Massive vibration/shaking after supra gearbox swap

[DrNick]

The car is a 1995 JZA80 SZR Supra, originally with the 5 speed W58 transmission.

I have replaced the following parts

R154 gearbox swap
Rear main seal
1JZ Flywheel (secondhand flywheel, was machined before use)
ARP fasteners
XTreme 6 puck clutch kit (with new pilot & throwout bearings)
JZZ30 front driveshaft
OEM gearbox crossmember and mount

Everything looked promising, started up the car and there is a massive vibration sitting there at idle. It is mostly between 1-2K rpm but I drove the car and it does it all the way through the rev range. The vibration is the same whether it is neutral or driving.

The gearbox itself is not noisy or clunky and the clutch feels very smooth.

I have since replaced the engine mounts as they looked a bit flat, but it made zero difference. I also just looked through the gearbox inspection plates with the engine running and there is nothing visibly wobbling etc. Same goes for the engine, everything seems smooth. In fact if you put your hand on the engine it doesnt feel shaky like it does when you sit in the car.

It's pretty disheartening as the project has taken a few weeks and now the car is worse than when we started! Has anyone encountered something like this before? Please tell me what I am missing here.

[IN 05 NT]

id be pulling the box back off and checking pressure plate/flywheel bolts, as its something rotating making that vibration

thats if everything external looks fine,

[LeeRoy]

I have replaced the following parts

R154 gearbox swap
1JZ Flywheel (secondhand flywheel, was machined before use)
XTreme 6 puck clutch kit (with new pilot & throwout bearings)
JZZ30 front driveshaft

Any of these could be out of balance. Chances of the box being out of balance would be slimmer than a bee's dick, generally would only happen if you knocked some teeth off, have rooter bearings, shafts etc.

By driveshaft im guessing you mean front section of the tailshaft. I'd say its probably that. If its not this then i'd be looking at the clutch or flywheel.

[DrNick]

Any of these could be out of balance. Chances of the box being out of balance would be slimmer than a bee's dick, generally would only happen if you knocked some teeth off, have rooter bearings, shafts etc.

By driveshaft im guessing you mean front section of the tailshaft. I'd say its probably that. If its not this then i'd be looking at the clutch or flywheel.

Yes I mean the front half of the shaft is from the JZZ30, the rear half is the original one I had on there before. I thought this was a bit suspect before, but the vibration is there when the car is in neutral so those shafts would be disengaged.

[Hen]

If it still vibrates in neutral, then you've narrowed it down to input shaft, clutch or flywheel (or maybe the motor itself but I think that's unlikely).

If it still vibrates when the clutch is pushed in then you've narrowed it down to flywheel and clutch pressure plate.

Whatever the case I think you'll have to drop the box again and take a good look at it.

Hen

[the_random_hero]

I'd put money on clutch.

[allencr]

In fact if you put your hand on the engine it doesnt feel shaky like it does when you sit in the car.

Trans. hitting the tunnel or cross-member if it isn't the clutch or flywheel.

[Z2TT]

Gearbox mount maybe?

[IN 05 NT]

Everything looked promising, started up the car and there is a massive vibration sitting there at idle. .

this pretty much rules out anything exernal as nothing else will be moving....most likely internal, clutch/fly

[lexsmaz]

I would put my money on the clutch pressure plate being the cause ... I fitted a clutch years ago, that had a massive vibration as well when the car was running, removed clutch again & inspected, found the pressure plate main face ( clamping face ) was actually off centre, ( slightly ) i suspect the pressure plate had been dropped as some of the side tension straps were actually slightly bent ..

Fitted up another new pressure plate & all good again ..

Obviously check all that when you pull it out & if in doubt get the pressure plate & the flywheel etc balanced .. But get them balanced individually though ..

Rob ..

[andrew_mx83]

do u get clutch shudder on takeoff? if so it is probably not aligned properly

otherwise flywheel balance
it wont be tailshaft it it does it whilst sitting still....

[DrNick]

The car shakes so much its actually hard to tell if i'm getting clutch shudder! Although I would be inclined to say yes there is a bit, but not every time I take off. I thought that was consistent with the harsher puck style clutch plate though. I'm going to go and take another look at it this morning, looks like either way the box has to come off again. Thanks for the tips so far, I will keep you posted

[petergoudie]

After you take the pressure plate off put a dial gauge on the flywheel. It's possible there is a piece of dirt under the flange face that bolts onto the crank.

[DrNick]

Well I'm taking a break from it and the car is locked up in my mates shop while he is away on holiday. Will tackle it in a week or two.

However, when I last saw it I had a look at my old flywheel and that had holes drilled in it for balancing purposes. Please tell me that the flywheel is not balanced with the crankshaft.. That would be disastrous as we didn't mark the position of the flywheel/crank flange when removing it.

[petergoudie]

My understanding is that manufacturers balance the crank with the flywheel and pressure plate fitted. The pistons & conrods are not fitted though as they match the weights on the production line so the weights are the same.

However, when you fit a new pressure plate several years later it can't be balanced to the crank. Similarly if you buy a new flywheel. I suspect that the vehicle manufacturer only wants to balance everything once rather than the individual bits separately whereas with aftermarket parts the cost of the individual balancing is included in the sale price.

Whilst it's better to fit all the original parts back on the same way they came off I doubt if it would make 'massive' differences in vibration as you describe but I could imagine it might be detectable.