Hello guys, I have a 3rd gen 1986 Camaro with a 2.8L v6 FI. My father replaced the engine a few years ago with a rebuilt one that he purchased from Advance Auto. The engine was the same engine we already had but the eingine we received was labeled as an "Internal Balanced" engine. Once we got everything setup and back inside the car we started it up and it was shaking like crazy due to the weight on the flexplate from the first engine. My father being the man that he is, cut the weight off of the flexplate, put it all back together and it was working, but I got a noticable hum at 75+ miles per hour. I got hit recently and am moving the engine over to a new frame. I want to replace the "modified" flexplate with a balanced one, however I am unable to find any that fit and don't have that extra weight. Any ideas on where to start looking? This has become a highly frustrating ordeal. I have ordered a couple flexplates and they either dont have the right bolt pattern or are slightly too big.

 

Sometime in late 87, the 2.8 went from being externally to internally balanced. Your father did the right thing by cutting the weight off, which would make it a neutral balanced flexplate. To be sure, you could take it to a machine shop to have it checked for balance. If some of the flexplate metal was removed along with the weight, it could have thrown the balance off. And I believe the harmonic damper is neutrally balanced for both engines, so that shouldn't be an issue.

 

my 91 hums when i hit 65+ any tips for me camaro 69?

 

Yeah, teach it the words, turn up the stereo, or don't go faster than 64.
What hums? Your car has many moving parts.

 

The whole car just kinda vibrates...pretty violently. Not at a certain rpm but at a certain speed. so does that rule out the engine?

 

Have your front end alignment, front suspension parts (for wear), and wheel balance checked.
it could be any of these.