Author Topic: An overhead cam Listeroid??  (Read 4902 times)

Mr Lister

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An overhead cam Listeroid??
« on: February 01, 2006, 04:53:57 PM »
Guys,

Just got back from the auto parts store where I noticed a manual on Diesel engine
servicing.  It covers most of the popular European models and describes the
modern fuel injection systems in fairly good detail, with cross sectional drawings.

Of particular interest was the Volkswagen Audi Group  "Pump Duse"  which from the German
means "pump injector".   Here the injector has the pump built into the top of
it and it is driven by a rocker off the cam shaft all on top of the cylinder
head.

This system of combining the high pressure pump with the injector has been
used for a while in larger diesel engines and also smaller aircooleds, but I
think VAG are the first to use it for car engines.  Sometimes this
arrangement was called a unit injector and cheaper to make and fit than
separate devices, with no high pressure line to connect between them.

Of key interest is the fact that the timing of the injection event or
multiple events is controlled by an electromagnetic solenoid which activates
the injection nozzle.  This way the EMU can control the exact timing of each
cylinder depending on the load and the emissions etc etc.

The book also stated that the effect of compressing the fuel to 20,000 psi
in the pump duse, raised its temperature so significantly that frequently a
fuel cooler had to be used (underneath the car) before the fuel could be
returned safely to the plastic fuel tank.

So imagine a Listeroido with a new cast aluminium / cast iron head, with a timing belt
driven overhead cam which worked both valves and the new pump duse (from a
VW dealer).  A simple EMU is made from a microcontroller to sense the
flywheel position and the load, and control the magnitude and profile of the
injection.

The veg oil is automatically heated by the pump process.

The engines in the new VW Golf TDI and Jetta/Passat are exceptional in terms
of torque and fuel consumption.  Could perhaps the introduction of some modern
fuel injection and valve gear improve the fuel economy and reduce emissions on
the Listeroid?


Any thoughts?



Ken

Tom

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Re: An overhead cam Listeroid??
« Reply #1 on: February 01, 2006, 07:21:44 PM »
Sounds good, when do you start shipping?  :) Well except for the aluminum head. I had an Audi diesel that corroded the head bolts clear through. Are you trying to improve the power to weight ratio.  :D
Tom
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n2toh

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Re: An overhead cam Listeroid??
« Reply #2 on: February 02, 2006, 12:14:55 AM »
Audi/VW will be retiring the PD soon and transition to the comin rail setup like most other modern auto diesels. The reason cited was to comply with new emmision regs.

My only gripe with your idea is the use of a timing belt, on a TDI they are only rated for 60K miles/2000 hours/4 years service intervals, but the newer ones last a little longer. A timing chain would laster longer like the one on my Mercedes 300D 378KMi and still going.

« Last Edit: February 02, 2006, 01:26:24 AM by n2toh »
About 60 years is all it takes to make science fiction a reality.

dieseldave

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Re: An overhead cam Listeroid??
« Reply #3 on: October 27, 2007, 04:36:59 AM »
I own a 2002 Jetta TDI. Very easy on diesel. Getting 60mpg,(imperial gallon is 5/4 of us gallon)

An overhead cam Lister with an aluminum head?    Make sure it looks the same on the outside!!! Complete with 150 pound flywheels!!!

Speakiing of us gallons being smaller than imperial gallons,this is interesting:  Around the time of the revolutionary war,the imperial gallon was the same volume as the us gallon. It was afterwards that the british upped the size. Basically went from 8 to 10 lbs/gallon!!

Doug

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Re: An overhead cam Listeroid??
« Reply #4 on: October 27, 2007, 04:59:54 AM »
Personaly I don't see what you gain by putting the cam on top.

The roid is a slow machine and doesn't need OHC or belts.

Here is a better idea.....

A listeroid CD engine with enclosed valve train and a realy top notch oiling system.

A precup from a Wak with a Stelite cup that runs realy hot.....

A very high presure injection system, like a Detroit with the injector and pump all together.

Change nothing else, keep the speed below 1200 rpm.

Make the engine a uniblock so you can put bigger bores and strokes in the same crank case ( very long rod ).

Keep it simple, metric nuts and bolts.

Piston with a cast steel crown but alum skirt.

OH.... WHAT A MACHINE!!!!

A man can dream.

It's a Good Life, If You Don't Weaken

rcavictim

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Re: An overhead cam Listeroid??
« Reply #5 on: October 27, 2007, 08:13:05 AM »
For engines in colder climate zones you might want to use an ostrich instead of an EMU.   :D

I also would like to see a Listeroid design with a good oil pump, crossdrilled crank and pressurized lower rod bearing and enclosed pushrods and pressurized upper oil system like the Petter design.  I vote to keep the taper roller bearing mains.

As for overhead cam, that`s like outting wings on a turtle.  Not needed.  Yes, keep the RPM under 1000.  Hell, make the new one just 500 RPM, long stroke, long con rod. 250 lb. flywheels x 2.
« Last Edit: October 27, 2007, 08:16:07 AM by rcavictim »
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vwbeamer

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Re: An overhead cam Listeroid??
« Reply #6 on: October 27, 2007, 10:44:02 PM »

They are good for 80,000 miles now. But even this number is conservative.  I know a lot that have gone 120K with no change.

Audi/VW will be retiring the PD soon and transition to the comin rail setup like most other modern auto diesels. The reason cited was to comply with new emmision regs.

My only gripe with your idea is the use of a timing belt, on a TDI they are only rated for 60K miles/2000 hours/4 years service intervals, but the newer ones last a little longer. A timing chain would laster longer like the one on my Mercedes 300D 378KMi and still going.



dieseldave

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Re: An overhead cam Listeroid??
« Reply #7 on: October 28, 2007, 01:56:59 AM »
On a VW TDI the cam belt for an automatic trans equiped car was 64000 kms. On the manual trans it is 128000 kms. I questioned VW about this and thier answer was: The auto trans equiped cars come with a narrower cam belt to make room for the transmission.

I.E.: Looking from the front of the car,the engine is shifted more to the left,and thus requires a narrower belt.