Morris Minor Owners Club

Clean the tops of the pistons and send us a picture! The pistons all have some sort of marking on them - even if it is just the 'grade' marking inside a little parallelogram mark.

Alec- yes, I glaze-bsted the bores. BMC- If I can get a decent pic, I'll send it!

Okay, so my wife is right: I AM the least observant man in the world (don't tell her I admitted that). Upon further cleaning and inspection, on the top of the piston there appears to be a large "A", followed underneath by M (or N) 2213 X38 (or X3B). What, had I paid attention, should this have told me? Thanks!

Nothing much.... if they were oversize they would be carrying a '10' or '20' or '010' or '020' etc etc. You will HAVE to measure the bore - digital caliper required.......beg borrow or steal one......

Will do, BMC, and will report back. In the mean time, my cheap dollar-store caliper says the bore is a smidge over 2 3/4".

Hmmm - standard bore is 2.780" - so that is a smidge over 2 3/4"....... It's going to need to be a bit more accurate - but does sound like standard bores.

Digital caliper in hand and: all bores 2.78". FWIW, I did notice that one piston- probably the one I initially inspected for markings- is different from the other three, and is completely devoid of markings. This particular piston has a finely mottled surface, while the others are very smooth. So it is apparent the engine has had work done, although this doesn't really bear on my original oil-burning problem. So,tomorrow, oil pan off, pistons out, and...

Finely mottled surface suggests either something has been rattling around in there - or pinking/detonation..

My first thought, too BMC, but this looks more like a "factory finish"; it just looks like a different piston! I'll try to get a picture.

Okay, Roy, when you're right I'm man enough to admit it! I used some emery cloth on the "mottled surface" of the suspect piston, and lo and behold, after some vigorous rubbing, the very faint outlines of a the large "A" were visible- meaning it is the same as the other pistons. So, something must have hammered the thousands of tiny dimples into the piston's surface. Really, it was so fine, evenly distributed and uniform that it had the appearance of a sand-casting.
No time today to drop the pan and remove the pistons, but at least I know I've got a matched set.

I know everyone on the forum has been sleepless with anticipation about the climax to my smoke-filled saga, so I thought I'd better finish this up: I removed the engine and tore it down completely, cleaning and inspecting everything. The journals were in fantastic shape, so new shells went in. Same for the bores, nicely within specs, so a hone and rings and they were ready to go. I fitted a new oil pump as per Roy's advice, reassembled the lot and put it all back in. The result is (drum roll Please!)...no smoke!
Engine runs great, with very good oil pressure.
Now, since I had recently put new rings in (read earlier posts in this thread), had honed (de-glazed) the cylinders and upon inspection, found all the rings to be assembled on the pistons correctly, then why the horrendous gobs of smoke? Well, here's the only possibility I could find: when I took the OLD new rings off the pistons and pushed them down the bores, I found that there was at least 1/8 inch end gap. That's a lot. There was a little more on some others. The NEW new rings had just a tiny gap.
I hadn't done this originally, and if I had, I may have caught this before installing them. Serves me right, I guess, for skipping a step. I don't know if they were mislabeled, but the box did say standard rings for the 1275. They were a rig company I'd never heard of, but then, I could only name one or two off the top of my head; the new new rings are from one of the companies I could name. Moral of the story? Take your time, double check, and spend the money for good stuff. Oh, and don't be a doofus.
Thanks for all the advice.
Now, a curiosity: after putting the engine back in, my clutch action was completely different. All the components are the same, but now the engagement is very 'snappish'. Before it was very progressive. In fact, I always wondered what the complaints were with a Midget clutch in a Moggie, but now I understand. The whole feel of the pedal is different- very 'on/off'.
Any thoughts on this unexpected change? Thanks for putting up with a long post!

If you have just fitted a new midget clutch, then yes it will operate the way you descrbe (assuming you are using the Moggy mechanism). The midget clutch is meant to work with a hydraulic system and only uses a small action to operate the clutch.

If my memory serves me right, please correct, anyone, if I omit something.
A way round it is to remove the 'clutch relay shaft' (look this up on esm to view) and modify it. This means cutting and welding. The relay shaft has two 'prongs' on it. Basically, the one that connects directly to the foot pedal needs to be longer (it should be extended, so that it is approx. at the same level as the bottom of the chassis leg).

By making it longer the input effect of the pedal will be reduced and so, you'll get more 'feel' on the pedal and less 'on and off'.
'Mogwai' gave me this tip a few years ago and it worked perfectly.

Thanks for that- except that eery component that went in is the same as what came out. Before the engine R & R, the clutch actuation was smooth and easy. Now, it's on/off. It is a Midget clutch assembly, but something about taking it out and puting it back in has changed everything. I'm willing to give the relay shaft thing a try, though!

Has anyone got a photo of this clutch mechanism modification? Thanks!

Sounds horribly like you may have inadvertantly got oil on the clutch plate- this can make it very juddery/grabby

Well, anything is possible, I suppose, although I was very careful to avoid that. Thing is, the entire action is different: the pedal has very pronounced "throwover" point, and when I reinstalled the engine, I had to loosen the adjustment rod to the throwout arm quite a bit. The engagement of the clutch itself is not juddery, just, as I described it, "on/off", so it takes a fair amount of feathering to get it to engage smoothly. I can learn to live with it, just thought it very curious that removing and reinstalling the sae components should result in such a markedly different clutch feel. BTW, anyone got that pic of the "extension" yet?

Have not done the mod yet for my 1275 engine/clutch but I think Mike Perry has. It appears quite simple - you just weld an additional inch onto your existing clutch relay shatft on the leg that attaches to the clutch pedal and then re-drill the hole on the new piece of the shaft. Again, I have not installed this yet but a ball release bearing as opposed to the standard carbon one gives a better and more controlled release too.

Other things to think about might be whether the linkage needs greasing and whether the various bushes both copper and fibre are still in place, in good condition and lubricated. Also that the copper spigot bush is still in the end of the crank. Not sure that failure in any of these would account for the sudden change of clutch action but worth checking anyway all the same.

There is an alternative modification to the relay shaft mod above which was posted in an old copy of Minor matters and featured in the first generation of the technical manual - in the days when we drew things rather than photographed them! - have added this below but have no knowledge of which is better. If I now say discuss .... there will probably be loads of views posted [frame][/frame]

Thanks, Bruce. I hope people will weigh in on the relative merits of both approaches.I'm leaning toward the weld-a-bit on technique myself. Just seems like less work...wasn't there another trick which bypassed part of the relay shaft? Seems to me I read about it on this forum last year...

I found some of the earlier posts regarding the "extended" linkage modification. However, I'm stil unclear as to which of the arms on the relay shaft should be lengthened: the one that connects to the pedal, or the one that connects to the release arm? Any advice welcome!