I have a 73 350 block and recently installed a T56 in my 68.
I started the car without the tranny attached and it did not vibrate. Only thing on the engine when I started it was the centerforce flywheel that is specifically for this application.
I installed the tranny and drove it today and it vibrates. Is my problem caused by using the neutral balanced flywheel and the stock LT-1 pressure plate together?

I think my fix for this will be to pull the tranny again and installed a factory LT-1 flywheel to the original LT-1 pressure plate and clock them in the correct position.
I clocked the pressure plate to the centerforce flywheel. BUT, if the pressure plate isnt neutral balanced and the flywheel is, then I would get a vibration, correct?
Need help here guys. Budget account is completely drained. I have the stock LT-1 pressure plate mounted to the neutral balanced centerforce flywheel now. I think I will pull the tranny and pull the centerforce flywheel and install the stock LT-1 flywheel. I hope that will make the vibration go away.

FWIW- A T56 in a 68 Camaro is a freakin last to drive!!!!!!!! Shifter is in the perfect position.
You guys are right, Im gonna find away to cover the hole with some metal and figure out how to get carpet to cover that up. I thought a small inconspicuous handmade console would look good, BUT having just the boot on there looks kewl too.
HELP GUYS!!

Are your u-joints ok, did you have to get the driveshaft shortened, if so is the length correct, and is the angle correct at the back of the trans. its not pointing down is it? Did you have any vibration w/ previous trans? Also if your driveshaft was shortened was it put back together in phase and rebalanced? Does it vibrate idling in neutral?

Dan E.
69 SS396 4spd. 4.10 posi. x66 coupe

THe drive shaft was shortened and balanced. I know its not the driveshaft. It shook with the drive shaft out of the car. It doesnt shake with only the flywheel attached to the motor. It shakes with the pressure plate and tranny installed. I believe the neutral balanced flywheel and the stock LT-1 pressure plate are the reason it vibrating.

Yeah Harley, put that stock flywheel back in there and give it a go.

Did you see if it is out of balance with the PP installed?

The flywheel had a dot, like it had been hit with a center-punch on one spot of it. So that is where I put the mark on the pressure plate. Before I realixed I had to clock the pp to the flywheel, it shook REALLY REALLY bad. I thought just from idling it was goona throw out the rear main seal.
After I clocked it the vibration isnt so bad but it still shakes. I think its because the Centerforce Flywheel and the Stock LT-1 pressure plate arent balanced together.
I will install the stock flywheel and see what happens. Ill bet that fixes my problems.

ANYTHING ELSE I MAY HAVE MISSED GUYS?

With the severe arthritis in my mid spine and getting stabbed in the hand (thumb actually) with a drill bit and really nowhere to do the work, I havent gotten around to fix this problem. I need help, I may have to sell the car.

SO, Can I bolt a 97 camaro flywheel to my 73 block?

I need to fix this car,....I may have to sell it.
Anyone out there have a suggestion?

Which pressure plate or flywheel can I use? Is there a way to fix this on the cheap?

Help guys, PLEASE? I dont have a huge income and with everything thats going on now that Im going to go to college, I need to fix this cheaply.

Wow Harley ,sorry to here ,just a suggestion ,Can you put your other motor and running gear back in, and go from there at the least you have a working Car to sell ,and sell your LS T-56 set up separately,I know for me when $$$ is an issue (all the time here), just leave things alone and enjoy is the way to go ... and now to comment (not answer) your question ,I don't think so...Good Luck Pal

Harley....yes you can, but I'm not absolutely sure it's the same balance....but I'm about 99+ sure it is. All you can do is bolt it up, then crank it up. No vibes.....install the PP and try again.

Remember the line up mark we discussed.

Take it easy man.....I'd love to come and help, but I just can't justify the drive man. If I am that way by chance, I'll be sure to knock on your door and help out.

Call me if you need anything Harley.

~Joe

The paint mark on the PP is right next to, up against maybe a better choice of words...up against or next to a PP bolt hole.

The chalk mark on the flywheel is in the middle between two holes.

How do I line that up? LOL... Put the PP paint mark(on the inside of a PP hole) Between the two holes in the Flywheel?

This is getting aggravating but Ill get it.
Thanks Joe!

bump

Harley, I was wrong. There is a guy that told me the following......he knows his stuff and he races LT1 cars every weekend.......


Old style SBC's are two piece rear main seals vs an LT1 one piece. Now also the old style SBC"s are externally balanced where an LT1 is internally balanced. What he needs to do is take his old style flywheel and LT1 flywheel to an engine machinist and have them balance match the LT1 flywheel to the the sbc flywheel's specs. Should then be good to go.

Hope this sheds some light on your situation man.

~Joe

Thanks. Does he know what is different about them? as far as why I cant use my LT1 flywheel on my 2 piece block? They look exactly the same and the bolt pattern lines up....

Thanks. Does he know what is different about them? as far as why I cant use my LT1 flywheel on my 2 piece block? They look exactly the same and the bolt pattern lines up....

Harley, for what it's worth, I asked for help on my local forum and came up with mixed results. Seems like it should all work out, but one says the old SBC is int bal and the LT1 is int bal. I think they should be the same no matter what, but I have been wrong once before.

CLICKY CLICKY (http://www.afbforums.com/forum/index.php?showtopic=33198)

Do a search and see what is internally balanced and what isnt.

Good luck man,

~Joe

I dont know if this is relavent or not but when I put in my ZZ502 it came from GMPP with a flex plate for a auto trans and I have a 4 speed. When I ordered the flywheel it had to be a internaly balanced one to work on my engine. So I would think there is a difference. But I am just guessing here. I got my flywheel from scoggin dickeys maybe a call to them will shed some light on this for you. Good Luck!!!

Harley, for what it's worth, I asked for help on my local forum and came up with mixed results. Seems like it should all work out, but one says the old SBC is int bal and the LT1 is int bal. I think they should be the same no matter what, but I have been wrong once before.

CLICKY CLICKY (http://www.afbforums.com/forum/index.php?showtopic=33198)

Do a search and see what is internally balanced and what isnt.

Good luck man,

~Joe


Ok 85 and older 350's are internally balanced and a 2 piece rear main seals.

86 and up including the lt1 out of the Camaro are 1 piece remain seals that are externally balanced.

454 New and old are externally balanced. but have different bolt flange mounts.

If you fired the motor and no vibrations then installed the trans there are several things to look at.

1. Is the trans touching the tunnel anywhere.
2. Pressure plate's can be out of balance.
3. Drive line angle's

When does the vibration come in it is when the car is in gear or at idle and in neutral?

Can you drive out of it. Does it come in at certain RPM or at certain speed.

You have lots of things to check.

Start by process of elimination and lets see if we can determine what the issue is.

Vibration is ALWAYS there. Doesnt matter stopped or driving. I think that if I have the Pressure plate balanced to neutral like the flywheel, Ill fix it. Drive line is almost straight. It angles down just a little. Trans is rubbing tunnel tho. Its a little piece of the trans, like an ear on the right upper side, front. I could cut it off I guess.

Thanks Gene, Joe and Robert. Once I start felling better, I will get on this. Ill post the outcome.

Help guys, PLEASE? I dont have a huge income and with everything thats going on now that Im going to go to college, I need to fix this cheaply.

Harley,
As of 1 August you need to look at the VA for the 9/11 GI bill that was just passed. It can pay for alot more than the other education bills and you are eligible for it. No out of pocket.

OK. Now this is starting to be a PITA!

I have all the correct parts according to various ppl and forums that have done this exact swap on the cheap. I have everything installed correctly.

WTF IS IT STILL VIBRATING! AARRGGHHH!
It is a small shimmy no matter what. driving, idling, left front tire off the ground... I dont get it.
Guys/Gals, name the components that would cause this shimmy/vibration.
Ive tried motor mounts, trans mount, driveshaft, flywheel, clutch disc, etc, etc. I learned that if the centerline or runout is off it wouldnt cause a shimmy it would be a moderate shake.

HELP! lmfao.... All about Hot Roddin'. That 55 is next once this one is fixed. I still think its the PP but 98% of the guys that did this swap are using the same parts and the car never had problems.
Thanks in advance.

Ok 85 and older 350's are internally balanced and a 2 piece rear main seals.

86 and up including the lt1 out of the Camaro are 1 piece remain seals that are externally balanced.

2. Pressure plate's can be out of balance.
3. Drive line angle'sAgree, '70's 350 LT1 is internal balanced as all SBC's were, except the 400 CID. Later LT-1's of the '90's bolt circle diameter is smaller than a two piece rear seal.

Pressure plate and flywheel should be neutral balanced for your '73. Balanced together is better.

Driveline angles should be within 1° of each other, in both planes.

I keep thinkin PP too.... Ill be back.

Harley ,I have been following along and feel for you big time , I have been fighting the same, as all the guys have done a TKO600 swap with no prob, but me I have viberation ,and been through everything ,I had to make a CV joint driveline to 98% fix the Viberation, like you why me :confused::sad: ......Good Luck pal

Did you install a new pilot bearing in the end of the crankshaft. If it is an old one or a brass bushing that is worn out you will get a vibration no matter what else you do.

Yeah, new roller bushing. I have an idea to try out. Yall let me know if this will work.

I have a hydraulic clutch in my car. It is a slave cylinder style (pull-type LT1), when I mash the pedal, the hyd cylinder pushes the fork towards to radiator pulling the TO bearing towards the tranny.
NOW, can I buy a hydraulic TO Bearing (one that doesnt have a hyd cylinder but a push-type) and use my regular hydraulic line and master cylinder? Im thinkin if I get rid of the pull-style clutch assembly for the hydraulic TO bearing style, I can use my original push-type Centerforce Diaphram Pressure plate because it IS Internal/neutral balanced. ? Wat you guys think? Im in this dilema due to having the pull-style clutch which is making me use the pull-style clutch assembly. What do I need to eliminate the pull-style (LT1 type) and use the old style push-type that works hydraulicly(sp)?
Im I going crazy? Would that work? I have a good centerforce I pulled out of the car originally.

McLeod makes a hyd T/O brg.

Did you do this diagnostic procedure we discussed earlier?

Install the flywheel only, fire it up and look for vibration.
If no apparent vibration, install the pressure plate, fire it up and look for vibration.
If no apparent vibration, check the alignment of the bellhousing.
If no apparent vibration, check the runout on the input shaft of your T56.
You could also short cut steps 1 and 2 by taking the flywheel and pressure plate to a machine shop and have them checked for neutral balance.

If you have a LT style t56 trans you have to use a pull clutch, the input shaft is too sort to use a regular push style clutch.

I would try something like what Mkelcy suggested to narrow down the source of the vibration, not just swapping out parts and guessing.

Mike, I checked everything we discussed. Its the fact that my motor is internal balanced and the PP is for an LT motor which is external. I need to install a regular pushtype clutch setup and use a pushtype hydraulic TO bearing.
OR
Find someone who can balance the PP to the flywheel. If I could figure out how to do it myself I would. The PP has extra weight were the mark is. I dont know if I can add weight to the opposite side or try to get the weight off by shaving with a grinder or a cutoff wheel.
Thoughts?

Mike, I checked everything we discussed. Its the fact that my motor is internal balanced and the PP is for an LT motor which is external. I need to install a regular pushtype clutch setup and use a pushtype hydraulic TO bearing.
OR
Find someone who can balance the PP to the flywheel. If I could figure out how to do it myself I would. The PP has extra weight were the mark is. I dont know if I can add weight to the opposite side or try to get the weight off by shaving with a grinder or a cutoff wheel.
Thoughts?

So no vibration with the flywheel, and vibration when you installed the pressure plate?

If that's the case, I'd call around to local machine shops and see if someone balance the combo for you. I think the hydraulic push style solution is going to be well north of $400 unless you can score a good deal on a rare part.

Do you have a LT or LS style T56?

The input shaft on the LT style is too short to use anything other than the pull style clutch.


I would pull the trans, remove the ear that is hitting the floor (or adjust the floor to clear the ear). That way the trans and floor are no longer in contact.

Knock, grind or otherwise remove the weight from the pressure plate.
Install the clutch and whichever flywheel is setup for an internal balance, I would prefer the old one as you had no vibration with it on the car. (this should mean the flywheel-clutch assembly has a neutral balance)
Start the engine and run it without the trans and check for vibrations.
I would put money on the vibration being gone.
Install trans and recheck for vibration.
Should still be gone.

this may sound silly, but did you break it in properly?

You I broke it in. I think the prob is my clutch assembly. Im gonna save up and buy parts from weir or ATS.

I wouldn't do that. Is your T56 a 2.66 or 2.97 first gear? If 2.66, I'd swap input shafts for an LS1 T56 inpout shaft, and then use a standard Chevy flywheel, PP, bellhousing and mechanical linkage - just as I did in the blue car you rode in.

Harley,
2 things I noticed.

1. If you have ANY part of the trans contacting the tunnel, you need to remedy this regardless of your internal/external issues because this is going to cause an issue when driving.

2. When you installed the bell housing, did you index it? Did you take measurements with a dial indicator to check for runout? This is just a thought, but you may have too much runout. What type of bell housing did you use? I ask because if you a piecing this setup together and are using a bell housing from 1 manufacturer and a tranny from another, then more than likely, you have too much runout and are going to require adjustable dowel pins.

Just a thought.


I too am having a vibration issue, but mine is with a TKO and mine is only while driving. Starts at 70mph. I think mine is driveline angles. I have been told to shim the tranny mount, but I can't because it's already too high. Any higher and it makes a horrible growling noise. Besides, when I install the poly mount(which is taller than an OEM rubber mount), it makes the vibration worse(starts at 62-65mph and by 70mph, it's so bad, it feels like the car is going to come apart. When I switch back to the OEM mount, the vibration starts at 70mph and is much less violent so that means the tailshaft is already too high. I need a way to try to make the tailshaft even lower. I have tried shimming the pinion, but I think the tailshaft is just too high to be able to bring the pinion to the correct position. My only other options are to find a crossmember with an adjustable tranny mount pad, cut and reweld the current tranny mount pad in a lower position or have a cv joint driveshaft made. I can't believe that I am just going to have to live with a vibration at 70mph-on. Some say how often do you drive at 70mph? Well, very often. ANY time I go to visit my parents in Virginia, they have a 65mph speed limit at some points and I like to drive 3-5mph over the limit and there are places that have a 70mph limit. That would mean I would be at 73-75mph. There has to be something. Check you bell housing runout and fix the area where the tranny is contacting the tunnel.

Good luck and keep me posted. I know how frustrating a vibration can be. I feel for you man!!!

My only other options are to find a crossmember with an adjustable tranny mount pad, cut and reweld the current tranny mount pad in a lower position or have a cv joint driveshaft made. I can't believe that I am just going to have to live with a vibration at 70mph-on. Some say how often do you drive at 70mph? Well, very often. ANY time I go to visit my parents in Virginia, they have a 65mph speed limit at some points and I like to drive 3-5mph over the limit and there are places that have a 70mph limit. That would mean I would be at 73-75mph. There has to be something. Check you bell housing runout and fix the area where the tranny is contacting the tunnel.

Good luck and keep me posted. I know how frustrating a vibration can be. I feel for you man!!!

Not to get too far off track from wiskeesour's post...
You should actually measure your drive line angles. (Search, there was a resent post on how its done)
They should be equal but opposite, one pointing up and one pointing down.

Just use shims on the rear spring perches to get the numbers correct, no need for an adjustable transmission crossmember

I've done this until I was blue in the face. I need to try to find a place that builds race cars or something. Someone who has more experience with this than me. I have measured driveline angles so much I am sick of them. I can't shim the tranny up because it's already high. Any more and it makes a growling noise. The tailshaft has to come down. I know this because I installed the poly type tranny mount(taller than a stock rubber type) and it made the vibration harsher and start earlier. Reinstalled the rubber mount(shorter) and the vibration lessened and started at a higher MPH.

I was not trying to hijack the thread. I was simply stating that I too am having a vibration issue and I wanted to relay some things I thought Harley may want to look at. One being driveline angles and the other being the indexing of the bellhousing or scattershield.