TCM IO 520 scam ?
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TCM IO 520 scam ?
In recent years I have been led to believe TCM was dragged kicking and screaming into the 21st century and that their injector nozzles whilst slightly inferior to the GAMIs were at least balanced to meet the different fuel requirements of the individual cylinders.
This belief was strengthened when I noticed each nozzle was numbered 1-6 and installed in the corresponding cylinder. What I didn't notice was that part numbers after the 6 different first digits are all the same.
Shock horror. I've now discovered that all 6 nozzles have identical sized bores and all flow the same rate. No wonder I couldn't lean my new IO- 520 properly.
I've now been informed that while TCM do make balanced injectors for some IO-550s they don't bother with IO-520s
If there are still any troglodytes out there that don't believe 520's need balanced injectors I have a set of TCM injectors hardly used - cheap.
I'm now wondering how many other owners and LAMEs believed TCMs numbered injectors meant they were balanced .
Cheers RA
This belief was strengthened when I noticed each nozzle was numbered 1-6 and installed in the corresponding cylinder. What I didn't notice was that part numbers after the 6 different first digits are all the same.
Shock horror. I've now discovered that all 6 nozzles have identical sized bores and all flow the same rate. No wonder I couldn't lean my new IO- 520 properly.
I've now been informed that while TCM do make balanced injectors for some IO-550s they don't bother with IO-520s
If there are still any troglodytes out there that don't believe 520's need balanced injectors I have a set of TCM injectors hardly used - cheap.
I'm now wondering how many other owners and LAMEs believed TCMs numbered injectors meant they were balanced .
Cheers RA
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Both standard and "balanced" injectors are available form TCM for the 520 and 550. About 30% of the balanced injectors are "balanced." TCM cannot tweak them to be balanced like GAMI can on theirs. Comparing TCM's "balanced" injectors to GAMIjectors is a very poor comparison.
If, OTOH, you get lucky and get a good set of TCM balanced injectors… good for you.
If, OTOH, you get lucky and get a good set of TCM balanced injectors… good for you.
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I'm now wondering how many other owners and LAMEs believed TCMs numbered injectors meant they were balanced .
One CMI (TCM) employee admitted that their injectors are balanced……they weigh exactly the same amount.
Probably true.RU, as you should know,
, the only way to ensure you have balanced F/A ratio's is to do each engine in its own airframe and do the work. CMI are not able to do that nor could they on 3000+ engines a year.This is part of the reason GAMI have such a good business. They do what others can't.
So the answer for you is order a set of GAMI's and then do the GAMI lean test to verify they are within acceptable limits.
The number of LAME's and engine builders in Australia that I can be sure have the understanding of all this is able to be counted on my fingers (no thumbs required) so the chances you have a LAME that understands all this is highly unlikely.
Review your online course subscription for fuel air ratio analysyis
The Fork Tailed Dr Killer has a newly installed factory-reman IO520. Hope to fly it next week.
I am under no illusions that its injectors are anything more than .................... just injectors!
Dr
I am under no illusions that its injectors are anything more than .................... just injectors!
Dr
Last edited by ForkTailedDrKiller; 29th Nov 2013 at 03:32.
PinkDick, at risk of drifting this thread any further, this would be the BEST picture by far that I have of the Forktailed Dr Killer!
The old donk had Gamis but IMO was never quite happy LOP.
Dr
The old donk had Gamis but IMO was never quite happy LOP.
Dr
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RU, as you should know, 
, the only way to ensure you have balanced F/A ratio's is to do each engine in its own airframe and do the work.
, the only way to ensure you have balanced F/A ratio's is to do each engine in its own airframe and do the work.
I bought an Australian overhauled exchange IO-520.Fitting GAMI injectors was discussed but as I was having new fuel components from TCM fitted and TCM nozzles came with the kit I decided they would be ok. Lending strength to this decision was the good experience I'd had with my last engine which had TCM injectors.It was very smooth.
After reading Walters post I realize I was just lucky last time.
TCM -CMI should lift their game. They put out a handbook that condones running their engines on the edge of disaster based on a CHT reading from only one cylinder and an EGT reading which is the average of three cylinders. All this when they know their temperatures are all over the place due to their failure to rectify known design faults.
They treat us like mugs because they know that cylinder failure is a gradual event that normally occurs outside of warranty and if earlier it's the pilots fault anyway.When the revolution comes CEOs from companies that overcharge and under deliver will be first up against the wall.
Cheers RA
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**TCM -CMI should lift their game. They put out a handbook that condones running their engines on the edge of disaster based on a CHT reading from only one cylinder and an EGT reading which is the average of three cylinders. All this when they know their temperatures are all over the place due to their failure to rectify known design faults. They treat us like mugs because they know that cylinder failure is a gradual event that normally occurs outside of warranty and if earlier it's the pilots fault anyway.**
To be fair, those recommendations do not come from TCM/CMI, but from the airframe OEM.
I do hear what you say, however.
To be fair, those recommendations do not come from TCM/CMI, but from the airframe OEM.
I do hear what you say, however.
Shock horror. I've now discovered that all 6 nozzles have identical sized bores and all flow the same rate.
The diameter of the hole and the surface finish of the hole are critical to the amount of fuel dispensed. A score from the tool machining the hole can affect the fuel flow. With all due respect, you are unlikely to be able to measure the bores with the required accuracy to tell a difference. If you wanted to have a go at looking for differences you should try jerry rigging a flow bench with a fuel pump and a safe-ish fluid, maybe diesel. It won't be completely accurate, but should show a difference when you time a measured amount squirting into a bucket.
All this means that manufacturing quality is critical, which is where Continental fails & GAMI wins.
The other issue is that the design of the Continental intake tubes is from somewhere around the Jurassic era. The lack of any hint of attempt to create tuned length intake runners, similar length intake runners, smooth intake runners, matched plenum tube volumes or apply any scientific design means that the fuel charge is not even from cylinder to cylinder. Tuned injectors is really code for delivering different fuel quantities to different intake runners in an attempt to get each cylinder to receive the same amount of charge (fuel/ air mixture).
If this was a car engine and didn't have the certification issues of aircraft, there would be some guys making replacement intake manifolds by now.
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Praise the Lord and clear the airways! The Fork-tailed Dr Killer is about to fly again!
Quote:
Praise the Lord and clear the airways! The Fork-tailed Dr Killer is about to fly again!
It's been so long, I'm surprised 'the Doctor' hasn't died of old age before the V-tail had a chance to get him!
Praise the Lord and clear the airways! The Fork-tailed Dr Killer is about to fly again!
It's been so long, I'm surprised 'the Doctor' hasn't died of old age before the V-tail had a chance to get him!
I had a dream the other night: - test flight of the FTDK - EFATO - put it down wheels up off the end of 01 - walked away unhurt!
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I wonder how many of you guys have used a portaflow test box to adjust fuel flows. Drain lines to analog gauges and compare between that and the test box.Found the portaflow box fantastic when I can source one, especially on Turbo charged engines.
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Old Acro:
Essentially, you are correct, but it may interest you to know that TCM created a pulse injector system more than 40 years ago. It worked. They discovered that at the rpms and power settings these engines operate, it showed little to no improvement over the constant flow nozzles… but with much more cost and complexity, so the project was scuttled.
It is easy to throw stones at TCM about the "old technology" but in many cases the "old technology" is still better than anything available "for the aircraft application."
There is nothing, and I mean NOTHING that has come out of the auto industry that can compete with the TCM or Lycoming engines at the power settings we consider "normal." According to one engine test engineer in Detroit, if the best engine test facilities in Detroit run their best auto engine at 75-80% power, they can only get about 300 hours out of them. If it were easy, everyone would finish the 24 hours of LeMans. Not all even make it 24 hours at the same powers we ask of our aircraft engines every flight.
It's worth pondering.
Essentially, you are correct, but it may interest you to know that TCM created a pulse injector system more than 40 years ago. It worked. They discovered that at the rpms and power settings these engines operate, it showed little to no improvement over the constant flow nozzles… but with much more cost and complexity, so the project was scuttled.
It is easy to throw stones at TCM about the "old technology" but in many cases the "old technology" is still better than anything available "for the aircraft application."
There is nothing, and I mean NOTHING that has come out of the auto industry that can compete with the TCM or Lycoming engines at the power settings we consider "normal." According to one engine test engineer in Detroit, if the best engine test facilities in Detroit run their best auto engine at 75-80% power, they can only get about 300 hours out of them. If it were easy, everyone would finish the 24 hours of LeMans. Not all even make it 24 hours at the same powers we ask of our aircraft engines every flight.
It's worth pondering.
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Do you think there is much of a future in piston engine R&D....?
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I am not so sure. The laws of physics apply the same now as they did before, and Diesel and low octane mogas struggle to provide sufficient power, efficiency and light weight.
These are three things a GA plane needs, and so far JetA burning diesel and turbine do not tick all the boxes. Nor can low compression mogas burning.
As Walter has mentioned above, these old technology engines still lead by a long way when you boil down the hard facts of what a GA plane needs. When you look at it, this is why we have had piston high octane burners for so long.
Invent a few new laws of physics, and it may be different.
These are three things a GA plane needs, and so far JetA burning diesel and turbine do not tick all the boxes. Nor can low compression mogas burning.
As Walter has mentioned above, these old technology engines still lead by a long way when you boil down the hard facts of what a GA plane needs. When you look at it, this is why we have had piston high octane burners for so long.
Invent a few new laws of physics, and it may be different.
Just remind me - How many companies have gone broke chasing the lure of JetA-1 powered piston aircraft engines?
In Europe (for cars) the pendulum is swinging back from diesel to petrol cars. It is believed that petrol engines can be ultimately more efficient than diesel. A lot of development work is now being done on small capacity (sub 1.5 litre) turbocharged petrol engines.
In Europe (for cars) the pendulum is swinging back from diesel to petrol cars. It is believed that petrol engines can be ultimately more efficient than diesel. A lot of development work is now being done on small capacity (sub 1.5 litre) turbocharged petrol engines.