Grease, oil, studs, gaskets

[Theo_NL]

Reassembling my engine again, any advise on:
- Grease of studs, bolts, nuts
- Paper gaskets for waterpump, thermostat housing
- O-ring, paper gaskets oil filter housing, oil pump
- Paper gasket, cork sealing for sump

Thanks

[mike.perry]

A drop of oil on the studs so the nuts run freely
All the gaskets should be in the head or sump gasket set

[philthehill]

DO NOT put oil or grease on nuts/bolts that require a torque setting as it will allow you to tighten up the nuts/bolts tighter than they should be.
Yes grease on all gaskets.

[Theo_NL]

I have read different opinions about the grease on bolt or nuts and the right torque.

With the high torques I guess there is no grease anymore on the surface that is in contact with the other part. And the frictional resistance of a 'clean' surface can vary a lot. Applying a torque in such a case is not reliable either.

[philthehill]

The grease will be carried down the thread no matter how high the torque.
Whilst it is up to you whether you oil or grease torqued threads there is a possibility that over tightening the cylinder head studs will cause them to pull up out of the block causing problems with seating the gaskets.
The stud holes in the block should be relieved as per attached diagram before assy.
The Minor was designed to have the threads torqued up dry.
There is no reference in the BMC wksp manual (section AA10) or any other wksp manual I have that specifically refers to oiling/greasing the cylinder head stds/nuts or any other torqued nuts/bolts.[frame][/frame]

Looking at the attached charts you will see that a dry 3/8" UNC bolt/stud will reach its correct torque setting before a lubricated 3/8" UNC bolt/stud. All that will happen is that the lubricated stud will start to pull up out of the block as well as being stretched. Also with old studs there is the possibility that you will snap the stud as they stretch.
The better studs to use are the ones with either the 'P' or dimple on their top end. In conjunction with the flanged cyl head nut you can set the cyl head torque to 50lbft

http://www.repairengineering.com/bolt-torque-chart.html

http://www.wellheadservices.net/techdoc ... _Studs.pdf

[Theo_NL]

Hi Phil, thanks for the data.

Assembling the crankshaft and con rods, the manual advises to use plenty of oil on the bearings. Keeping the threaded holes clean is impossible . You mentioned the Minor engine data are related to 'dry' assembly. Should I correct (reduce) the torques of the bolts for the main bearings and big end bearings with 10-15%?

Similar problem for the nuts to tighten the head: one side (under the cover) is greasy, the other side pretty dry. How should i proceed?

[Theo_NL]

The better studs to use are the ones with either the 'P' or dimple on their top end.

BTW someone mad a nice mixture: the large studs: 3 with a dimple, one without.
The small ones are all without.
I assume I do not have to replace as long as I use the standard nuts and keep the torque within the standard?

[philthehill]

When assembling the engine - oil only the bearings contact faces or better still use a engine assy lubricant such as TORCO MPZ especially if the engine is going to be stood for some time before being used. I am a firm believer in the use of a engine assy lube and would not build an engine without using it.
When put together and torqued up then plaster all with oil. The engine assy lub does not drain from the bearings as oil would do so you do not get that initial scuffing of the bearing on initial start up. Also fill your oil filter with oil - refit and with the plugs removed turn the engine over on the starter until the oil light goes out plus 30 secs. Better to get the oil around the engine before starting and running.
The big end and main bolts will be alright as they are of a better quality than the cylinder head studs but you may want to remove them and de-grease and refit to the correct torque. Personally I would do just that.
It is important that the cylinder head studs are not over torqued because you may cause the problems outlined above.
If you have already fitted the head and used a new head gasket DO NOT undo/slacken the cylinder head nuts as that may cause the gasket to fail. Better to leave as is and re-torque after the first heat cycle.
If you have not fitted the head or fitted but not torqued down the head I would remove the nuts clean/de-grease the stud/nut threads and set to the correct torque.
It does not matter what mixture of cylinder head studs/nuts you use so long as they are all done up in the right sequence and to the same torque.

[bmcecosse]

I have stripped down engines that have 'stood' -and always found plenty of oil on the shells... This 'assembly lube' is just a gimmick..in my view. And I was always taught that nuts/bolts/studs should be lubricated on assembly - dry assembly will always a variable thing. But each to their own! Lightly oiled has never let me down....

[philthehill]

Whilst I have nothing against the lubrication of torqued threads per sae the torque setting must be adjusted to suit the lubricant used.
I always use ARP bolts/studs/nuts and washers for the head/rods and flywheel etc. when building 'A' Series engines; and they do recommend using a lubricant but most importantly they do specify a torque settings for use with specific lubricants.
If you use a lubricant on a thread without adjusting the torque setting you can get to the yield point earlier and as I pointed out above if you use a lubricant on an old Minor head stud you are more likely to stretch or even snap the stud.
I do use oil and grease on bolts/nuts that are mechanically locked i.e. by the use of spring washers/shake-proof washers but unless there is a specific torque setting quoted for oiled threads I would always torque the threads dry.
As regards engine assy lube it is one gimmick I would not do without.
But as with everything it is all down to personal taste but my engines are expensive to build and as a well known supermarket says "every little helps".

[bmcecosse]

Indeed - each to their own. I've never snapped or pulled a head stud - and for many many years I had no access to a torque wrench - so simply pulled them till I felt the 'yield', But always just using either a normal ring key - or a socket with ratchet bar. Never a long bar...

[smithskids]

I think you will find the cylinder head studs are 3/8 unf at the nut end and 3/8 unc at the block end, careful with the torque wrench!! as bmc said use the correct length spanner and you can feel when its tight enough. It is good practice to countersink
the stud hole slightly to stop the top thread pulling up and damaging the gasket.

[Theo_NL]

OK, thanks for the help.