Quick fly wheel question.

[ozbrad]

G'day,

I've bought a rebuilt 6.2 for a project vehicle.
It came with a flex plate and it looks like I'll use a manual trans.

So my question is: Are the fly wheels balanced to each individual engine or are they all balanced to the required spec?

If they are ballanced to a spec, was there any variation or change to this over the years? Is an 6.2 fly wheel interchangable with 6.5?

Cheers.

[john8662]

You should be able to use a 6.5 flywheel with the 6.2, the bolt pattern is the same, as is the requirement for external balancing.

J

[Robyn]

I am not real sure but I think the 6.2 uses a different flywheel and or flex plate than a 6.5. I think all 6.2's are the same as are all 6.5's but not interchangable between the two.
I checked a while back and the 6.2 flex plate is different than a 6.5
When I did my 94 Burb the ring gear was toast and I had a 6.2 plate. They are different.
Most likely a slightly different ballance weight me thinks.
I would be safe and get one for the engine you are going to use. Be sure the crank will accept the pilot bushing/bearing that is needed for the manual trans too.
I dont think GM made tranny specific cranks BUT??? Look and check it out!!
Robyn

[NH2112]

The 6.2l and later 6.5ls use a single-mass flywheel. Earlier 6.5ls use a dual-mass flywheel. I'm pretty sure you can use either one on either engine, as long as you also get the correct clutch for it (SMF or DMF.) In theory you should install the counterweight in an NV4500 if you switch to a SMF flywheel, but from a couple friends' experiences the counterweight is there to reduce tranny noise when lugging the engine more than it is to dampen vibrations.

[john8662]

I checked a while back and the 6.2 flex plate is different than a 6.5
When I did my 94 Burb the ring gear was toast and I had a 6.2 plate.

You're referring to the difference between a TH400 flexplate and a TH700 flexplate, the plate on the 6.2 was likely a TH700 plate, not for a 4L80E as in what was in the '94.



Be sure the crank will accept the pilot bushing/bearing that is needed for the manual trans too.
I dont think GM made tranny specific cranks BUT??? Look and check it out!!
Robyn

FYI, all the cranks are machined out in the center to accept the pilot bearing (either roller or brass).

The 6.2 and 6.5 share the same bolt pattern on the crank for mounting flexplates and flywheels to. Afterall, the 6.5 is an acceptable replacement for the n/a 6.2 in the field.

J

[Robyn]

I had a TH 400 plate for the 6.2 and it is not the same as what is used on the 6.5 with a 4L80 .
I do believe the 6.5 has a slightly heavier ballance weight than the 6.2
I am just not sure enough on a stick flywheel that I would make a point. I would check the GM store and have then run the numbers on the flywheel used with both engines and see what shakes out.
Anyway there is enough info here to at least get you on the right track.

[ozbrad]

Thanks everyone. That great info.

Brad.

[poolmike]

As far as flywheels go, I have one that came off of the 6.2 that I built and it has the same part number as the 6.5 trans donor truck. So I would imagine that the flexplate numbers would be the same depending on the trans used.

NAPA list flywheels for the 6.2 and 6.5 with the same part numbers...