OIL Lines :
A number of months ago I added a second oil feed line to gear box. I
drilled
a 3/32 hole paralell to the face of the bell housing where the gear box
bolts on and almost to the rear oil seal and then drilled a 1/16 hole 90
degree to the face to intersect the 3/32 hole. I located these holes so
that the exit hole lined up with with a hole in the back face of planetary
gear set, this would spray oil directly on one of the planetary gears. I
teed the oil feed line into the existing line and opened the restrictor
hole
up to .040. I also added a clear plastic HI-Temp (500 degree) 1/8 vent line
to the gear box, exiting 1/8" behind behind the large internal gear on
output shaft. This was to stop seals blowing from the large volume of oil
now flowing thru gear box ( 7 imperial gals. per hour at idle ). My PSRU
came with 2 drain holes ( 1/4 NPT ) , if you do not have 2 you may want to
install a small scavaging pump as the oil is coming under pressure (80
psi )
and returning by gravity. I suppose you could add your own second drain,
but
you would have to careful to remove all cuttings from behind output shaft
gear.
REAR THRUST BEARING:
I machined the bell housing where the the rear seal would normally sit to 2
13/16", the back internal face of the bell housing would have originally
been machined square to the seal bore ( check ). I machined a 4" dia. x 3"
long alum. bar with a good clearance bore for th input shaft and bored the
back end near flex plate to accept 2 - 1 7/16 I.d. seals, this now moves
your seal back about 2 1/2" and runs on the input shaft just forward of the
spline that fits into flex plate. I then mounted a thrust washer on the
front end of the 4" dia. seal retainer plus loose a thrust bearing , thrust
washer and a hardened 3/16" thick spacer, these will slip on input shaft
with the spacer first behind sun gear, so the hardened spacer will run on
the back of sun gear. The whole thrust bearing assembly will be in approx.
the same position that the original rear seal was.
PLA NETARY GEAR SET:
My PSRU came with the planetary set fastened to the matching machined face
of the bell housing with 4- 3/8-16 F.H. socket head screws, I used these
same screws to fasten the 4" dia. machined thrust bearing unit to the
inside
back of the bell housing. This mounting of the planetary set by Ross is
what had caused all my problems, for some reason Ross had counterbored the
3/8 screw bolt holes in the back of the gear set to 3/4", he then supplied
4 - .085 hardened washers to fit in these counterbores, but he had only
counterbored 2 holes .060 deep, 1 hole .070 and the last .073 , when you
bolted this together the whole gear set was twisted, not only that but the
outside flange sat at .238 from the machined face of bell housing , but
the face of the gear box where this outer flange fitted was only .220 deep,
so again when you bolted the gear box to the bell housing the gear box face
could not bottom on the bell housing, again putting another twist to the
planetary set. Long story short I surface ground the 4 washers to fit the
depth of the counterbores and machined .025 of the back of planetary set,
surface ground one of the large thrust washers behind the sun gear to
adjust
the fore and aft clearance between thrust bearings to .006-.008.
My sun gear is a little suspect as I had to tickle of slight spalling on
the
teeth with the DREMEL. I'll check the unit in another 10 hours to see how
the sun gear has faired.
At this point with 8 hours on the unit my gear box oil temp is 2 degrees
higher than engine oil as compared to 40-50 degrees before mods..
I can supply part numbers if I dig into my records. Neil K has photos in
the
archives of the parts we had to machine, if you can't follow my rambling.
My personal opinion of the Ross gear box are, the casting are good and the
machining is good just not close enough attention to details, its to bad
that Chris is such a lousy business man, with a rear thrust bearing and
perhaps better bearings up front it would be a good unit.
Jim Mosur
RV6 C-GAPF
Jim M wrote:
You guys are scaring the hell out of me , Finn's and Chucks Sun gears look
like the rats have been at them, especially Chucks. I had slight spalling
when I did the mods. below but nothing like Finn's. I guess I better take a
look its been around 25 hours now.
Funny you should mention that Jim. I was just about to suggest that.
Is your planet carrier free to move around a bit?
Paul Lamar
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