Hi Folks,

I have delivered the whole lot back to the machine shop.

We did all the measurements again. It looks like everithing is at or quite near the tolerances. There are no mark on the pistons, and the marks on the cylinder wall are only very-very light scrathes.

The chef at the workshop told me, that he would bet that the oil is coming in under pressure and not next to the rings. . Crack between the oil galery and the cylinder??? How??? The engine was sleeved? Maybe the oil is coming from under one of the sleeves?

After much lamenting they told me, that they have never sen such thing (in the recent 30 years), and cannot help.

Bang! 400kms driving for nothing...

Hear my bet for today: what if the rings are a bit tight in their gooves, and when hot, the oil controll ring (2nd ring) gets stucked. This causes the lines on the cylinder wall. As the compression ring is working (as it is of a harder material), the engine runs on, and does not blow the oil of the wall.

??? Maybe some ring polishing tomorrow?...

The clearance is 0.05mms now (just ok)

But there is sooo much oil... donnnnno...

What is the problem with the honing?

Maybe just the photo but the honing lines don't look even around the bore and the cross hatch pattern is not very clear, there are also lines vertically which I don't think should be there

Vertical lines ar very light scratches.

We have 2 alternatives for their origin: heat seizure (but the piston-cylinder wall clearance is ok) or oil controll ring loading spring (it is slightly biger then original.

From what you have just posted, yes check all your ring to grove clearances, this will not help if it is too tight on the groove the ring can not move and do its job. the clearances should be in teh Mini workshop manual from memory

Neil

I have polished the rings (thus took 0.02mms of them). Assembled the engine, and started. It smokes...

Nearly ran out of ideas.

One final thing I have obsereved: the cylinder head nuts were a bit funny to torque down. It felt a bit "spongy". After removing the head, there were "bumps" around the cylinder head threads on the block surface. The head was torqued down to the right amount.

This block was velded and thus heated up to 700 degrees. Is it possible that the cast iron softened a bit during the heat treatment?

Can the engine such oil in from the pushrod holes if not torqued down enough?

Any experiences like this?

f the studs have pulled at the block to leave raised sections, you may need to countersink the holes that the studs are mounted to. If this has raised enough, then you won't have correct pressure on the gasket and could result in the oil getting passed it and into the cylinders.

That would be my next step. Then see what happens.

I have done it with no success.

When I torque down the head, it just feels not "right". Feel something like something is streching. I can reach the requested amount, but... well...

Have You got experiences, how much oil can get in the engine through the gasket leak?

This does sound possible, and if the threads have deformed the block and now the cylinder head is not sitting correctly all sorts of problems will raise, Are you sure your torque wrench is OK and a what are you torque value are you using,

I have seen people use torque wrenchs wrong and wonder why they have problems,. I am sure you know how to use yours, I recently stopped using one of my torque wrenches as i was not happy with the way it felt it seemed inconsistant, so i have replaced it.

Neil

Thats a poit I am usure of. I will test it and compare it with a frieds wrench.

It can be out od measurement.

First time I have torqued it down to 70 Nm. Second time to 60 only as i have seen the problem. Nothing cahnged.

I have sanded out the bumps naturaly before fitting the head, although it could deform again.

I have sent my cylinder head bolts to the lathe and have some more thread cut on them. If it fails I will drill out the holes and have special bolts manufactured to 11mms thick and fit them. They must be enough to hold tight.

This is worth reading. The studs are also good.



Mini Spares C-AHT280 COMPETITION HEAD STUD, NUT & WASHER KIT

Fitting instructions

Performance orientated engines, particularly those utilising large over-bore sizes (i.e. 73.5mm), can suffer from premature head gasket failures because of the inadequate quality and performance from the standard head studs. Mini Spares has therefore produced a replacement kit to eliminate these problems.

The mass-produced standard head studs/nuts suffer from compromised specification - both in material and machining quality. Worst affected are the threaded portions, giving rise to inaccurate torque-down; thread deformation, stud distortion and stretch, off-square seating of the nut to head and so on.

Specific and tightly controlled design, machining, materials and manufacturing processes have been stipulated by Mini Spares to ensure a truly high standard finished product. This optimises even and accurate torque-down, eliminates stud distortion and minimises thread deformation. A bonus is prolonged usage. The use of special washers greatly improves even clampdown; the extra thickness used helps avoid thread bottoming when using seriously skimmed heads.

A far superior clampdown is attained from the strength and accuracy of design and manufacture. Consequently excessively high torque settings are not required. Although possible to torque these studs to 70lb ft, this will cause the threads to pull out of the block or severe distortion and deformation of current head gaskets to render this practice pointless. Where Genuine Rover or Payen head gaskets are used a torque setting of no more than 45lb ft is highly recommended to avoid distortion of the fire-ring. The non-stretch feature of these studs combined with this lower torque setting has proven totally reliable in all properly built engines.

Fitting notes:
- wash the studs and nuts thoroughly to ensure no swarf or dirt is in the threads
- Fit studs into block dry, finger tight only
- Oil thread very lightly before fitting nuts
- Smear oil on base of nuts
- Fit washers with large countersink to head, and on short studs only. The two smaller washers go on the studs either end of the rocker cover
- Replace nuts after 4 or 5 uses to retain accurate torque-down (part no. 51K1193).


If you over torque the head nuts it is easy to pull them out of the block or stretch them.

70Nm equals to 51.6Lb ft. I dont think it is overtorqued. I always use this on my engines and never gave me a problem. Although I must check my torque wrench as it may foul me badly...

I'm by no means an engine guru, but here's my take on this:

If all bores are full of oil, it's not a cracked head or block.

Do you have sufficient crank case breathers? Are they clear? Do they return to the inlet? Are they "breathing" a lot?

Are you getting oil pressure in a sensible range?

What condition are your valve guides in?

What oil are you using?

Have you got the correct oil dipstick?

I assume there's no water in your oil?

I'm very doubtfull that it'd be caused by headgasket/torque settings unless block or head has been skimmed out of true. Other problems would show up at the same time.

Then it's only pistons/rings/bores left.

Thanks Pantera for Your attention!

1. I have a crancase vent on the clutch housing, and one on the valve cover. I have some gas at the clutch side, but not much. The gas looks clear. Nothing on the valve cover. All holes are clean.

2. oil pressure perfect hot and cold, idle and reved.

3. Valve guides all new (AE), the head casting is also new old stock .

4. I have tried 2 tpes of 20/50 and two types of 15W40 - no difference. All mineral.

5. Dipstick looks correct. I have filler the engine up approx. 4.5literes each time.

6. No oil in water and no water in oil.

I have blocked the oil at the rollers base, thus left the head running dry. It gave no difference.