well its a '92 camaro with a 305 tbi, was auto. the auto blew so i swapped in a nwc t-5 and since then ive had a weird vibration in the driveline. had a few freinds drive it around and they said the motor is out of balance. im sure its the flywheel, guy told me its from a 305 but maybe its for a 350? or differently balanced?

Idk but the question is how do i fix this?

was told i could buy a new flywheel (tho they are hard to find) have a shop rebalnce it (tho i dont have the orginal flex plate so maybe they cant?) or put a 350 harm. bal. on. the only restriction i have on fixing this is it needs to be cheap. so ideas?

 

no 350 had a manual, try rotating driveshaft 180 degrees. Also t5's are junk and have play in the input shaft and can cause this vibration.

 

theres ppl here that will fight you on here wether or not a 350 came with a t-5, i know what GM said bout the issue but theres still ppl who swear they have a f-body factory 350/t-5 combo.

ill try rotating the driveshaft, and if that doesnt work?

and my input does wiggle like that(1st part of the vid), not as much but still has that play and sound, could a rebuild fix that?

 

In this case it doesn't matter if they came with it or not. The engines are balanced the same unless someone has done something stupid.

 

First - does it shake when RPM's are brought up in neutral? If it does then you're fighting an engine balance problem or a misfire causing the shaking. If not then it's drive line related.

Since you said the T5's input shaft is loose - You may get by with just sitting it up on it's end, pulling the bearing retainer off the front and pulling the input shaft out - inspect the end of the shaft where the needle bearings ride for wear and inspect the needle bearings for pitting/wear and replace as necessary. Once those are deemed good then re-shim the input shaft for as close to '0' endplay as possible but don't preload it. While it's out - pull the tailshaft housing off and put in a new bushing and seal in the rear as play there will be real noticeable at speed.

The T5's are decent transmissions if they are maintained and not allowed to have the mainshaft endplay go out of spec for too long. There is also a guy I knew that used to machine the shaft and mating surface for a tapered roller bearing like the "z-spec" T5 and that helped increase torque holding capacity.

 

The flywheels for the 1-piece RMS engines are individually balanced. I have a post somewhere on here that describes the factory method of balancing them. It consists of using slugs that are placed into the holes around the perimeter of the flywheel.

And it is done by feel. That is, the trans and bell removed with the car on a lift. The engine is run to see what level of imbalance there is. A weight or weights is placed into the holes, the engine then run up again, if the balance is better or worse, the weights are adjusted some and so on until the engine runs smooth.

RBob.

 

As for the play in the input shaft of the T5, this is normal. The pilot bushing holds the shaft in place. IOW, once the trans is installed the shaft can't move around.

Which is also why it is important to have the bell housing properly aligned with the crankshaft.

RBob.

 

aperion, this 305 seems more peppy then factory, i suspect theres been a rebuild with different internals, but is unconfirmed. however there is an under-drive crank pulley.

bwiencek, it doesnt shake in neutral, well not the shaking im talking about(seems i have a slightly off plug). as i was test driving it i did find the shaking im talking about starts at ~3250 rpm, how ever if you shift up the shaking goes away and if you let off the gas it goes away, so im now thinking trans problem?

rbob, im un sure of which engine and flywheel i have, i hear the engine should be 1 pms but not sure how to verify it, havent pulled block numbers eighter. and for the flywheel, well same thing. but if i do have a 1 pms motor and a 2pms flywheel could that cause a problem? also the bellhousing came with the trans (as the flywheel didnt, thus why the uncertainity) and the trans is from a '86 firebird with a 305 carb. so there shouldnt be an allignment problem, i wouldnt think anywas.

 

you can't put a 1 piece RMS flywheel on a 2 piece RMS block

 

are you sure? dont they have the same bolt patterns? bc if you cant mix them then i dont have to worry bout that.

 

You can see if it is the driveline that is out of balance by depressing the clutch and just rolling at whatever speed the vibration is. That will eliminate the driveshaft.

 

the virbration isnt at a speed limit, its at a rpm limit ~3250 rpm it starts but if you shift or let off the gas or depressing the clutch in it stops. thinking its more driveline/trans problem so might switch the thread to there.

 

Just to confirm - you can NOT put a 1pc flexplate or flywheel on a 2pc rear main crank.

There was however a kit a long time ago to put a 2pc rear main seal crankshaft into a block that was designed to use the 1pc rear main seal - it was primarily used to build higher HP engines and strokers before there were forged and stroker 1pc rear main crankshafts...

If you go to say 4000 RPM and then let it coast down with foot off the throttle does it shake all the way down to the ~3250 you mentioned? Also does it still accelerate up to the "redline"?

If it doesn't shake coasting and accelerates up to higher RPMs then I'm going to suggest that you have a secondary ignition problem and a misfire which is causing the shaking - could be as simple as bad plug wires, plug gap too large, wrong heat range plugs, bad cap or bad rotor or even a weak ignition coil. When is the last time that you did a complete tune-up? (cap/rotor/plugs/wires)

There is also a slight possibility that it's a bad ignition module or pickup but that's less likely and would take a scope to really diagnose that accurately. Just remember that these older EFI systems didn't detect misfires like the OBD-II ones have to.

 

sweet, i didnt use nothing special to put it on, and if it doesnt matter if its a 305/350 flywheel i guess that pretty much elimates the flywheel beening a problem.

when gone up to 4000rpm and coasted downt he shaking stops, but if you get on the gas above 3250rpms the shaking comes back.
not sure what you mean by accelerate up to the redline? redline starts at 5000 or 5500 rpms on the tac.

as for the igntion, primary or secondary, trying to chase down vapor lock (bc apperently no one knew tbi only has 12 psi and can get vapor lock) i replaced dam near everything; coil, module, dist. wires, cap, rotor, plugs, IAC, tps, filters, and a few other things. the plugs i gapped properly how ever they are platnum and im not happy with them, from the day i put them in the motor seems to of lost power (again was recommended to put platnum in instead of copper)

 

If it stops when you depress the clutch then the vibration is coming from the motor side of the clutch. I'd look into the mis-fire idea that one poster had.

 

ugh every electonic thing has been replaced im serioulsy about to give up

 

Can we recap?

1) It vibrates above 3250 RPM but only while accelerating. It is RPM dependant not speed dependant, so in any gear?
2) It stops vibrating if you let off the gas and coast.
3) It stops if you put the clutch in.
4) It doesn't vibrate if you rev it in neutral.

Is that correct?

 

yep thats correct, some ppl ive talked to is strongly suggesting the transmittion needs a rebuild, which makes sense to me seeing as how 2nd gear snyco is bad and the input staff has that play in it.

 

305 & 350's are internally balanced so theoretically any flywheel/flexplate & balancer can be used. 400's are externally balanced so you have to use a certain balancer and flywheel.

So if the problem only started occurring once you put in the new transmission clutch and flywheel then you can eliminate or 99% chance that its nothing to do with the engine. I would say something is wrong with the flywheel. Pull the flywheel, take it to a shop and have them check the balance. Your engine is internally balanced and stock so it shouldn't matter. If you had a high hp race engine you would get everything balanced but you don't. Pull the flywheel, take it to a machine shop and have them check it out.

 

hmm i had the flywheel resurfaced and i would assume if it wasnt balanced the machine shop would of told me (if anything to get more money outa me) but still a good idea

but the problem is only only above 3250 rpms and when in gear and on the gas would would suggest transmission... lol i dont now thats why im here asking you guys for options.