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MG Midget and Sprite Technical - Oil consumption with Mobil 1

I know there have been some other (long!) threads about oil but I'm not sure that they answered my query. Apologies if I'm repeating previous discussion.

I 'ran in' my 1275 engine on Halfords Classic 20/50 and had no oil leaks and very little oil consumption. At around 1000 miles I changed to Mobil 1 ?/60 (I've forgotten the lower number - its the Extended Life version of Mob 1). Now I have lots of leaks and increased oil consumption. In a distance of around 300 miles the oil level went from 'max' to 'min' (not sure what that means in terms of volume of oil). I also gets puffs of oil smoke on start up and after idling for a few minutes. I would normally suspect worn valve guides for the latter but the head is newly rebuilt with new valve oil seals fitted. Recent compression tests (pre rolling road) have been excellent and there is no oil smoke even on full throttle (just done a track day at Silverstone with no obvious smoke).

So, my question is this - is Mobil 1 just too thin/slippery for a classic engine? Anyone else had the same experience?
Chris H (1970 Midget 1275)

I used to run Mobil 1 back in the mid 80's and through the 90's. I didn't have a problem with excess oil consumption or leaks. Maybe the current mobil 1 is "thinner" and that is causing the excess consumption. I can't quite remember what the spec of the oil was back then.

However, as regards leaks, where are the leaks from?

If it is from the rear oil scroll, then you have crankcase pressure. If it leaks from elsewhere, such as the sump semi circle corks, or the rocker cover gasket, etc, then you have gasket issues.
Lawrence Slater

Chris,
I sawpped back to Mobil 1 0w-40 (New Life?) on Sunday - I can't confirm the name as I left the bottle at my mate's by mistake (or he hid it!)

your probably using 10w-60 Extended Life

I used Mobil 1 (0-40 I think) in my my previous Spridget and other classics and 15w-50 Motorsport in the V8s

I done tens of thousands of miles on Mobil 1 in different classics without (noticeable at least) increased oil leaks or consumption

immediately I change the oil on Sunday things were better, oil pressure is very slightly higher, the tappets can be heard more which upsets some

the previous oil was Castrol XL 20w-50 put in Oct '11 only about 2,000 miles of use

I changed the (Castrol or Halfords) oil and filter and sump plug washer every 6 months

the 20/50 made starting very sluggish during this very cold weather

my car is a daily (though not used much last few years) and sits outside always

I was going to do a report on the Mobil 1 0w-40 later



in summary on your car check for leaks or the engine breathing is clear

I wish I'd switched back to Mobil 1 just after running the engine in instead of leaving it until now
Nigel Atkins

I use Mobil 1 15/50 (or 5/50 when I can get it) in my MED-built race engine, no leaks and minimal consumption.
David Smith

We found mobil 1 0-40 tended to give low oil pressure when very hot....warning buzzer/light on on race cars. The large volume oilways in oldie worldie engines tend to favour gloopy thicker oils. Easy turn over is a bonus as Nigel has said. The best oil we found was silkolene pro 4 15/50 semi....NLA :( held good oil pressure when hot, esp in minis with gearbox chopping up oil. The pro 4 had long chain polymers which suited A and B series. We now tend to use 15 or 20/50 semi synthetic when we can obtain it.We are beginning to get reports of folk with skew gear and follower wear maybe with less ZDDP in oil, we haven't found this as a problem on our race engine winter rebuilds as yet so cannot confirm. We now stock Chemodex ZDDP additive just in case.

Peter
Peter Burgess Tuning

David,
have you tried Opie oils, especially good value when they have the free delivery for over £40 orders - 15% off oils at the moment and they do a wide range of specialist and race oils - http://www.opieoils.co.uk/c-406-mobil-engine-oil.aspx

looks like Mobil 15w-50 has been replaced
Nigel Atkins

Hi Peter,
(I'm pleased with those leads)

my car keeps too cool rather than hot until you stop of course but I'll monitor the hot oil situation

by the present and previous oil gauge readings at least I've got loads of oil pressure so you can have some of mine if you need it

I must admit if they'd still done the 15w-50 I'd have tried that first

perhaps you'll get some engine rebuild work off me then :)

I might be contacting you soon anyway on another mate and need your rollers

cheers
Nigel Atkins

My guess is you glazed the cly.... You will need to rehone and install new rings

Thats the problem with these new oils they dont allow enough frition to allow the rings to bed in...theres just to much luberication and the rings are sliding on a bed of oil instead of metal to metal contact, almost as bad as treating a new engine very gentle and nice


Prop
and and the Blackhole Midget

Chris,

because of Prop's post I've just noticed you've put 1,000 miles run in personally I'd give it 5-6,000 miles run in on a road car (10-12,000 on a RV8)
Nigel Atkins

Chris I think I would simply change back to a cheap 20/50 oil and see if the problem goes away, if it doesn't then perhaps you have developed a problem that has coincided with you change of oil type.
Robert (Bob) Midget Turbo

That sounds most logical Mr midget Turbo sir :) Cheap is relative these days!

Peter
Peter Burgess Tuning

Apparently it's a myth that synthetic oils prevent rings bedding in. This is backed up by the use of synthetic oils in new cars, for years.
Lawrence Slater

Hi Lawrence the problem of arrested running in is due to the additives in oils as far as I am aware, not the base oil. It is difficult to find any oils without additives.

Peter
Peter Burgess Tuning

Hi Peter.
Does that apply to the likes of "classic" oils too then?
Lawrence Slater

smart used Mobil 1 in the (599 cc turbo) engines from new and I remember an article about a smart engine being stripped down at 120,000 (IIRC) and it was found that even at this mileage the wear difference was within the tolerance of a BMW engine leaving the production line

as for running in which I've done on a few new engines, rebuilt engines (and brakes and tyres) I particularly remember a Zetec engine that felt better at 3,000 and better still at 6,000 miles of real life use which was just as I traded the car in, then a reconditioned RV8 engine that seemed better after about 10,000 miles of various real life road use

these where just how it felt to me, no technical scientific testing equipment to back up my claims
Nigel Atkins

I'm going to get some of this stuff - put 1/2 in the engine and swallow the rest.
http://www.youtube.com/watch?v=tQ9-yx3NRV4&feature=related
F Pollock

Interesting that. How much of that vid is fake, who know's, and what's prolong?.

But Slick50 (ptfe in oil) works to some degree.

I know, I've read all the reports, but I've also used slick50 in my Sprite engine, and my Triumph and honda bike engines in the past, and it definitely made a difference to running temp and petrol consumption. Now there seems to be a concencus that the claims for slick50 are also bs.

Who else has used it here?

Lawrence Slater

if Prop see that stuff he'll coat his throat and eyes with it

Fergus'
don't drink it as if it works it'll cause embarrassing ‘body’ leakage worse that some of the fats already added to cheapen cheap foodstuffs that are already sneaked in by the manufacturers
Nigel Atkins

Chris,
I'll report on my Mobil 1 0w-40 oil consumption after my Bears weekend tour around some parts of Cumbria/N. Yorks at the end of this month

or that the engine has blown apart

I can't remember my previous Spridget using much oil but I don't know if it's engine blow apart as I sold it after a few years with 90,000 miles on and when I saw it at the NEC the next year I didn't look under the bonnet
Nigel Atkins

I used to use slick 50... Its a good product, but i found a better additive at 1/2 the cost

Lucas oil additive.... I use it in my trucks and will use it in the midget when its fully " broke " in

Had it not been for lucas oil additive... Id still use slick 50

Prop
and and the Blackhole Midget

Whats in lucas oil additive? Is it ptfe, same as slick 50?
Lawrence Slater

when its fully " broke " in

Petrol will be almost unobtainable and only for very special license holders.
Alex G Matla

I think Prop's it would be fair to say you've fully broken your engine in and out

I've used Slick-50 and always thought it did more good than harm
Nigel Atkins

It's not a myth that the use of synthetic oils prevent the piston rings in new engines of some cars from bedding in. A few years back a couple of leading manufacturers had a few problems that were directly attributable to synthetic oil on initial fill. I don't know how they overcome it apart from the obvious solution.

I think Mobil 1 in a 40 grade is on the thin side for an A-Series.
Daniel Thirteen-Twelve

it was too thin before but it might be now I'll keep checking

you must bear in mind I don't motor sport my car or engine strictly road use sometimes in a spirited manner

if during this type of use during a very long hot summer's day I see any kind of problem I'll just drop it out and use Mobil 1 10w-60 instead as I don't mind admitting my mistakes and even reporting them as I'm not that competive

if the 15w-50 had still been about I'd have tried that first
Nigel Atkins

another typo - first line should be
>>it wasn't too thin before (15+ years ago) but it might be now I'll keep checking<<
Nigel Atkins

I do mind admitting my mistakes but do admit them. And to prove it how else would I have come to the opinion that Mobil 1 in a 40 grade is on the thin side. First discovered at the traffic lights driving into Northampton where the right turn goes up the hill to the Hospital. Engine survived as did underpants.
Daniel Thirteen-Twelve

Daniel,
I wasn't getting at you

I know where you mean in N'pton so I wonder if it was after coming off the dualled A45 having giving the car some good lick for a good number of miles then taking the twists of and off the r/about then coming to a full stop at the lights that caused it in a modified engine

to the best of my memory, which is saying very little, I used standard Mobil 1, which I think was 0w-40 on my Spridget and B for many miles with no noticable extra oil loss or drop in pressure

but that Mobil 1 0w-40 of 15 or so years ago might be different or 'thicker' than the present one so I will monitor the situation carefully and the car will be fully road tested
Nigel Atkins

Well Daniel and Peter and others were quite right

and - I was wrong - to try

Mobil 1 0w-40 New Life seems too thin (for summer use at least)

exactly as Daniel had warned I got a dip in oil pressure on a hot day after a fast run and suddenly stopping on a steep slope

I've not noticed any consumption issues but have noticed my oil dropped on the ground even if it doesn't show on the dipstick

I used Mobil 1, up to 20 years ago, in my previous Spridget and thought it was 0w-40 but perhaps I remebered wrong about the numbers but certainly I used Mobil 1 15w-50 to very good effect

so as Chris H has reported increased consumption and leaks when using Mobil 1 10w-60 Extended Life that doesn't seem to be the answer

I'm going back to the now discontinued Mobil 1 15w-50 by buying some of the last stock whilst it's available

in summary I should have listen to Daniel, Peter and others but I thought it might only effect more powerful and tuned Spridgets than mine - and I've not noticed an increase in oil consumption but the leakage has slightly increased
Nigel Atkins

I've now refilled NOS discontinued Mobil 1 15W-50 Motorsport

as I had no problem with consumption of the 0W-40 New Life I don't expect it with the 15W-50 but I will report on this if I do

Lawrence will be pleased to know the 15W-50 is already over 4 years old (made 14/04/08) before it went in the engine
Nigel Atkins

This thread was discussed between 27/03/2012 and 07/06/2012

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