4age 20v Balance problems, please help!

[downunder]

Hi, very new to all this so I hope this is posted in the right place! I have a 20 valve silver top 4age and I have just replaced the flyweel with an identical one (long story as to why) but now it has a slight vibration just above idle (1200rpm) The thing is now that I am not sure if it was there before or not!! Silly me. Does anyone out there know if the flywheels are match balanced to the crankshafts etc at the factory therefore cannot be interchanged???

[Tsuchiya]

nah, they're usually not match-balanced as the engine ( crank, internals, etc) are balanced on their own, and the flywheel done the same. (that's y u can purchase lightened flywheels and clutches without having to check your engine's balance before installation.)
so check your flywheel at a machine shop

[Krakkle]

(Agree with Tsuchiya's post)

My 4AGE came w/TODA flywheel & 3-puck copper disk

(I expected to see a TRD part at most !)

Anyway, an ACT 6-puck copper disk was installed without any "negative vibrations"

Perhaps your flywheel needs re-installing, proper torqueing with all correct bolts after inspecting it thoroughly. Good luck.

[Aarong420]

what is the corret torque setting for the flywheel and pressure plate on a ST 20V ?

[Krakkle]

what is the corret torque setting for the flywheel and pressure plate on a ST 20V ?

The six bolts should be tightened in a "cross" pattern (similar to lug nuts) using : 75N.m (750 kgf.cm) OR 54 ft.lbf

[downunder]

Hey thanks, going to put original flywheel back in on sat, will let you know how it goes!!

[downunder]

Put old flywheel back on and vibration gone, wierd huh?

[Aarong420]

the flywheel probly wassnt balanced properly, carry it to a mechine shop and have them check it for you..

[downunder]

Old flywheel back on and no vibration!, and yes your right Aarong, machine shop has checked balance of the flywheel in question, it was out. does not matter now. Old one back in. I changed it cos I wanted one pre machined so I could replace the clutch without waiting for my flywheel to get machined. Never again!

[Aarong420]

lol good for you man, soon enough im gonna have to take down my gbox, im dreading that time..

[Tsuchiya]

Unbalanced flywheels are dangerous. If you had run alot of rpms it could've broken the flywheel bolts and exited your car. It could've also destroyed your crankshaft and bearings. Good thing you found out the reason.

[turbohead]

ah fine wen u put copper clutch in dem engine it have a tendency ah vreakin mount quicker dan other engines wit copper y is dat?

[Tsuchiya]

^^cuz copper clutches are so aggressive. With a regular clutch, the clutch itself will absorb some 'shock' loading. Whereas copper clutches grab so aggressive it transmits the 'shock' all the way thru the driveline, where it'll find the softest link, which often times is the weakest. Thus in this case being the mounts. If you were to stiffen and reinforce the mounts, you'll find u'll start breaking other things like g/box, axles, etc

[Aarong420]

hey downunder, Im thinking about what youve said bout the vibration your getting. When exactly did u feel the vibration? from idle to high rpm, only at high rpm?...

[turbohead]

i no bout dat but if u have a copper in a sr u doh buss mounts like a same type copper in a 4age. dts wat i wanna no.

[Aarong420]

im not sure why it would bust mounts quicket than an sr, but i know the sr mounts are huge. Also im not familar with the sr clutch, but i know the 4A clutch is bigger than a standard size. so the grip the cuppoer clutch will get will be more agressive.

[Tsuchiya]

i no bout dat but if u have a copper in a sr u doh buss mounts like a same type copper in a 4age. dts wat i wanna no.

which follows what i've been saying. Basically the mounts are bigger in the SR, as AArong420 pointed out, so most likely its stronger and so I know a couple SR-equipped cars that destroy axles and CV joints quickly becuz this is probably the weakest link in an SR's driveline
yuh dig??