I swapped a 700r4 with a T5 worldclass. Getting a vibration that increases with speed. Any idea's?

 

What flywheel did you use? 87-92 305 flywheel should work just fine. It's what I used for my 92 formula (350tpi /zf 6speed swap).

 

I used one, yes. Still got the vibration problem. So I bought a new one and had it installed, still vibrated. After that went through the trans, switched driveshafts, no change. Took the car to a 9 bolt expert, thought that might be the problem. He says 9 bolt is fine. After putting up on a lift he says it's coming from the flywheel area. I'll describe it for you. The faster you go you can hear the vibration getting louder. Recently, I passed someone on the highway at 90. When I let off of it I thought the dash and console were going to vibrate apart. Really stumped.

 

Unbalanced flywheel will vibrate whenever the engine is running. It will be entirely engine RPM dependent. Won't depend on ANYTHING else. Purely, solely, completely, totally, engine RPM dependent. Won't matter what gear it's in; whether it's in gear or out of gear; vehicle speed won't make any difference; it'll still do it if the drive shaft isn't even installed; won't even matter if there's even a transmission there; won't matter if the engine is applying power (accelerating) or absorbing power (coasting down); etc. PURELY engine RPM dependent.

Eh???

If those FACTS don't fit your proposed "explanation", then your "explanation" is most likely wrong.

See my signature. Pay particular attention to the part about "fits all the facts". Concentrate on ALL in that quote.

If I was the guessing kind, I'd guess you have a pilot bearing/bushing problem. Did you install one?

 

i did install one, yes.

 

There is a procedure to balance replacement flywheels. The one thread below describes it, with the other thread having good ideas of what may have been causing his issue:

https://www.thirdgen.org/forums/tech...balancing.html

https://www.thirdgen.org/forums/tech...an-i-dial.html

RBob.

 

So, is it ENTIRELY dependent on engine RPM, and ENTIRELY independent of ANYTHING else? If it's not, that is, if ANYTHING ELSE besides engine RPM affects it, then it's not the flywheel.

That's still no guarantee that it's the flywheel; but you can certainly rule the flywheel out by way of that logic.

 

It happened to me 20 years ago and it was a bent driveshaft steel one I paid dealer 600 and they said the had it balanced and rebuilt and didn't fix it
4 years ago just for fun I found a 2002 aluminum driveshaft trans am ls1 140k and it fixed my vibrating issue
smooth as silk all the way up past 200kmh
it took me years but I finally ficed it
aluminum dampens vibrations

 

Drive shafts are indeed a major PITA for vibes.

However, they ONLY vibe when the car is moving, and then, they vibe ONLY in relation to vehicle speed. The OP needs to do some basic logical investigation:

When does it vibe? and, what thing that speeds up and slow down, changes the vibe?
.

• Vehicle speed exclusively, at wheel speed (wubba-wubba-wubba-wubba-wubba, more wubbas as the car speeds up, no wubbas when sitting still): tire separated or out of round, bent wheel, bent axle, various brake problems
• Drive shaft speed (car speeds up, sound goes hhhhmmmmmmm and gets faster as vehicle goes faster, NOTHING ELSE changes it): drive shaft unbalanced or bent, U-joint not installed in the yoke properly
• Drive shaft speed (car speeds up, sound goes hhhhmmmmmmm and gets faster as vehicle goes faster, changes according to whether accelerating, floating i.e. match engine speed to wheel speed such that all torque is removed, or coasting): pinion bearings
• Either engine or drive shaft speed, or seems to switch from one to the other sometimes ((hhhhmmmmmmmmmm, changes when the gears change, and is different depending on what gear it's in, even if engine RPM is the same): transmission internals
• Engine speed exclusively (hhhhmmmmmmmmmm, doesn't matter what gear it's in, doesn't matter if the clutch is engaged or released, whether the car is moving, whether there's even a drive shaft or a transmission IN THE CAR): flywheel balance, clutch balance
• Engine speed, but can be altered either more or less by creating the "float" condition and pushing and letting go of the clutch: pilot bearing/bushing

It's SO BASIC. Before trying to fix a vibe, you gotta figure out what's actually vibing. Posting on the Internet about "what flywheel should I use" or "my drive shaft is farkled" is USELESS until and unless the VEHICLE OWNER is willing to do some LOGICAL fact-gathering, and lays off of the "Internet!!! Fix my car for me NOW while I don't do ANYTHING because I'm LAZY!!!!!!!!!!" crap.

Incidentally, it doesn't matter which T-5 design it is, including the sh**ty BUZZWORD from the 80s that starts with "W". Doesn't matter if it's a T-5 at all. ANY manual transmission can be treated the same way to find a vibe.

 

When you push in the clutch does the vibration change?

 

It's just a little surprising that no mention has been made of the pressure plate.

 

Clutch = pressure plate

Could be the clutch disc too I suppose, if it vibes when the clutch is out and the trans is in neutral, but shuts up when the pedal is pushed and the trans is in gear with the car sitting still.

 

Dammit. I should have known. I missed that in the Book of Diagnosus, Intermediate Testament, and then later in the Book of Remedius.

 

no. I"m getting some advice from some Corvette mechanics who tell me that the clutch/pressure plate have to be balanced on the flywheel.

 

Yes, sometimes that happens. Ideally, clutches are supposed to be balanced before they go into the box, but... maybe whoever is doing the supposing, isn't supposing quite hard enough. "Have to" is a whole other matter. Basically, you're doing SOMEBODY ELSE'S quality control, if you "have to" do that.

Then there's the problems of installation: using the wrong bolts (clutch bolts have short threads and a shoulder to "dowel pin" the clutch to the flywheel positively), and over-enthusiastic tightening of the bolts.

 

Vibes are there when clutch is depressed. lessened somewhat but there.

 

Since it hasn't been asked yet (directly), did the flywheel installation go smoothly? Dowel installed in teh crank flange and aligned? Bolts torqued properly? No runout issues? As long as it wasn't a flywheel for a two-piece RMS or SBC400, the rest should be correct.

 

You can completely remove the clutch and start the motor. Obviously, in that state, with the clutch and bell housing laying off to the side, the trans and drive shaft will also be laying on the ground somewhere, and therefore not causing vibes. The only thing left at that point that can be vibing is the flywheel. If it runs smooth, then the flywheel is OK. Start putting on parts one at a time, and see when the vibes start.




And of course, make sure you are using real clutch bolts; and when you install the clutch to the flywheel, tighten all 6 until they just make contact, then go around them in a circle tightening each one only one turn at a time. Should take about 6 trips around the circle to get them all fully tight that way.

You can run it with just the flywheel, and add the clutch and work on it until true (simplest place to start there would be to rotate it on the flywheel 180° if it vibes and see if it gets better or worse), then take the clutch back off and add the disc being EXTREMELY careful of course to get it EXACTLY centered (such that your alignment tool slips freely in and out of it), and so on.

 

I installed flywheel number one that came with the T-5 I bought. Flywheel number 2 was installed by a transmission shop. Vibration did not change.