Back to the Engine rebuild ...

[JustinMinor1000]

Fed up with Moggie interiors .. Going back to the engine ...

Father in law came round .. Admired the bits .. Informs me that he made the bearings (he worked for a bearing manufacturer in Maidenhead before he retired) .. He thinks the engine is fine ...

I'd kind of thought that that would be the case ...

I've changed what I want to do with my cars. I'm going to keep the green monster (POD) for three years and then get a traveller (the children will then be able to climb in on their own so a four door will no longer be required). Pod will get a new interior but it may not be green, she will also get a respray but it may not be perfect (but will be green).

So this rebuilt engine needs to last for 30-40,000 miles (but probably will last alot longer than that).

For this reason after inspection I've taken the in laws advice and decided not to have a rebore and oversize pistons. I've checked everything else and the Crankshaft is still within the spec laid out by the workshop manual and there is no ovaling on the bores ..

So ...

I've ordered a new ...

Oil Pump
Main Bearings
Big end bearings
Gasket Kit
Tab washers
Piston rings

Can anyone think of anything else I should change ?

[bmcecosse]

Well worth doing over the head - or getting a better one ! Timing chain is better if changed to the later Mini type with proper tensioner. Also consider a screw-on oil filter also from a Mini.
Vandervell were in maidenhead - sponsors of the original 'Thin Wall Special' as driven by Stirling Moss. They were bought over by Glacier in Kilmarnock (I used to work there) - and the business was brought up to Bathgate. Original plan was to combine the two in new factory - but Kilmarnock had huge investment in Al/Sn bearing line which would never be economic to relocate - so it still exists !!

[JustinMinor1000]

Well worth doing over the head - or getting a better one ! Timing chain is better if changed to the later Mini type with proper tensioner. Also consider a screw-on oil filter also from a Mini.
Vandervell were in maidenhead - sponsors of the original 'Thin Wall Special' as driven by Stirling Moss. They were bought over by Glacier in Kilmarnock (I used to work there) - and the business was brought up to Bathgate. Original plan was to combine the two in new factory - but Kilmarnock had huge investment in Al/Sn bearing line which would never be economic to relocate - so it still exists !!

Vandervell was the name I was looking for:)

What do you think think I should do to the head ? Just reseat the valves or something more severe ?

Should I change the core plugs ? How do you change them ?

[rayofleamington]

Should I change the core plugs ? How do you change them ?

only if they leak, or if they look like the steel is heavily corroded.
To replace you drill a hole in them to screwdriver them out, then clean the seat carefully and put the new one in. Then hammer the centre dome to spread it to make a tight fit.

What do you think think I should do to the head ? Just reseat the valves or something more severe ?

Well if you're going to do 40,000 miles and then get a traveller it will be worth to get an exchange unleaded head. You can then transfer the head to the traveller and use it some more ;-)

So you have lots of choices. You can save a days work and leave the head alone - then run it until a valve burns or until you get smoke from worn valve guides, then exchange it.
Or exchange it now and not have to worry about burning valves.

Or reseat the valves... once upon a time when people did regularly maintain cars the guestimate was about 8 hours to decoke and reseat the valves. When they are heavily pitted it takes a long time with coarse paste to grind the pits out. If you have to grind them in a long way then the seat shape can become a bit modified, which doesn't make noticeable difference on a standard Minor but would be sacrilidge on a tuned engine.
A lot of places these days will just machine cut the seat and fit a new valve to reduce the man hours.
Manualy reseating the valves using a grinding stick and paste... It's a very rewarding although time consuming job. Then the next day your hands still hurt more than you'd expect

If you've reseated the valves you'd probably be more inclined to protect them, but using an additive over ~40,000 miles compared to the £price of an exchange head is a pretty close call.

[brixtonmorris]

I've checked everything else and the Crankshaft is still within the spec laid out by the workshop manual and there is no ovaling on the bores ..

How did you check these?

how about honing for your new rings, and crank thrust washers. and spigot bush in the back of the crank.

[bmcecosse]

Can't remember now - is this a 1275 engine ? If so - very often unleaded heads on ebay for only £15/20 - an economic solution ! They can of course be fitted to small bore engines too - but unless you are seeking performance this is not really for a high mileage daily runner.

[JustinMinor1000]

I've checked everything else and the Crankshaft is still within the spec laid out by the workshop manual and there is no ovaling on the bores ..

How did you check these?

how about honing for your new rings, and crank thrust washers. and spigot bush in the back of the crank.

Digital Vernier Guage ..

I've ordered the thrust washers (I thought they would be with the Main bearings)

Spigot bush ? Now I'm lost ..

[rayofleamington]

Spigot bush ? Now I'm lost ..

The gearbox input shaft fits in a hole up the end iof the crank. It hould be a snug fit in this baring but if the bearing gets worn, the shaft can runout causing increased wear in the box. If the bush is badly worn or not there at all it can allow the clutch disk to sit off centre causing nasty vibrations.

[bmcecosse]

You really need a proper micrometer to check crank bearings. However - if they are not scored - nice shiney finish - you have a good chance of success. Any scoring, forget it.

[Onne]

I have always said shiney is good!

[brixtonmorris]

http://www.justtools.com.au/prod2052.htm

these are required to measure the bores. vernier calipers can only measure the top diameter of the clyinder, where there is no wear. most of the wear will take place along the lenght of the bore.

[rayofleamington]

I've never got as far as measuring the bores (although yes - the bore gauges ar ethe right tool for the job).
I always figured that if the bores are worn, you will see a wear ridge.
When they are heavily worn you can see the ovality as the wear ridge is much deeper cross-axial to the crank and much smaller inline with the crank.

Would there be much chance that the bore would be worn or oval if there were no wear ridges at the top?

[bmcecosse]

No - even then I have rubbed away the ridge (or at least reduced it) in the past and made up perfectly good engine without re-boring. Most of the problems come from stuck rings - which can then break and damage the lands of the pistons. Nice springy rings, free to move in the lands - but not too loose - and the engine will be fine for 'normal' use.

[eastona]

crank bearings are toleranced to a tenth of a thou (0.0001") generally, so a proper micrometer is required, a vernier is usually not accurate enough.

bores require an internal micrometer, usually quite expensive, and not as ubiquitous. Although measuring the gap in a piston ring can usually reveal way, it is harder to detect ovality like this,

"Shiny is good" is not a bad rule of crankpin thumb

Andrew

[brixtonmorris]

if you compare the surface finish on the on the crank. look at the differance between the finish where the bearing (lets say) makes contact with the crank and the centre part, where the oil is fed to the bearing. on this part, there is no contact with the bearing, as it is an oil way. the surface finish here will be as from the grinding machine, and to either side, will be the wear. any difference in these 2 surface finishes indicate some amount of wear on the crank. a step means a regrind.