My IMS Solution DIY installation thread...
07-27-2016, 08:19 PM
#63
Rennlist Member
07-27-2016, 08:39 PM
#64
Race Director
07-28-2016, 12:58 AM
#65
Shameful Thread Killer
Rennlist Member
Rennlist Member
An interesting off-shoot to follow:
Back in the 50s, the good folks at Paxton engineering came up with a supercharger that was of the aviation design using a free impeller in a scroll housing, driven by a speed multiplier. The Paxton centrifugal auto unit had a dual row pulley, driving a set of planetary ball-fork spiders that were caged to a sandwich outer race, and the inner small race drove the shaft of the impeller. The whole thing started life being lubed by a 80wt trans product. Not long after it was installed on some Studebaker Golden Hawks, they began to notice spalling of the inner race which drove the impeller. It would set up a small whine/howl which was engine speed dependent as the metal was shed from the inner race. One of the pioneers of tribology figured out the failure mode was actually the inability of the inner race to skid on the rotating drive ***** when the throttle was closed, thus causing a pressure bubble in the intake and back through the scroll housing, putting strain on the impeller blades. A fascinating root cause analysis.
So, the inner race shaft was designed for a slightly higher Rockwell number, and they changed to a type of auto trans fluid(I don't know which one). This new polished inner race, and the new type of lower EP fluid worked to solve the spall/scuff problem and extended the service life of the supercharger up over 35k miles, which was considered high art for the day.
Back in the 50s, the good folks at Paxton engineering came up with a supercharger that was of the aviation design using a free impeller in a scroll housing, driven by a speed multiplier. The Paxton centrifugal auto unit had a dual row pulley, driving a set of planetary ball-fork spiders that were caged to a sandwich outer race, and the inner small race drove the shaft of the impeller. The whole thing started life being lubed by a 80wt trans product. Not long after it was installed on some Studebaker Golden Hawks, they began to notice spalling of the inner race which drove the impeller. It would set up a small whine/howl which was engine speed dependent as the metal was shed from the inner race. One of the pioneers of tribology figured out the failure mode was actually the inability of the inner race to skid on the rotating drive ***** when the throttle was closed, thus causing a pressure bubble in the intake and back through the scroll housing, putting strain on the impeller blades. A fascinating root cause analysis.
So, the inner race shaft was designed for a slightly higher Rockwell number, and they changed to a type of auto trans fluid(I don't know which one). This new polished inner race, and the new type of lower EP fluid worked to solve the spall/scuff problem and extended the service life of the supercharger up over 35k miles, which was considered high art for the day.
07-28-2016, 01:09 AM
#66
Drifting
"the inner race shaft was designed for a slightly higher Rockwell number"
Interesting but do you mean Rockwell hardness or Ra finish? It sounds as if you mean Ra.
Interesting but do you mean Rockwell hardness or Ra finish? It sounds as if you mean Ra.
07-28-2016, 01:15 AM
#67
Shameful Thread Killer
Rennlist Member
Rennlist Member
I recall rebuilding one that was howling with the new inner shaft, and shimming the impeller out to the scroll housing to improve pressure, but I just bought the inner race shaft and kept it clean, clean, clean. I put it on an Avanti which was supposed to be limited to 12PSI, but I was able to get it up to about 14 or better. Sadly, that spun a rod bearing, which required a whole new set of checks to solve.
07-28-2016, 09:43 AM
#68
Nordschleife Master
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07-28-2016, 12:25 PM
#69
Rennlist Member
Thread Starter
In reference to the serial number on the bearing seal - I found this video and he does a nice job of explaining things. Apparently those seals are from a completely different bearing and Porsche used them in this bearing.
07-28-2016, 12:37 PM
#70
Drifting
We've seen this guy before. He is a noob who would do well to read more on Rennlist. Many points he makes are partially true but lack the details he could glean from reading more Rennlist Posts.
I'll leave it to others to pick apart his theories and statements.
Bottom line is go to a trusted, experienced and competent source for your IMSB advice - probably not this guy but certainly Rennlist YEMV
I'll leave it to others to pick apart his theories and statements.
Bottom line is go to a trusted, experienced and competent source for your IMSB advice - probably not this guy but certainly Rennlist YEMV
07-28-2016, 04:21 PM
#72
Former Vendor
Amazing.
I guess he also hasn't figured out that the IMS assembly does;t see "high speeds" like the crankshaft does. It's funny how people start copycatting bad ideas, and thoughts, just like the good ones.
I guess he also hasn't figured out that the IMS assembly does;t see "high speeds" like the crankshaft does. It's funny how people start copycatting bad ideas, and thoughts, just like the good ones.
07-28-2016, 04:50 PM
#75
Drifting
The power of Rennlist is that your proposals need to be robust enough to withstand rigorous ,intelligent and very well qualified debate
The weakness of You Tube is that you can pontificate without effective rebuttal.
If he had debated here first and then made a video of the collective wisdom shared, it would have been a useful piece.
Is he a Member here or just a Lurker?
Perhaps we should invite him to come out of the shadows and discuss his theories before he makes yet another video?
The weakness of You Tube is that you can pontificate without effective rebuttal.
If he had debated here first and then made a video of the collective wisdom shared, it would have been a useful piece.
Is he a Member here or just a Lurker?
Perhaps we should invite him to come out of the shadows and discuss his theories before he makes yet another video?