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 Midget and Sprite Technical - Is this bad?

Running with an Oil cooler, my 1275 never gets up to the 'N' on the gauge. usually stays around the spot shown on the photo (oil pressure is usually around 80 - I'd just stopped to take the photo).
Is it ok to run this cool or am I doing irreperable damage? The heater certainly feels as hot as it did before I added the oil cooler.

Any thoughts?



graeme jackson

my take is you only need an oil cooler for racing or for hard road use in warmer/hot weather (or for long M-way cruise above the speed limit). Make a sheet ally cover which is quick to attach & remove and have a play around.
David Smith

Also check that your gauge is working properly.

On cold days, I used to put tape over half of the oil cooler and part of the radiator on the racer.

At one meeting, the engine didn't seem to be getting hot, so I added some more tape, only to discover that the engine was actually overheating and the gauge had developed a fault!
Dave O'Neill 2

I certainly don't think you are doing irreparable damage. I have owned my 1275 with factory fitted oil cooler since 1997 and it runs with a similar temperature reading. I have not experienced any problems. I don't know the previous history of the car but the engine appears to have been tuned judging by how it goes when compared to a friends MGB GT V8 and some research I did on its valve sizes when I first owned it. From memory (dangerous!!), the valve supplier said they fitted a Metro head from the 198? Halfords Metro racing series.
Ray Rowsell

Graeme,
allowing for a gauge is just that a gauge then that's where the needle would be on my present and previous gauges, like yours

this would be when the car was running fully warmed up and travelling above 40 mph on an open road with a 82c stat fitted - when pulled over the temp would rise reasonably quickly

your oil pressure also seems about right - but that's not the whole story for the oil, an oil temperature gauge might give readings that would concern you more

personally I don't think a road going Spridget much tuned from standard needs an oil cooler and without fitting an oil thermostat that the oil is overcooled for a lot of time, even in summer
Nigel Atkins

Ray,
I didn't realise you had an oil cooler fitted (do you also have an oil thermostat fitted?)

this might explain why you and your car seem happier than me and my car with an 88c stat

for various reasons I've not been able to really test the 88c in hot weather but I've not been comfortable with the lack of margin when driving the car hard on only warm days (say 70f)

I'm keeping the 88c in over winter and to the next heatwave to fully test it, obviously it should shine in winter use
Nigel Atkins

Thanks for the comments. I think I'll leave it 'as is' for now if running cool isn't harming the motor although I will be covering part of the cooler when it gets really cold out.
At some point next spring I may fit a thermostatic valve in the oil cooler pipework.
For the record, the motor's bored out to 1298, running a piper 270 cam with high lift roller rockers and big valves (inlet and exhaust). LCB and HIF44 with a maniflow manifold. Since I fitted the HIF it's been running like a rocket. Accelerates well from all speeds and idles very smoothly.
graeme jackson

Hi Graeme
Im fairly sure your slightly low temp won't be a problem whats it like in the winter? I'm also sure you don't need an oil cooler, we found after fitting oil temp gauges in the sump of our race midgets that the oil was way too cool and now run without oil coolers to get anywhere near hot enough.
G.J. Puxty

Graeme,
I'm just north of you here in Tayside....
I suspect overall your Midget is running too cold.

I removed the oil cooler from my MGB years ago. One of the best moves I've made. Your old oil pump will have far less work to do, also if you have an original oil cooler on the car in our cool climate it is almost certainly going to be partly blocked with oily sludge... mine was...!!!

My " B " also ran between C & N, I replaced the thermostat with an 88c, as per Nigel. It now runs dead on N and even on steep long climbs or idling in traffic barely move above N. Fuel consumption should also improve with your engine running at the correct temperature.

P.S sorry just noticed you had recently add the oil cooler.

M F L Sherrit

Graeme,
running with over cooled oil is bad for the oil which ultimately is bad for the engine

I'd be adding a cooler blind well, well before winter, now in fact

as has been put already unless you're going to be regularly travelling on a motorway at sustained (very) high speed for a long distance or such like or towing a big boat or something then you don't need the oil cooler - you might want it but you don't need it

I wonder if Bill has an oil cooler, he goes from Brum to that-there-Lundun and back at high (totally legal of course) speed

don't confuse your tuned road car with a tuned track car, totally different animals and last (but one now) post says oil coolers weren't even good then

(disclaimer - Spridgets are involved in many different types and classes of motorsports with the cars in various states and levels of tune)
Nigel Atkins

MFL,
I'm not convinced about the 88c stat being good in my car

I can set my electric fan (engine driven fan removed) to keep the needle just before the N or only have the fan cut in after the needle goes passed the N but on hills or stress the needle quickly rises from the N which I'm not used to

the 88c experiment is ongoing but for my car I'm certainly not convinced yet
Nigel Atkins

my K series sits there under normal use on my gauge. No oil cooler on mine.
Rob Armstrong

Yes, I agree Nigel,
Graeme would need to experiment with his car and I was refering to my " B ". The fact is up here on the Scottish east coast the summer average is barely 20c...I would be willing to bet Graeme's engine is running too cool.
I suspect many MG's north of the border are running cooler than they should.

Mike
M F L Sherrit

Mike,
I totally agree with you about removing the oil cooler on road going Bs and Spridgets (1500s might need them if they have worn engines maybe(?))

in my experience the 1275 x-flow rads seem to over cool, well as far as what shows on the dial at least

I ran up a Welsh mountain earlier this month when the weather was 20c and with my 88c stat the needle was well passed the N, no cause for alarm I know but where might it have been if the weather was 30c instead

have you no steep inclines in Tayside, I've never really been there but have been to the Highlands and around, first time in our first over priced old car that they call classics to raise the purchase price, a BGT, then later in a V8 converted B roadster and couple of other cars

one day we had a fabulous run up the A9 coast road from Dingwall to Wick, the sun was out, roof down, V8 burbling, we felt like film stars in a movie, and I don't even like the sea, at any time, but even I enjoyed seeing the bright blue sea
Nigel Atkins

x2 what they said: for the most part a 1275 with modern oils doesn't need a cooler.

If you do want to fit a cooler, for whatever reason (pulling trailers, running at top speed for extended periods, etc.), then DEFINITELY fit a thermostat to the lines as well. As stated, too-cool oil is bad for the engine durability, and bad for the oil as well. The worst case scenario is a car driven mainly on short trips, the oil doesn't get fully warmed and the acids that build up don't get burned off (well, "cooked off" is more apt), and those acids attack things, like the bearings over time.


Putting a cover over the cooler is a useful temporary stop gap, but it is not able to be adjusted to control the temperature to keep it within the ideal range for the engine, and is easily forgotten about, or skipped for short trips, or whatever. A thermostat does all that is needed, automatically, and it doesn't forget.

By the way, every time you change your oil, some of the old oil remains in the cooler (no way to drain it).



Norm

Norm Kerr

Im running a cover on mine, and seems to work well,

Personally Im a fan of oil coolers esp during years with summers with super hot temps, this year was a very mild summer, and ive left the cover on the oil cooler, as ive also not removed the hard top, but several years back... the oil cooler was a god send

I think an oil thermo is great but on a budget cardboard works just as well...

(lawerance what have you done to me)

Prop
Prop and the Blackhole Midget

When I ran my car with an oil cooler without a thermostat in the lines the car ran too cold on all but the hottest days. The main thing I noticed was the engine oil started looking dirty a lot quicker than normal and it used more fuel.

john payne

oil coolers also seem to gunge and crud up possibly because they hold the old oil, being too cold, etc.

Prop the cardboard isn't as good, you need to remember to put it in at the first start of the day at least, and you need to judge when to stop the car to remove the cardboard as the oil may be warm enough now - but you also need to judge if and when to put the cardboard back in front of the cooler when the oil gets too cooler or the engine has cooled down

ever heard of 'having a dog but barking yourself'
- not that I'm suggesting you're barking before anyone suggests I am, as if

the cardboard will only reduce the cooling of the cooler and oil by so much as the oil is still circulating in the cooler
Nigel Atkins

Nigel,

You have been proven correctly ! Congrats

I just went out for an hour long drive tonight, its muggy out and around 75 F.

My water temp never got above 150 F (stat is 165F ) my oil temp ran consistantly at 160 F. At round 50 psi at 2000 rpm ...city driving

And thats with the cardboard in front of the cooler

So NOW im rethinking what I want from santa cluase... an oil thermo stat.
Still it was a great evening for a drive around town ... sadly only a 1960s era firebird was out and about, I waved, and he turned his nose up in the air, im guessing he felt ashamed because he over paid to have his built (guessing).

Prop
Prop and the Blackhole Midget

I think I solved the problem of old oil in the cooler. I have remounted the oil cooler upside down so the oil always flows back to the sump. Over the winter I am redoing my car to add a thermostat. It's an autocross car so its always running in hot weather and full out. No photo now as it is already apart.
J Bubela

Upside - down? Are you sure it will fill properly, or won't it just create an air lock and prevent it from draining properly?
Guy Weller

Prop,
great to hear you were out driving your car, 75F is a warm day over here
Nigel Atkins

if you mount it upside down then it heats up the oil, instead of cooling it


Just like when you microwave water with negative time to make ice.

":o)

Norm
Norm Kerr

Norm,

Thats why I reverse my winter coat inside out during the summer

Prop
Prop and the Blackhole Midget

Guy. I made new brackets so it does fit. I don't know about an air lock. The oil should stay in the cooler once its primed. The oil would have to be displaced by air which couldn't get in the cooler.

Norm. If I mount it sideways would it cool only halfway?:')
J Bubela

This thread was discussed between 30/09/2014 and 06/10/2014

MG Midget and Sprite Technical index

This thread is from the archive. The Live MG Midget and Sprite Technical BBS is active now.