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MG Midget and Sprite Technical - 1275 Spigot Bearing
|Hi, hope everyone has had a great Xmas!|
Managed to steal a few hours to work on the car today and have a question which I hope you can help with.
Whilst the engine is out I'm trying to do all the jobs that will be very hard or impossible to do once the engine goes back in, one of these being to renew the spigot bush.
My car has a 12CE engine which according to Moss should have the roller type bush (part AHU1026A) as the bronze type are for very early 12CC engines.
I have a bronze type fitted but wondered if the larger recess just in front of it is where the roller type should go (I've read on this forum that the roller type is wider)?
Other than that I suppose I could have an earlier crank or the info in the Moss catalogue could be incorrect.
All help greatly appreciated.
|I have a Moss/Heritage parts book that says the bush was only fitted to early 12CC and that late 12CC onwards had the bearing.|
I also have an M&G International catalogue from 1988 which says the bearing was only fitted to late 1275s.
From experience, I think the latter is more likely to be true.
|Dave O'Neill 2|
|What are we calling early and late model?|
I have a 1971 USA and it came with the brass and NO roller bearing, and im using a modified brass for the datsun 5 speed
I know that peter may engineering has rollers
|Prop and the Blackhole Midget|
|Hi, thanks for the info Dave, would you say that my crank has the correct type of bearing fitted in the proper place then?|
Prop, the catalogue worked on engine numbers 12CC, 12CE but I think that the info is suspect.
It's not possible to fit a bush into a crank that is supposed to have a needle roller, as the hole is just too big.
|Dave O'Neill 2|
|Thanks Dave, will order another bronze bush with my next batch of parts.|
|a quick google turned up this post on an LBC forum from 2003:|
'late 1275s had a needle roller spigot bush as standard (part No. 13H4653 or AHU1026); this has a bigger OD of 0.750" as opposed to 0.625" on earlier engines, so they're not interchangeable. The factory parts catalogue doesn't state when the change occurred, so it's a case of
measuring/checking what you've already got.'
The plain bush that the majority of engines has is 1A1559.
|I assume my question is getting lost in the Type 9 thread, so this is a better place to ask it.|
Has anyone actually got the '1275 gearbox' needle roller spigot bearing described below in their car, or have one to hand to have a look at?
I spoke with Sussex, and was told that it doesn't have an oil seal in it, which surprised me.
Can someone/anyone confirm that?
Also, without an oil/grease seal, how long does it last?
|Lawrence. Sussex are correct, the needle bush doesn't have an oil seal (not sure where it would go anyway ) The bush is greased and the rollers bear against the gearbox spigot. no idea how long they last. I bought one and found it wouldn't fit as I had the earlier crank. It's probably still rolling around in a box of spares in the garage.|
|I have some NOS at home, surprisingly!|
|Dave O'Neill 2|
|Thanks for confirming that graeme.|
Dave. Could you confirm that the NOS don't have them either?
This will make sorting out a spigot bearing for T9 conversions easier, better, and cheaper too I think, because you can buy the exact size needle roller needed, albeit without an oil/grease seal, for circa 10 quid.
This type of needle roller is a Drawn Cup type. The oil/grease seal -- if it has one, is in the end of the cup. See the white arrow in my picture below, of the bearing for a Ford Type 9 g/box.
So assuming then that the originals from BMC didn't have this oil seal, and the bearings kept enough grease around the shaft not to sieze up, then the Type 9 bearing could also be replaced with one that didn't have a seal too.
|Just a heads up...|
The peter may roller bearing looks exactly like the one in the toyota 22re 4 cylinder engine for 1993 toyota pick up truck with 5 speed manual trans.
So if you can determine what that bearing is, you can probably cross referance the size at a bearing shop like IBT
It dosnt look like the one lawerance posted and it does have a grease seal...I replaced mine with nothing wrong with it at around 200,000 miles when I pulled the flywheel last time
|Prop and the Blackhole Midget|
|Don't know if it helps, but I am in the process of switching the engine in my MGA which has a T9 box. I had to remove the spigot bearing from the old crank to reuse in the new one - not hard because it is an adaptor with threads on the flange to do this. The point is that the spigot bearing inside the adapter is just the same approach as a standard MGA, it's an oilite bush. Unfortunately the new engine also had a new oilite bush in the crank so I had to cut it out (as an aside the spell checker keeps telling me I have an olive bush in the end of the crank, which would be an interesting approach to green motoring!).|
So do you really need a needle roller at all, could you just use an oilite / olive bush
|Cheers chaps. I 'could' do all sorts of things ;). Yes I could use an oilite.|
But what I am want and prefer to do, is confirm that the oil seal isn't needed. And then if that's the case, there is an exact sized needle roller bearing avialable off the shelf for cira 10 quid. And because it's the correct O/d, it won't need a sleeve to fit in the crankshaft.
I've just had a look at a bearing. It's kind of difficult to see, as they are sealed in green plastic bags and I don't particularly want to open one, but... there does appear to be some sort of seal, possibly felt. The ends of the needle rollers are definitely nearer one end of the cage than the other.
I must admit that I never gave it a second thought when fitting one to a crank.
It may well be that current parts don't have a seal, as whoever put the order in just asked for a caged needle roller bearing of a given size.
I will see if I've got a late crank or an engine with one in, that I can have a look at.
I didn't have a chance to look for a cam today. Hopefully tomorrow!
|Dave O'Neill 2|
Don't know if this helps but the Ford Escort bearing looks similar to your pic and it has a plastic/nylon type seal exactly where you arrow points
Idea-- If you fitted one without a seal, a nice tight fitting O ring could be stretched onto the spigot on the input shaft and then when the g/box is fitted up it would seal against the end of the bearing- -it's only a dust seal really as any lubricant would throw outwards into the shell of the bearing anyway
That's just what I suspected. It'll be interesting to see if you do have a late crank. Maybe one day I'll pull the engine from my '73 RWA midget, and see if that has a needle roller Spigot. But it does seem, that the new needle roller replacements aren't the exact spec that BMC issued. I wonder how long they last without a seal?
I thought of an o-ring too. It would be better than now't. I don't think it is just a dust seal. But how to ensure it remains tight against the needle roller to keep the grease in. Maybe if a light coil spring was also put on the shaft?
With the oilite, you are supposed to soak them, and the amount of oil in them then lasts for a long time. As you say, without a seal on the needle roller, the grease might well be thrown out, resulting in the bearing eventually seizing on the g/box shaft, or spinning and damaging the crankshaft orifice.
My quest was to find a needle roller bearing for the Type 9 g/box, that doesn't need a sleeve to make it fit the 1275 crankshaft. I found one, but as it doesn't have a seal, given that the original BMC needle roller for the 1275 g/box does appear to have had one, I think I'll stick to sleeving the bearing in my picture below.
But this is a useful result anyway I think, for those with a 1275 g/box, contemplating replacing their needle roller spigot bearing.
Make sure you get a NOS item with a seal of some kind.
This thread was discussed between 30/12/2014 and 05/03/2015
This thread is from the archive. The Live MG Midget and Sprite Technical BBS is active now.