Having decided to tackle the rumbling rear main bearing on my box saloon that has been getting increasingly noisy since I bought the car in October, I ordered a new bearing from The Seven Workshop. To be fair, Jamie did tell me that he was currently unable to get the RHP bearings and offered me a Hoffman bearing instead. Knowing that Hoffman are a well known brand ordered one, which arrived today. When i unpacked it, although it says it is an MRJ1 1/4" bearing, it is uncaged and, of course, fell into it's component parts as I examined it. The old bearing is a Ransome and Marles caged bearing.
Has anyone experience of using uncaged rear main bearings? And, if so, am I likely to run into any problems with running and what is the best way of fitting them so that the rollers don't end up all over the workshop floor?
David, have you tried talking to Jamie?
This doesn't sound right to me.
I have a Hoffman Rr. Main in my spares box & it is caged in just the same manner as the RHP.
Not yet. My order was waiting for me when I got in at about 7.30 this evening. The bearing is the correct dimension. I shall give him a ring in the morning.
yes, David, they did! I stuck the rollers back into the inner track with some grease to get the bearing back together again. I notice there are 10 (with brass cage) in the old Ransome and Marles bearing and 15 rollers in the Hoffmann bearing. There doesn't appear to be enough room for a cage I have tried to do a bit of research on the net this evening to see the differences between a caged and uncaged roller but there appears to be no information about the subject except for linear bearings which is of little help.
I attach a photo of the two bearings side by side. The old R & M bearing is on the left and the new Hoffmann bearing is on the right.
I think I shall speak to Jamie at Seven Workshop tomorrow.
Bit of b*gg*r! I was hoping to fit the new bearing in this evening and get the flywheel and clutch back on.
HI David,
Once assembled and fitted the rollers can not fall out and the bearing will perform as usual .
so would not worry about not having a cage
Cheers
Colin
NZ
20-02-2019, 08:31 AM (This post was last modified: 20-02-2019, 08:36 AM by Bob Culver.)
At least to the mid 50s with the oils of the time Sevens used for short runs developed significant corrosive wear of the roling bearings and the engines became rough and harsh. (Len Sothward of museum fame and one time Seven specialist told my father around 1940 that cars often presented with the flywheels rubbing! My father was somewhat fussy and used to replace the rear or all bearings every two years or so; the frequency of modern oil changes! At one period when he was very occupied with our new house and the engine deteriorated to the stage where the engine developed a sort of cyclic roughness. But I would not expect noticeable change in a few months on modern oils. Is the race a firm fit on shaft?
I understand that rollers are selected to give correct clearance and that all within a bearing are and should be the same within incredible tolerance for acceptable life. If loose rollers had been extensively used mixed up rollers would have been inevitable in many circumstances. But from schoolboy bicycle days crowded races cf cages do appeal!
Am curious as to unfitted clearances of currently supplied bearings.
