Flex plate

[BuickSix]

Is this the correct flex plate for my 87 LC2?
I have a vibration, and this one seems warped and out of round.
Also, are they 160 tooth or 153? This one is 160.
When the starter turns it over it doesn't sound bad, but it doesn't sound good no matter how I shim the starter.
Thanks.

 

[pacecarta]

its a 3.8 turbo plate ,
the circle with the flat toward crank is for turbo pistons ,
small circle with flat toward teeth is for NA pistons,
4.1 has more small balance holes and will be stamped "4.1"
the 3.8 turbo flex plate is also available from pioneer fra-147 listed as 160 teeth

 

[David Husek]

Each plate is balanced to your engine. Try to find an original used replacement with similar balance holes and pins. The aftermarket ones are not close in balance. I have copied flexplate balance for customers in the past. Any questions feel free to contact me.

 

[BuickSix]

My original one is long gone. I've compared the one in the car now with a NA flex plate. The ring gear definitely has high spots on it. I've ordered one from Amazon which I can return easier if I don't like it. I work in the transmission business, back in the day changing flex plates was a regular thing. I find it strange that it's balanced to individual engines....how would the dealer do it? What's the solution?

 

[chris romani]

Is this the correct flex plate for my 87 LC2?
I have a vibration, and this one seems warped and out of round.
Also, are they 160 tooth or 153? This one is 160.
When the starter turns it over it doesn't sound bad, but it doesn't sound good no matter how I shim the starter.
Thanks.

I had a brand new one from TA performance out of round pissed me off because I had it sitting for a long time before I used it.Could not return it.

 

[BuickSix]

I received my Amazon flex plate.....$100 Canadian dollars. Pioneer FRA-147. It looked good, the ring gear had more meat to it, less holes drilled into it, but it was also flat. My old one and the NA one are slightly bent ....dished, this one was flat. It fit nice on the crank but because it's flat, the ring gear moved 0.120 towards the engine......way to close to the starter. I would have needed to remove some material from it for me to feel comfortable.
I decided to return it.
Externaly balanced SFI one's are $500 Canadian to my door. I found a factory used one on e-bay for $150 Canadian.
I really want to get rid if this vibration.
To be continued.............

 

[chris romani]

I received my Amazon flex plate.....$100 Canadian dollars. Pioneer FRA-147. It looked good, the ring gear had more meat to it, less holes drilled into it, but it was also flat. My old one and the NA one are slightly bent ....dished, this one was flat. It fit nice on the crank but because it's flat, the ring gear moved 0.120 towards the engine......way to close to the starter. I would have needed to remove some material from it for me to feel comfortable.
I decided to return it.
Externaly balanced SFI one's are $500 Canadian to my door. I found a factory used one on e-bay for $150 Canadian.
I really want to get rid if this vibration.
To be continued.............

Yes the vibration in park is annoying my seat belts where shaking.

 

[chris romani]

Each plate is balanced to your engine. Try to find an original used replacement with similar balance holes and pins. The aftermarket ones are not close in balance. I have copied flexplate balance for customers in the past. Any questions feel free to contact me.

Good to see you are back on Dave haven’t seen you here in years.

 

[TR Custom Parts]

I wish more people would come back on here. The FB stuff is not the place for tech stuff.

 

[pacecarta]

i look at fb regularly (not a member there, requested removal many years ago ) and can see about the first page of most of the forums before it blocks me out. what i see posted still makes me not want to go back there .

 

[chris romani]

I wish more people would come back on here. The FB stuff is not the place for tech stuff.

I agree mark it’s very quiet here for the last few years.I don’t come on much because there aren’t a lot of new posts.

 

[1KWIKSIX]

I received my Amazon flex plate.....$100 Canadian dollars. Pioneer FRA-147. It looked good, the ring gear had more meat to it, less holes drilled into it, but it was also flat. My old one and the NA one are slightly bent ....dished, this one was flat. It fit nice on the crank but because it's flat, the ring gear moved 0.120 towards the engine......way to close to the starter. I would have needed to remove some material from it for me to feel comfortable.
I decided to return it.
Externaly balanced SFI one's are $500 Canadian to my door. I found a factory used one on e-bay for $150 Canadian.
I really want to get rid if this vibration.
To be continued.............

Where are you located ?
I am in Mississauga , Ontario
Went thru a similar situation with LC2 flex plates.
I found a place in Scarborough that can straighten bent flex plates & can also match balance for you .
The name is D.Garland & Son on Milner Drive in Scarborough .
My factory flex plate had 0.115” run out & they straightened it so o didn’t need to replace it with another & get that one match balanced .
They do good work & very reasonable prices.

https://dgarlandandsons.ca/

Thx
Dave

 

[BuickSix]

Waterdown. I don't think mine was bent, just low quality. I replaced it 15 years ago with a King-O-matic part sourced through work when the engine was rebuilt. With all the work I did at that time it was difficult to nail down the source of the vibration. What had happened was I was coming down the 400 and the left rear tire tread separated from the side walls at around 130kph. The side walls stayed on the wheel. Anyway, I limped it home on the spare and since I was newly married and in need of 4 tires I decided to park it for a couple years, pull the engine and clean the compartment and motor because it's cheap and I had time. Thats when I found the plastic timing gears loosing teeth.....so the engine went to the builder and another year passed.
Once it was all back together, this vibration showed up. So I went over everything. We had a Camaro in the shop over night, I went back in the evening and put its wheels on my car with no change. I kept thinking I have a bent axle tube because of the blow out. Have Moser axles now. Since then I've gone over everything!!! I had the body off fixing all the mounts which took 6 years! Im going to very happy and pissed if it all turns out to be that this crappy flex plate was the whole problem.
Thats the story, me and IT are going on 25 years.
Thanks for the replies, I won't know until late winter as I'm repainting the intake and going through the 37 year old 2004R.

 

[1KWIKSIX]

Waterdown. I don't think mine was bent, just low quality. I replaced it 15 years ago with a King-O-matic part sourced through work when the engine was rebuilt. With all the work I did at that time it was difficult to nail down the source of the vibration. What had happened was I was coming down the 400 and the left rear tire tread separated from the side walls at around 130kph. The side walls stayed on the wheel. Anyway, I limped it home on the spare and since I was newly married and in need of 4 tires I decided to park it for a couple years, pull the engine and clean the compartment and motor because it's cheap and I had time. Thats when I found the plastic timing gears loosing teeth.....so the engine went to the builder and another year passed.
Once it was all back together, this vibration showed up. So I went over everything. We had a Camaro in the shop over night, I went back in the evening and put its wheels on my car with no change. I kept thinking I have a bent axle tube because of the blow out. Have Moser axles now. Since then I've gone over everything!!! I had the body off fixing all the mounts which took 6 years! Im going to very happy and pissed if it all turns out to be that this crappy flex plate was the whole problem.
Thats the story, me and IT are going on 25 years.
Thanks for the replies, I won't know until late winter as I'm repainting the intake and going through the 37 year old 2004R.

Do yourself a huge favour …:while you have the transmission out & are able to access the flex plate , remove it and take it (along with your original flex plate) to D. Garland & Son to have them balance match it to the original . These are internally balanced engines so your original balance & flex plate are needed to keep your engine properly balanced . Now if you replaced pistons or rods during your engine rebuild ………all bets are off as this would totally change the balance .
There’s an old saying that my Mother would say…….”an ounce of prevention is worth a pound of cure”

 

[1KWIKSIX]

Do yourself a huge favour …:while you have the transmission out & are able to access the flex plate , remove it and take it (along with your original flex plate) to D. Garland & Son to have them balance match it to the original . These are internally balanced engines so your original balance & flex plate are needed to keep your engine properly balanced . Now if you replaced pistons or rods during your engine rebuild ………all bets are off as this would totally change the balance .
There’s an old saying that my Mother would say…….”an ounce of prevention is worth a pound of cure”

Here’s an interesting read

Google Search

 

[Chuck Leeper]

"These are internally balanced engines so your original balance & flex plate are needed to keep your engine properly balanced ."
Nope.

 

[Jason dcpt]

Don't you have that backwards chuck?

 

[Jason dcpt]

My bad. I see the "NOPE"