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MG MGB Technical - crank shaft shims

Hello,

I am about to reassemble my mgb engine (standard 1800cc), but as I didn't take it appart in the first place I have no idea what size thrust washers were fitted originally. Can someone advise what I should do?

Here is the part I am talking about:

http://www.moss-europe.com/Shop/ViewProducts.aspx?PlateIndexID=187#66

Please see item 66

Many thanks.
Alex Davies

Alex. Order a set of standard sized thrust washers, then install them and check the end float on the crankshaft. Every MGB engine I have rebuilt still used the standard sized thrust washers with no problems. If it turns out that the standard size is not sufficient to control the end float, you will have an excellent idea of whether the oversize ones (.005" from memory) will work without modification.

Les
Les Bengtson

hello,

Thanks for that.

Ive also come across problems determining which spigot bearing i need to buy, as them come in different lengths.

This is the spigot bearing.
Item 69
http://www.moss-europe.com/Shop/ViewProducts.aspx?PlateIndexID=187#69

Can anyone offer any guidance?

Secondly, should i replace the camshaft bearings? I haven't seen it mentioned that these should be replaced, but as the engine is stripped down I wondered if it is a job worth contemplating.

Many thanks,
Alex Davies

Alex. It would be good to know what engine you are working on as there were several versions with the most significant difference being the three main vs. five main bearing types. But, there were also two different transmissions, three syncro and four syncro, which would affect the size of pilot bushing/spigot bushing needed. The engines for the four syncro transmissions used two different pilot bushings with the same inner and outer diameters with there being a difference in the overall length of the two. I have read that the shorter bushing will work with both.

Camshaft bushings, commonly, do not need replacement. The ones commonly available need to be reamed after they are installed. There are a couple of brands, DuraBond is, I believe, one of them, which are precision made and do not require reaming after installation. This is something to discuss with your machine shop if you decide to replace the cam bearings.

Les
Les Bengtson

Thanks les much appreciated. I have a five bearing 1800 CC MGB Engine and a four synchro gearbox with overdrive. Which is the correct bush (as originally fitted)? Would you recommend fitting the smaller one?

Many thanks
Alex Davies

Alex. All of my rebuilds have been of 18V engines which used the shorter bushing. It would be useful to know what model engine you have and what is the length of the current bushing (if it is there). I would, probably, use the shorter bushing if it were my engine, but it is not my engine.

Les
Les Bengtson

To save the cam bearings, do not have the shop "hot tank" the block in caustic. It can be cleaned by other means.
Art Pearse

This thread was discussed between 17/03/2010 and 19/03/2010

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