revs will multiply exponentially at hi revs! Leading to a rougher run and increased wear on your bearings etc! Not what you want when you're building from scratch!

 

There is a lot of maths and working out for the machinist where making the counter balancers required for V6 balancing is involved to actually make all this work so they need to be top end. These counter balancers need to be worked out from the piston/rods you're using so if this stage is skipped then just having piston/rod weights matched and crank balanced on its own once all assembled will not give you a rotational assembly that's balanced.

 

Although all this will dynamically balance the engine, V6's will always have an imbalance due to uneven firing order. Luckily Nissan have done a great job of the VQ 60degree V6 for us to start with!!

 

If you'd consider sending your parts to the UK for the work to be carried out I'll send you the details of the machine shop I've used for 14years and they have done VQ DE before too.

 

 

Thank you.

 

Also great info, and i might send it all out as I haven't found any shop over here that Can do the work.

 

 

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53 minutes ago, Ortega_9 said:

I have found a shop here in Denmark who Can do the balancing for 650£ all included.

 

thats not too bad i my book. And they specialice in V6 and V8 rebuilds.

 

i might go for that when i have all other parts ready. 

 

Sounds like a result! For what you're gaining I'd say that's worth it.

 

Sorry if the info is already posted but just interested........What stage are you at with your build and what are your goals?  

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36 minutes ago, 350Butcher said:

 

Sounds like a result! For what you're gaining I'd say that's worth it.

 

Sorry if the info is already posted but just interested........What stage are you at with your build and what are your goals?  

Yeh!

 

im fixing some minor things in the setup on the car, and buying parts for the new engine. 

 

i'm going for broke. I don't know how that will translate hp wise, but i'm guessing 700ish with the two gt3076's i Got on the car now.

Edited by Ortega_9
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If you're gonna do it you got to do these things properly! So many people try and cut corners/save a few quid here and there when it comes to builds and it never has a happy ending.

I can't wait to getting started with my 3.7 n/a build.

 

I know big power numbers are becoming more and more normal but 700Hp!! I just cant imagine my car with double the power and well over double the torque.....have you got a build thread at all or thinking of doing one? Always good to see projects from people doing them properly.

 

@Snjur is your man for all things VQ, turbo'd and producing massive Hp! 

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Just now, 350Butcher said:

If you're gonna do it you got to do these things properly! So many people try and cut corners/save a few quid here and there when it comes to builds and it never has a happy ending.

I can't wait to getting started with my 3.7 n/a build.

 

I know big power numbers are becoming more and more normal but 700Hp!! I just cant imagine my car with double the power and well over double the torque.....have you got a build thread at all or thinking of doing one? Always good to see projects from people doing them properly.

 

@Snjur is your man for all things VQ, turbo'd and producing massive Hp! 

I'we spend quite a few £ over the last years.

i have a Gtm Twinturbo build thread.

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