Gear driven cams?

[Billzilla]

Seems our 186 has an alloy replacement. Still no noise that I can pick.. Why would they be any noisier than a gearbox?

It depends if they're helical (angled) gears or not. Helical gears are nice & quiet as they slide gently together and then apart. Straight cut gears don't, and so make a bit of noise.

The close-ratio gearbox in my Sprinter had 2nd & 3rd gear straight cut and it'd echo off the buildings around me as I drove along.
Highly grinworthy. :D

[BigMuz]

They are helical, but only slightly- helical gears create end thrust issues, so they minimised the amount of helix (something like that :D)

The fibre ones strip and everything goes quiet. The alloy ones are only slightly noisier- but put some stiffer valve springs and a big cam and the noise increases dramatically.

The v8 gear drives are straight cut with a floating idler conatining 2 gears usually. The timing floats around a bit with either chain of gears, although gears are probably better. They tend to be harder on the valvetrain than a chain, which can absorb some shock loads.

Muz

[Ben Wilson]

The close-ratio gearbox in my Sprinter had 2nd & 3rd gear straight cut and it'd echo off the buildings around me as I drove along.
Highly grinworthy. :D

For a while, then it starts to get old in a big hurry....

[goose]

Bugle, the noise of the cam gears are probably hard to hear over the rest of the clunking going on in a Holden 6!

[summoner]

Heaps of kits for old 308's and 304's
Makes a beautiful noise imho that whinge from gear drives.. Very similair to Gilmer pulleys

[dog poo]

Do they suffer from more wear than a belt? Im guessing it'd be far more expensive to replace the gear over a belt.

[XEFalconUte]

As noted helical cut gears are usually quiet and straight cut gears sound not unlike a rootes blower. There is a school of thought that says that gear drives transmit all sorts of cam killing shock loads and harmonic vibrations to the valve train, though I'm yet to see evidence of this. Cheaper gear drives for v8's usually have two floating idler gears. Better gears drives use only one fixed idler gear. The best setup of cause is only two gears but the your camshaft runs backward and you need a custom camshaft, not to mention that altering the clearance between the gears requires smaller or larger gears to be installed. Many of the latest v8 race engines use belt drives, I suspect this choice has more to do with ease of cam timing change without having to remove the front of the engine. Lol

I chose to go with a Milodon single idler gear set for my engine in build (Big Block Ford) a quality piece with a Torrington bearing behind the cam gear to take care of any side loads.

Just my 2 cents

Simon