damn vibrations coming on boost

[PACEMAKER]

Hi all,

Since i pretty much rebuilt my whole vr4 during the last 6 months ive had some serious vibration problems. I replaced both centre bearings and all the uni joints. It made it sligtly better but not much. I sent the tail shaft to drive line services and had it balanced. When i picked it up they said they couldnt believe how bad it was but ok now.

On the high way at cruise its smooth as since getting it balanced. But at about 2500rpm until 7000rpm under acceleration the whole car shakes to the point it frustrates me and i hate driving it.

Today i tried putting spacers between the bearing carriers and the chassis. I tried many different thicknesses and combinations such as same thickness for front and rear bearings, thicker front, thicker rear and so on.

After putting the car on and off the hoist a dozen times between test drives all i managed was to change where the car viabrated ie. no spacers starts viabrating at 2500 with spacers doesnt start viabrating until about 4500 but viabrates on the highway at cruise.

When i rebuilt the motor the eng mounts were a bit soft so i filled the gaps with urethane and left them a few days to go hard. So in theory the engine should be sitting where it would be with new mounts just without the slight give as the gaps arent there.

So if anyone has any ideas im listening.

Oh and i have had the diff out but i cant see how that could be out of alignment. And on over run or engine braking there is a loud howling noise but only at 60kms and above.

Thanx, Michael.

 

[mattrat]

id take a stab and say transfer case

 

[PACEMAKER]

Are you saying that the transfer case could be causing the viabrations as the car comes on boost?

 

[mattrat]

yer, there as so many driveline gurus on here that will help you out, i dont know much

 

[PACEMAKER]

cant wait to hear from them!!!!!!!!

 

[GVR40]

have you replaced the yoke coming out of the transfer case and checked it for leaks and made sure it still has fluid. i know that was an issue with these cars from the factory. it sounds a lot like a transfer case issue to me.

 

[brisvr4]

There is absolutely no chance that this could be balance shaft related??

 

[CLuTZ]

Double check that tranny mount

 

[GVR40]

if you want to bring it down to my place tomorrow i can have a look for you, see if another pair of eyes can shed some light on it

 

[PACEMAKER]

Yoke is good, transfer has oil, there is not one oil or coolant leak in the entire vehicle, balance shafts are good i double checked that last week. I must have done 50 4G63 timing belts. The eng only vibrates under load. I can sit on the highway at 5000 rpm in 4th and reasonably smooth until i accelerate. Then its like a good quality dildo with new lithium batteries

Hey Craig what time suits you tomorrow. Just text me and ill give ya a call.

CLuTZ, My g box mount is pretty solid now since i filled the gaps. It has to be an alignment problem!

Thanx guys, Michael.

 

[Kane_GSR]

centre diff??

i had a vibration always under acceration.

 

[CLuTZ]

Some people still get the balance shafts 180 out, no matter how many times they have done it

 

[JAP63]

Mate im on the Gold cost too, where abouts are you at?

Give me a call if you like on the weekend and ill come sqwizz it with you. I had simmilar things occur in my VR4, I feel your pain, I fkin hatd it, with the windows up theyd shake etc, jeez i hated it.

Ive got a real strong felling its driveshaft related, I say this because you describe a pretty bad shake, and the only thing rotating with enough inertia to give you such grief is either the driveshaft or the wheels.

Im on 0435 23 4476
Feel free to text or call

jamie.

 

[CLuTZ]

Intermediate shaft loose?

Could be a bunch of things!

Bearings about to collapse in the g/box!??

 

[bazeng]

Have you tried driving it on the hoist to inspect for the vibrations?

Drive it with your wheels, then take them off and see how you go.

 

[GVR40]

come round anytime michael, i'm home all day today, i don't have your number sorry, i lost it when i got my new phone

 

[EVO-00X]

Mate of mine had similar problems but in lower gears and it was the bearings in the gearbox were fukd. Changed gearbox and the problem disppeared.

 

[rob323]

I sent the tail shaft to drive line services and had it balanced.

[/QUOTE]
Last time I checked, Driveline Servies could only spin a drive shaft up to about 3000 rpm or so, nowhere near fast enough for a performance car but fine for trucks. Hardy Spicer can spin them up much faster and have successfully corrected a couple of drive shafts supposedly balanced by Drive Line Services that I know of.

A "driveshaft out of balance problem" is usually a harmonic problem and will not be constant over the entire rev range. It will appear and disappear and reappear and the revs increase.

Have you checked the rear diff mounts to make sure the diff isn't rotating under load? It may also pay to have the rear diff checked incase it is the cause.

I second the idea of putting it up on a hoist and starting the car up, although it won't show you what is happening when it is under load, it may though show up any out of alignment problems in the drive shafts.

Have you swapped the wheels and tyres over with a set that are known to be good and free of vibration?

 

[GVR40]

i had a look at it and the front engine mount was fairly worn and under load the motor would twist down and looked like it could be touching the chassis rail

 

[JAP63]

i had a look at it and the front engine mount was fairly worn and under load the motor would twist down and looked like it could be touching the chassis rail

I had this too once, man it was obnoxious, the gearbox was touching though, it was a real bad vibration, more of a noise though.