A new Oz engine on the way?

[bexrbetter]

This country is losing its ability to manufacture many things giving the Chinese a monopoly that will come back to bite us in my opinion.

Yes, I used to wonder around a number of engineering workshops that had amazing variety of machine and skills as a kid in the 60's with Dad and go to Repco with him where he would order custom pistons for which ever race engine he would be building at the time (Tasmania made the pistons IIRC). It is sad.

 

Bex depending on the rpm range there would be little advantage in double overhead camshafts and 4 valves just a weight disadvantage.

Well there a little advantage but the thing is it's getting harder to get off the shelf SOHC 2 valve heads. Anyway, I not only have one it also runs it's own distributer from the cam forming my second ignition system which has made life very easy and cheaper maintenance for the client.

 

 

[facthunter]

Four valves per cylinder were common in larger cyl sized engines like Bristol for good breathing and high BMEP. Camshaft heads are bulky and heavier than push rods and hemispherical combustion chambered heads would be rare in aero engines. Arguably piston engines are not particularly reliable in aero service. The fight between strength and weight needs careful balancing. Liquid v/s aircooled will always be argued but except for para drops etc aircooling is adequate and simple if it is done properly. Direct drive is sometimes OK but any high revving motor rules itself out for that and requires a well engineered reduction drive. Nev

 

 

[AVOCET]

SDS is a grate multi piont FUELINJECTION system and Ross is a great guy to deal with . The difference it's makes to smooth running is to second to none , coupled with liquid cooling , seems to be the way to go ,

 

 

[bexrbetter]

and hemispherical combustion chambered heads would be rare in aero engines.

Except for all those rare Lycoming and Continental engines and all 2 strokes I guess.

 

SDS is a great multi piont FUELINJECTION system and Ross is a great guy to deal with . The difference it's makes to smooth running is to second to none , coupled with liquid cooling , seems to be the way to go ,

Yep, Ross came to visit me personally in China to sit down and discuss it, he is very modest about his knowlege and abilities. He has a nice EFI package for the engine including wire harness and instrument package, looking forward to working with him on it.

 

 

[facthunter]

Most of the radials are ( I forgot about them) but the others have parallel valves and quite "ordinary" combustion chambers. The really modern four valve heads flow really good figures. like Ducati. Nev

 

 

[ozbear]

Four valves per cylinder were common in larger cyl sized engines like Bristol for good breathing and high BMEP. Camshaft heads are bulky and heavier than push rods and hemispherical combustion chambered heads would be rare in aero engines. Arguably piston engines are not particularly reliable in aero service. The fight between strength and weight needs careful balancing. Liquid v/s aircooled will always be argued but except for para drops etc aircooling is adequate and simple if it is done properly. Direct drive is sometimes OK but any high revving motor rules itself out for that and requires a well engineered reduction drive. Nev

Hi Nev please forgive my ignorance what is BMEP?

 

 

[Gentreau]

Hi Nev please forgive my ignorance what is BMEP?

Wiki is your friend :)

 

http://en.wikipedia.org/wiki/BMEP

 

 

[eightyknots]

Why is there a 'B' in Mean Effective Pressure?

 

 

[rankamateur]

http://www.factorypipe.com/t_brake.php does this help

[facthunter]

The word is Brake. I think it relates to dynamometer which applies a brake force multiplied by the rpm to give a horsepower figure. Nev

 

 

[Gentreau]

Why is there a 'B' in Mean Effective Pressure?

Reading a little further down the Wiki article you would find this:

 

Mean effective pressure (MEP) is defined by the location measurement and method of calculation, some commonly used MEPs are given here.

 

• Brake mean effective pressure (BMEP) - Mean effective pressure calculated from brake power
   
   
  

 

 

 

 

• Indicated mean effective pressure (IMEP) - Mean effective pressure calculated from in cylinder pressure, average in cylinder pressure over engine cycle (720° in a 4 stroke, 360° in a 2 stroke).
   
   
  

 

 

 

 

• Friction mean effective pressure (FMEP) - Theoretical mean effective pressure required to over come engine friction, can be thought of as mean effective pressure lost due to friction. BMEP = IMEP - FMEP
   
   
  

 

 

.

 

 

[ozbear]

Thanks Gentreau and Rankamateur

 

I have never come across it before.

 

 

[turboplanner]

If you really simplify an engine, freezing it in time, "torque" is the turning force - so imagine the crank pin at 90 degrees on the power stroke being forced down against a spring scale.

 

A simple dynamometer, driven by a chain, belt, direct coupling, or even wheel rollers can be just a spindle with a brake on it, say a geared water pump with a tap, where the brake rotates an arm which can be measured by a spring scale. That's where the word brake comes from.

 

Power, or horsepower is simply torque multiplied by revs per minute - it introduces a time factor to measure work done.

 

So you can have a slow revving engine with say 1,000 Nm of torque producing say 300 kW, or be revving it faster, producing 450 kW

 

 

[ozbear]

If you really simplify an engine, freezing it in time, "torque" is the turning force - so imagine the crank pin at 90 degrees on the power stroke being forced down against a spring scale.A simple dynamometer, driven by a chain, belt, direct coupling, or even wheel rollers can be just a spindle with a brake on it, say a geared water pump with a tap, where the brake rotates an arm which can be measured by a spring scale. That's where the word brake comes from.

Power, or horsepower is simply torque multiplied by revs per minute - it introduces a time factor to measure work done.

 

So you can have a slow revving engine with say 1,000 Nm of torque producing say 300 kW, or be revving it faster, producing 450 kW

Yes we'll said I know what BHP is but not the other terms.

Who Remembers The Repco Brabham Engine I wonder if Australia will Ever produce another formula one championship engine.

 

 

[turboplanner]

Yes we'll said I know what BHP is but not the other terms.Who Remembers The Repco Brabham Engine I wonder if Australia will Ever produce another formula one championship engine.

Not until Australia produces another Phil Irving, who was motor cycling's equivalent of a Sinatra or Presley - they just don't come along in every generation.

 

I religiously followed his recommendations when building four stroke race engines even to cutting the piston skirts to shape with a hacksaw, and making head pockets for the higher valve lift with an electric hand drill and a valve head with hand made teeth. With the exceptions (quite a few) when I screwed up the assembly, they all produced a huge G force in the back compared to the factory product.

 

 

[ozbear]

Not until Australia produces another Phil Irving, who was motor cycling's equivalent of a Sinatra or Presley - they just don't come along in every generation.I religiously followed his recommendations when building four stroke race engines even to cutting the piston skirts to shape with a hacksaw, and making head pockets for the higher valve lift with an electric hand drill and a valve head with hand made teeth. With the exceptions (quite a few) when I screwed up the assembly, they all produced a huge G force in the back compared to the factory product.

Not until Australia produces another Phil Irving, who was motor cycling's equivalent of a Sinatra or Presley - they just don't come along in every generation.I religiously followed his recommendations when building four stroke race engines even to cutting the piston skirts to shape with a hacksaw, and making head pockets for the higher valve lift with an electric hand drill and a valve head with hand made teeth. With the exceptions (quite a few) when I screwed up the assembly, they all produced a huge G force in the back compared to the factory product.

Turbo you need to get yourself a second hand RVR or Serdi machine .they make that kind of work so much easier there would be a few around with all the engine reco shops closing down.

 

 

[turboplanner]

Had a look at those machines and they scare the hell out of me - think I'd probably get someone to do it these days, but I just worked with plasticene, grinding the head out until I had some clearance, which involved a lot of assembly and disassembly of the head, but you only ever had to do it once.

 

 

[ozbear]

Your right and their heavy and take up a bit of space in the workshop you would need to be doing it a lot maybe a Chinese milling machine you could do a lot more with one of those.

 

 

[turboplanner]

Lol, I got sucked in and bought a Chinese drill press. There's not a tooth that meshes, so when you are trying to wind a drill in it has to jump in little steps, and the clamps keep coming loose.

 

Today I'd just get a specialist to do the job.

 

 

[ozbear]

I hear u Turbo lol

 

 

[rankamateur]

I think a mill drill not a drill press would do the job. I have had a chinese lathe in my workshop for about twelve years and it works fine but leaks more oil than a perkins engine.

 

 

[turboplanner]

My drill press was only for odd jobs, but I find I'm just using the hand drill.

 

 

[damkia]

[Powerin]

Excuse my ignorance.....how do you have a cylinder head with valves on an OP engine?

 

 

[bexrbetter]

Excuse my ignorance.....how do you have a cylinder head with valves on an OP engine?

No problem, everything can't be everyone's field of expertise heres a crayon drawing for you ...