6.2 gear drive

So I found new source for the 6.2 gear drive to replace the timing chain. I plan to install this on my truck as soon as I can afford it.

Kennedy Diesel

You might read & check around... I ran across an article online a couple weeks back regarding gear drive assemblies used on GM 6.5 motors... the shop citing the article recommended staying with the chain drive due to drivetrain harmonics issues when using geardrives. Whether this is true or BS is not my call -

I'll see if I can locate the site - here it is:

Gear Drive Timing WARNING for GM 6.5 Diesel & 6.5 Turbo Diesels, possible Crankshaft Failure and Serious Engine Damage and/or cracked engine block can Result!

You make the call, obviously... maybe it's a legit concern, or maybe someone is simply screaming that the sky is falling - FWIW, I'd simply go back with a new chain & gearset.

'Tanner'

yes your always fwiw that's your opinion and fwiw i really dont take your opinions to heart. to bad i dont have a 6.5 in my truck.

Cucvnut said:

yes your always fwiw that's your opinion and fwiw i really dont take your opinions to heart. to bad i dont have a 6.5 in my truck.

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WOW! A little bad blood here?

I would just stick with the chain, it will outlast the truck.

the 6.5 and 6.2 blocks are about the same and gear are always worse on diesels now if we were talking gas racing engines then gear would be better.

I have talked to a few diesel mechanics and all of them have said the gears are fine to run in a truck. yes they transfer vibrations but a chain streches.

Taken from a 6.2 build up.

One of the optional upgrades in the rebuild is converting the old timing chain assembly to the gear-drive. The Diesel Service Group is the only one offering this kit, which it calls the Phazer Kit (PET 62GD, $325). DSG says, "The timing chain used on the 6.2L and 6.5L engines cannot withstand the continuous shock loads transmitted to it via the injection pump, which can reach peak pressures in excess of 12,000 psi. These shock loads cause the chain to wear, and the resulting vibration can lead to several expensive problems, such as broken main bearing castings, sheared crankshaft keys, broken harmonic balancers, unstable timing, and poor performance.

Read more: GM 6.2L Buildup - Diesel Power Magazine

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I look at it basically pick your poison.

true i have read that story and the way i see it is if you want to add put alot of money in a truck then i would go with gear but if you are just going to do what most of us do (run them day to day) and not hotrod the truck then the chain will be fine

Thanks for posting the link cucvnut! I was wondering if anyone was making them now. I just wish they weren't so dang expensive. I think it is a pick your poison kind of thing on chian vrs gear. I may go with the gear on my motor to me it just gives me peice of mind.

Ya I remember a while back a few people were asking for them and some company stopped making them. nice to know some one else does.

The thing with the gear drives transmitting the crankshaft's harmonics is absolutely true. I would contact Cloyes or another good brand timing chain company and see if they offer a higher tensile version chain. Best that's out there is a timing belt; that virtually eliminates any crank harmonice from getting into the cam and valve train. This is a big concern on racing engines.

Cucvnut said:

yes your always fwiw that's your opinion and fwiw i really dont take your opinions to heart. to bad i dont have a 6.5 in my truck.

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6.2 & 6.5 use many of the same drive train parts. DSG & Kennedy are both selling them - probably from same supplier -

I see you're still keepin' it classy in California...

My preventative maint for the web cracking was the DSG stud girdle kit. I had to reseal the pan and do the rear main anyway so it was a no brainer. Depending on the value of the dollar it is $179.00 shipped from Canada which is alot less money. The stud girdle kit is listed with the 6.5 parts and then you need to select the correct studs for the 6.2 application. My 6.2 only has 23K on it so the chain will be there for awhile but I agree that harmonic transfer may be an issue but since I have installed the girdle I have noticed a change in the harmonics in my 09 and the engine seems a little smoother at all RPMS which may be what needs to be done before the timing kit. The gear system originated in Drag Racing Apps so that engine timing would not fluctuate as the chain stretched allowing for more consistent ET's. Just my

Tanner said:

6.2 & 6.5 use many of the same drive train parts. DSG & Kennedy are both selling them - probably from same supplier -

I see you're still keepin' it classy in California...

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no need to Diss CA.

6.2 and the 6.5 are about the same chevy just wanted to make there own turbo charged engine and wala we have the 6.5 basically a 6.2 with electronics and a turbo because banks turbo was kicking a**

epartsman said:

My preventative maint for the web cracking was the DSG stud girdle kit. I had to reseal the pan and do the rear main anyway so it was a no brainer. Depending on the value of the dollar it is $179.00 shipped from Canada which is alot less money. The stud girdle kit is listed with the 6.5 parts and then you need to select the correct studs for the 6.2 application. My 6.2 only has 23K on it so the chain will be there for awhile but I agree that harmonic transfer may be an issue but since I have installed the girdle I have noticed a change in the harmonics in my 09 and the engine seems a little smoother at all RPMS which may be what needs to be done before the timing kit. The gear system originated in Drag Racing Apps so that engine timing would not fluctuate as the chain stretched allowing for more consistent ET's. Just my

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Good to know that the girdles cut down vibration. I may spend some money in the fall.
I installed Fluidampers on my M1008 6.2 and my T400 6.5 turbo. It noticeably cut down the felt vibration in the steering wheel. The old harmonic rings were moving. My baseline vibrations could just be that the old GM balancers were used up.

Cucvnut said:

yes your always fwiw that's your opinion and fwiw i really dont take your opinions to heart. to bad i dont have a 6.5 in my truck.

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Not sure where that came from. I almost wanted to play Dr. Phil for a moment and ask if we could "all just get along".

Anyhow, more to my input on this. All HMMWV's with a 6.5 that I've seen run the gears. Uncle Sam does tend to waste money but he also is a fan of reliability. I do agree that timing belts are great for not allowing lower and upper harmonics to be transmitted but please take note that alot of auto manufacturers are moving away from timing belts and going back to chains. My wife's last two Nissans, an 03 Maxima and 05 Pathfinder had timing chains. The reason is that alot of engines are of the interference design meaning that when the belt breaks, the engine is toast. The owners simply cannot be bothered with a timing belt service every 50,000 or 60,000 miles as many cannot do this themselves and don't want to pay a skilled technician to do the maintenance as it is labor intensive or expensive. A chain is cheap, lasts a long time and in mostly maintenance free. Gears are expensive but as long as they receive oil on a regular basis, which they will at no concern of the owner, should last dang near forever.

Cucvnut said:

no need to Diss CA.

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Nor was there any need to talk smack, Sport....

We're all one community here. I'm not talking out my ass in regards to 6.X issues - I've got tons of time on them, sold hundreds of them, and know the issues well. My point is that the chain works well for 99% of the users - adding gears brings additional issues & you'll simply expose the next weak link in the 6.X chain of issues.

Roll on, sir -

'Tanner'

hatzie said:

Good to know that the girdles cut down vibration. I may spend some money in the fall.
I installed Fluidampers on my M1008 6.2 and my T400 6.5 turbo. It noticeably cut down the felt vibration in the steering wheel. The old harmonic rings were moving. My baseline vibrations could just be that the old GM balancers were used up.

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Once I get the severe rust issues resolved (including a rotted metal rear brake line) and move on to installing my A/C I will go with a fluid damper as well because I have to change out the crank pulley from the 3 sheave to the 4 anyway to accomodate the compressor.

Thats nice I think you come off cocky especially with your little signature. i was not talking smack you seem to not like CA that's fine but you bring it up like your trying to hurt my feelings or something(bringing up CA for some reason). so its not ok to be different and want to run a timing gear set? im not trying to be a jerk but i just don't need or want your opinion(fwiw). have a good night.

OK, now I'll ask if we can all get along. If ya'll don't agree with one another, don't read each other's opinions or posts. An internet forum is a not really a good medium to channel your anger through, PM each other your phone numbers, call, talk or curse each other out and let it be. FWIW IMHO CA is not a terrible state, I train folks in Barstow from time to time and I tend to like El Pollo Loco even though some of the locals think it's crap? The original intent of the thread I think was to express an opinion about gear drives vs the other options for spinning the camshaft and injection pump. Nothing too personal to read into there.

And to keep it MV related, I think chains, belts, or gears are a fine choice depending on your budget and commitment to maintain your ride.