Gents, I am re-assembling my gearbox after fitting sealed bearing on Mainshaft output.
I am also changing the other bearing in the inner cover.
This replacement bearing also came with seals. Is there any advantage in leaving either of the seals on this bearing in place ?
Baz
email (option): binnawan@iinet.net.au
Barry no harm in removing the inner seal to allow normal lubrication and not have to rely on the steel shield to keep the oil from creeping into the outer cover. Others sometimes advice that you can leave both seals in on both bearings as they are supposed to be sealed and lubricated for life. Personally I like to have them open and lubricated in the normal manner. Ron
email (option): ronpier@talk21.com
I agree with Ron...The gearbox oil cools as well as lubricates....Ian
email (option): ian@wright52.plus.com
I would remove the seals but keep in mind, many gearboxes in modern cars, all the bearings are sealed. They are trying to make a gearbox that requires no oil changes for the life of the car and the seals will keep metal particles out of the bearings. At least that's the theory.
Oil will eventually seep past the seals so the original grease is washed away and replaced by oil.
OK, thanks gents. I will remove the inner seal
Baz
email (option): binnawan@iinet.net.au
What ever you do, Don't remove the seals. I expect it's to late now?
Mark
email (option): pes.sales@btconnect.com
Well, I took my advice from an acquaintance who was a developement engineer at RHP bearings (now retired), a chartered engineer and is also a BSA enthusiast...His advise was to remove the inner seal...'You pays your money and makes your choice'....:relaxed: ....Ian
email (option): ian@wright52.plus.com
Using a magnetic drain plug would help to offset the mistake of removing the seal ;)
https://pesltd.uk/?product=28-0043
Mark
email (option): pes.sales@btconnect.com
Personally, I think 'mistake' is not the correct or proven term regarding removal of one of the seals and my own experiences and those of others seem to support that after years of using the method.....
I certainly don't profess to be an expert on the subject of bearings and their applications but I think it's fair to say my source of advice is more than qualified to make a judgement (see my previous post)... To my mind it would be odd to completely ignore his qualifications and knowledge without supporting evidence to the contrary.....
However, it's for anyone to form their own opinion at the end of the day...Ian
email (option): ian@wright52.plus.com
I work on the theory that they were built with open bearings 100,000's of times (which are still supplied and fitted) and fitting a bearing with an outer seal to stop the usual leakage is far better.
I had my G3 crankshaft rebuilt with a needle roller big end by a specialist who advised me to fit a sealed main bearing to the drive side but to remove the inner seal. He was also concerned that I should wash the grease out first lest it contaminated the oil by not mixing with it. I must say, I actually ignored that bit! Maybe I'll regret it one day:scream: Ron
email (option): ronpier@talk21.com
I also always fit a sealed bearing (minus one seal) to the cranks of all the BSA singles I build and have done for decades...(I don't wash the grease out in either bearing so don't worry Ron..:laughing:) ....Ian
email (option): ian@wright52.plus.com
As it feels like I have been prompted to defend myself.
There is nothing clever about how I have come to my conclusions, despite 45 odd years of high end motor racing.
When inspecting failed ball or roller bearings it's quite obvious to notice why.
Riveted cage failure is normally found in small high revving engines. High frequency vibrations seem to be cause.
Very small Honda two stroke engines were prone to it with the main bearings. They were a loose fit on the shafts.
I'm sure if the fit could have been made tighter the problem would have gone away too.
Flaking/Pitting of the surface if normally overloading. This must be witnessed in the early stages or other damage can mask it.
Normally fixed with a higher capacity bearing.
The most common of all and normally found in big end bearings and gearboxes is particle contamination. Hard to see with the naked eye, but fine pitting and a greyed surface are good signs of it.
No magic fixes, just keep the bearings clean. Pressure side oil filters and bearing seals and to a lesser extent shields help.
Unless you use bearings with very high quality seals, they don't seal that well. As the bearing pressurizes and depressurizes it will displace the grease and replace it with oil. I've yet to open one up yet where this hasn't happened.
Mixing grease with oil, yes this put me off originally. The gained life on leaving the seals in place seems to outweigh any losses.
Even the mixing of vegetable with bearing grease hasn't shown any problems to my surprise.
But seriously do what ever makes you happy. I doubt if any of us will live long enough or do enough highly stressed miles to notice a problem. I only try to help using many years of first hand experience.
Mark
email (option): pes.sales@btconnect.com
No need for aplogies/explanations Mark.
Your opinions and information are always appreciated Mark, same goes for everyone else on this site, very helpful.
I am now mid 80's and no longer ride 2 wheels, twice a week rides on my Spyder keeps me in touch.
My M20 will be as good condition as I can make it, utilising all the advice I receive on this site, and will eventually pass to my son, but unfortunately I can't ride it. (did plenty of that in 50's t0 70's).
It is never going to cover high mileage in my lifetime.
Now back to try and insert gear cluster. BTW, army manual is good at giving 'bits' of info. e.g. 'when removing inner cover, watch out for small plunger and spring falling out, don't lose them'. Well, they fell out and I didn't lose them, but...fell out from where? where do they fit back in ? They don't mention that.
Baz
email (option): binnawan@iinet.net.au
Barry the little spring and plunger 37 and 38 fits in it's little tube behind the gear change mechanism. Ron
email (option): ronpier@talk21.com
It's also worth checking that the little recess in the back of the plate (35) that the plunger fits into when in the 'centered' position is clearly defined to accept the plunger and there is not have a heavy 'score' in the plate either side of it...It makes for more positive 'self centering' that way....Ian
email (option): ian@wright52.plus.com