do they make any gear drives?

[jdm93dsm]

I was wondering if they made any gear drives rather than belt, my dad has a set of liek pete jackson gear drives on his plymouth w/ a 360 mini heimi engine and it adds some to the sound of the car and my past experience w/ timing belts.... yeah, not good. just wondering, i really havent seen any 4cyl cars gear driven.

 

[TalonESi]

No, rubber is lighter and has better contact.

 

[Doug99RS]

Um, actually, the gear to gear is better for contact. There is no "belt slippage" nor breakage to worry about. Gear drive does make a little more noise because they are touching each other.

A gear to gear setup is used mostly on engines where the cam is in the block and not the head. There's about a foot and a half distance between the crank and the cams on both the 4g63 and 420A. So it's gonna have to be some really large gears in order to bridge that gap. The cam and crank on your dads 5.9L are only a few inches apart in comparison.
Doug

 

[Defiant]

Really large, or enough of them to span the distance-- which would quickly destroy any advantage through gear backlash.

Now then, if you'd look into Cardan shafts....










o god, now someone will.

 

[Morphius]

GM uses a chain for a main timing "belt". I've often thought about it and wondered what it would take to adapt that system to a 4G63.

A supplier I work with has a Saturn with the DOHC 2.2L(?) that has 250K on it and NEVER has had the motor apart.


Would be an interesting project? Anyone?


-DaimlerChrysler Engineer

 

[BUCK]

Seems like the Kevlar Belt would be the way to go - why do we never hear about them?

 

[Morphius]

Originally posted by BUCK
Seems like the Kevlar Belt would be the way to go - why do we never hear about them?

Interesting. Tell me more. Is anyone in the industry using them? Maybe on a different application?

 

[Doug99RS]

Mach V (pronounced "five") has the kevlar belts from what I hear. I just started hearing about them in the last two weeks for the first time.

As for the timing chain they've been out there for years maybe even since the Model T but I didn't work on them and couldn't tell you. One of the reasons why the manufacturer went to the belt is because it's quieter than a chain. Chrysler 3.9L, 5.2L, 5.9L in the trucks and the 3.3L and 3.8L in the vans tend to be noisier than engines with belts. That's one reason why the belt is used more.

Personally I agree though. It would be really nice to have a chain set-up requiring little to no maintenance given the amount of money we've all sunk in to our cars and the risks of belt breakage.
Doug

 

[Morphius]

Originally posted by Doug99RS
As for the timing chain they've been out there for years maybe even since the Model T but I didn't work on them and couldn't tell you. One of the reasons why the manufacturer went to the belt is because it's quieter than a chain. Chrysler 3.9L, 5.2L, 5.9L in the trucks and the 3.3L and 3.8L in the vans tend to be noisier than engines with belts. That's one reason why the belt is used more.

I've worked with a ton of big 3 engines. All timing chains. Some have easily over 200K miles and they still look like new. Some added slack in the chain, but still usable. Noiser, yes. But I'd sacrifice the noise for reliability anyday. I've never had a timing chain go bad.

Originally posted by Doug99RS
Personally I agree though. It would be really nice to have a chain set-up requiring little to no maintenance given the amount of money we've all sunk in to our cars and the risks of belt breakage.
Doug

(^^^^^) I second that. Someones got to be up to the challenge? This has and will contiue to intrigue me, but I'm too strapped with the projects I've got going. I know a chain works. Like I said GM uses it. Now, the underlining question: Can we adapt it to our cars?

-DaimerChrysler Engineer

 

[BUCK]

Personally I agree though. It would be really nice to have a chain set-up requiring little to no maintenance given the amount of money we've all sunk in to our cars and the risks of belt breakage.

Well the old Duplex roller chains on the 70's & 80's Toyotas were like that - but now that they all "cheaped out" to a single row timing chain like the Datsun's, etc had - the chains are shot on a manual trans 4 cylinder in a little over 100K - might as well have a belt.

 

[Defiant]

Originally posted by Doug99RS

Personally I agree though. It would be really nice to have a chain set-up requiring little to no maintenance given the amount of money we've all sunk in to our cars and the risks of belt breakage.

Don't get your hopes too far up- when Datsun made an OHC from their forklift motor, and used a second chain driving the cam from the nose of the jackshaft that replaced the in-block cam, they found out [the hard, noisy, expensive and messy way] the cam chain's good for about 30,000 miles.
It'd take quite a chain to take the place of the DSM belt, plus you have to account for oiling, sealing of the oiling chamber, chain guides and tensioners.... belts really do have advantages.

Any feedback about that MACH-V kevlar belt?

 

[slodsm]

I too would prefer a Kevlar belt. A chain would not be reliable for us for one large reason. The belt allows no slop because of the tensioner keeping it tight. The Chains however that I have used on past hot rods I have owned were a different story. Even when using a double roller setup that was a VERY nice chain, it was as defiant said only good for 30k or so. When they start to wear, they will never break causing damage (never is a strong word, let me change that to very seldom) but when they wear, it gets a lot of slop due to no tensioner and timing gets erratic. Not valve smacking the piston earatic but causing a loss in performance eratic and not something we are willing to accept here being that we are pretty much all gear heads. I will take my properly installed belt and change it 10k before the service life and be happy with it.

 

[Doug99RS]

Chains have tensioners too in some of the newer vehicles. I know my old duster did not but the new 2.7L in the intrepids and stuff have three chains which each have their own tensioners. One chain drives two cams on one head, a second for the other two cams, and then a third that goes through both heads, over the water pump, around the crank and one or two more places.

The 4.7L has three chains as well each with their own tensioner.

Regardless, the point still stands that the chain would require oiling and in the DSM's this really isn't a set-up that most people will want to switch to.
Doug

 

[Morphius]

Originally posted by Doug99RS
Regardless, the point still stands that the chain would require oiling and in the DSM's this really isn't a set-up that most people will want to switch to.
Doug

I think a sealed chain would solve that. Even if you had to grease it once in a while wouldn't be so bad.

I still think the GM/Satrun setup could work.

-DaimlerChrysler Engineer