[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 AG

Do you have the bobweight sheet?

I was told that the bob weight card does exist at the shop that balanced the engine 14 years ago.

[MPKind]

Originally Posted by grivera

Maybe I missed it but have you already tried a neutral balanced FW along with the neutral balanced clutch assembly?

No I have not tried that combo. From what I’ve been reading in other posts, the neutral balance FW may not be that far off from a factory balance FW. Still waiting on what the factory specs were.

[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 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 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?

[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 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.

[MPKind]

I can clearly see what holes the driveline shop made. If the engine shop drilled holes physical evidence of that was destroyed. I am trying to find out if they did drill it. So far I’ve been ghosted. Will rattle their cage again on Monday.

Driveline shop claims there were 2 holes about 90-100 degrees from the 2 Pontiac holes untouched. They hit those and added 3 more. So good luck figuring out its previous balance.

[Kenth]

The two holes from the factory should correspond to 6 inch ounces.

HTH

[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.

[MPKind]

So that’s where it’s at now. ‘75 FW with a neutral balanced PP. It’s not a good match. I will talk to engine shop Monday that did the original balance with the ‘65 wheel. If you saw the photo I posted you’ll notice the 5 holes are 90-100* from the factory drill holes. Any attempts to zero balance the FW would require holes opposite if the factory ones. The driveline shop claims that there were some drill holes at the 90d position. Right. The lack of specs on the ‘75 FW other than it came off an F Body car (what else) raises doubt that it’s the same spec as the 65 FW. It could be an alternate design different from the typical 65-75 spec. Still waiting for someone to post the flywheel specs from the H-O publication.

[KEN CROCIE]

Kenth is correct. from the H-O engine book, 6in/oz. is the number. I believe we got that info from a blueprint that Pontiac sent us. The info from the balance shop should clear things up. The question to the shop should be:
Do they routinely balance assuming a zero balance flywheel?
Do they routinely balance with the supplied flywheel (or flex plate) without modifying the flywheel?
Do they routinely modify the flywheel along with the balance job?
Hopefully, the balance card will have a note about the flywheel, and/or the shop owner will be able to respond.

[MPKind]

I’d like to the see the published docs from H-O regarding the Pontiac stock FW. Snap a pic and post it. The book is impossible to get so I think it’s important to share. Or PM me then text it to me.

Today others pointed out that the neutral balance attempt on the ‘65 FW is suspicious. In theory, any attempt to zero balance it would need 2 equal holes opposite of the factory holes.more or less. These are 80d off. The driveline shop used a primitive static balancer. I guess I’m not surprised. So many miscues and lack of process. Not acceptable for a driveline shop that uses “expert” on the website. They claim it had a couple holes in that area already. I’ll confirm that with the engine shop. I will ask them the questions as Ken Crochie suggested. The whole idea of a driveline shop balancing a FW is plain wrong. Only an engine shop should attempt that. And only when really needed.

The 75 wheel may not be the same factory spec as the 65. Per Ken C. It could be for a different crank design. So it could cause vibes even if in perfect condition and look similar.

[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

[MPKind]

Measured the voids of mass removed. Factory wt removed is about 24 grams total or 0.84oz. Radius hole to hole is 5-7/8”. So that’s about 5 oz-in
Assumed a unit wt of cast iron at 4.128oz/in^3.

The modified (f’d up) area lost about 17g total.

[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.

[AG]

The bolt pattern offset was used so that the flywheel could only be oriented one way to maintain stock balance.