2.8 LB8 RWD balance

[Linlor]

I have a 28 LB8 RWD engine from a Camaro that I swapped into my '86 Fiero but I have a terrrible vibration in the engine at about 2500-2800 rpm when I started it up the first time. I shut it off so I did not wipe my bearings but I have a question.

Is this year V6 internally or externally balanced? When doing the swap, I made an assumption that the engine was internally balanced since it was RWD and I thought all RWD GM engines are internally balanced. I put a 1988 Fiero flywheel on it which is for internally balanced setups.

If this engine is externally balanced, then I immediately know where my vibration came from and I hope I have not started my bearings down a bad road.

Any help would be appreciated.

Thanks very much in advance.
Don

[1meanz]

im almost certin that its externaly balanced. i have NEVER messed with a RWD 660. and i have never really been around them, but ill still say im 99% sure its externaly

[ForcedFirebird]

I would guess you used the wrong flywheel. Do you have the flywheel from the donor?

[geoffinbc]

Well what year is the Camaro motor? 87 and later should be internal balance.

[Linlor]

Sorry;

It is from an '85 Camaro. I am 99% sure I have the wrong flywheel in there now from more reading on the net and looking at dates of manufacture etc.

I do have the donor flywheel from the Fiero so I will be putting that one on. Pulling the engine out again I guess. Checking and possibly replacing the bearings and changing the flywheel and putting it all back in. It never seems to end........

Thanks for all the help.

Don

[ForcedFirebird]

You can pull the trans instead, but yeah one has to come out

[geoffinbc]

The bearings will be fine as long as you didn't rev the piss out of it. I know people who drove for a whole day and never hurt anything. The only thing that will make the crank journal actually break the oil wedge and contact the metal of the bearing is detonation. An imbalance can't exert even a portion of the force caused by detonation.

[Linlor]

Thanks for the help everyone;

I dropped the cradle last night and checked the main and connecting rod bearings and they are fine. Plastigauge is well within tolerance on all of them and the journals are clean with no scratching and the oil was clean. Looks like I dodged a bad day after all.

I have changed the flywheel back to the externally balanced and put the engine back into the cradle. I will put it back into the car tonight and get it ready to go.

One thing I found though when I took it out again was my starter was well on its way to disintegrating. The gear area was cracked about 1/8" open straight across its entirety. No wonder it sounded so terrible when I turned it over the other day. New starter and all will be well.

Now that I have this engine in the second midlife crisis toy, I can start working on my 3.4 DOHC I bought to put in my first midlife crisis project car (Ferrari 355 replica) that I pulled this engine from. I am sure I will be back on the board with lots more questions on that build.

Thanks again for the help.
Don

[geoffinbc]

Yea I figured the bearings would be alright. You are at least the 20th person I have talked to on the forums that has done the same thing. None of them have ate the bearings yet.