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Without timing belt?

Dear all readers and mechanics,

I’m more familiar with diesel engine on trucks like Detroit, Cummins and Caterpillar than cars. I’m wondering is it possible diesel engine runs on gear driven without timing belt or chain be found in any cars? I mean any gas engine cars? I would like to know



Are you asking has anyone made a Diesel engine with a gear driven camshaft? For large truck or private car/truck application? I have seen gear driven injection pumps.

What I am trying to say is yes it is gear driven camshaft goes with gear driven crankshaft other gears all together fully gear driven without belt or chain but on gas engine? and gear driven injection pumps no longer in trucks it is fully ECM control. Do you know what I am trying to say?

2.5 chevy 4cyl eng had no chain or belt it had gear driven cam.

Maybe if you say what you are trying to do I will get it. Are you making a engine swap or just doing some reasearch or is this a “bet” type question. Like “I bet they made this that way”.

I remember some Volvo engines in the early 70s which had only a gear-to-gear arrangement to drive the camshaft. There was no timing chain or belt.

Summit Racing sells kits to give any small block Chevy a set of gears rather than a belt. They are rather noisy though.

I think you are asking, "Are there any gasoline engines which don’t have timing chains or timing belts, similar to diesel engines not have timing belts/chains?"
As far as I know, in today’s cars, all four-stroke gasoline engines have timing chains/belts, or gears which perform the same function. Two-stroke gasoline engines may be what you are thinking about. Maybe, a hundred years ago there may have been four-stroke gasoline engines with a different design; but, I’m not an automotive historian.
On the two-stroke engine, the piston itself acts as the intake and exhaust valve…as this little video shows:

The old Chevy 250 straight 6 used a gear driven cam.

Overhead cam engines all use either a timing belt or a timing chain. They are all overhead valve. Overhead valves may either be driven by an overhead cam (see above) or by a gear-driven cam + push rods + rockers. Side valve (flathead, L-head, etc.) designs have a gear-driven cam + push rods (usually) + the valves themselves. Two cycle engines generally have no valves (except a reed valve to keep fuel/oil/air mix from blowing back through the carburetor). Various other designs have been built, including sleeve valves. Diesel (compression ignition) and Otto cycle (spark ignition) can have any of these valve configurations.

80 or 81 Olds Starfire had a timing gear.

Light aircraft engines do not have timing belts, in the early 2000’s Cessna made a Diesel engine for it’s popular “Skyhawk” and i’m sure it didn’t have a timing belt. In these engines the Crankshaft is mated directly to the camshaft.


Mostly straight six cylinder engines with cam in block.

While they’re not diesel, the old VW air cools (Beetles, Buses Types 3s and 4s, older Porsches, Subarus up through most of the 80s, etc. used a gear driven camshaft.
Just a few off the top of my head anyway.

The reason I posted it is that I noticed some people wanted to know when and how regarding timing belt/chain needed to replace so my thought is why didnt the auto manufacturer desgin to eliminate belts/chains to save our cost and headache on maintnance schedule. It is one less maintenance to make customers happy:).

I can’t say what engines had gear driven cams but I know there have been some in the last, say, 20 years.

I suppose you could have a series of steel gears up the front of the engine (with appropriate lubrication), but the preferred method of getting an overhead camshaft turning is a belt or chain. If you want a gear-driven camshaft instead, your only choice is pushrods activating rocker arms and overhead valves. I don’t think the old side-valve designs are efficient or clean enough to do the job anymore. And all the extra weight and lubrication needs of the old-fashioned mechanism need to be considered (not to mention the inertia and moving mass of the parts).

Some of the reasons there aren’t gear driven camshafts in mass produced cars: 1. It costs more. 2. Nosier than chains or belts. 3. Design limitation of the basic engine layout. 4. When there is maintenance to the cylinder head(s), the gearing would have to re-geared because of the difference in deck height.
Is there an engine designer, out there?

I have a Chilton book on light trucks and minivans from '80 to '87. I checked it for gear driven cams and found the following; Chev 250 and 292 6s. Ford 171 (2.8) v6 and 300 “big six”. Dodge/Chrysler 446 V8 (7.3 liter) I never heard of this one. And Jeep 151 4 cylinder.
Hellokit, I don’t see why it would cost more or be noisier than a chain??? Also doing repair on the head would not change anything EXCEPT on overhead cams