[MPKind]

The 65 factory flywheel had an imbalance according to the “driveline” shop, but the “engine” shop could have taken a small amount out previously.

Kenth can you share the flywheel balance specs and how they are mapped on the part?

[Gary H]

Originally Posted by MPKind

The 65 factory flywheel had an imbalance according to the “driveline” shop, but the “engine” shop could have taken a small amount out previously.

Kenth can you share the flywheel balance specs and how they are mapped on the part?

Is this the original flywheel you took out? If so, it looks like someone, probably the people who balanced the engine, drilled holes in it to neutral balance it. Personally, I'd but a new neutral flywheel and try it. I bet that's what the engine is balanced to.

[Held for Ransom]

Originally Posted by MPKind

The 65 factory flywheel had an imbalance according to the “driveline” shop, but the “engine” shop could have taken a small amount out previously.

It wasn't Wagamon Brothers, I hope?
https://wagamonbrothers.com/

[MPKind]

Originally Posted by Held for Ransom

It wasn't Wagamon Brothers, I hope?
https://wagamonbrothers.com/

Not Wagemon Bros. Was told long ago to stay clear of them.

[Held for Ransom]

Originally Posted by MPKind

Not Wagemon Bros. Was told long ago to stay clear of them.

I think you were warned wrong. My Pontiac engine after them ran very smooth.

[MPKind]

Originally Posted by Held for Ransom

I think you were warned wrong. My Pontiac engine after them ran very smooth.

This is a FW issue that affected the engine. Has nothing to do with who built it.

[PAUL K]

Originally Posted by MPKind

The 65 factory flywheel had an imbalance according to the “driveline” shop, but the “engine” shop could have taken a small amount out previously.

Kenth can you share the flywheel balance specs and how they are mapped on the part?

The balance on the flywheel in the picture is completely screwed up. Everyone involved in the project needs to be replaced with competent people.

If you know the shop that originally balanced the rotating assembly they should be able to tell you if they removed weight from the flywheel to balance the rotating assembly, it's called "standard operating procedure". If they did they need to be replaced, if they can't tell you they need to be replaced.

Plan B since you didn't like my first suggestion, would be to have the engine shop figure out what balance holes they made. Then have the clutch shop figure out what balance holes they made. Report back and we might be able to figure out what's going on.

Sorry you're going through this.

[mgarblik]

I did my best to try and read and understand everything in this thread. I have to admit, I don't fully understand everything that happened, when and by who enough to make a recommendation that I know will fix it. So, if I was faced with this situation and was committed to make it right, I would do the following. Your probably not going to like this. I would remove the engine and and the crankshaft. Have the crankshaft zero balanced +- 2 grams and verify. That completes the engine. Then I would buy a steel zero balance flywheel and a zero balance clutch. Problem solved. Time consuming and possibly a little expensive, but now it's fixed. Mixing, matching, drilling, bolting , welding, guessing, removing, installing, you may get lucky and hit the right balance, but it may be an even more time consuming exercise than just biting the bullet and doing it all one more time, correctly. I wish you the best. Very frustrating I am sure. I hope you get it.

[MPKind]

Originally Posted by mgarblik

I did my best to try and read and understand everything in this thread. I have to admit, I don't fully understand everything that happened, when and by who enough to make a recommendation that I know will fix it. So, if I was faced with this situation and was committed to make it right, I would do the following. Your probably not going to like this. I would remove the engine and and the crankshaft. Have the crankshaft zero balanced +- 2 grams and verify. That completes the engine. Then I would buy a steel zero balance flywheel and a zero balance clutch. Problem solved. Time consuming and possibly a little expensive, but now it's fixed. Mixing, matching, drilling, bolting , welding, guessing, removing, installing, you may get lucky and hit the right balance, but it may be an even more time consuming exercise than just biting the bullet and doing it all one more time, correctly. I wish you the best. Very frustrating I am sure. I hope you get it.

It's a series of events that involved 2 clutch sets (Centerforce & McLeod), 2 flywheels ('65 & '75 factory pieces), 2 shops (Wheeler Racing and Midwest Transmission), 3 trans RnRs to date.

Engine was well balanced with the '65 FW and HB by Wheeler Racing. Worked great.

It was assumed that both the '65 and '75 FWs had factory balance. I'm not so sure about that now given the huge difference in behavior.

The PP on the McLeod had weights added and removed 2 times! Could that cause issues? Maybe.

The trans shop tried to neutral balance the '65 FW by drilling into the factory holes and adding 3 more, so I have no clue what they removed vs what was already removed by Pontiac. To this day I don't know what possessed them to modify a flywheel.

To date there's been 4 different FW and PP combos

1. '65 Factory FW with Centerforce PP (factory neutral balance). Worked great.

2. '65 Factory FW with McLeod PP (2 large washers welded to it). Bad vibrations at idle and beyond. FW was not modified at this point. I think they tried to neutral balance the FW/PP combo not knowing it was supposed to have a slight imbalance.

Here's where my car went from a buddies shop to the transmission shop.

3. '65 Factory FW with McLeod PP. This is when they drilled into the FW to neutral balance, then ground off and welded back weights on the PP to neutral balance the FW/PP assembly. This combo had the least amount of vibration of the 3. When I received the car, I was not told they drilled into the flywheel. I assumed they only removed the weights from the PP to restore it's original balance. In a phone call a week later it was revealed the flywheel had been drilled. After a week of arguing with the shop owner about it, the car went back to the trans shop.

4. '75 Factory FW with McLeod PP (all added weights removed). This time it was balanced dynamically at Wheeler Racing. The combo did not produce. Vibration above 2500 rpm and beyond. Worse than combo 3.

It's a guessing game now. Could try the '75 FW with the Centerforce PP Attempting a 5th combo vs. engine/crank removal? The trans can go in and out in a day, the engine work will take way more time and money. So far the trans shop covered 2 RnRs, but that can't go on forever.

[MPKind]

Originally Posted by PAUL K

The balance on the flywheel in the picture is completely screwed up. Everyone involved in the project needs to be replaced with competent people.

If you know the shop that originally balanced the rotating assembly they should be able to tell you if they removed weight from the flywheel to balance the rotating assembly, it's called "standard operating procedure". If they did they need to be replaced, if they can't tell you they need to be replaced.

Plan B since you didn't like my first suggestion, would be to have the engine shop figure out what balance holes they made. Then have the clutch shop figure out what balance holes they made. Report back and we might be able to figure out what's going on.

Sorry you're going through this.

I think your first suggestion was fine, it's a matter of time and logistics at this point. The car is home now, so I'm planning my next move.

I agree with the assessment of personnel. I ask questions and I get attitude that implies I'm questioning their work. As I should!

The engine shop said they have the bob weight card, what can be determined from that without the crank out of the engine? I asked if they could figure out what the original FW balance was, I was told no. I'm not savvy with what can and cannot be determined from that info. If it can be determined, how? Don't you need the crank and the bob weights to verify and measure the FW balance?

[PAUL K]

Originally Posted by MPKind

The engine shop said they have the bob weight card, what can be determined from that without the crank out of the engine? I asked if they could figure out what the original FW balance was, I was told no. I'm not savvy with what can and cannot be determined from that info. If it can be determined, how? Don't you need the crank and the bob weights to verify and measure the FW balance?

The engine shop should be able to tell you if it's standard procedure at their shop to remove weight from the balancer/flywheel when they balance a crankshaft. This should be avoided if at all possible, but I've seen many shops over the years practice the bad habit.

If they did remove weight they should be able to identify the holes they made from the recently added holes. The last guys should be able to also. When you know the location of whose holes are where, we might be able to figure out why they were added. When one neutral balances a factory flywheel the majority of weight needs to be removed 180 degrees from the factory balance holes. Your picture looks like the majority of the holes are roughly 90° from the factory holes.

[mgarblik]

Thank you for explaining the situation again more completely. I think I understand better now. My suggestion from here which would be fairly easy, is to get a good used flywheel from a 1965-1972 same displacement engine and put it on the engine with a pressure plate that has been zero balanced. IMO, that's your best chance of getting back to what you had 14 years ago when everything worked properly. The 1975 flywheel may have been matched to the lighter crankshaft Pontiac was just phasing in at that time. Things get a little confusing in that time period. Pontiac narrowed the counterweights a little in that period and the crankshafts were a little lighter. They also changed the pilot diameter on the crankshaft/flywheel in that time period. If there was some way to verify the crank was balanced with the old 1965 flywheel and harmonic balancer and these parts were NOT modified to get the proper balance, a replacement used flywheel from that vintage should be close enough to operate properly. The complicated issue is from the factory, the final precision balance was achieved after the engine was assembled and the flywheel was installed. The factory would spin the rotating assembly at a low speed and take measurements. Then a final balance would be achieved by removing a little extra metal from those giant divots in the flywheel. So essentially the born with flywheel was matched and mated to the crankshaft. Made for a smooth engine but caused some trouble in service later when parts needed to be replaced. But it was only a finish balance. The small mismatch should not cause terrible vibration.

[Kenth]

Originally Posted by mgarblik

The complicated issue is from the factory, the final precision balance was achieved after the engine was assembled and the flywheel was installed. The factory would spin the rotating assembly at a low speed and take measurements. Then a final balance would be achieved by removing a little extra metal from those giant divots in the flywheel. So essentially the born with flywheel was matched and mated to the crankshaft. Made for a smooth engine but caused some trouble in service later when parts needed to be replaced. But it was only a finish balance.

Wrong.

The final factory balancing, with a fully assembled block and flywheel/flexplate, was achieved by removing metal from the crank counterweights.
The flywheels and flexplates were all the same, and this for NOT causing problems when these parts needed to be replaced.

And, If you were to buy a new flywheel from Pontiac back when new ones were available you would get a 9779232, same for all 1965-75.

FWIW

[mgarblik]

Originally Posted by Kenth

Wrong.

The final factory balancing, with a fully assembled block and flywheel/flexplate, was achieved by removing metal from the crank counterweights.
The flywheels and flexplates were all the same, and this for NOT causing problems when these parts needed to be replaced.

And, If you were to buy a new flywheel from Pontiac back when new ones were available you would get a 9779232, same for all 1965-75.

FWIW

Thank you for clearing that up. My information came from an old GM film that showed the build process of Pontiac engines at the plant. I was almost sure I was watching the final dynamic balance being performed on rotating engines and just small amounts of finish balance material being removed externally. I remember thinking that was really bizarre as that would sort of marry the flywheel to the crankshaft which would be wrong. How in the world did they drill cast iron counterweights on an assembled engine without leaving metal in the engine? Amazing!

[PAUL K]

I'm no expert but always thought the crankshafts were balanced by the holes drilled in the counterweights that were figured out by the engineers. Crankshafts were made to a specification and weight. All the holes were machined in a specific location, size and depth to meet the Pontiac desired bob weight. I know a lot of 103 cranks have the same size holes in them and in the same location. All the SD-455 cranks I've seen are in a different area of the counter weight and sized different compared to the 103's.

I'd like to know more as the factory assembly techniques always amazed me. I'm also curious why they needed the slight offset in the flywheel.

[Kenth]

Originally Posted by mgarblik

Thank you for clearing that up. My information came from an old GM film that showed the build process of Pontiac engines at the plant. I was almost sure I was watching the final dynamic balance being performed on rotating engines and just small amounts of finish balance material being removed externally. I remember thinking that was really bizarre as that would sort of marry the flywheel to the crankshaft which would be wrong. How in the world did they drill cast iron counterweights on an assembled engine without leaving metal in the engine? Amazing!

This may be the film?
9.45 into it they describe the balancing of the assembled block.

https://www.youtube.com/watch?v=9LuXf6gJ-jg

[mgarblik]

Originally Posted by Kenth

This may be the film?
9.45 into it they describe the balancing of the assembled block.

https://www.youtube.com/watch?v=9LuXf6gJ-jg

I am not sure if that's the same film. Some of it looks familiar because I remember being surprised by the number of women working the engine line. This film clearly shows and the narration states the balance involves removing metal from counterweights and all engines get this treatment. It also shows cranks being installed with major balancing completed before installation as the large balancing holes can be seen before the crank is lowered in he block. For some reason, I think the film deep in my memory was about 30 minutes long, not 10. This may have been an edited version. Also, my foggy memory seemed to to remember some manual transmission engines getting the final balance with the flywheels in place. This film showed all auto trans ones in that section. In any event, your explanation makes much more sense and would allow for much greater interchange without problems later in the engines life. Thanks for finding that.