From Newsgroup: uk.d-i-y

My car has a 1.6 litre TDI engine (EA288 if you're interested), belt
driven overhead camshafts. Why?

It only revs to 5 000 R.P.M. and the Chevrolet small block V8 revs
higher and is gear driven cam-in-block and pushrods.

I know otherwise there are large differences with these engines, but my question remains: why are diesel engines not pushrod? Seems like you'd
never have to worry about belt or chain wear.

Thanks in advance.
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From Newsgroup: uk.d-i-y

On 05/10/2025 21:54, David Paste wrote:

My car has a 1.6 litre TDI engine (EA288 if you're interested), belt
driven overhead camshafts. Why?

It only revs to 5 000 R.P.M. and the Chevrolet small block V8 revs
higher and is gear driven cam-in-block and pushrods.

I know otherwise there are large differences with these engines, but my question remains: why are diesel engines not pushrod? Seems like you'd
never have to worry about belt or chain wear.

Only pushrod wear, camshaft wear etc.
--
mailto : news {at} admac {dot} myzen {dot} co {dot} uk
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From Newsgroup: uk.d-i-y

On 05/10/2025 23:00, alan_m wrote:

On 05/10/2025 21:54, David Paste wrote:

My car has a 1.6 litre TDI engine (EA288 if you're interested), belt
driven overhead camshafts. Why?

It only revs to 5 000 R.P.M. and the Chevrolet small block V8 revs
higher and is gear driven cam-in-block and pushrods.

I know otherwise there are large differences with these engines, but
my question remains: why are diesel engines not pushrod? Seems like
you'd never have to worry about belt or chain wear.

Only pushrod wear, camshaft wear etc.

Cam gear on a 4 stroke runs at half crank speed so there is always need
for reduction gearing.

Belts are quieter than chains., and chains are quieter than spur gears.

Chevy small block is out of the ark...and you still need to pull a lot
apart to change the cam.

I.e there isn't a lot of advantage to any particular layout. Its
probably easier to arrange VVT on a twin overhead cam though
--
There is something fascinating about science. One gets such wholesale
returns of conjecture out of such a trifling investment of fact.

Mark Twain

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From Newsgroup: uk.d-i-y

On 06/10/2025 09:47, The Natural Philosopher wrote:

On 05/10/2025 23:00, alan_m wrote:

On 05/10/2025 21:54, David Paste wrote:

My car has a 1.6 litre TDI engine (EA288 if you're interested), belt
driven overhead camshafts. Why?

It only revs to 5 000 R.P.M. and the Chevrolet small block V8 revs
higher and is gear driven cam-in-block and pushrods.

I know otherwise there are large differences with these engines, but
my question remains: why are diesel engines not pushrod? Seems like
you'd never have to worry about belt or chain wear.

Cheapness? So not needing galleries for 2 push rods per cylinder means
the block can be smaller and lighter. Easier to assemble, no need to
line up push rods with rockers. No need to supply push rods.

Yes there is a cam belt and tensioner but the just bolts on the front.

I would say also easier to design gas flow, with no pushrods to get in
the way.

The chevy small block v8 is others have said an old design, but uses a
single cam shaft, where as if ohc it would have needed 2...

Dave
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From Newsgroup: uk.d-i-y

alan_m <junk@admac.myzen.co.uk> wrote:

On 05/10/2025 21:54, David Paste wrote:

My car has a 1.6 litre TDI engine (EA288 if you're interested), belt
driven overhead camshafts. Why?

It only revs to 5 000 R.P.M. and the Chevrolet small block V8 revs
higher and is gear driven cam-in-block and pushrods.

I know otherwise there are large differences with these engines, but my
question remains: why are diesel engines not pushrod? Seems like you'd
never have to worry about belt or chain wear.

Only pushrod wear, camshaft wear etc.

When was the last time you wore out a pushrod? OHC engines still have camshafts.

I imagine itrCOs all just down to manufacturing costs (and possibly weight).

Tim
--
Please don't feed the trolls
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From Newsgroup: uk.d-i-y

On 06/10/2025 10:47, Tim+ wrote:

alan_m <junk@admac.myzen.co.uk> wrote:

On 05/10/2025 21:54, David Paste wrote:

My car has a 1.6 litre TDI engine (EA288 if you're interested), belt
driven overhead camshafts. Why?

It only revs to 5 000 R.P.M. and the Chevrolet small block V8 revs
higher and is gear driven cam-in-block and pushrods.

I know otherwise there are large differences with these engines, but my
question remains: why are diesel engines not pushrod? Seems like you'd
never have to worry about belt or chain wear.

Only pushrod wear, camshaft wear etc.

When was the last time you wore out a pushrod? OHC engines still have camshafts.

Very common in these engines around the 160,000 mile mark, and in the
USA they do that sort of mileage relatively quickly.,

I imagine itrCOs all just down to manufacturing costs (and possibly weight).

And other things like VVT. You meed to split exhaust and inlet
camshafts to do VVT properly And on a V engine that tends to mean twin
DOHC is the answer.

Tim

--
In a Time of Universal Deceit, Telling the Truth Is a Revolutionary Act.

- George Orwell

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From Newsgroup: uk.d-i-y

On 06/10/2025 10:55, The Natural Philosopher wrote:

On 06/10/2025 10:47, Tim+ wrote:

alan_m <junk@admac.myzen.co.uk> wrote:

On 05/10/2025 21:54, David Paste wrote:

My car has a 1.6 litre TDI engine (EA288 if you're interested), belt
driven overhead camshafts. Why?

It only revs to 5 000 R.P.M. and the Chevrolet small block V8 revs
higher and is gear driven cam-in-block and pushrods.

I know otherwise there are large differences with these engines, but my >>>> question remains: why are diesel engines not pushrod? Seems like you'd >>>> never have to worry about belt or chain wear.

Only pushrod wear, camshaft wear etc.

When was the last time you wore out a pushrod? OHC engines still have
camshafts.

Very common in these engines around the 160,000 mile mark, and in the
USA they do that sort of mileage relatively quickly.,

I used to own a Rover 3-Litre which had an odd engine design: Overhead
valve inlet, side valve exhaust, all driven by a single camshaft.

I bought it when it had nearly 250,000 on the clock (it had been a
minicab mostly used for long journeys and it had 3 drivers working 8
hours each, so the engine never got cold). I used it for commuting
between London and Bath. When that was no longer necessary I sold it
with 350,000 on the clock. It was still the original engine and apart
from routine maintenance I had never needed to do anything to it.

I imagine itrCOs all just down to manufacturing costs (and possibly
weight).

The other possibility is the deliberate re-use of parts fitted to other production models, because that avoids any potential spares shortages
after a new product release.

And other things like VVT.-a You meed to split exhaust and inlet
camshafts to do VVT properly And on a V engine that tends to mean-a twin DOHC is the answer.

Tim

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From Newsgroup: uk.d-i-y

On 06/10/2025 10:47, Tim+ wrote:

alan_m <junk@admac.myzen.co.uk> wrote:

On 05/10/2025 21:54, David Paste wrote:

My car has a 1.6 litre TDI engine (EA288 if you're interested), belt
driven overhead camshafts. Why?

It only revs to 5 000 R.P.M. and the Chevrolet small block V8 revs
higher and is gear driven cam-in-block and pushrods.

I know otherwise there are large differences with these engines, but my
question remains: why are diesel engines not pushrod? Seems like you'd
never have to worry about belt or chain wear.

Only pushrod wear, camshaft wear etc.

When was the last time you wore out a pushrod? OHC engines still have camshafts.

I imagine itrCOs all just down to manufacturing costs (and possibly weight).

And the development of reliable toothed drive belts?
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From Newsgroup: uk.d-i-y

On 05/10/2025 23:00, alan_m wrote:

Only pushrod wear, camshaft wear etc.

I know it's swings abnd roundabouts, but I'm not convinced a toothed
belt (especially not a wet belt either) will have anywhere as near the longevity of a pushrod or a camshaft, which are lubricated.

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From Newsgroup: uk.d-i-y

On 06/10/2025 08:47, The Natural Philosopher wrote:

Belts are quieter than chains., and chains are quieter than spur gears.

In-block gears probably the quietest of the lot though.

Chevy small block is out of the ark

Indeed it is. Not half reliable though ;)

I.e there isn't a lot of advantage to any particular layout. Its
probably easier to arrange VVT on a twin overhead cam though

Horses for courses? Cheers.
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