Hi,

Apparently my Ram 750 is super old and needs a new ECU(measures case pressure), fuel pump, and Start box(maybe). The engine is very but I can't go out and buy a whole new engine righ now. I am tryign to shave down the repair bill by finsing these parts on my own. If anyone has these parts and would be willing to part with them for a good price I would really appreciate it.

Thanks so much!

Brian

What kind of turbine is it?

Ram 750

Try asking Carlos at RTI or Andy Low at Electrodynamics (the original maker of the pressure ECU).

Carlos is actually the one who told me to post a question here to find the parts because he doesn't have them.

Brian

Fadac has a pressure sensing ECU that will work,
as well as the behotec hornet for 209.00 convert over to jetcat like setup.

Thanks John. Thats a little more than I want to spend. I am trying to keep the parts cost at a minimum. I am up to a $1000 repair bill with the parts(if carlos can get them). At that price its not even worth fixing it to me because its so old.

Brian

The airplane only knows thrust..not the age of the engine pushing it...

Right, but I am not goign to invest $1000 into a 15 year old air start engine. Its not like its going to appreciate in value like an old car haha.

I know what you mean I'm not found of parting with my money ethier.
it can be converted to manual electric start with
a $25.00 jetjoe starter but you have to have the short front aluiminum cover to mount it on.

John,

actually a buddy of mine made me a wand starter i use. It can be used on engines mounted externally, which is what I have. It was going to cost $300 for RTI to put the cover and starter motor on it so I didn;t bother.

Brian

If you have the stock aluiminum cover you can do it yourself,
otherwise the nut is to deep to get reached by the bendix with the fiberglass cover.
it was pretty easy. Jetjoe's use a 6v motor, so dont stick your starter battery to it.
I blew one starter motor up that way, but replacements are cheap...

Brian,

Let me make sure it works this evening, but I have a spare pressure ECU & a start box that I'm not using. I believe someone may have shortened the data cable on it at one time, but it should still be functional. I bought it along with some other RAM stuff that I needed.

Can't help you on the fuel pump as I need my spare one (750 still runs good!) but the Flightworks pumps are a reasonable price, much smaller than the original, and work well. Someone had said once somewhere that the 200 series couldn't be controlled by the pressure ECU because it wouldn't slow the flow enough to idle, but I've had zero problems with mine. You'll have to make your own power connectors off of it though.

Curious about the starter motor setup that John Casey is talking about. I have a short (original) cover as well as a longer (new) cover. I also have an original motor mount with the "small" bendix, but the bendix is shot. I bought a newer motor hoping to be able to mount it, but found that the bendix is much larger & requires a different nut to mate with it. If I could use the JJ bendix / motor on the original RAM mount WITH the original RAM "flat" nut and make it onboard electric start, I'd be a real happy camper! I'd also have a freshly hydrotested & inspected pony tank / regulator available if anyone needed it!

Hate to send a perfectly good running motor in to have a new nut put on it / rebalance....

John, could you elaborate a bit, or maybe post some pictures?

Thanks

Bob

Bob,

Thanks!! I apprecite you checking into it for me!!!

Brian

Tumbler;

I know how you can do it for less than $250.00, auto start and all the works if you have the aluminum fornt cover, send me a PM, I will answer in a couple of days, I'm traveling until Friday.

Brian,

I checked out the ECU last night but found that it's not working properly. It powers up, but I can't seem to get it into setup mode, and it constantly says "throttle low" regardless of my throttle setting. I'll dive into it a little more this weekend when I have some time, but right now I'd say it's probably toast.

I do have an extra start box that you can have. PM me your shipping address & I'll get it out to you over the weekend, no charge. Display has a few scratches in it but it works fine, started up my 750 no problem.

Bob

Too bad about the ECU, but great news about the start box!!! Thanks so much! I'll send you a PM.

Brian

I've never seen the ram engines with the flat nut, only the acorn style,
with short stock (alum) cover the distance to the nut is pretty small so
bolting the starter right to the front cover is a no brainer.
Maybe you could get an acron style nut from Carlos....

www.jetjoe.com

see the $25 dollar starter with bullet tripod mount

I have two I want to convert over for "internal use".

I can give you a new replacement fiberglass cover to boot if your your going to run it externally.

How much for your aluminum cover?

Hi John,

The nut that I have is slightly domed & has a pattern knurled onto it. The small bendix looks like it's supposed to come out & "push" on the face of it, trapping the o-ring in between the bendix and the nut. Problem is that the bendix is shot.

The new RAM bendix / motor is substantially longer than the original, and the bendix is larger in diameter. Looks like it goes over the top of the "acorn nut" that you're talking about. I'm sure i can get one from Carlos, but won't the turbine need rebalancing if I replace the nut? I suppose if I'm careful about not moving the parts when the old nut is removed it would be the same, but how do you know the new nut is balanced?

I'll try one of the JJ starters after the snow flies here.... in a couple weeks. [&o]

The second cover cap that I have is the original RAM starter housing one (for the "short" starter) so I may be able to use it still. Sorry!

Bob

This comes up every now and then-you can do a search or Ram starters and find old info. A short recap: You CAN NOT use the new Ram "X" style bendix ( or jet joe bendix) on the older Ram compressor nuts. Ram had two types of starters/bendix/compressor nut combos. The original ( and indeed most of the RAMs out there not converted) had a mostly flat faced compressor nut that was slightly convex. Most have hash marks ground into the face of the nut. It may or maynot be magnetic for a Hall sensor. The bendix had an O ring that sat proud on the face of the nut and pressed against the ridges. The 750/1000 had a coreless BB starter. It was made by Fulhauber and the motor alone cost $125.00 IMO this starter and the early autostart software is what killed RAM. The motor was not up to the job, the O ring bendix was prone to slipping on the higher mass 750/1000s (worked OK on the 500s) this resulted in low RPM on startup and a ton of flame.
Towards the end they went to the "X" style starter. This style is what is used by everybody else now. It has a recessed O ring that slips over the new "Acorn" shaped compressor nut and grabs it around its circumfernce. Better grab, no slipping. You will notice the bendix is larger and longer.
If you try and use a X style bendix on a flat comp nut all that will touch will be the outside of the brass bendix on the aluminum nut-no workee.
Yes the turbine will need to be rebalanced if you change the compressor nut.
Carlos can convert it over but it is pricy as not only does it need balancing but the compressor case needs to me machined to fit the new starter.
You can use a WREN wand starter to start a flat faced nut Ram-I did it for a while to get rid of the bottle. Scott

Hey,

Explain "pressure ECU"?

Measures case pressure, not RPMs. Oooold school technology.

The old, original RAMs were not controlled by the ECU sensing RPM (as most modern model turbines do). The RAM ECU sensed CP, or Compressor Pressure. Andy Low built a small pressure sensor into the ECU that read the pressure at some bleed off of the compressor. The old RAM 750F was nominally about 17.5 lbs at 1300 mb of pressure. Idle was down around 90 to 100 mb.

Scott,

Thank you for the explanation. I figured that the nuts were substantially different between the old / new style, & it's pretty obvious that the new bendix style won't work with the "old" nut. Guess I'll stay airstart with this "relic" until it dies.

Bob

You dont have to stay stuck on the bottle, you can start it just fine with a Wren starter wand ( or heaven help us , a jet joe wand) You would need to replace the wand motor with a Speed 280 bb motor as the standard 300 motors brushes will melt after about 4 starts. Scott