Tauras engine prices
 

OK,the Taurus is like a Mercedes 500 SEL. The ZDZ is more like a Porche 911 GT2......it woudn't even be close.

Tauras engine prices
 

ya know -- application is a good term here -
I was after a design which was a rear intake - makes carb setup a lot better for me - and a design with a rotary valve -something I do some tuned exhaust work with.
I started out with a side port engine -an O&R 23 - over 50 years ago -and tho it worked - everyone went to rotary valves to get the power up.
But I understand - the very simple design has an application.
I just am after something which better fits my applications.
Now I can even get a rear exhaust - "what a country!"

Oh no, here we go.
 

Ok,

I'll give you that "The ZDZ is more like a Porche 911 GT2"....

....so.....that would mean:

engines
 

With a little work the Polan 46cc Pro chainsaw engine would be right in there with the best of them. My 2 cents Captin John

Poulan?
 

Hi captinjohn,

Ralph Cunningham at RC Ignition (www.rcignition.com) builds a conversion of this motor and it is light and is a great conversion, at a great price....but the RPM numbers for this motor are several hundred under the Taurus. At 7000ft Ralph's Poulan turns a Mejzlik 22X8 at 6400RPM. I have not run that exact prop, but the Taurus turns a Zinger Pro(higher load prop than the Mejzlik) of the same size at 7200 when new, and a friend's broken in 2.6 turns a Mejzlik 20X10 at 8200RPM. The altitude difference probably makes a 2-300 RPM difference.

I agree that it is a great alternative when price is the driving factor, but I think after you're done with "a little work" to make this engine a match in power, you'll have a lot more money in it than the Taurus costs and you still will have a chainsaw conversion and not a custom built motor.

Bill

Tauras engine prices
 

Any comparisons between the Taurus 3.7 and ZDZ 3.7?

Re: Oh no, here we go.
 

I recognized the Fuji -but what were the slot cars?
Aurora?

Fuji? Slot cars? Aurora?
 

Very funny Dick. Good one. :p

Bill

Tauras engine prices
 

I recieved my taurus 2.6 about 10 days ago, I'll be ready to fire it up in a few days. I was shocked when I recieved the engine. It's built like a swiss watch. it's a work of art! I'll let you know how it runs

John

Tauras engine prices
 

don't forget to wind it every seven days!

Tauras engine prices
 

I have a broken swiss watch. It gives the correct time twice a day.

I'm still not buying any motors that look like they escaped from a concrete saw...... :D

Tauras engine prices
 

Not trying to add fuel to the fire, but? D HANSON have you ever owned a taurus engine?(btw congratulations on your performance. I just saw it in MODEL AVIATION MAG.)

re: concrete saw...... ??
 

Diablo says:

>>I'm still not buying any motors that look like they escaped from a concrete saw......

Hmmm, not quite sure what that means, but I'm surprised with your expertise in metalurgy that you'd chose a motor cast in sand rather than one machined out of a solid block of aluminum.

Care to elaborate on the advantages of the cast crankcase. I thought this process was used to save money and time.


Bill

Tauras engine prices
 

Any body weigh the complete crank assy. of each motor then we
should talk about inertia upon impact.Piston port cyl.with two
transfer ports and no boost (chainsaw)and they all break when
they bite the dirt even the taures I seen one!
Just my 2 cents worth

Tauras engine prices
 

Hold the phone!
The Dick Hansen -who was in the latest mag -is another guy --I met him the time I also flew scale -at the 84 Nats - I got 2nd place - my first -only time at a scale contest - I was on the Dec Aviation cover that year.
Don't blame him for my transgressions.
As far as cast vs bar stock -- Be careful which you assume is superior!
A good casting guy can blend aluminum to produce some pretty exotic stuff.
Most machined aluminum in the US model industry is 6061- tho the Taurus may not be .
The casting s on the ZDZ's I have looked at are pretty darn good - .The only one I have crashed -which was a lulu of a vertical into the ground -actually the engine went completely underground.
It was an 80 single
Neither the crankcase nor the crank was harmed - The bearings were ruined from impact -bearings get ruined in an abrupt stop ! the prop shaft was bent - (big deal)
the carb got smacked in the choke butterfly by the ignition module -which was destroyed.
I tore it all apart - checked it put it back togather - runs great .
Back to casting-
Silicone aluminum pistons are cast - and are among the best - bar stock pistons chafe /wear faster -
K&B made a series of engines which were all cast aluminum - no bushings -no sleeve--(that's right) and with good fuel -set up right - ran and still run very well.
I will take a well designed cast crankcase anyday -
My BMW even had a cast oilpan!
So- cast vs barstock -- ? both can work
My new 160 has a nifty cast passage added to the case to equalize fuel flow to th front cylinder.
It could have been a machined case but wow -that would have been a job.

Tauras engine prices
 

I didn't think so. :cool:

Cast vs. bar
 

Hi Dick,

Obviously I was not talking about car engines. Once you get into complex designs, such as car blocks, pans, etc, you aren't going to machine them out of bar stock, it would make no practical or economic sense at all. We were talking about a specific application(remember that word) and in this case(no pun intended) you're not going to convince me ZDZ went with a cast crankcase because of it's superior strength and design qualities, it is much more likely that it was for ease of manufacture, and the associated cost savings. It would not make economic sense to mass-produce an engine like this and machine the case out of bar stock. ZDZ's are massed produced, Taurus' are not. Taurus had a choice, ZDZ did not.

As I've mentioned in other places I know of one engine builder(well known - not Taurus) that has studied the ZDZ's closely and was very disappointed in their fit and finish, including finding rough unfinished flashings inside the crankcase, a direct result of casting the case and poor quality control. This is only one example and may not be typical, but it should raise some red flags.

Bill

crankshafts
 

Wow..Go away for a few days and lots of stuff gets put on here..
Cantilever cranks..I have straightened lots of A&M cantilever and a few ST 3000 cranks..No big deal, except the ST is brittle and sometimes breaks..The A&M has a long 3/8 end, not a short stud. The material is soft and straightens easily..
If cantilever crank is properly designed with a short taper ,just sticking out of the front bearing, and is the diameter of most bearings(.588) ,it should be very stiff and hard to bend..
Cahinsaw cranks are usually not very long but will sometimes bend, mostly twist, when crashed.
I have a 3W 140 hub that came from a VERY hard crash..The impact broke the front half of the case in half, tore both cylinders off, and BENT the taper in the aluminum hub 3/16 sideways..The crank sticks out of the front bearing just far enough for the hub to clear the case..The impact broke both rods in half...NO engine design is immune to bending, given enough impact..
I have never seen a machined case broken apart....
I don't know how large the crank diameters are fot the ZDZ and the Taurus, but the are almost certainly no bigger than the 6202 front bearing used in almost all engines...The larger chainbsaw engines use a slightly bigger bearing..My 289 cc Herbransdson twin race engines have the largest diameter cranks, but we bent one of those in a crash....RC....

Tauras engine prices
 

OK- model engines - or even - CHAIN SAW engines - they come with -- shhhh - cast crankcases!
As for ZDZ choice- -what would you have done?
bar stock? are you kidding?
The only bar stock engines I ever had -which were produced for the public - were the Cox Tee Dee type. and they were jewels of their day.
I spoke with the guy (same one I believe you spoke with) -and yes he thinks the ZDZ is a piece of crap - and said so to me.
Having had hands on experience with some of his stuff - he is very experienced with crap.
No names please!
A polished case doth not performance make-
Or as we used to say - if it won't go - chrome it.
Pretty nasty comment.
Shame on me.
As for rough finishes etc-- Early stuff was no where as good as present stuff - but HEY- I was looking for new design and engines which suited my own needs-
Bar stock engines are perfect low production production engines . Especially if it is only the case that is the only big part to be fabricated.
That is not an insult - simply a fact.
It is economically, the only show in town.
I have on my shelve of "days gone by , 100% bar stock, glo racing engines.
The whole darn thing.
These would boggle you .
from the late 40's all hand tooled.
If a guy want's to build his own engine for sale -the economics of it are a real consideration.
take the complete design of a rotary valve engine -from scratch-
Any size.
Now take a much more simple design - a piston ported -no reed bank engine .
Which one would you choose if you were only making a few?
Engines which may appear "cheap" to some - may actually have a lot of money spent in development of castings, special crank manufacturing -discs (harder to do than they look!)
Lookat an old Chev 265 V8-from the mid 50's
cheap - crude looking low parts count - absolutely devoid of any shiny bits.
And they would suck the doors off almost any of
the engines we carefully fitted and polished -etc..
I know - I been there dun it .
Hand built hand fitted engines have a particular appeal - no question.
Engines with performance features that fit particular applications - also have appeal.
I want rear induction - will not settle for less. It is handier for me and my planes.
I want an induction system suited for/ intended for tuned exhausts.
I also wanted rear exhaust - and now I can get it.
Those are features that mean something to me.
They may mean little to some others - I can't speak for them.
Having come from a background whre I searched out the performance features I wanted -these little engines fit the bill- Hell I even put up with the first Honda Accords - tho the guys I worked with in the heart of the US manufacturing belt (Ohio)-said they were just junk.
Now they build them.

Tauras engine prices
 

The method for producing any engine part is based on both economics and fitness for use. If you are going to make 10 engines a year, you can't afford to make a permanent die mold for casting and recoup your investments. Dies and tooling cost money. For small production runs, you have a couple of choices. You can machine the part from a solid bar and generate a lot of scrap ala Brison, Taurus, and Fox. If you already have the machining center, then there is no big investment. Another choice would be to use investment cast (lost wax) parts or sand cast parts. As DH points out, there are certain casting alloys that make excellent engineering materials, and for some applications are superior to a wrought alloy or forging. One example is a hyper eutectic silicon aluminum cast piston. It has less thermal expansion than a forged piston so you can run a tighter piston clearance. For a crankcase, the requirements are that you want it stiff enough and dimensionally stable. Also for our use, you want it as light as possible - this means a consistent and thin wall thickness.

Tauras engine prices
 

Taurus Engine prices are ?????????????


I have two Taurus 3.7's. I'll get the rpm numbers up within a few days for yah JB. I have yet to pay much attention to these engines. So little time for em all. One has only passed about 1-1/2 gallons of fuel and the other has nearly five gallons through it.

My concrete saw would eat a ZDZ without a groan; it'd probably look nicer thereafter. ZDZ's are ugly, like VW engines... Taurus Engines are puurrty and well finished ladies....

The weight of the reciprocating assembly is incidental. The rotating weight would provide something to ponder, but come on... In any event I was alluding to the ability of the Taurus crank to absorb the rotating inertia in the event of an impact, relative to twisting forces. No way a ZDZ crank can do it, no way...

I think we can agree that a ZDZ and a Taurus represent engines that appeal to us each in there own way... It's kinda like women, so many choices, options, performance standard's, ancillary equipment, mileage, baggage and more... Who really knows what looks and works best for them is a representation of what another will find dear to his heart...

...and back to power.
 

Hi Dick and Ralph and Diablo,

Great info and ideas from all of you. Very good food for thought....but Dick, I have to come back to some of your statements. You indicate that you like the ZDZ for its superior design and of course the rear induction and rear exhaust, and if those are features you need, there is nothing to argue about....but I have to go back to the bottom line....

If the ZDZ40 is of such a superior design then why doesn't it have a bunch more power than the Taurus. It actually appears to be the opposite, but that can't be proven very easily in either case, though even if they are the same, it doesn't make sense if the ZDZ is a superior design and has superior manufacturing methods. We can talk about all these issues as long as we want, but the bottom-line is how the engine performs.

And then there's the smoothness issue. It certainly can't be decided easily, though Michael Glavin's recent acquisition might help add some quantitative data to this discussion. Also, Taurus will have a dyno in the near future where, as time goes on, all of these engines can be dynoed and compared across the whole powerband.

Bill

Tauras engine prices
 

when the weather gets up to freezing temp!, I will get out the test stand and break in (or out) my next new 40- and give you the rpm figures - good bad or ugly - BUT don't expect me to give readings on in cowl downspout "mufflers - they are too noisy -for me -and do not complete the power package .
I am after latest stuff -quiet very broad power band and this is - as far as I can see - the only game going for that.

Cases
 

Most Giant scale engine cases are machined from solid..The D 150 and 150,also J&A,BME,Precision, Eagle, Walker, Brison,A&M,..The Fitzpatrick .61 glow engine, and more...Cast are outnumbered greatly.....

Mufflers
 

I'm with you Dick. I'd really like to know the results too. As you know, I'm trying to get together a couple of pipe and can setups to test too. What are you planning on using on the new rear exhaust ZDZ40?

I think the only practical can to use easily, without major mods to the airframe, is the KS can you used on your Edge(among other projects, I'm sure). They're cheap too if you order it from Europe.

Bill