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rotax 912 edge performance big bore kit failure


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Posted

Hey Guys,

just came across this very detailed Norvegian (in english) accident report involving a rotax 912  fitted with the edge performance big bore kit. Among other things, It seems clear that the small piston skirt on the big bore kit is problematic and induces a connecting rod failure on the original 912 connecting rods according to the rotax engineers.

Also I remembered Trent palmer having a rod failure...even Hall had a rod failure going to Oshkosh .....all running the edge performance kit.

I have not read anything about this issue and am wondering if I am the only one who did not know about this.

Let me know your thoughts....

 

2019-04 LN-DLH eng.pdf

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Posted

Wow that was a fascinating read and very informative. Thanks!

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Posted

It would be good if the FAA or the Canadian TC did an as good job as the Norwegian civil aviation authority.....

It seems that in the US and Canada if you have an incident (like an engine failure) without any dead people they don't do any meaningful research and don't establish an in depth report for us.....a shame

 

my 1/2 cent

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Posted

Yes, very detailed report. Some stuff might get fixed around here with his kind of investigation. 

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Posted

Yes, the detailed investigation is very nice. BUT look at all the regulations and now he's in legal trouble for violations. I'm thankful for more freedom - and yes I know there are risks and responsibilities that go with that freedom.

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Posted

Yes, the detailed investigation is very nice. BUT look at all the regulations and now he's in legal trouble for violations. I'm thankful for more freedom - and yes I know there are risks and responsibilities that go with that freedom.

Why not the detailed investigation to help others but without the overregulation....now that would be smart!!

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Posted (edited)

**RUMOR CONTROL**

Trent and Hals engines were **NOT** Edge Performance kits.  They were/are both Zipper Kits designed and produced by Hal.

 

Trent's engine failed due to case fretting and closing of the main bearing clearance.

Hals engine failed at the wrist pin due to running in excess of 120 hp through a first generation STOCK 80 hp crank and rod assembly.  The first gen cranks had inferior design bearings at the wrist and rod.

I have over 400 hours on my Zipper with no problems.  I know of several with over 1000 hours on them now.  This is Rotax engineers throwing the aftermarket under the bus.

Edited by Av8r3400
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Posted

I was wondering when you were going to chime in Larry.  Not being negative in any way.  Just was hoping to hear some first hand experience from someone who is flying one of these.  Is yours the smallest increase in HP that Hal does?  Did you start with an 80 or 100 HP engine?  I was thinking of sending Hal one of mine.  At the rate I'm going, I don't need it on the plane any time soon.  Just wondering after rereading your post, what caused Trent's closing of main bearing clearance?  Does the fretting narrow the crankcase so much the bearings tighten up?  JImChuk

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Posted

**RUMOR CONTROL**

Trent and Hals engines were **NOT** Edge Performance kits.  They were/are both Zipper Kits designed and produced by Hal.

 

Trent's engine failed due to case fretting and closing of the main bearing clearance.

Hals engine failed at the wrist pin due to running in excess of 120 hp through a first generation STOCK 80 hp crank and rod assembly.  The first gen cranks had inferior design bearings at the wrist and rod.

I have over 400 hours on my Zipper with no problems.  I know of several with over 1000 hours on them now.  This is Rotax engineers throwing the aftermarket under the bus.

Thank you Avr8r3400 for shedding light, my bad as I thought they had the edge performance kit fitted vs the zipper big bore. Also after some research it seems the big bore kit fitted to the accident aircraft is an old/outdated version. Edge performance have changed the shape of their pistons a few years ago..

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Posted

Yeah from my view of Edge's turbo Yamaha (EPeX) build, I will say that they definitely do NOT take any shortcuts in what they do.

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Posted (edited)

I was wondering when you were going to chime in Larry.  Not being negative in any way.  Just was hoping to hear some first hand experience from someone who is flying one of these.  Is yours the smallest increase in HP that Hal does?  Did you start with an 80 or 100 HP engine?  I was thinking of sending Hal one of mine.  At the rate I'm going, I don't need it on the plane any time soon.  Just wondering after rereading your post, what caused Trent's closing of main bearing clearance?  Does the fretting narrow the crankcase so much the bearings tighten up?  JImChuk

Yes, my big bore kit is the most "mild" version of the kits.  It is the low compression version.  I started with an early ('96 model) 80 HP engine.  Since installing the kit, I have added the slipper clutch and changed the ratio in the gearbox to the 2.43:1 set.  Since my engine is an early version with the lighter crankshaft and lacking the through bolts of the later engines, I wanted to keep it mild.  Again, thus far I have been extremely happy with the engine and how it runs.

Fretting of the case is a common issue with 912 engines.  It is most commonly caused by lugging the engine, high manifold pressure with low rpm.  This is why the new maintenance manuals all include a test to be done annually (100 hr) of rotational torque.  This tests if the bearings are "pinching" the crank case.  

Trent had commented at one point that he thought the engine seemed "stiff" to him prior to the failure.  If you look back at some of he's old videos, you will see he took his original engine (which was a mid-90's 80hp 912 case) to Hal's shop to fix an on-going oil leak issue.  Hal exchanged to him a case he had in his shop.  This new-used bottom end had very limited (if any) history documentation to it's condition and usage, but was known to have at least 1000+ hours. This case set was also from a older 80hp engine, as it lacked the more robust newer crankshaft assembly and through bolt improvements.  It was then assembled with high compression cylinders and larger cam (creating even more case pressure) and turned out 120+ HP.  IMO, failure was inevitable.

 

Edited by Av8r3400

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Posted

 

**RUMOR CONTROL**

Trent and Hals engines were **NOT** Edge Performance kits.  They were/are both Zipper Kits designed and produced by Hal.

 

Trent's engine failed due to case fretting and closing of the main bearing clearance.

Hals engine failed at the wrist pin due to running in excess of 120 hp through a first generation STOCK 80 hp crank and rod assembly.  The first gen cranks had inferior design bearings at the wrist and rod.

I have over 400 hours on my Zipper with no problems.  I know of several with over 1000 hours on them now.  This is Rotax engineers throwing the aftermarket under the bus.

Thank you Avr8r3400 for shedding light, my bad as I thought they had the edge performance kit fitted vs the zipper big bore. Also after some research it seems the big bore kit fitted to the accident aircraft is an old/outdated version. Edge performance have changed the shape of their pistons a few years ago..

There isn't anything "old" or "outdated" in the kits installed in either Trent's or Hal's engines.  They are the same as the kit that I have as far as piston design is concerned.  

What could be considered "sub-standard" would be the use of the older 80 hp crankshaft.  The older crankshafts had a different design wrist pin and rod bushings from the newer engines which has proven to be a weak spot when "hot-rodding" the engine.  Combine this with case fretting/main bearing problems and crank failures are the result.

 

Edge performance now makes/sources their own big bore kits, having started by buying kits from Hal.  I do not argue that they offer very high quality parts and engine assemblies.  Also important to note, they assemble all of their 912 engines from brand new, "in the crate" engines from Rotax.  Most of Hal's kits are "budget projects", fitted to used, much older engines which may or may not have been treated the best throughout their lives.

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Posted

 

**RUMOR CONTROL**

Trent and Hals engines were **NOT** Edge Performance kits.  They were/are both Zipper Kits designed and produced by Hal.

 

Trent's engine failed due to case fretting and closing of the main bearing clearance.

Hals engine failed at the wrist pin due to running in excess of 120 hp through a first generation STOCK 80 hp crank and rod assembly.  The first gen cranks had inferior design bearings at the wrist and rod.

I have over 400 hours on my Zipper with no problems.  I know of several with over 1000 hours on them now.  This is Rotax engineers throwing the aftermarket under the bus.

Thank you Avr8r3400 for shedding light, my bad as I thought they had the edge performance kit fitted vs the zipper big bore. Also after some research it seems the big bore kit fitted to the accident aircraft is an old/outdated version. Edge performance have changed the shape of their pistons a few years ago..

There isn't anything "old" or "outdated" in the kits installed in either Trent's or Hal's engines.  They are the same as the kit that I have as far as piston design is concerned.  

What could be considered "sub-standard" would be the use of the older 80 hp crankshaft.  The older crankshafts had a different design wrist pin and rod bushings from the newer engines which has proven to be a weak spot when "hot-rodding" the engine.  Combine this with case fretting/main bearing problems and crank failures are the result.

 

Edge performance now makes/sources their own big bore kits, having started by buying kits from Hal.  I do not argue that they offer very high quality parts and engine assemblies.  Also important to note, they assemble all of their 912 engines from brand new, "in the crate" engines from Rotax.  Most of Hal's kits are "budget projects", fitted to used, much older engines which may or may not have been treated the best throughout their lives.

 

**RUMOR CONTROL**

Trent and Hals engines were **NOT** Edge Performance kits.  They were/are both Zipper Kits designed and produced by Hal.

 

Trent's engine failed due to case fretting and closing of the main bearing clearance.

Hals engine failed at the wrist pin due to running in excess of 120 hp through a first generation STOCK 80 hp crank and rod assembly.  The first gen cranks had inferior design bearings at the wrist and rod.

I have over 400 hours on my Zipper with no problems.  I know of several with over 1000 hours on them now.  This is Rotax engineers throwing the aftermarket under the bus.

Thank you Avr8r3400 for shedding light, my bad as I thought they had the edge performance kit fitted vs the zipper big bore. Also after some research it seems the big bore kit fitted to the accident aircraft is an old/outdated version. Edge performance have changed the shape of their pistons a few years ago..

I agree with you when it comes to the very early rotax 912 ul 80Hp crankshaft wrist pin and rod bushings being weaker than the newer engines. In the accident aircraft however the engine was a 2010 rotax 912 ULS with 230Hrs TT, not an old 80Hp case/crankshaft. Also when I compare the zipper vs edge performance piston, they look very alike with a substantial part of the skirt missing to make them lighter. If I understand the report it seems that the minimizing of the piston skirt induces excessive side loads on the original rotax 912 uls con rods....

I did modify my old 80Hp 912 to the 912 uls specs but I used 100Hp rotax pistons (full circumferance piston skirts) and cylinders vs the edge  or zipper kit with tiny skirts..

Maybe a badly synchonized engine for example exacerbates the side loads ......and most guys with the zipper / edge kit with well tuned engines will never have a rod failure...who knows. 

Also from the report, the aircraft owner who installed the pistons did buy them used (10Hrs TT) from edge performance...who knows the story behind the first 10Hrs???

 

Below a picture of the zipper big bore piston with tiny skirt

453C7FA1-31D4-4A51-B3CE-32EE731FB433-1024x768.jpeg

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