Hi
I have 2 engines I am getting ready to put together - a 3rd perhaps too will follow
Looking for bearings this side of water - I have been offered sealed outer bearings 6205 with either rubber or steel shield - both types are C3 clearance - drive side I must add
Is there any advantage to using a sealed bearing even if the inner is removed - eg - less oil reaching the primary casings in event of wet sumping or would I interfere with crankcase breathing by blocking this route
I am hoping that with a new pump & new oil pump parts I have here I can eliminate or significantly possibility reduce wet sumping on these motors - but just wondering about the seal inclusion or not
On my gearbox - I chose to leave the bearings used to retain their seals - this in my opinion protecting the bearings from any contaminants etc that might cause issues - but the motor is a different story
Br
Jo’b
email (option): jonnyob1@googlemail.com
I always fit a rubber sealed bearing on the drive side with one seal removed (inner) for the reason you note...The BSA engine doesn't rely on breathing into the primary case so the seal has no effect in that regard....Ian
email (option): ian@wright52.plus.com
Hi Ian
Thanks for that - that’s confirmation of what I was thinking
Br
Jo’b
email (option): jonnyob1@googlemail.com
Use both seals on the bearing John, it will last longer.
Mark
email (option): pes.sales@btconnect.com
[' Use both seals on the bearing John, it will last longer...'] The jury is out on that..I was advised by a retired RHP developement engineer and BSA enthusiast to remove the inner seal...In the gearbox as well...
However, I don't profess to be an authority myself so I guess it's a case of which expert you believe...Ian
email (option): ian@wright52.plus.com
with or without the seal I suspect the bearing will last longer than most of us :anguished:
I remember remarks about 'an open engine' a few years ago, think it was from down under, Trevor? Open engine, breathing partly through the bearing.
Can imagine a modern sealed bearing will have some influence on the breathing, either positive or negative..
In the back of the primary chaincase is a vent hole, I often wonder if that has something to do with the breathing of the engine. Pressure release?
Two things often ruin a ball race or roller bearing.
The first is debris of some kind.
Secondly is too much oil or grease.
The seals fitted to most roller bearings are not as good as you'd expect, it a surprise as to how much oil they will pass in use.
In reality most builds never get finished and those that are seldom rode, so why use any new bit's?
Mark
email (option): pes.sales@btconnect.com
'Stop coming at me with those negative waves...'...:relaxed: ...Ian
email (option): ian@wright52.plus.com
In many modern car and motorcycle gearboxes, all the bearings are sealed. BMW motorcycles started putting sealed bearings in the gearbox about the year 2002 and still does. So it obviously works. Many other manufacturers do the same.
The theory being that the seals will keep metal particles out of the bearings. Oil eventually will get past the seal but not metal. The are trying to make a gearbox that does no require an oil change for the life of product. BMW motorcycles has not achieved that yet as you still have to change the oil but not very often.
As for cars we have an old 1999 Isuzu my wife bought new that we keep for getting the dogs to the Veterinarian so their hair does not get all over our newer car. The manual states to check the gearbox oil level but no need to ever change it. So it is still running happily on 24 year old oil with no problems. My 2008 BMW R1200RT motorcycle has a 154,000 miles on it with all sealed bearing in the gearbox and no problems.
Now as for an engine, I have never seen one with sealed bearings in it. As everything modern has an oil filter, metal getting in the bearing is probably not a problem. On a M20 or any other old bike, I would remove the inner seal. I have seen more than one M20 where the outer drive side bearing had corrosion so am guessing not a lot of oil gets to it.
With only the outer seal fitted, wouldn't it been easily blown out by crankcase pressure...?
Re the outer crankshaft bearing, i wouldn't bother fitting a sealed bearing as not much oil seemes to blow past this anyway. M20 gearbox bearings in the past i have always removed the inner rubber seal, my thinking was that with the original oil baffle shim still fitted then this would keep most debris away from this bearing as originally intended. I may re think this now on my next build and leave both intact.
The cooling effect of the oil was one of the factors mentioned to me as well as the lubrication of the bearing....The intrusion of debris of any form into the bearings doesn't appear to be a practical issue when the engines can reach extended mileages without any attention....For example I didn't even remove the barrel and head from my B33 for some top end work until I had completed 78,000 miles on it after a rebuild...
It appears though, from the anecdotal evedence here, that either way serves OK...Ian
email (option): ian@wright52.plus.com
Was not me talking about breathing through the primary on an M20 .
I do it on all of the unit singles but they are different cases.
Seals in so far as a bearing goes is a misnomer
They are shields at best as none of them actually seal
I go through dozens of 6202, 6203 & 6204 bearings every year on ride on mower spindles where the idiot owners use those wash out ports on a hot deck so the bearings suck in the water as they cool down
If you want to stop debris entering then use a ZZ ( 2 metal shields ) as these do not pretend to be seals
The seals are designed to keep the grease in not contaminants out and ZZ's have lots of tiny holes .
I use them to replace 2rs on spindles where grease nipples are installed as the grease can flow through both the shields
If you use 2rs in the same situation the grease will cause the inner side to push in onto the race and breakup over time.
Similar story for the crankcase a zz will do a good job at slowing the sump draining into the primary but will not blow out when you try to start a wet sumped engine.
Now if Ian or others are worried about cooling use ZZ's but in reality the heat flow from the outer to the aluminium case will be orders of magnitude greater than between the balls & the oil
Next time you have the box out, remove the inspection cover , fill it to the corret height with oil and look at how much of the bearing would be in contact with the oil so you are really only talking about splash when going strait and very partial immersion when cornering depend how much of a cornering hero you are,,, on universal blocked tread tyres !!!!.
What is far mre important when selecting bearings is to get them from a trusted source , not evilpay or scamazon .
I can get 6000 series bearing from China for as little as $ 2 a piece , OK for shopping trollie but that is it.
And the most faked item on the planet is not Rolex watches it is brand name bearings so stick to the trusted names and make sure they come in a box .
['What is far mre important when selecting bearings is to get them from a trusted source , not evilpay or scamazon .
I can get 6000 series bearing from China for as little as $ 2 a piece , OK for shopping trollie but that is it.
And the most faked item on the planet is not Rolex watches it is brand name bearings so stick to the trusted names and make sure they come in a box'].
I agree totally with Trevors last paragraph...Branded bearings are the only way to go...
On the subject of the post generally, I took advice, decided to go with that and basically do what I have proven to work over time...I'll readily admit there may be other ways of getting to the same place though...Ian
email (option): ian@wright52.plus.com