[jdemaris]

So I just finished checking the two out-
I think I'm going to go with the first one - the clutch disc I have will fit either. They are made by standard Flywheels Inc. and the PN's are 7576788 and 7576572.

I spoke to the tech. manager at Standard Flywheels and he says they do not sell new flywheels with no core-charge. With the part #s you gave - 7576788 is for the original GM casting # 14050525 and is the most common 6.2 flywheel I've seen. The other 7576572 is for OEM casting # 14022675. The mangager did say that once in awhile they do make a few new ones when they get short of good cores - but still never sell them without either getting a good core back or charging and extra $70 core-credit. So, it seems if you bought your's outright, you got a heck of a deal and Kragen's screwed up.

 

[fsr7]

That price was after a core charge was taken off- so you're info was right on. I just turned in the flywheel that I had for a core-- I don't need it.

 

[D.Camilleri]

The 6.2 and 6.5 are externally balanced engines just like high sierra 2500 stated! To prove this point, look at a 6.2 or 6.5 balancer, flywheel or flex plate. One side of the balancer has a great deal more mass just like a small block 400 or 454. The same goes for the flywheel. Look at the flywheel and on one side of the flywheel the casting has a heavy point. On flex plates, there is a heavy piece of steel welded to one part it. These heavy spots provide for external balancing. Having spent the time and money to have 6.2 balanced by machine shops in the past shows that the internal parts aren't out a lot, but balancing requires the use of the harmonic balancer and the flywheel. The last 6.2 that I had balanced required every bit of balancing ballast that the machine shop had, much more than any 454 he ever did.

Back to the flywheel discussion. When I discuss flywheel part numbers, they are factory GM numbers only. I suggest you do your research a little better to be better informed. If I am wrong, I will gladly admit it. So I will preface my comments with (In my experience) yours could be different. So with that said, all 6.2's used a one piece flywheel. Since I never worked on a 6.2 with the light duty manual transmission, I will not comment on this. All 6.2's with the sm465 tranny used the same flywheel and same clutch. Some did use different throwout bearings depending on if the clutch was manual linkage or hydraulic.

In 1992 the 6.5 turbo was born, as was the NVG 4500, at this time the dual mass flyweel also was used. I personally ran several 6.5's with 6.2 flywheels and center force clutches for over 400,000 miles. Might I add, that with over 1,000,000 miles driven, I never suffered a crank failure! They are direct replacements. 6.2 engines and 6.5 engines are balanced the same, the pistons weigh the same and the rods are the same part # the crank has the same throws with the only difference being the back end of the crank that is machined for a one piece rear main seal. The dual mass flywheel was used through 1997 and then the design was changed back to a one piece flywheel do to repeated dual mass flywheel failures. The 1998 and up one piece flywheel is the same as the early hd flywheel. Dimensions are the same bolt pattern is the same and the same clutches will fit. The clutch lining for the late model 6.5 is slightly different to handle the increase in torque to 430 ft lbs.

So if you are looking for clutch parts, just order 6.2 clutch parts because most parts houses can't tell the difference and many times their information is wrong.

If you get a flywheel that doesn't have a heavy side cast into it take it back or be prepared for a broken crank.

 

[High Sierra 2500]

As further proof that the 6.2 is externally balanced, I happen to have a flexplate that I removed from my 6.2 right here. It has a large piece of metal welded to it for balance. If the engine was internally balanced and you put that on it would cause the engine to vibrate really bad... It didn't.

You'll also notice that the flywheels and flexplates are all drilled and the crank has a pin on it so that they can only be installed in one position...

 

[jdemaris]

The 6.2 and 6.5 are externally balanced engines just like high sierra 2500 stated! To prove this point, look at a 6.2 or 6.5 balancer, flywheel or flex plate. One side of the balancer has a great deal more mass just like a small block 400 or 454.

The fact that some external components have some offset weights does not prove a thing. Many engines have the same and are classified as "internally balanced." I don't believe there is any set rule that any company has to use - when describing their engines. But from anything I've read on the subject of engine design - the phrase "externally balanced" denotes and engine that MUST have external balancing or will fail prematurely. An "internally balanced engine" has enough internal mass to hold itself together - but often can still benefit from additional external balancing to eliminate vibration. General Motors lists the 6.2 and 6.5 as "internally balanced" in many sources - and I've yet to see any source list it as an "externally balanced" engine. If you have one - please post.
I have had many engines custom balanced over the past 40 years including many SB Fords and Chevys. None were ever perfectly balanced and with some we'd even balance the clutch-assembly and used larger than stock harmonic balancers and put "timing marks" on the clutch when done. When I worked as a Deere mechanic, we had several engines that Deere considered "internally balanced" engines - and they did so with internal balancing shafts. Later, as a cost-cutting measure - Deere left the shafts out and stated it would not affect engine life. But . . . vibrations were so bad at certain RPMs that the exhaust pipes would crack. I suspect GM used many external parts to cut down on "nuisance" vibrations. GM service bulletins discuss this with the 6.5 and the dual-mass to solid flywheel conversion.
Again - I don't see where you've proved anything. You have made some technical claims in the past that also seem to be from anecdotal sources e.g. like GM having TBI on all 84 and later trucks? Or one test on one 1982 block for nickel content thus proving none had it? If you have verifiable information, please provide some sources.
The reality is - I don't care what the 6.2 is called. I do care about proper engine setup and part's matching.

Back to the flywheel discussion. When I discuss flywheel part numbers, they are factory GM numbers only. I suggest you do your research a little better to be better informed.

I don't claim to know it all, and I also cannot verify every source I read. I am well trained as a records researcher and learned the need for primary source citations long ago. But, this is not a Master's Thesis or a Doctoral Dissertation. I have to mix a little common-sense along with prior experience and sort this stuff out best I can. That being said, I have discussed this subject with some part numbers as well as casting numbers.
GM had two different flywheels for use on the 6.2 diesel. Casting #14050525 weighs 45 lbs. and seems to be the most common. It is GM part # 14077160. Counterweights are symmetrical. Several GM parts lists as well as military documents describe it "internal balance" and GM lists it for use with the Muncie trans. only. Casting #14022675 weighs 31 lbs. and counterweights are not symetrical -and I think this is the flywheel used in light-duty manual trans. setups, e.g. the NP833 four-speed overdrive.

I personally ran several 6.5's with 6.2 flywheels and center force clutches for over 400,000 miles. Might I add, that with over 1,000,000 miles driven, I never suffered a crank failure!

Since you mention Centerforce, here's a blurb from their catalog for their 6.2 diesel flywheel.

" . . . Centerforce flywheel - Part #: 700100
Notes: CENTERFORCE BILLET STEEL FLYWHEEL -- SFI Spec 1.1, Weight 30.2 lbs., No Counter Balance Fits - 6.2L V8, Diesel . . ."

In regard to you driving X amount of miles and never having a crank break? Do you truly think that means anything? I drove my 87 6.2 Suburban 520,000 miles before the crank broke. So - does that make me some sort of diesel god? I don't think so. I took good care of it and I consider myself lucky. I've been driving 6.2s since they came out including our 1 ton service truck. Personally, I've had only one failure and I've presently have many 6.2 trucks with well over 200K each. I have also known of well-cared-for 6.2 engines that broke cranks at less than 100K. Some of those were only used for transportation and never worked hard. One still ran fine, didn't even vibrate. The crank broke right off at the flywheel mouning area and the flywheel was no longer turning. And, of the ones I personally worked on - none had a bad harmonic balancer.

If you get a flywheel that doesn't have a heavy side cast into it take it back or be prepared for a broken crank.

Yeah - like my 1982 K10 with the NP833 and 240K miles on it. I guess you better be prepared for any 6.2 to break a crank - because with some, it happens. And, I have yet to see anyone offer anything that even closely resembles proof of what causes some 6.2 blocks to lose their main bearing webs and some to break crankshafts. It seems to me - that often when someone posts something that sounds good ( and may, or may not actually be good), thanks to the Internet, it gets repeated all over the place - and then just the repetition is given as its proof.
Here are a few aftermarket photos of flywheels. I don't have any from GM that show the backs.

And again - if you can show any reputable source that denotes the 6.2 as an externally balanced engine - please cite it.



(Image has been resized. Click it for full size.)




(Image has been resized. Click it for full size.)

 

[High Sierra 2500]

The fact that some external components have some offset weights does not prove a thing.

Yes it does... If it were internally balanced it wouldn't have to have external balance weights...

Many engines have the same and are classified as "internally balanced." I don't believe there is any set rule that any company has to use - when describing their engines. But from anything I've read on the subject of engine design - the phrase "externally balanced" denotes and engine that MUST have external balancing or will fail prematurely.

And the 6.2 WILL suffer a failure without the external balance weights on the flywheel and the harmonic balancer...

An "internally balanced engine" has enough internal mass to hold itself together - but often can still benefit from additional external balancing to eliminate vibration. General Motors lists the 6.2 and 6.5 as "internally balanced" in many sources - and I've yet to see any source list it as an "externally balanced" engine. If you have one - please post.

And I have yet to see a reliable source that says it is internally balanced...

Again - I don't see where you've proved anything. You have made some technical claims in the past that also seem to be from anecdotal sources e.g. like GM having TBI on all 84 and later trucks? Or one test on one 1982 block for nickel content thus proving none had it? If you have verifiable information, please provide some sources.

I don't see either of those things being mentioned in this thread. Nor have I seen them mentioned by anyone who is on this thread. I also don't see any sources behind YOUR information besides "GM"... And you don't tell us where we can look up the same information to verify it.

 

[jdemaris]

I don't see either of those things being mentioned in this thread. Nor have I seen them mentioned by anyone who is on this thread. I also don't see any sources behind YOUR information besides "GM"... And you don't tell us where we can look up the same information to verify it.

Hmmm, let me get this straight. You don't want information taken from outside this thread? Seems that limits the fact-content a bit.

I frequent mechanical forums mostly looking for new information - or owner's personal experiences - not seeking a gossip-laden chat-room.

On the subject of proof. I didn't jump into the thread telling anyone they were wrong. That was first done by you - High Sierra 2500 and D. Camilleri. If you are going to tell people they are wrong, I think it's up to you to back it up.

This thread was started by fsr7 - trying to make his clutch and flywheel match.

I told him that all the solid-flywheels for 6.2s and 6.5s are not the same - and also mentioned, as a side-note the Luk setup - since I suspected that was the problem. Luk describes the flywheel as "internally balanced." They make it and that is how they describe it (they also make it for GM).

D. Camilleri posted - stating the flywheels are the same, i.e. what I previously posted was incorrect.

You came into it - and wrote that you agree with D. Camilleri and also that the engines are NOT internally balanced.

fsr7 got his problem fixed, apparently because the 6.5 flywheel was indeed different of the 6.2 flywheel.

Now you spout off about things such as cranks failing due to failed harmonic balancers. Fine for anyone to believe it - I don't. Just don't post it as verified fact - unless it IS verified fact. I suspect I have a lot more hands-on diesel experience than you as well as more technical training in several related fields. At the least, that qualifies me to make an "informed" guess. And my guess on the failed crankshafts is one of underbuilding and quality control. I can't come up with anything else that accounts for the often inconsistent and unpredictable crank and block failures. But, I make it clear - it's my best guess - I have no proof - and don't need it.

 

[King Pin]

Disagreemants

I'll go with the old concept of if it has some sort of a "offset balance" on the flywheel or Harmonic Balancer then it is externally balanced!! No matter what some magic engineering bible has to say. By the looks of this thread up to this point it looks like most everyone agrees that the 6.2-6.5 is Externally balanced. Thats my vote to.

 

[High Sierra 2500]

Let me make some things clear.

But, I make it clear - it's my best guess - I have no proof - and don't need it.

Oh yes, yes you do if you are going to tell people that they are wrong unless they can provide proof... If you are going to ask other people to provide proof on their theories you had better back up what you say with some facts.

Hmmm, let me get this straight. You don't want information taken from outside this thread? Seems that limits the fact-content a bit.

I don't mind information coming from outside this thread in the least if it is relevant and true. If you can show me where anyone on this thread said that all GM trucks were TBI from '84 on I'd be happy to let that information into the thread (although it is irrelevant), but I assure you that nobody who is currently on this thread said that.

The fact of the matter is this... The 6.2 is externally balanced, like it or not.

 

[High Sierra 2500]

I'll go with the old concept of if it has some sort of a "offset balance" on the flywheel or Harmonic Balancer then it is externally balanced!! No matter what some magic engineering bible has to say. By the looks of this thread up to this point it looks like most everyone agrees that the 6.2-6.5 is Externally balanced. Thats my vote to.

:exactly:

 

[D.Camilleri]

This thread is going in the wrong direction. We are here to give good information to help people fix their trucks.

1) If you are going to post pictures of parts (flywheels in this case), post pictures of factory parts. Aftermarket part pictures may or may not be the actual picture of the part in question.

2) Take a good look at the harmonic balancer on any 6.2 or 6.5 engine. You will notice that almost half of the balancer is solid cast (counter weight) the same can be said for factory 6.2 and 6.5 flywheels they also have counter weight. Factory and after market 6.2/6.5 flex plates have a heavy piece of counter weight welded to the flex plate, they are not neutral balanced.

3) If you take a neutral balanced flywheel and run it on the opposite end of a counterbalanced harmonic balancer, I can guarentee you that the vibrations will be terrible and the crankshaft will break.

4) With the purpose in mind of helping people that are asking for help, it is very important to make sure that the best possible information is being given. This doesn't mean opinions, but facts.

 

[D.Camilleri]

Engines are either balanced internally or externally. Flywheels used with internally balanced engines are "zero balanced" as are the harmonic balancers. This means the engine and flywheel are in balance whether they are bolted together or not. It also means the flywheel can be rotated and bolted in any clock-position on the crankshaft without affecting the engine balance as a whole. Externally balanced engines, technically known as "Detroit Balanced" are completely different. The engine and the flywheel are both out of balance until bolted together - and the flywheel must be bolted on in a preset position.

By this statement alone, it shows that the 6.2/6.5 is an externally balanced engine.

The flywheel can only go on one way, it can not be clocked. The heavy non neutral weighted portion of the flywheel is opposite of the heavy non neutral weighted portion of the harmonic balancer exactly the same as a small block 400 or a big block 454.

Quotes from publications that can not be verified are useless as many articles are written with wrong information.

If someone here can post a picture of a 6.2 or 6.5 factory flywheel that doesn't have the counter weights on it, I will buy him a steak dinner at his favorite steak house.

 

[farmer0_1]

if this would have happened this summer when i changed out my brothers 84 that had a factory flywheel and aftermarket clutch kit i would have taken pictures . his had manual clutch linkage. hard not to take this stuff personal some threads are just that way. can't remember been three clutches ago but is there an alignment pin or one way bolt pattern to get the flywheel on right usually denotes balance for me.

 

[High Sierra 2500]

By this statement alone, it shows that the 6.2/6.5 is an externally balanced engine.

The flywheel can only go on one way, it can not be clocked. The heavy non neutral weighted portion of the flywheel is opposite of the heavy non neutral weighted portion of the harmonic balancer exactly the same as a small block 400 or a big block 454.

:exactly:

 

[fsr7]

Parts in, bolted up

I got the flywheel/clutch/tranny bolted up- It all fit- Thanks to all for the help. It'll be a couple weeks yet before I can let you know if it actually works right, but I will... I'm not sure if I took enough out of the bellhousing, as there is still a tiny gap at the bottom of the starter to the bellhousing. I will take the starter out before I try to turn the motor, make sure its not still in contact with the bellhousing, and put it back... or something like that. thanks again!