30 replies to this topic

[phildward]

That's good advice tiger99 and if I had bought the car recently that is exactly the approach I would take.

 

However I have owned the car from new and when it was last started, over 20 years ago, there were no issues with oil pressure. Its last journey was over 100 miles on the motorway flat out.  OK it's been dumped in the garden in the interim but it did have an oil change before being abandoned.  I can’t think of anything that may have changed mechanically????  

 

In theory it should be fine but it behaves very differently to cars I have driven and maintained in recent years.  Cranking with the plugs in appears painfully slow to me now.  But I have a memory that it did turn over slowly but fired quickly and then quickly establish pressure???

 

As things stand I plan to start the engine on Sunday and watch for a quick response from the oil pressure switch.  Could I have missed anything?

[Dusky]

Oil grade doesn't matter that much on cold cranking pressure wise, you have a bigger problem than just the wrong oil.

[phildward]

Oil grade doesn't matter that much on cold cranking pressure wise, you have a bigger problem than just the wrong oil.

 

Any suggestions?

[cal844]

Depending on who you believe, 20W40 may be correct for manual cars. If so, I have been wrong as I generally used 20W50. Did it do any harm? No way of knowing, but it may have hindered performance and fuel economy slightly.

I doubt that the gade of oil is the problem here. You really NEED a pressure gauge to tell you the whole truth alongside a switch which only tells you if the pressure is above 10psi, which is far too low if the engine is running.

You may not reach 10psi at cranking speed, plugs in. If you crank it well with the plugs out there will be sufficient oil in the bearings to put the plugs back in quickly, give it another quick crank and then briefly fire it up. If the gauge climbs immediately (1-2 seconds) relax. If not, switch it off and investigate.

Oils are designed to remain in the bearings for quite some time to allow engine start without damage.

However it would not be unreasonable for up-market cars to be fitted with an electric priming pump, although I suspect that none are, unlike trains and such like. You pay well over the odds for something big and flash and get the same cheap tat in the lubrication system as a bottom of the market Hyundai Getz....

As I say, unless it is an automatic mini use 20/50

As you Will wreck the gearbox bearings etc in 20/30 k miles

HOWEVER::

The op does need an oil pressure guage to confirm oil pressure(or lack of)

[gazza82]

If it's been sitting for 20 years I would think a few things may have got stuck or blocked, new oil or not. Not sure I'd simply try and start one that old without checking internally.

[phildward]

Just got back from the garage and discovered your responses thank you.  Now Im going to accussed of being wreckless but this is what happened.

 

I set up a funnel of petrol feeding the fuel pump (the tank is wrecked) I checked all electrical and fuel pipe connections, pulled out the choke and turned the key.  The orange light went out but no ignition.

 

Checked No1 cylinder and no smell of petrol, checked the float chamber, full of petrol.  Pulled the choke out further, turned the key and he fired instantly,  He ran very smoothly with the only noticeable issue being the dying screams of the water pump bearings.  I’m going to let it cool fully and try again while watching that oil pressure light.

 

I had the head off over Christmas and the oil ways were clean as far as I could see.  Yes the cooling system was badly gummed up but oil appeared fine.  I may have been lucky but I can’t see how a clean lubrication system can deteriorate significantly?

 

Back to the oil, I need to establish what Rover recommended for these cars because that is what it has had from new.  I believe the car was on a 12000 mile service interval but this was halved to 6000 miles.  The engine and gearbox are original and have clocked up 120,000 miles.  So whatever went in has been good for it.

 

That said I do like the idea of the 50 at high temperature protecting the gearbox bearings.

 

PS the exhaust didn't blow either :0)

Edited by phildward, 16 March 2017 - 05:29 PM.

[Spider]

 

Back to the oil, I need to establish what Rover recommended for these cars because that is what it has had from new. 

 

 

From the Rover factory Workshop Manual that covered cars from 78 to 92;-

 

 

The gearboxes and engines in these cars, despite what ever badge maybe on the front or back of the car, were pretty much internally the same from 1959 to 2000. From many of our collective long term experiences, most of us have found that for a Manual Gearboxed car, a 20W50 Oil is best for the life and function of them.

Edited by Moke Spider, 16 March 2017 - 08:30 PM.

[phildward]

Thanks Moke Spider that’s exactly the info I was looking for.  I can see that this car has been serviced from new with 10/40 oil.  That said and taking account of the advice being provided it will be serviced from this point onwards with 20/50.  The car is never going to be used in sub-zero temperatures and I like the idea of that extra protection for the gearbox at higher temperatures.

[Dusky]

Oil grade doesn't matter that much on cold cranking pressure wise, you have a bigger problem than just the wrong oil.

 
Any suggestions?

You could have a duff starter etc. All depends on the oil pressure once running hot. :)

[Cooperman]

Don't just use any 20w50 oil. For the Mini you need a mineral 20w50 with a high ZDDP level for the gearbox.

No-one has ever properly explained why the manufacturers changed their recommendation to 10w40 when nothing changed mechanically. 

 

It does seem very risky to run an engine with suspect oil pressure without an oil pressure gauge. The cost of a gauge kit is nothing when compared to having to have the crankshaft re-ground and the engine rebuilt.

[tiger99]

I think the mileages I got from standard 998s driven hard, ie thrashed, confirm that. About 120k for the engine and the gearbox reached 180k in the highest mileage car. I often wondered if 10W40 would have been better, but now I don't think so.

The earlier mention of a 12000 mile service interval was wrong, surely? How do you use a synthetic, which is not at all gearbox friendly?

In this case with 120k miles I would expect the engine to be worn out, which would explain the problem. It "may" only need new bearing shells but usually there is much more.

[phildward]

Cooperman and tiger99, some good points thank you; Ill try and cover them off in one post.

 

The oil grade decision was made back in 1985 using the very information posted above by Moke Spider.  Having had two previous Minis on both on a 6k mile service interval I was very sceptical about a 12k interval and a shift from 20/50 to 10/40 oil.  I compromised and fitted 10/40 on a 6k change interval. At the time (from distant memory) Rover sold three grades of Unipart oil, I think one was gold synthetic? but the others were mineral oil one labelled for new cars up to 60K miles; 10/40.  The third I think in a red tub was labelled for older cars and cars over 60k miles; 20/50. This car has only ever been fitted with that mid-range Unipart oil and never missed a 6K change.

 

I think the engine has lasted very well and sounds good despite running on its original timing chain and tensioner.  There’s no significant bore wear but I haven yet looked further at the cranks and cam etc; however they work and sound good.  I'm not able to drive the car so not able to comment on the box, however I recall it worked but the rod change was loose resulting in frequent seal changes.  All in all not bad for 120k on 10/40 and 20 years in the garden.

 

I accept the oil that is currently in there is wrong but I had loads in my garage for a Golf I own and just needed to know if I was wasting my time with this car.  I had reservations about the correct additives (concerns about bearing degradation), thanks for the reminder Cooperman, the correct oil and grade 20/50 will be fitted before this car is driven and probably before I run more tests.  I need to finish cleaning and repairing and then checking the cooling system and run the car up to full temperature, will check the oil pressure before but I don’t expect any issues.

 

Yes tigger99 this car has also only known two throttle settings, full on and full off.  My excuse was Minis thrive on hard work :0)

 

Now off to locate an oil pressure tester and some of that 20/50

[phildward]

Would this do the job?

 

http://www.ebay.co.u...WUAAOSw-vlViBJJ

 

Appears to have mainly metric adaptors but it does list 1/4 and 3/8 NPT?  If not any suggestions please.

[Danyul1275]

Would this do the job?

 

http://www.ebay.co.u...WUAAOSw-vlViBJJ

 

Appears to have mainly metric adaptors but it does list 1/4 and 3/8 NPT?  If not any suggestions please.

 

Something like this may be better for in the car, narrower range and still relatively cheap 

[mini13]

Just somthing to chuck in here regarding oil grades...

Since the a series was designed oil has come a long way, and will hold its grade a lot better, also, a thinner oil can get heat away from bearings quicker which is important at high rpms