From: peon@pacific.net.au
To: "Rotary motors in aircraft" <flyrotary@lancaironline.net>
Date: Wed, 11 Feb 2004 11:04:38 +1100
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Subject: Buying an Engine Rant was Re: [FlyRotary] Re: nonEFI fuel systems
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In-reply-to: <list-2985629@logan.com>

Hi Dale,

See my comments below marked ## for clarity

On 10 Feb 2004, at 8:57, Dale Rogers wrote:

> Hi All,
> 
>    I want to thank Jim Mosur <jmosur@interlog.com> for refreshing in
>    my mind what I am trying to accomplish.  

SNIP >>

##
Like real estate,  where its 'Position,  Position,  Position" is what 
matters,  with buying rotary engines,   "BUDGET,  BUDGET,  
BUDGET" is virtually everything.  Therre is no substitute for 'cubic 
dollars".

##
So before you even think about buying an engine, you MUST have 
a VERY clear idea in your mind about how much money you want 
to spend.

##
The next thing to do is work out how much power you need - 
realistically. No point in buying a turbo engine unless you need the 
neddies,  or want to fly at high altitudes.   Basically,  how much 
power do you really need to make the aircraft safe under the 
conditons you intend to operate.

##
On this issue,  I think I'd always prefer an engine that is a little 
more powerful than what is  needed is preferable to one that is a 
little underpowered. you can always limit the power by use of the 
throttle,  but it's nice to know that it's there if you need it..

##
Once these two issues are decided,  then you can go to a variety 
of engine plces and ask the right questions.  I've found that one will 
usually only ever get what you pay for.  You might, on rare 
occasions,  get more than you pay for (usually means the seller 
doesn't know what he's got).  So you need to know what you want,  
and what it's worth,  and how much you can afford.

##
However,  you might NOT necessarily get what you pay for (in this 
case the seller will con you -  a common occurrence with rotary 
sellers - usually not out of any malice, but just thrrough ignorance). 
 Her,  it behoovesd you to be fully clued up on what is what.   
Additionally,  if you are looking for a bargain,  beware, you might 
just end up getting FAR more than you bargained for.  Again, you 
need to know what is what,  what is Gold,  and what is Pyrites.

##
So have it quite clear in your mind what you require specifiaction 
and power wise,  the correct model engine for that power level,  as 
well as how much money you have available to acquire it. 

##
Currently,  in this country,  you can buy say a 1991 Series V FC  
turbo engine AND gearbox complete with wiring harness,  air flow 
meter, Radiator oil cooler,  and all the accessories inc coils,  
alternator etc for around $2,000 - $2,500 AUD.  We have dozens of 
them available here in Oz..  they are rated at 250 BHP approx @ 
around 8 PSI boost with 9.0:1 rotors.

##
These engines all have around 80 -120 thousand Kms on them.  
The importer I know personally always has good quality engines.   
There are two partners in the business who go to Japan turn about 
every 6 weeks or so and do all the buying abd stripping etc 
themselves - good help is hard to find the world over..  They only 
buy "runners",  and they do all the stripping themsleves. They run 
them in the cars in Japan,  and then pull them out an mothball 
them personally on the spot.  .

##
No doubt there are importers in the US who do the same.  if not,  
contact me privately.  But many of the importers don't "mothhball" 
their engines.  During the cleaning process,  if they are not oiled 
and sealed properly,  they will be rusty when you buy them.  Many 
that were good engines when stripped from the cars turn out to be 
'duds" if they are not properly mothballed..

> 
>    I have a multiple-part question: 
> 
> (A) Since my intention is to use Tracy's EC, I'd expect to 
> have to build a custom intake anyway; but can I use the 
> distributor as a crank angle sensor, much the way that 
> Chrysler point distributors could be upgraded to hall-effect 
> sensors for it's electronic ignition?

##
If you are going this route,  be prepared to pay the extra money 
and just get an engine that has all the stuff on it already.  Injectors, 
crank angle sensor,  coils  etc. Then all you then need is Tracy's 
EC-2.

> 
> (B) Leon, in an exposition about a year and a half back, 
> rated the 12A at 125 HP; is that before or after mods such 
> as removal of mufflers and smog equipment, and/or porting?  
> All the tables I've seen rate the 12A at only 101 HP.  
> Moving from 125 to 160 HP (the minimum for a COZY) seems 
> fairly doable; from 101 does not - at least within my 
> budget.

##
Ken Welter will bear me out on this.  Ain't nuthin wrong with carbs,  
or 12As.  I think Ken used a 12A in his Coot for a while?  I think 
Ken has also been using the stock carb as well.  That right Ken??

##
A 12A makes 125 BHP in the car.  But you want the ones with the 
BIG ports to start with.  The Series II '81 - '83 and Series III  '83 - 
'85 are the ones.   the imported Jap only engines have really tiny 
centre ports - they came out in things other than RX7s.  Beware.

##
So if you pull it apart,  mild port it,  stick a decent low restriction 
(but still quiet) exhaust on it,  and it will make 160 -165 BHP ALL 
day @ 7,000 - 7,500 RPM on the stock Carby.   A 12A RX7 engine 
weighs close as dammit to 80 with the sump,  but no accessories 
and manifolds.  I call this a "bare - long" engine.

> 
> (C) I understand I can use the center and end housings with 
> 13B rotor/housings and end up with a four-port 13B, but 
> would I also have to come up with a 13B eccentric shaft?  If 
> so, does that mean that my flywheel and counterweight are 
> now useless?

##
Yep,  a 12A is 20 mm shorter than a 13B.  Different E Shafts.  
Also different models have differnt counterweights.  Not even 
interchangeable between different model 12As  and different model 
13Bs,  let alone 12A TO 13B.  So danger - BEWARE.

##
A correctly balanced rotary is a thing of beauty and a joy forever.  
One that is out of balance is a "pig".  Not only that,  swapping a 
12A counter weight for a 13B one is a quick way to end up with a 
pounded out bearing.  been there,  seen the results MANY times!!

##
Soooo,  if you WANT a 13B,  BUY a 13B.  If you want EFI,  BUY 
and engine that already has all of what you need.  Otherwise,  you 
will end up going down any one of a dozen or so different 
"boondoggles" and waste lots of money and time,  and energy, and 
become throroughly depressed and frustrated..

> 
> 
>    In case y'all haven't already figured it out, I'm 
> building my COZY on a shoestring.  I can ill afford to make 
> any major mistakes; so I am desparate to sort as much out 
> before I tie up my meager funds.  It would appear that my 
> best choice for the money is a 86-87 FI engine from from an 
> automatic RX7.  Finding that combination has been ... an 
> *interesting* excercise, so I'm trying to sort out reasonable 
> alternatives.

##
If you are doing it all on a shoestring,  then it is incredibly important 
that you buy exactly what you need,  and make sure you get 
exactly what you pay for.  You can't afford the luxury of buying a 
dud.  i'd steer away from the series IV '86-'87 engines.  the cast 
housings are known to fail around the water "O" ring groove.  If you 
are going to use the turbo,  the Series V '89-'91 turbo is pretty 
good.  the previous model is prone to bad cracking.

##
If you only neeed about 200 BHP, probably the best engine is the 
NA engine that came in the '89 -'91 RX7s. They have the 9.7:1 
rotors,  and as Ed will atest,  make a lazy 200 BHP if ported 
correctly and the manifolds are done right.  They also are good on 
fuel.

##
the alternative is to pick up a turbo engine that is "down on it's 
luck",  and get it properly rebuilt with the high comp rotors and new 
seals and hosings.  I think this is where I came in.  All depends on 
your budget,  and the power you require for your project. 

So I hope this all helps.  

Cheers,

Leon

> 
> Thanks,
> Dale R.
> COZY #1254
> 
> 
> 
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