Morris Minor Owners Club

Yes, its the worst I have seen for a long while, and I just cant get what happened, it really was all running so sweetly.

Thats the side that joins No3, the opposite side is also scuffed but nowhere near as bad. No3 on the side it joins to No4 is also showing signs.

All the oilways are crystal clear, all the rods are the right way round in the right order and everything was moving on rebuild. One at a time and test, on the basis of 'if it's tight it's not right'.

Looks to have been no awkward sideways loading on the shells, they and the crank all look fine.

The bore is not looking too well either, but they are at least liners.

Going to have to study it all in more detail to see if I can see whats gone wrong, it really does look like no oil.

Anyone used pistons from BM or ESM ?.

Looks like it could be due to local overheating especially as No 3 is showing signs as well. Is the water able to circulate around the two back bores OK, can this be checked when the liner is removed. The reason I mention it is I have seen the rear water ways blocked with silt in the past, damned hard stuff too and with a rebuild the engine would be running hotter than a worn one. Hope you suss the problem and get it running OK again.

do you know the history of the crank,I had the same (Exactly ) damage to one piston and marking to the adjacent side of the next one on an mgb and after having the crank checked at the engineers found it to be very slightly bent. Not enough to cause binding when I rebuilt it,well ,not enough to be noticeable . I discovered afterwards,from the previous owner that the engine had seized at some time and obviously damaged the shaft Could be worth you having it checked before refitting.

personally i think it's overheating problem and as said before scale and rust in the block , i have seen ford pinto engines do this with poor water circulation and it's always no 4

I hope the crank is true, it was re ground late last year prior to this rebuild and I would seriously hope that there has been no error in the grind, the place I had it done has been around for years and I have dealt with them for years.

I cleaned as much muck and crud out of the block as I could, I assume there is no actual water way between 4 & 3 as the join is the waist of a fig 8 if that makes sense. It was 100% not lack of oll, so that is ruled out, and I would go with over heating.

At least I had not broken a ring, just screwed it up someway else.

The rad is clear and clean, as I spent ages flushing that out, the stat is there and operating, but I do agree it looks over heated. The engine has done 650 miles since rebuild and I have only just started to open it up in bursts, running it carefully on the build up.

I don't want to just rebuild it without coming up with a reason, the damage is only the effect, there is a root cause somewhere. Perhaps I just didnt run it in long enough and it was too much for it too soon.

Whatever the block is heading off down the machine shop to have all 4 renewed, any good tips to clear the block of any muck other than the obvious. Need to borrow an endoscope from work to have a poke down there.

Endoscope is a good idea. I came across an Escort mk1 engine in the 90s that had been striped down for rebuild and when we looked in the casting the whole back part of the casting was gunged up so that the bottom half of number 3 cylinder was covered and no water could get to it. We tried scrapping with a long screwdriver but it was rock hard so ended up chipping it out with said screwdriver. Got most of it out but hard work. I think it must be caused by sediment collecting there as the water flow is at it's least at the back of the block. I wonder if some of the over heating probs we hear of can be attributed to this. I don't know if acid would shift it or not.

Well the water ways are clear, there is very little muck and gunge in there at all, stripped back to a bare block now, other than the obvious damage I'm taking a new engine apart. All the shells are fine, polishing evenly with no pronounced wear to the edge of the big end shells which would surely show if the piston was being pushed over against the wall.

I cant believe the crank is out of true along with anything else, but I will be checking it all.

I am wondering if the engine just wasn't ready for 65-70mph and it was too much right foot too soon. If the rings had not finished bedding with hot gas passing them would that screw it up. Next to nothing with blow by and no fumes out the oil filler when running hot.

Think its another careful rebuild and run in again for longer, was hoping to go the national in her next year but it may just be a bit much for a newly done engine if indeed too much foot has killed it.

How many miles had the rebuilt engine done before you ran the car at 65/70mph?
Did the bore have a good cross hatch on them when you rebuilt it? The cross hatching helps to retain oil on the bore wall whilst running in.
The old fashioned way of running the engine in for at least 500 miles still stands good for the Minor engine whether it be fitted with an 803cc, 948cc or 1275cc engine. The 'A Series is not a modern high specification engine so must be run in to get the long term benefit of an engine build.
I would not even consider running an 'A' Series engine at those sort of speeds unless it had done at least 500 miles or more.
Even my 1380cc comp engine was gently run in before it was used to its full potential.
Phil

Is the water pump ok ? And did you have the heater valve open ? I wouldn't say 'running in' is the root cause here -and yes even shells suggest the crank is fine. Was/is the piston free enough on the gudgeon pin -and check carefully the oil hole in the con rod..

i know this is a long shot but could the block have distorted when the liners were fitted or as a result of the heavy machining required to fit them , i don't know how thick the castings are from new and given age and natural internal corrosion could possibly lead to distortion , i would think the engineering shop could check the block with the liners out just to make sure

The engine had done around 580 miles, with careful running in, with running in oil there for 460 miles. We started off doodling around - 10mph in 1st, 20 in 2nd, 30 in 3rd and 40 in 4th. Gradually increasing and up and down through the box, varying the speeds, no labouring or lugging. At the time of failure it had done 619 miles, and this was after 3 miles at sustained speed, we hadnt been belting along for miles as she was not ready for that.

Ironically I said to the wife who was with me 'we'll go along the dual carridgeway so I can give her a short 6 mile run at some speed' as I believed her to be in fine order.

I put a good cross hatch on the bores, good sliding fit on the gudgeon pins and oil flow all good.

Water pump is fine, it had been put on new when I got the car. The rad is fine, allthough 30 yrs old I have no reason to suspect it, it had a complete flush and back flush, and I have a temp gauge as well (from a mini) that sits just under the N and allways has done.

I didnt have the heater valve open, it was a pleasantly warm day down here and no need for heat inside.

I can see straw colour on the rings radiating from where the damage is, so things have got pretty warm in there. I did find the engine to be running a little lean, but this was corrected before this happened, I have to wonder whether that has caused some harm, being the furthest most cylinders from the pump/rad and causing a hotter burn.

I have a horrible feeling it was down to me, I have just bought a new C class merc and the book says I even have to drive that carefully for a 1000 miles to get the best out of the engine as regards longevity.

I can't afford a merc but the bike I bought also needs 1000ml to run in, and i kept to it

The heater valve should NEVER be closed - to ensure good water circulation around the back of the block.....

what happens to the models with out a heater

They overheat and the pistons seize in the block........

Same thing happened to my morris eight at 700 miles after a rebuild. New pistons and crank regrind. this engine has no water pump and it was a stinking hot night 2 years ago. I pushed it just a little too hard and No 4 piston had a partial siezure. Luckily I eased off straight away and kept the engine running whilst cruising down the slip road into the car park. RAC home and strip down next day. All ok except the piston and only a faint mark on the bore. I tried for months to get 1 twenty thous o/s piston without success. I ended up using the top of one piston and the bottom of another machined and spigoted then screwed and rivetted togrther as the only spares I had in that size were low compression ones. I then ran it in for another 600 miles and it has been ok since.

Well by eliminating overheating ,the crank,the oil supply,and the rings,I would say that it may be due to the piston not being fitted correctly to the con rod,maybe it was slightly off line,but would have thought you would feel the tightness on reassembly .Whats the damage like to the front and rears of the piston skirt,is the damage only to the gudgeon pin side,is there any free play across the axis of the pin ,which would also the piston to slop about.

Perhaps the running -in was actually too gentle. None of my engines got that sort of namby pamby treatment - maybe 100 miles without too much strain - and then ......

I wasn't doodling around all the time, just for the 1st 100 or so and did it give it sme bursts of right foot thereafter.

Think this was a burst too much though and I have just been unlucky, everything fails for a reason and I will just have to be even more sure on the rebuild that everything is better than spot on.

There is damage on the opposing side of the piston, the damage is uniformly in line down the piston, sure if had have been skewed the damage would also be diagonally opposed. No slop on the pins, a good fit.

Is it wise to use the used shells or are new ones the right way to go, I have always been of the if you disturb it you change it ruling with them.

The block is off to be sorted next week while I get the parts in that are required.

If the shells are 'perfect' I would certainly use them. You will need to check the conrod is dead straight - it is the most likely explanation. It's not a 'running in' error - nor is it 'bad luck' - there will be a reason.