Gear driven cam shafts exist? y/n

[pib]

I have been wanting to ask this ever since I read a piece on the Carrera GT that said Porsche opted not to use them due to NV&Harshness. So which cars have or have had them? I assume they are more efficient and have longer life spans than belts or chains.

[tvrjohn]

Honda VFR 750 v4 config engine for motorbikes
has been in production since 1994 with gear driven cams, still in production as the vfr 800 & a vtec model.

[love machine]

Fully, Ford Essex, etc, etc, etc. Bugattis used gear driven TOHC's IIRC. Quite a lot of pushrod engines have gear driven cam upgrades, they are noisy but do the job more reliably. The customer wants a quiet cam drive. A belt is cheaper, you find gears where costs are not the key issue.

[Trooper2]

Some aftermarket gear drives for "V" OHV engines can be had with helical cut gears now so the new ones aren't as noisy.

As we all know cam belts wear out the soonest but the advantage to using a belt is that it doesn't pass vibrations from the crank on to the valve train which can help the valve train last longer and work more efficiently.

[love machine]

Which was the point of the fibre gears in Ford V4 and V6 engines. (which disintegrated as well). The helicity of the gears is usually pretty minimal and a bit of whirring is residual. I've heard this mentioned about several engines as a pain. I suppose the jerkyness of the cam drive would cause wear on the cam thrust washers which would be necessary. Straight cut cam drives are the deal

[Trooper2]

You just run a "Torrington" bearing (radial needle bearing) between the cam gear and the block to take the load off of the thrust bearings and a rubbing block on the camshaft cover so the cam can't walk forward. Especially if running a roller cam and lifters, you have to.

Good morning Love Machine.

[pib]

Fascinating, you folks know a lot! Is there anyone who makes a gear driven cam for the SBC (pushrod V8)? It sounds like there are some problematic issues to make conversion parts for most cars or at least the benefits are too small to out weigh the negatives.

[Trooper2]

pib said:

Fascinating, you folks know a lot! Is there anyone who makes a gear driven cam for the SBC (pushrod V8)? It sounds like there are some problematic issues to make conversion parts for most cars or at least the benefits are too small to out weigh the negatives.

Hi Pib, yes there are many gear drives available for the small block Chevy. Easiest way to let you see is a link so here are a couple:

http://store.summitracing.com/

www.jegs.com/index.html

Just type cam gear drives into the search field, then narrow down to Chevy.


Hi from Phoenix, Pib.