Morris Minor Owners Club

drain the oil,remove the sump remove a big end and main bearing cap and have a look at the condition/wear.

Firehor5e is saying that you can check the condition of the bearings without taking the engine out and if you find they are suspect you can then make your mind up whether or not to take it further and take the engine out for a rebuild. When you examine the bearing shells for wear you are looking for discolouration on the surface, they should be a silvery colour all over but if worn you will find a bronze sort of colour showing.

peterscott wrote:I think I may have answered my own question. Have just done an oil change and decided to try a straight sae50 oil. Now runs much quieter, although the noise is still there once warmed up, but not so severe. This is making me think it's most likely main/big end bearings, but which? Or is it likely to be all of the above. What I don't understand is why I can rev the whatsits off it while out of gear with no untoward noises.

You will not get the same amount of noise out of gear as you are not putting any load on the bearings/gears etc.
I have to say that using a straight SAE50 grade oil is only masking the reality that your engine and/or gearbox requires an overhaul.

So many things it can be. You have excluded water pump, generator. But there is crank bearings, timing chain and a few others as possibilities.

You need to isolate this to engine/gearbox/rear axle initially and go from there. Growling is not a term I relate to engine bearing failure. They either knock or rumble (big ends or mains). Small ends tend to 'rattle'. Oil changes need to be stated as gearbox or engine, if the same oil is being used - not leaving us to guess which you mean.

My best guess is timinng chain at the present amount of information. How about some rpms with oil pressures? They are important!

Thanks to all. I have sae50 in both engine and gearbox. Hot oil pressure holds steady at 50psi at speeds above 30, dropping to 20psi at idle. Many years ago I had a Morris 1100 with very worn crankshaft bearings. The oil light didn't go out at speeds below 30, even running with a very high proportion of STP in the sump. It rumbled on for a good few thousand miles like that until I sold it. My noise doesn't sound like the 1100 did. However, I have adjusted the timing, and had a 20 mile run this morning. If the noise was there, I couldn't hear it, so we'll see how it goes. I do have a spare engine which needs rebuilding. I may have a go at that at some point in the future. Can anyone recommend any good books/dvds to help with this? I know there are some items on youtube which seem quite good.

I also asked Practical Classics for help with this. Their advice centred round the timing which I had already adjusted following advice given on this forum. Pleased to say the problem is now sorted.