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Post by speedgeeza on Feb 18, 2016 16:45:18 GMT -5
This is a yarn related to lab seals, but not bikes. May or may not be worth a read... It's winter, so what have you got to loose?
Once upon a time, there was a young apprentice serving his time with RR aero engines. It was the norm for all apprentices to spent six months to a year in the various sections related to producing and maintaining jet engines. One day, whilst working in the "deep strip" bay for the Adour 151 series engine (a military ECU), he and his buddy decided to put together the highest spec 151 they could. Many of the modules had time out on this particular ECU and were getting replaced with zero time items, so it was an ideal candidate. HP compressor, HP & LP turbines for example. They paid particular attention to setting the clearances for the lab seals as tight as possible. This is a very time consuming process as it requires a complete build/strip of the nozzle guide vanes and turbine installation for the inner and outer spacers, with a change in either affecting the other, for each turbine. Finally, the deed was done and the engine awaiting it's turn for "pass off" over in the engine test house. Couple of days latter, the chief tech from the test house came over scouting out the two apprentices who had assembled the particular ECU on test. He informed the that it had just produced 5600lbs thrust, the most he'd seen! "Pass off" was 5200lbs. Well, as it was just on afternoon tea break, this provided the two young smarty pants with considerable bragging rights in the crew room, as you might imagine...
Epilog soon. : )
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Post by JA-Moo on Feb 18, 2016 16:59:03 GMT -5
I'll have to ask Gary just what the failures were.
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Post by triplepoweredgpz on Feb 18, 2016 17:44:07 GMT -5
Nice to see Jorgen and John playing nice
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Post by Deleted on Feb 18, 2016 20:57:21 GMT -5
Some H2 cranks came from the factory with labyrinth seals, just saying.
They seem to work fine in my H1B that Charlie did. They have no O-ring however I did use sleeve retainer during the installation (like with crank bearings) and they have not shifted or spun.
rt
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Post by Walms on Feb 18, 2016 21:13:51 GMT -5
Yes, sleeve retainer would do the job. If you didn't use that, it would fail for sure. This is what I'm hedging my bet it's the reason for the failures Gary is seeing.
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Post by Jim on Feb 18, 2016 21:16:55 GMT -5
Some H2 cranks came from the factory with labyrinth seals, just saying. Which ones?
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Post by Walms on Feb 18, 2016 21:17:47 GMT -5
Wasn't it H1 that had non-contact seals of some sort in the early years?
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Post by JA-Moo on Feb 18, 2016 22:45:09 GMT -5
Yes, early 500's had rubber lab seals. Not sure for how long.
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Post by triplecranks on Feb 18, 2016 23:21:51 GMT -5
My supplier will do the groove for the oring if I desire. I don't care for the oring. If the cases are flawless, you don't even need loctite but it doesn't hurt so long as the drop of loctite used is about the size of a 12 font period. It is also crucial that the cases are torqued down within minutes of the loctite application. IMHO the oring can push the seal off center if the OD of the seal is not within .0002" of the OD of the adjacent bearing. This will cause the seal to make contact with the collar. Also, if lab seals are not centered, they WILL friction weld to the bearing. That will lock up the crank and possibly shatter the seal.
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Post by lc on Feb 18, 2016 23:27:21 GMT -5
Yes, early 500's had rubber lab seals. Not sure for how long. 69-72 They were sloppy on the sleeves when new, similar to what Dave Singleton has demonstrated with his old removed seals. J
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Post by Deleted on Feb 19, 2016 5:00:53 GMT -5
The one I tore apart when I was 19 LOL!
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Post by Jim on Feb 19, 2016 9:12:19 GMT -5
Sounds like someone had it apart and put them in before you got to it. Were these aluminum seals?
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Post by Deleted on Feb 19, 2016 10:11:51 GMT -5
Black rubber coated.
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Post by Walms on Feb 19, 2016 11:41:12 GMT -5
My supplier will do the groove for the oring if I desire. I don't care for the oring. If the cases are flawless, you don't even need loctite but it doesn't hurt so long as the drop of loctite used is about the size of a 12 font period. It is also crucial that the cases are torqued down within minutes of the loctite application. IMHO the oring can push the seal off center if the OD of the seal is not within .0002" of the OD of the adjacent bearing. This will cause the seal to make contact with the collar. Also, if lab seals are not centered, they WILL friction weld to the bearing. That will lock up the crank and possibly shatter the seal. We will have to agree to disagree on the o-ring... There can only be one thing that seats against the housing, the bearing or the seal. The seal must be smaller than the bearing or it's going to affect the installed bearing fit. Given that the bearing OD tolerance is +0 / -.015 microns, a properly sized seal would have a tolerance of -.015/ -.030 microns.
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Post by Ned on Feb 19, 2016 18:37:41 GMT -5
This is a yarn related to lab seals, but not bikes. May or may not be worth a read... It's winter, so what have you got to loose? Once upon a time, there was a young apprentice serving his time with RR aero engines. It was the norm for all apprentices to spent six months to a year in the various sections related to producing and maintaining jet engines. One day, whilst working in the "deep strip" bay for the Adour 151 series engine (a military ECU), he and his buddy decided to put together the highest spec 151 they could. Many of the modules had time out on this particular ECU and were getting replaced with zero time items, so it was an ideal candidate. HP compressor, HP & LP turbines for example. They paid particular attention to setting the clearances for the lab seals as tight as possible. This is a very time consuming process as it requires a complete build/strip of the nozzle guide vanes and turbine installation for the inner and outer spacers, with a change in either affecting the other, for each turbine. Finally, the deed was done and the engine awaiting it's turn for "pass off" over in the engine test house. Couple of days latter, the chief tech from the test house came over scouting out the two apprentices who had assembled the particular ECU on test. He informed the that it had just produced 5600lbs thrust, the most he'd seen! "Pass off" was 5200lbs. Well, as it was just on afternoon tea break, this provided the two young smarty pants with considerable bragging rights in the crew room, as you might imagine... Epilog soon. : ) That is a great story. I can't wait to hear more! Can you make it to my place next Saturday? (lol)
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