~ Engine Bearings
Explained ~
As noted by Marcel van der Heijde <[email protected]>
on
The BevelHeads List 12/12/02 - Use
this info as you please but...
Don't get mad at anyone if things don't work out as you planned
Hi heads,
Since somebody wanted to post my comments regarding bearings on a website I did some additional homework. When I had my 860 GTS engine open ('76 # 852554) I went through the bearings as well. As it was opened by somebody else a couple of years before I got it, I had to in fact replace all bearings. This is the list I came up with at that time with the help of a local bearing supplier who still had access to old RIV codes. In fact RIV was bought by SKF. I took the part numbers from an 860GT parts manual because that is the only one I have (so not the GTS version), but for most bearings these will be the same as used on my engine and later SS or Darmah engines. So here is my list. If you want to put it on a website feel free to do so, as long as you include some sort of disclaimer that anybody is still responsible for his own actions or something like that. (Use it, abuse it, but don't blame me!) The notes on the suffixes were taken from the catalogues of bearing suppliers, as was the limiting temperature for the reinforced PA cages. FAG and SKF use identical temperature limits by the way. Cheers, SKF suffixes used: Angular contact ball bearings (72xx / 73xx)
Deep grove ball bearings (6xxx)
Dual row self aligning ball bearings (12xx)
Roller bearings (NUxxx)
In general bearings with a sheet metal, pressed steel or brass cage are preferred for applications where continuous use over 100� C is expected. Ducati advised metal cages only for the bevels as far as I know, but for the lower end of the engine the use of glass fibre reinforced polyamide cages shouldn't be too much of a problem (up to 120� C). The bearings on the tower shaft and on the camshaft should have metal cages if you can get your hands on them. In fact the bearings in the lower end are easier to get with metal cages. Ask the bearing supplier if he can supply specials with metal cages. They might not be included in the standard bearing catalogue on all occasions but they might be available if he is willing to ask the manufacturer. There also is some discussion on the main crankshaft bearings. As far as I know ordinary B-types were used, but since I don't have the originals to check (previous overhaul before) I cannot be sure. The old RIV code was checked by an SKF representative and they told me it was a 7307 BE or equivalent. The only bearings where Ducati uses C3 tolerance are the camshaft bearings so one could use normal clearance on all other bearings. I prefer to use C3 tolerance deep groove ball bearings in my engine and I used a 6008-RS1 on the output shaft, making it oil lubricated instead of the grease filled 6008-2RS1. If you use the 2RS1 keep an eye on the application temperatures for the grease used. The only bearings where Ducati uses C3 tolerance are the camshaft bearings so one could use normal clearance on all other bearings as well. Clutch housing up to engine no 851193
from engine no 851194
The GTS uses a modified clutch housing with one 6005 NR and one 7205 BE bearing. Tower shafts Top bearing
For this application it is probably worth searching for the metal cage types, but they should be considered specials and will be hard to find. Lower bearings
The B-types have a contact angle of 40� instead of 30� for the A type.
Right hand side engine casing Layshaft bearing
Output shaft bearing
Main crankshaft bearing
Left hand side engine casing Main crankshaft bearing
Output shaft bearing
Layshaft bearing
Bearing on end of crankshaft
Bevel shaft support on RH side Bearings for horizontal bevel shafts
Bearing for crankshaft
Cylinder heads Camshaft bearings
Use metal cages on these bearings and ask for C3 clearance. |
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