Hello, Michael

I'm installing a new flywheel for my T56 swap on my 87 Trans Am. My question is, isn't the pressure plate supposed to be aligned with the flywheel, via some kind of mark? I thought that the pressure plate and flywheel each had a mark on them and you were supposed to align the two marks (as close as possible) so that the assembly is balanced. My pressure plate has a yellow spot of paint on it, but my brand new flywheel from NAPA doesn't have any mark on it. The only thing I see on the flywheel is some kind of smudge that looks like it could be either dirt or a pencil mark. It's not an X, a line, or a dot. It's literally a gray smudge that's slightly darker than the flywheel itself. If it is a marking, it's a half-a$$ed attempt.

Hello, Michael

I forgot to mention that the trans is an LT1 T-56, with a stock flywheel replacement.

jmd

iTrader: (4)

Using the correct pressure plate bolts indicates the PP to the FW.
This is by the smooth section of each bolt setting into the slightly countersunk bolt holes in the flywheel.

Hello, Michael

I'm not following. I have the correct pp bolts from McLeod. I'm referring to the orientation of the pp relative to the flywheel. Shouldn't each have a mark, and those marks should be aligned to properly balance the pp / fw?

sofakingdom

iTrader: (1)

The PP is supposed to be neutral balance, and isn't supposed to affect the overall balance, therefore. No mark is required ordinarily.

Hello, Michael

So I can install it in any orientation? I'm replacing the flywheel I originally installed that I got with the Trans swap. It was the stock flywheel that had been resurfaced and looked like it had been rebalanced as well. But after the install, i was getting a pretty bad vibration, and I thought the flywheel could be the problem. I pulled the Trans last night and the pilot beating is Ok, so i know it's not that. I'm wondering if the flywheel wasn't balanced properly?

sofakingdom

iTrader: (1)

Possibly...

Or, not balanced at all, after whatever was done to it, disturbed it.

Hello, Michael

I don't know what else could be causing the vibration. It even vibrates in neutral while revving the engine. i don't think it's my motor mounts, and the trans mount is in good condition too.

jmd

iTrader: (4)

No. The pressure plate should be able to install all 6 possible ways without issue.
No.

Did the engine ever run vibration free before? Do you have a known-good flywheel or flexplate for an 86-up engine? Bolt it on without any clutch components. Problem solved? If yes, take the new, improperly balanced flywheel back.

Hello, Michael

There was no vibration prior to the trans swap. When I swapped the trans, I used the flywheel that the guy gave me with the trans. It was used, but he said he had it resurfaced. I have a brand new flywheel from napa, but I have not installed it yet. I want to make sure I do it right, cuz I don't really feel like pulling this trans again.

Hello, Michael

Won't the engine vibrate like crazy if i run it with just the flywheel on without the Trans installed and bolted to the cross member? I mean, I'm pretty sure the motor mounts are designed to incorporate the Trans mount in order to effectively isolate the vibration of the engine.

Tony89GTA

iTrader: (7)

The original flywheel has extra weight forged into it to make it externally balanced, the previous owner might have had it neutral balanced? I seen what a unbalanced flywheel does first hand on mustang once, lot of vibration, not pretty. Think you'll be fine after you swap flywheels.

Hello, Michael

It's strange because the new Napa flywheel I have does have the weight cast into it on the back, but the one I originally used and took off the other day doesn't have a cast in weight. It was drilled a lot to remove material though. A lot of dimples drilled into it. Maybe it was neutral balanced, causing the whole engine to be out of balance because of the absence of the weight?

Tony89GTA

iTrader: (7)

Sounding like it.

jmd

iTrader: (4)

And the only item that should affect the crank in this swap is the flywheel. Everything else is either not directly bolted to the crank (disc) or neutral balance (pressure plate.)
I guess in your case you should prop the engine up under the oil pan to assure the distributor doesn't push into the firewall. But running a good engine with a good flywheel and no "transmission weight" won't hurt anything in the case of a SBC with integral flywheel ring-gear and balance done only with the flywheel.
It's starting to sound like someone whose brain stopped developing around 1982 made a decision to balance an engine and it's flywheel "custom" instead of making future parts replacement straightforward. Because it sounds like you have an 86-up bolt pattern flywheel balanced "neutral" like 85-down flywheels. Who wants to have a flywheel modified every time they replace it? Not me.

Good perseverence.

Hello, Michael

Thanks for all the help guys. I'm really hoping this new flywheel does the trick.

jmd

iTrader: (4)

Update?

Hello, Michael

It was the flywheel. Swapped it out and no more vibration. Whoever resurfaced it also ground off the weight that's cast in, I'm assuming to neutral balance it. They obviously didn't know that the weight completes the balance of the crankshaft. Thanks for everyone's help!