MG-Cars.net

Welcome to our resource for MG Car Information.

Recommendations

Parts

MG parts spares and accessories are available for MG T Series (TA, MG TB, MG TC, MG TD, MG TF), Magnette, MGA, Twin cam, MGB, MGBGT, MGC, MGC GT, MG Midget, Sprite and other MG models from British car spares company LBCarCo.

MG MGB GT V8 Factory Originals Technical - oil and oil pressure

A conundrum!
Since building this Rover 3.9 V8 five years ago, I have been using Morris' 20w 50 Golden Film Classic oil. It has a decent ZDDP package.
Whilst these engines do not work high pressures, even with the deeper pump gears I installed, it would hot idle at 15psi, with 40psi at higher engine speeds on a hot day.
I recently did an oil change and used, the same Mann filter and, on a recommendation, Valvolene VR1, (better Zinc package), resulting in an immediate drop in oil pressure of 10psi across the board. Coolant temp, according to my infra red thermometer, was normal.
I checked with the supplier, Opie Oils, and they compared the actual oil specs for me. Surprisingly the Morris oil was at the bottom end of a 50 rating, i.e., in the 40's whilst the VR1 was over 50.
To me this seemed counter intuitive, more viscosity leading to less pressure. Opie suggested I measure oil temperature, on the grounds the VR1 was running hotter for some reason. Not done that yet, but I started thinking it through in my amateurish way.
Could it be that retaining a higher viscosity at high temperatures means the oil is not circulating fast enough? Particularly through the cooler!
Still working at that, but an obvious step is to return to using the Morris oil and see or even put a 10w 40 in!
Any theories?
Allan Reeling

Allan,
my (totally non-expert, in anything) thoughts for the very little they are probably not worth.-

Have you got a thermostat on your oil cooler to prevent over/unecessarly cooling.

Then how accurate are your gauges.

Are you fully warming the engine on your runs.

(Possibly generally as a batch for the oil, perhaps from a smaller blender) for spec bottom end of the 50 would still be 50 from new but with wear could go into 40s. VR1 rated at 50 should be in the 50 band but it might be top end when new.

Dating rivals - someone who is 49 might (correctly) say they are "in their 40s" and go on to (correctly) described their rival as being "in their 50s" which might give the impression they are years apart in age when the rival is only 2 years older at 51.

ZDDP is only one part of an additive package and possibly not the best or most effective part of the additive package (marketing to fashions sells) - what was the correct number of ZDDPs and how many ZDDPs went in what oils and when and with what else.

Different oils can give different results with neither being wrong (or even possibly neither being spot on or right!).

Don't get too hung up on exact numbers on cans and gauges.

And your 10w 40 might be 19w 49 or 11w 41 - it won't but you get what I meant.

They stopped putting true and accurate gauges in general road cars to stop these anxieties.

I know a Rover with a TVR (Rover/Buick) Chim 3.9 engine that showed just about 10 at tickover and around 40 running, it proved the needle on the gauge was registering and as long as it continued to show something like these numbers then that was normal running for engine to gauge. Gawd knows what figures would be on the TVR gauge (if it worked!).

Finally, if you feel up to it you could leave the last millenium and get an oil from this century.

https://www.kewengineering.co.uk/Auto_oils/index.htm



Nigel Atkins

Thanks Nigel, all interesting stuff.
I'm not particularly anxious, but the conundrum just interests me. i.e., more viscous oil, lower pressure?
No to the oil stat, but have been checking the sump temperature after a decent run.........70c. Which is just about rad temp. But one has to assume hotter, which the oil can easily deal with of course, would mean less viscosity and less pressure?.
Today (Saturday) was a warm day, 20psi at 40/50mph, barely 5 at idle when the oil was up to temp.
Before I start looking at the PRV i've got an external pressure gauge which I will connect and see what that reads at high temp.
It could be gauge of course, Sods Law, it goes south by coincidence! Similar for the PRV!
Interestingly MG/LR specify 10W 40, semi synthetic(21st Century!) for the RV8.
Also interestingly the racers, using older flat top tappet engines, tend to favour the high zinc oils, hence VR1 racing oil which has upwards of 1400ppm. Morris' is rated at 800ppm..Question; does zinc content affect viscosity???
Not a clue and way beyond my knowledge level!!!
Allan Reeling

Allan,
I really don't know anymore than I've read, and most of that I've forgotten or it's confused me.

Thoughts I have hare are -
it seems to me that motor manufacturers change their minds about which makes and weights of oil they recommend over the years to suit their tie-ins with the oil company at the time and to cover their range of vehicles. With BL the A-series is basically 20w-50 until it suddenly later becomes 10w-40, I'd suggest that perhaps the manufacture of the engines hadn't improved, might have changed or even worn so why the change in grade.

Personally I don't like oil coolers and can't see how they wouldn't at least initially overcool without a stat to prevent the flow to them, same as the 'water' stat.

If you measure oil sump at 70c what makes you think that isn't correct - infa-red guns may not give accurate reading because of (a word I can't remember).

As with all gauges (assuming the're accurate) and as with the temperature reading, it depends on where (location) you are taking the reading from.

An oil doesn't know it's a 20w-50, it's a 50 when in the temperature range for a 50 in whatever location it happens to be in.

Your pressure figures sound low for today but how sensitive and accurate is your gauge, 40-50mph would be low revs too, what is it at 2,500-3,000rpm.

Now without going into what is a synthetic oil, semi and fully can be marketing terms, a good oil is a good oil regardless of its title as mineral, semi- or full.

People who race old cars tend to be very conservative in their views and beliefs as regards the vehicles, if the competitors are using it and winning then it must be better (not better mechanics, drivers and knowledge) - plus you're not racing your car.

1400ppm is 1400 parts per million which is 0.14%, this is a high figure as far as I have seen, but in itself means nothing other than it has more ZDDPs than most/any other oils(?).

And is there too much ZDDP, what number is that (probably well above 1400ppm?)?

800ppm is 800 parts per million which is 0.08%, this is quite low in the bragging league of "high ZDDP" oils that I've seen, it does not necessarily make it worse, same or better as a single additive in a package to any particular oil.

ZDDP in an additive package is not necessarily a bad thing and maybe a very good or essential item depending on the additive package and application of the oil.

I might have a false memory but I think I saw in the 60s oils had 600? ZDDPs, perhaps it was 900 ZDDPs allowing for my bad memory and eyes but 900 in what mixture of what additives. But did they put the correct number of ZDDPs in then anyway, would they have known. Just about most people would say that the good oils today are superior to the same good oils of the 60s.

Currently high ZDDPs numbers for classics are fashionable, perhaps in 10 years time that might change or just increase the value and selling price as oils change again.

My conclusion is that people, including me, have their own oil beliefs but unless we can do metal and oil analysis we'd never be sure of what is best or correct and then it'd be a matter of degrees as we've got old cars running on the roads and not ultra-sophisticated engineering carrying out strenuous work.

You could look it up just as easily as me and I don't have a clue or the knowledge but I feel that the levels at least of ZDDPs might not make much difference to the viscosity as that is about the general makeup and grade of oil.

Many years ago I used to use Mobil 1 15w-50 in my V8s and A-series, despite being told it would ruin my engines, usually by those that rarely put any miles on theirs, yet I put on many tens of thousands of miles without any seeming damage. Unfortunately Mobil no longer do that grade, and you have to decide how much of the price you pay towards marketing, but then smaller companies will keep the price for higher profits.

I use an over-priced classic motorsport oil in my road going fairly standard midget engine just as a belt, braces, bit of string and piece of chewing gum reassurance but on looking up what Millers recommends for a TVR Griff (RV8 4.0 or 4.3), and they can get very hot, it has XF Longlife 5w 50 so there you go no hard and fast rules.

Halfords Classic (which is Comma) 20w-50 (as I think is Wilkos but I'm not sure) is favoured by many classic 20w-50 users as is Castrol XL - these three may give you higher pressure numbers.
Nigel Atkins

Nigel,
Like you I have all sorts of vaguely remembered information read many years ago.
As for the vehicle manufacturers changing their specifications. I seem to remember LR lowering their Winter viscosity to 10 to help with cold cranking when they raised the V8 capacity!
I know where you are coming from on the oil "fashion" issue. I probably succummed to a bit of that with my selection of VR1.
Oil temp at 70c??? Probably about half of what the oil can cope with, but too low? Wouldn't know.
Allan Reeling

Allan,
unfortunately my vagueness comes from what I've also read recently and stuff I've read more than once. :)

I was thinking of where the oil was measured at 70c, the bottom of the sump, up from the bottom, elsewhere, as the sump is usually cooled from air going under the car - but it doesn't really matter as I've never really pinned down (or forgot) what temperatures which engines are 'said' to run best at.

IIRC Minis with standard A-series engines, are said, should be at 90c but where is that figure measured at. My wife's car was showing 95c yesterday when it was quite cool weather and the car wasn't being driven hard.

I forget the figures now but the oil wants to be at a certain temp to reduce wearing effects on the engine and not above another for it to work properly.

The low figures are more likely to effect us unless we're taking our cars on a long track blast or the engine overheats. For both reasons I prefer an oil that copes well at both ends of the temp range, plus I use my Midget in the winter and it always sits outside.

I did notice one very cold winter period the engine was slower to start when using (can't remember which) Halfords or Castrol 20w-50 which reminded me that it was time to treat the engine to better oil as it was well and truly run-in by mileage and use.

Recently I was surprised to find a patriotic E-type owner was using VR1 instead of a local oil blender but he said the engine builder had recommended it. I think he wanted a "classic" oil too and I didn't like to mention VR1 is to a 2004 specification.

I was suggesting Millers Classic Sport 20w50, though I use Classic Sport High Performance in my road going Midget.

If you look up various cars that used the Rover V8 engines on Millers site it suggest a various range and grades of their oils for the different models which will be based on the car manufactures recommendations, for instance the TVR Chim 4.0 (3.9 engine) has XF Longlife 5w50 but for the MG RV8 it lists Trident 5w40, 5w30, 10w40 and EE10w40.

VR1 PI sheet - https://sharena21.springcm.com/Public/Document/18452/18bdee61-0a7e-e711-9c10-ac162d889bd3/a61538b4-0cbd-e711-9c12-ac162d889bd1

Millers Classic Sport 20w50 - https://www.millersoils-shop.co.uk/classic-sport-20w50-engine-oil

Millers Classic Sport High Performance 20w50 - https://www.millersoils-shop.co.uk/classic-sport-high-performance-20w50-engine-oil

Millers XF Longlife 5w50 - https://www.millersoils-shop.co.uk/xf-longlife-5w50-engine-oil
Nigel Atkins

Allan,
I've just remembered what I meant to put before (drip memory) - how did you know that the oil was up to temperature do you have an oil temperature gauge in your car (if so where does it read from)?

I had a temp gauge in a couple of my RV8 engined cars and I wished I hadn't particularly in winter as they could show so low, at the start at least, I gave up looking at them so don't know (or can't remember) the temps when the engine was fully warmed or in hot weather when fibreglass cars, even roofless (and doorless) with RV8s could get very warm in the cabin let alone engine bay.

My mate has a temp gauge in his A-series Spridget and it seemed to rise with the oil pressure gauge and showing what seemed to me to be high figures but my mate said it was fine so again I stopped looking. A lot of gauges relate more to track than road use, starting with rev counters and oil pressure gauges in our cars I'd guess.

Oh, sorry, but synthetic and semi-synthetic motor oils were about in the 1960s so the oil MG/LR specify could still be from the last millennium. :)

I know the oil for the LT77 and R380 changed over the years as we went through it on a RV8 forum thread.
Nigel Atkins

No Nigel, no oil temp gauge, just working on the fact that oil takes longer to reach operating temp than the coolant, plus after 10 -15 miles on the back roads of Shropshire it's going to be as hot as it's going to get, and firing the infra read at the sump and cooler!!
You throw up another conundrum, namely "particularly in winter as they could show so low, at the start at least". but that depends on the W grade of the oil I suppose. On a cold day my pressure is up!!
Hell you're treading on dangerous ground, talking about GEARBOX OILS!!!
Thanks for the oil links, made very interesting reading!
Allan Reeling

Allan,
as I'm the only one responding here I think you might be better posting this on the MGB forum to get more views, opinions and better still more knowledge.

This time of year you should be able to get the oil up to temperature certainly quicker than in cold winter. When I used my B converted V8 in cold winter for a 300 mile a week commute because I disconnected and partly removed the choke on the oversized Holley carb it was difficult to warm the engine without giving it some beans which I had to be cautious when I did this as parts of the road could have black-ice. Until then the engine would remain cold for a very long time and I could almost get to work without it fully warming if I was unable to open it up a bit.

Something to remember about the 10w-40 or 20w-50 numbers is, and please forgive the non-technical description, different oils have different "thickness" and "slippiness" because of their construction and additives, possibly the more synthetic it is and/or its additive package, the thinner it is so a particular bog-standard mineral 10w40 might be as around as "thin" as a particular real full synthetic 20w-50. Hope that makes sense.
Nigel Atkins

Allan,
sorry another thought - have you tried checking the electric sender is working correctly, correct resistance, and is a match to the gauge.

Also of course that all connections and wires are clean, secure and protected - just taking spade connectors off and on a few times can help to clean the connect but if it does a better clean and protect might help even more.

I always found the RV8s appreciated a (thorough) oil and filter change and a change of paper air filters (or perhaps clean if you have other types).

I think the (normal) low oil pressure encouraged me to use good quality oil and timely changes.
Nigel Atkins

Nigel,
Yes looks like just me and thee!! I got little response from the MG Experience site too.
To answer;
Mechanical oil pressure as Factory V8s and all all pre R/B B's.
And yes it does make, sort of, sense. The lubricating properties of oils is all about internal "slippage" . As far as I can understand all oils start from a "basic" stock, usually about SEA 20 and the additives produce the multigrades, hence the variations in grades. So a 20w50 could actually be 20w48 or 20w52!! Depending on the chemistry involved in getter there..................., and the chemist I suppose!
From what i have researched I have reached no conclusion as to why the oil pressure dropped after changing the oil. I'm left to conclude a "sods law" coincidence issue with either gauge or PRV!!
Allan Reeling

Allan,
what about asking on the MGB Technical instead of here.

When I put -
>>as "thin" as a particular real [full] synthetic 20w-50<<

I meant -
as "thin" as a particular real [fully synthetic] 20w-50.

In case my thickness confused my description of the er, oils' thickness.

I've not seen, or can remember probably, that the vase oil starts at about SAE 20 but AFAIK you've got the bit about multigrades.

Mechanical dials must sometimes go wrong or be inaccurate I'd guess I do remember reading they could hit a patch of flutatining and something was added to prevent this but it didn't.

Could you disconnect the gauge supply pipe and check with a thin wire there's no partial blockage (assuming the supply pipe is normally just an empty pipe).

Or could you remove the PRV and check it (and clean it? would it need cleaning?, clean and reoil couldn't hurt surely?). I know springs and balls are often mention on the B-series.

How about a real good blow-out run, hold the gears to get the revs and sustained (legal) high-speed over a good distance, amazing what an Italian tune-up can resolve, and if not it does the engine good anyway to have an occasional stretch.

Having a scale of 0-100 on the gauge would possibly make the reading and calibration a little more tricky too I'd have thought, but don't know.

I can't remember what the gauge was on the Rover but I think 5-10psi at tickover and if I recall about 10psi per 1000 revs was the oft mentioned figure. I know recently I saw MGB V8 was 42psi in the book, you'd need good eyes and be able to register the info quickly if you were driving to see 42 on the gauge!

Next oil change try the Millers, English blender of very long standing.
Nigel Atkins

One of the first things i did was to bleed the oil line at the gauge. I'm going to have a clean out of the gauge itself, but am currently being sidetracked by an electrical gremlin!!
Oh and i've had a few "boy racer" sessions....i.e., "blow out runs". AKA putting aggressive BMW drivers in their place!!
My factory GTV8 has a 0 to 60psi gauge, this roadster has a 0 to 80!
I haven't explored the access to the PRV yet, but am seriously considering, if cleaning the gauge achieves no improvement, just going back to Morris Golden Film.
Thanks for you input!
Allan Reeling

O-60psi sounds good if still a bit ott but I suppose it went in some other models too same with 0-80psi.

I thought BMW 'drivers' had moved on to Aldis.

You could do go back to Morris but you could also do better - and you'd not be embarrassed or have to exaggerate about the low toll of your ZDDPs when at tyre-kicking classic meets. :)
Nigel Atkins

Nigel,
My GT with the 0 to 60 gauge is a very early Factory V8, lots of "oddities" on that!!

Bill Guzman posted on the Experience site, the possibility of converting the PRV to an adjustable one, by the simple addition of an adjusting bolt to the end cap. Since I don't need much motivation to fire up my Lathe, I might go down that road too!
Still chasing the electrical issue!!! Grrrrrrrr!!!
Allan Reeling

Allan,
I didn't know or remember that they had a 0-80 gauge so the 0-60 didn't stand out so much but I was a little surprised by it, wonder which other cars it went in or was it bought in as a short lived thing.

There'll be plenty on the B-series PRV in the B section and on the A-series in M&S section. Can't remember now different ball bearing(?), adding a washer(?), snipping the spring(?) - or I've remembered wrong or imagined it.

If the engines normally run well with the standard PRV could adding an adjustable be covering over your issue rather than sorting it.

Have you put up a thread for the electrical issue, Paul seems good with electrics. I've had small problems that have been a combination of issues that can make it difficult to track down and/or intermittent.


Seen on the BBS plenty of times where problems are related to heat, wires and connections vary with heat. I had an issue by pushing an overtight HT lead boot on the dissy cap that caused an internal pressure that lifted the unseen HT lead connector out of fully connecting to the dissy cap post. I fitted a brand new brake light bulb on my neighbour's car that turned out to work on quick pressing test as the filament held until it heated then it broke away but as it cooled it dropped back into position to start the cycle again. Luckily I tested for the rest of the lights working with and without the brake light or I'd have not noticed. Even harder to believe, I had a blade fuse that appeared to be intermittent on the fuel pump unfortunately, when it was changed the new fuse gave no more problems. Whether it was a combination of the first fuse to the fuse holder I don't know but a fuse that costs a few pence cost me a lot more when the car stopped on the M1. As the fuse was just under the dash I assumed (always dangerous) that it must have got caught and slightly dislodged.

Of course previous owners wiring can be a whole new ball game. :)
Nigel Atkins

Nigel,
I just can't lay any PO blame, as I built the roadster from scratch!!!
As I remember the 0 to 60 was installed on the GTV8 to avoid owners suffering serious stress attacks when seeing the needle struggle to move off the pin!! They later changed it for a 0 - 80.
I take your point regarding the hiding of the problem. I just like the idea of doing it, just to do it!!!!!
Yes I posted the gremlin question.
Allan Reeling

Allan,
just seen it, doh! - but I really meant post in in the MGB Technical section.

It has to be then a wiring, part or component fault, no way assembly. :)

As there is no one else here, and despite failing with your oil pressure conundrum, let's consider generator.

Have these if you've not already seen them -
https://www.youtube.com/watch?v=lPmk2FXs_18

https://www.youtube.com/watch?v=TMgRfToSiLY
Nigel Atkins

Thanks Nigel,
After exploring the wiring and replacing some internally corroded wire, plus a couple more relays, one to reduce the load on the ignition switch (Replaced). I removed the alternator and cleaned the slip rings. The brushes were fine. When this made nil difference I took it to a local firm i have used many times, for it to be checked out, the assumption being current was "leaking" back into the ignition circuit, probably via the warning light circuit.
Yet to have a result!
If this proved negative then i really am scratching my head!!!!
Allan Reeling

Allan,
relays usually seem very reliable but I'd not add any that weren't there unless to reduce the load on poor wiring, switches and connections that you can't replace at the time for whatever reason.

AFAIK (well remember really), and I could well be wrong, the bulb is only for the charging bit so did you try removing it to see what happened then.

Otherwise, do a short test run with the alternator drive belt removed.

I wouldn't know how to do it or be confident enough to try but you can bypass a lot of items to start the car and have it running like the ignition switch, did you try any of those.

I'd also have a good look around for any contamination that might have given effect - not to this but just as an example on a B-series, heater valve leaking on to dissy (I use 4-Life (water based) coolant as it leaves evidence of leaks, splatter direction, colour to hot or cold leak residue).

Internally corroded wire can be difficult to se and locate so I assume (always dangerous) that you have also had a good look at all connections and switches, earths, and for shorts.

Have you got an electric thermoswitch controlled fan(s), I've had those give (very short) engine run-on which perhaps if combined with another issue(?). I've had issues with particular circumstances being present to combine small issues into bigger issues and often because of this they can be intermittent and difficult to track down - often I'm one of the issues in the set!
Nigel Atkins

ETA: sorry I didn't see your other post when I was posting here - your switch has covered my idea of removing the ignition light bulb.

That leaves removing drive belts and other various bypasses which I'll leave to others to properly explain (and get right).

ETA - I see Paul has posted.

Cheers.

Nigel Atkins

Thanks Nigel,it's solved!!! See the technical post.
The 77 issue was a North American problem which was masked by the anti run-on device. Which cut the engine, even though the ignition was still live due to the ignition relay being held live by BL's wiring fault!! And mine as it turned out!!!
Live and Learn!!
Allan Reeling

Allan,
I think the electric circuits on these vehicles were very simple at the start (like me) then as time moved on things needed adding they were added to the same very simple circuits. As these 'improvements' were made things got more convoluted as more changes improvements were added to the simple circuits and added to the existing improvements, multilayering or twining (series, tandem, twin, parallel). At some point things got too clever for the overall good.

I overloaded decades back and have been in limp-home since, not that it took much to overload as as if I'd have anything anywhere near a limp-home mode, more like default to very basic - if only I could get back up to that level!

I know I've got some issue somewhere in the purple circuit but as I've replaced some wiring and connectors already I've given up and just accept it, it's only minor, I don't think it'll cause a fire.

I also found the LED bulb for the ign (red) warning light didn't work and I was told it should so I probably have an issues with mu alternator or wiring. Given the very poor quality of the three-way socket and spade connectors I'm surprised anything works. Both have been like that for years causing no problems just that I know they are there - and they know I know and are playing the long game to catch me unaware, having forgotten several times before, and throw up an issue I can't ignore.

Nigel Atkins

Nigel, What's the problem on the purple circuit?
Allan Reeling

Just realised I've merged my personal wiring problems with the cars.

Nothing serious, I tried to introduce a LED festoon bulb to the interior light (early Spridgets didn't have this luxury but my later year does) and I'd get flicker. Very useful bright light but intermittent flicker. Probably an earthing issue but I changed to another make of LED festoon bulb and same problem so back to the half-candle incandescent bulb, which I was happy with until I saw the LED light!

I've replaced courtesy light, door switches, wiring to courtesy light, fusebox, fuese and obviously bullets plus bullet connectors.

Purple is only courtesy and boot lights and horns, IIRC, I do test the horns occasionally or use them going over hump-backed bridges otherwise I don't normally use them.
Nigel Atkins

Nigel,
Good news I've sorted the gremlin!!
I installed LED's for dash, courtesy and reversing.
The only problem I had, and that was intermittent, was with the central courtesy light. It would just go off!
Swapping the things made no difference.
In the end I stripped down the unit itself, remade connections and cleaned the sliding contacts..............cured it! I'm not sure how, but guessed because they draw so little current, even a slightly iffy contact can cause a problem.
Purple is also headlamp flasher, at least on a B.
Not sure about the LED for the ignition warning light.
From reading up about this circuit in the last week, I gather that the resistance of an incandescent bulb is necessary.
My gremlin was down to the way I had wired an ignition relay by the way! The output from the alternator ignition warning light brown/yellow, although very small, was enough to hold the relay contacts closed.
Allan Reeling

Allan,
yes I saw you'd got it sorted, well done.

I discovered when I had problems with my Revotec fan that there are different types of relays and Revotec use the cheaper sort.

Yes LED bulbs seem to be very sensitive to issues elsewhere in the circuit and seem to be best when in full sets. That would mean side and rear lights to go with dash for full circuit.

I bought my set of LED dash bulbs from Classic Dynamo & Regulator Conversions and I'm sure (I think) he said the LED should work, if not you need a diode or something but it just seemed easier to me to leave the incandescent there. Same as courtesy light I've got far too many other jobs I can't be ar*ed to do on the Midget already. I get so hacked-off with the piss-poor parts, components and fixings that fail on the car or even issues before fitting (don't bother with Don Hoods now, I'm not the only one to have problems, Bernie did and I think I recommended them to him from previous very god experience).

Relating to my warning light, the replacement alternator plug and spades are so piss-poor I'm surprised they work at all, and this is the second replacement I've tried. I did think about replacing with individual spade connectors but the wiring is already tight and to shorten it even a little for new connectors would made it even tighter. Plus it's all working and it's another thing on the to-do list but very low priority. I only enjoy driving the car nothing else, I do work on the car because I have to or need to, it gives me no joy at all.

Spridgets are simpler wiring, mine is one of the early ones to get an alternator instead of dynamo and that was in 1973. You must remember that our cars were out of date by the late 60s let alone late 70s, with updating being added to existing rather than redeveloped. On my Midget purple is just horns, interior and boot lights, headlights are blue, not that I can ever remember which is dip blue/white or blue/red but I know they're blue. Thinking about it dip is blue/red as I always think it should be the other way round, blue/white, but usually can't remember if it is!

Perhaps your oil pressure will turn out to be something as simple as your relay wiring.

Cheers.
Nigel Atkins

Amen to that last thought!
I've had 4 Spridgets, by the way!!
My alternators, on both cars, have bolt on connections.............I like them!!!
Allan Reeling

Allan,
sorry I missed your post until now. Looks like a private section just for us!

I'm behind you with just two Spridgets and a BGT and a "rubber bumper" roadster V8 conversion with I believe a SD1 engine and brakes up front. I've had my present Midget for 12 years now so have got to know some of its bits far too well, much beyond my real interest.

I didn't even know there were alternator with bolt on connectors!

Having seen some dodgy wiring on various items and how few stands something remain working on I'm happy to accept things more (provided they're safe of course) if they're working well. There are a couple of connections I'd like to completely rewire but I'm well into the stage of if it's working leave it alone. I would add some of them to the list of things to do on the car but the list is so long that I can't see half way down let alone anywhere near the end.

I spent Saturday afternoon doing some very basic servicing work, even managed to spill some of my fresh, clean, expensive engine oil down the side of the engine of course after cleaning up from changing the dirty, messy, expensive used engine oil - so Sunday I had to take it out for a run to make up for the misery of dirty, messy, oily hands-on work. Only done 50 miles but it was good and enjoy unlike the day before with the car.

Interestingly I got 2.5 litres of oil out, plus a bit more left in the old filter and a little lost from transferring and cleaning up, warm engine drain, the dry fill capacity is 3.7 litres.

I don't know how much I put back in as Millers now put the Classic High Performance in a metal can, instead of the plastic with a gauge, no doubt as a market ploy to satisfy the feeling of proper "period" oil. Big difference in colour of new oil to used oil.

Cheers.
Nigel Atkins

Nigel,
At least we are visiting this section, which few others seem to do!
Millers are probably reinforcing their "green" credentials, by using tinplate!
Still chasing the oil pressure issue!
I did, for a time, have a Mk11 Sprite. Still with 1/4 elliptics, side screens and removable hood. But it did have a 1275 engine and disc brakes. Bodily very good but sold to someone who, almost immediately, wrote it off!! Great shame.
Allan Reeling

Allan,
at least we're pushing up the post count here. :)

Never thought about tin for being "greener", two birds with one stone then. With your thought that might explain why the label wrapping around the tin seems a bit low rent, possibly a material that's still in development use for this purpose. Certainly the design of the text and images on the label suggest "classic" with Pistoneeze large in the centre.

I won't upset you with my oil pressure readings on my Midget gauge, if I remember I'll look to see if it's changed with the change to fresh oil, I don't expect much if any difference as it's the same oil but I'd think the oil is made in small batches but I might be wrong, perhaps they have a lake of the oil and just add the various additive packages to make the various labeled oils.
Nigel Atkins

Just an update on the oil pressure conundrum.
Yesterday I attached an "external" oil pressure gauge as shown.
When fully hot and fans running for 10 mins the idle pressure was 28 psi and at 2500 rpm, 43 psi.
As said before the in-car pressures never show anything like that.
If this gauge is to be believed, it looks like the dash gauge is faulty.
I've ordered a 0 to 60 psi Smiths, not cheap, but we'll see!!


Allan Reeling

Well done, good job that gauge isn't in the car, imagine trying to focus on that as you drive.

Why not just calibrate the present gauge. The gauges I've changed have had the same inaccurate readings as the previous ones when they worked.

I wished I'd have thought last week when I read a piece from someone who'd asked an expert about engine oil for classics and the expert was all for proper synthetic oil and put what I've heard before, that (high) ZDDP has been overtaken by the modern additive packages.

Unfortunately I've no idea where I saw the article as it was whilst looking for something else, bit like channel-flicking on the TV to avoid the overlong advert breaks then to find a more interesting program than I was originally watching, or as likely I've forgot.

More and more I think the conservative (small c) opinion that high ZDDP is needed in a good additives package has been taken a great opportunity for marketing and a way to continue to sell old formulas of oil - for some companies against their efforts to drag the classic owners into the twentieth (20th) century let alone the 21st.

Same way as oil pressure is just one element of an engine's health ZDDP is just one element in an oil package and not necessarily the most important element.
Nigel Atkins

I am not convinced by the arguments over ZDDP - I advocate frequent oil changes for long engine life - every 3000 miles or yearly - kind of rules out the modern oils purely on cost!

I have always used the cheapest 20/50 available and flushed the system through with oil each change.
Chris at Octarine Services

Chris,
with a cheap oil at once a year change for a classic that does 3k-miles a year or less I'm with you it's all about the thoroughness of the change, especially if the up to 3k-miles a year is made up of lots of short journeys.

But as we've discussed before most (not yourself) just do a simple drain and refill, often on cold oil so the new oil is diluted by the vast residue of existing oil and muck going back to who knows when from previous quick oil changes.

What do you use for a flush and its cost?

The add-to flush products are a PITA and farting about as you have to drain existing oil out to get the flush in.

Do they still sell the flushing oil where you empty all the oil out and drive with the flushing oil?

And the third sort I forget now.

Of course with a B you've also got the oil sitting in the cooler and hoses to add to the residue.

I done my annual (hot) oil change on the Midget last month and only got around 2.5 litres in the container for the recycling centre, there was some lost to transfer, spillage and clean up but not that much. Dry fill capacity is 3.7 litres. I probably only left it drip draining for about an hour as I didn't have much else I was prepared to do on the car.
Nigel Atkins

This thread was discussed between 20/09/2019 and 21/10/2019

MG MGB GT V8 Factory Originals Technical index

This thread is from the archive. The Live MG MGB GT V8 Factory Originals Technical BBS is active now.