Luk SMF vibration over 2500

[Laine D]

I have been running my luk single mass conversion with my zf5 behind my rebuilt 6.9 turbo. I am noticing a vibration at Around 2500 and up. At idle it kinda vibrates too. I don’t really notice a huge problem but it’s just annoying and I don’t like revving it that high with a vibration. Wondering if anybody had experienced this too? My transmission guy and I were taking and we kinda think it might be the pressure plate not engaging evenly. It’s not a huge deal just a little annoying.

 

[hce]

6.9 and 7.3 flywheels have different imbalance, though many have ran a 7.3 flywheel on a 6.9. When I did the z5 swap the 6.9 flywheel was spun on a balancer and then the 7.3 to match. I have also heard of pressure plates being off balance. If you pull the trans I would consider having the 7.3 flywheel rebalanced and the pressure plate balance checked. Could be as simple as the friction disk spit out a section too.

 

[Eli]

6.9 and 7.3 flywheels have different imbalance, though many have ran a 7.3 flywheel on a 6.9. When I did the z5 swap the 6.9 flywheel was spun on a balancer and then the 7.3 to match. I have also heard of pressure plates being off balance. If you pull the trans I would consider having the 7.3 flywheel rebalanced and the pressure plate balance checked. Could be as simple as the friction disk spit out a section too.

You sure about that? I know the IDIT and 'regular' IDI have different imbalances, but I've never heard of a difference between a 6.9 and 7.3

Eli

 

[hce]

You sure about that? I know the IDIT and 'regular' IDI have different imbalances, but I've never heard of a difference between a 6.9 and 7.3

Eli

Pretty much the default answer always involves the idit with its heavier wrist pins causing need for different imbalance, but neglect the .110" larger piston and rings affect on bob weight.
Anyways I did manage to find this, gets tougher every time this comes up

"Flywheel -
IMPORTANT. DO NOT USE 6.9 flywheel or vibration damper on 7.3 or vice versa. If components are intermixed, engine vibration and premature component wear may be encountered. For identification, compare these part numbers.
Vibration damper 6.9 1805414C1
Vibration damper 7.3 1809117C1
Flywheel Auto 6.9 1803219C1
Flywheel Auto 7.3 1809212C1
Flywheel manual 6.9 E7TA-6477-AB
Flywheel manual 7.3 E8TA-6477-AA"

I am going to assume the one year run of the E7TA-6477-AB coincides with the one year run of the zf behind the 6.9 in 87.

 

[Laine D]

Pretty much the default answer always involves the idit with its heavier wrist pins causing need for different imbalance, but neglect the .110" larger piston and rings affect on bob weight.
Anyways I did manage to find this, gets tougher every time this comes up

"Flywheel -
IMPORTANT. DO NOT USE 6.9 flywheel or vibration damper on 7.3 or vice versa. If components are intermixed, engine vibration and premature component wear may be encountered. For identification, compare these part numbers.
Vibration damper 6.9 1805414C1
Vibration damper 7.3 1809117C1
Flywheel Auto 6.9 1803219C1
Flywheel Auto 7.3 1809212C1
Flywheel manual 6.9 E7TA-6477-AB
Flywheel manual 7.3 E8TA-6477-AA"

I am going to assume the one year run of the E7TA-6477-AB coincides with the one year run of the zf behind the 6.9 in 87.

When I bought the kit I selected it for a 91’ f250 7.3 non-turbo. When I bought it I wanted to be sure it would be fine on the 6.9. So Are you saying that it could be imbalanced for a 6.9?

 

[hce]

When I bought the kit I selected it for a 91’ f250 7.3 non-turbo. When I bought it I wanted to be sure it would be fine on the 6.9. So Are you saying that it could be imbalanced for a 6.9?

Could be the cause. Lots have installed the 7.3 flywheel on a 6.9, but everyone has a different tolerance for vibration.

 

[Thewespaul]

You can use the same clutch, just get a different flywheel.

 

[Eli]

Pretty much the default answer always involves the idit with its heavier wrist pins causing need for different imbalance, but neglect the .110" larger piston and rings affect on bob weight.
Anyways I did manage to find this, gets tougher every time this comes up

"Flywheel -
IMPORTANT. DO NOT USE 6.9 flywheel or vibration damper on 7.3 or vice versa. If components are intermixed, engine vibration and premature component wear may be encountered. For identification, compare these part numbers.
Vibration damper 6.9 1805414C1
Vibration damper 7.3 1809117C1
Flywheel Auto 6.9 1803219C1
Flywheel Auto 7.3 1809212C1
Flywheel manual 6.9 E7TA-6477-AB
Flywheel manual 7.3 E8TA-6477-AA"

I am going to assume the one year run of the E7TA-6477-AB coincides with the one year run of the zf behind the 6.9 in 87.

I'm not sure there's a different imbalance spec so much as just revisions in part specifications, the '87 6.9 used a lot of '7.3' parts. Does anybody have the actual imbalance figures?

Eli

 

[Laine D]

You can use the same clutch, just get a different flywheel.

Will it mess up my engine if I leave it how it is? It seems like it’s getting less noticeable

 

[Laine D]

You can use the same clutch, just get a different flywheel.

I just looked back and the clutch and flywheel I ordered was for an 88’ 7.3 N/A so it shouldn’t be imbalanced