4.2 V8 engine parts required

Started by Lee, May 20, 2010, 05:37:15 PM

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Lee

Hi Guys--My Polo V8 has a vibration problem at idle although very smooth though the rev range.

My local engineering guru tells me I have spoiled the crankshaft balance by attaching a VR6 flywheel.

I need to borrow a V8 flexy plate to be able to determine the original balance and then to transfer the counter weight value to the new flywheel.

I also need a piston and rod assembly as this weight is also needed in the re balance.

Any help would be appreciated


qta4

That is really interesting, i thought that crank and rods/pistons were balanced as one unit , and flywheel is balanced as one unit, thus all is good.

So are surprised you have an issue.

The harmonic balancer is used to reduce vibration due to rotating masses, but not as a balance device.
Skill is, sucessfully tightrope walking across the Niagra Falls.
Intelligence is, having the sense not to do it.

Lee

As I understand it--because of the length of the crank there are balance issues as the crank twists.

Sounds like witchcraft to me.

But the vibration at about 1200 rpm is not reassuring and I am warned I can break the crank because of the in-balance

Maybe someone has inside knowledge on this???

qta4

Thats cool, i will do some researach for you Lee.
Skill is, sucessfully tightrope walking across the Niagra Falls.
Intelligence is, having the sense not to do it.

Lee

Thanks Noel---Appreciate anything you dig up

Otherwise does anyone know of someone with a v8 in pieces that I can hassle.

The Polo is amazing to drive but the vibration is a real pain

qta4

I doubt you will find anything here Lee, let me ask my Guru.........
Skill is, sucessfully tightrope walking across the Niagra Falls.
Intelligence is, having the sense not to do it.

qta4

#6
Just spoke to my guru.

The problem is that flywheel is off a v6, so is balanced as part of the engine due to its irregular firing order.

So if you take your flywheel ( the v6 one ) and get that balanced , you will be fine.

The V8 is balanced as i said earlier, but V6;s are not.

Ron says that they are not easy to balance, but with a good grip system to hold the flywheel, you will be fine.


Send me a PM or ring
Skill is, sucessfully tightrope walking across the Niagra Falls.
Intelligence is, having the sense not to do it.

AndyGti


Lee

The vr6 flywheel was lightened to the prudent minimium and then balanced by Engine Services in Cambridge

It was they who suggested that the original flexi plate was a part of the complete balance.

I just wonder- if the clutch itself is the problem??

qta4

Im lost here Lee, maybe they just lightened the flywheel.

So maybe it is still unbalanced???????
Skill is, sucessfully tightrope walking across the Niagra Falls.
Intelligence is, having the sense not to do it.

Lee

I'm sure they balanced it because of the trouble they had in mounting it on something--but I will ask tomorrow

80 Vert

Flywheel and clutch cover should always be balanced as a unit.
2010 T5 Transporter TDI  Tuned by Superior Tuning NZ
2003 Jetta Coupe soon to be R36TT
1991 Golf GTI 2.0 TSI swapped
1963 Type 34 Karmann Ghia, turbo 2.0
1990 Porsche 964 911 Carrera 4
1980 1303 Beetle vert, under restoration

Lee

So- one can not expect a clutch assembly to be balanced even if you buy one off the shelf ??

80 Vert

2010 T5 Transporter TDI  Tuned by Superior Tuning NZ
2003 Jetta Coupe soon to be R36TT
1991 Golf GTI 2.0 TSI swapped
1963 Type 34 Karmann Ghia, turbo 2.0
1990 Porsche 964 911 Carrera 4
1980 1303 Beetle vert, under restoration

wilco

In the meantime though I have an ABZ flexiplate you can borrow if still required. PM me.

AndyGti

i can grab it off wilco wensday if you need lee

Lee

Well we all like a happy ending eh

I took the flywheel and clutch off the car and gave them to the balancing guy in Hamilton.

The result was the fly wheel was out by 2 grams and the clutch by 8--which is apparently a lot.

Wilco kindly lent me a v8 flexiplate which was in perfect balance --- proving that the engine did not have a counterbalance.

So--I put it all back together and it runs absolutely smooth---end of sad story--but I learnt not to trust anything

Thanks for all your input--It's appreciated

AndyGti

glad to hear that it fixed the issue!! so much better than taking the engine apart!!

GTI's