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 - Hotter thermostat : Update


Fitted a 92'c thermostat to my Sprite, in an effort to improve the heater.

With the old standard thermostat, the needle never passed the N mark, sitting steady, a fraction below the N mark (if C-N-H = 100%, needle sitting at 45%)!

Now the needle fluctuates between the N and to just above the N (between 50% & 55%), but whereas the needle never moved before, now it's moving all the time, can actually watch the gauge and see the 'stat open and shut!

Does this mean that the 'stat I had in the car before was always open? Anyway, the heater is hotter, the lean running stumble has gone and the car feels a bit more "lively", (possibly), or it might just be relief that I've reassembled it time to get work!

Andy
a borris

Interesting.

I have a colder stat and like the security of that, but I never thought of advantages of warmer ones.

Paul who runs Fastparts dyno in Croydon did a trial on A Series stats and discovered that you get more BHP from a colder engine than hotter...
Rich Amos (1330cc Blaze Red '72)


"get more BHP from a colder engine than hotter..."

Not sure my engine is running hotter, think it might just have been running much too cold, still I'm just glad I can feel my toes once more (slight exaggeration!).

Having said that, I'm sure that my engine is nowhere near it's best horsepower, something a session on a rolling road should fix! And Croydon isn't far away and if he knows the A Series, might be worth a visit.

Andy
a borris

This thread has got to be a 1st, everyone and there brother is trying to figure out how to make them colder....Im guessing it must have been running open esp. for the needle to never move....on a hot day Im running 190 when its a cool day about 170


prop
Prop


Thanks Prop, rub it in just how rubbish this years summer has been in the UK!
a borris

Andy

It depends on how accurate is your gauge; you could carefully remove the bulb (very carefully if a capillary gauge to avoid any damage) and plunge into a pan of boiling water (probably not at 100C by the time you do this) and see what it reads. IIRC boiling should be a couple of needle widths beyond the N mark.

If your engine runs fine with 92C, then I wouldn't worry.

A
Anthony


I did check the stat before I fitted it (don't trust them new, out of box, let alone one that's been floating around the garage for x years!) and it opened exactly on 92'C.
Cars just had to crawl into Canterbury in rush hour and it's fine.

Andy
a borris

Canterbury has a rush hour at 10 in the morning? How very civilised !
David Smith

Canterbury is in desperate need of a ringroad that is not just outside the historic city walls, add in the tourists and you'll find that "rush hour" tends to be any time you happen to want to drive!
Will Munns

Boris,
For a rolling road nearer you try B D Engineering
H 1 Unit Newington Industrial , London Road, SITTINGBOURNE, ME9 7NU

01795 843980


Are you in Canterbury or ?

David
David @ work

Herne Bay, went into the city to get my windscreen "invisibly" mended, back home by 10am!

Chip has almost disappeared, just a tiny mark now. Although I was more worried about it stress cracking, insurance paid full cost too!
a borris

Canterbury has acontinous rush hour took me ages to go through last week.
M J Pearson

I think that my car runs a bit too cool as well. The needle holds pretty steadily at around the 7.00 o'clock position, 'though what temp that indicates I am not sure.(mine is a C - N - H one)

There are two pairs of small dots on the scale I have an idea they are callibtration marks; the position that the needle should point at two pre-determined temperatures. Does anyone know for certain?

Guy
Guy Weller

Guy

It's hard to know without checking/chucking the bulb into truely boiling water. My gauges have always had 212F just after the centre, just a bit before 5 o'clock.

And my K runs at the same point as the A did, just after 7 as you say... unless we're in traffic / stationary and it moves near to the centre. Don't you hate the later 'dumb' CNH ones?

A
Anthony

Not as much as the dumb oil "pressure" gauges in certain MX-5s -they're gauges alright, but the needle only ever indicates at two positions - 0, or some healthy figure that I can't recall. Its sender is obviously just an on / off switch - no better than a warning light.
They can be swapped for "proper" earlier MX-5 gauges apparently.

I don't have an issue with my C-N-H midget gauge - it sits stubbornly at 6 o'clock once we're warmed up, still seems as sensitive as the older graduated ones, and responds very quickly to overheating, and to cooling, as the electric fan kicks in.
Steve Clark

my old gauge (c-n-h)in combination with my 1500 always was on 8 o'clock and has moved to 5 o'clock only twice=1/London trafficjam 2/when my blades broke of my plastic fan.
The same gauge on the K-series gave almost no reading at all, probably a leak line.

Replaced it with a Celcius gauge with nrs to give me a better idea whats truly happening(as far as you can trust SMITS reliability).
Tested it first in boiling water which gave an acurate reading.
On a warm K engine on the move it reads 87C ish, not moving 91 ish but doesnt stay steady.
This summer on several occasions when i got in traffic jams the temp went up after about8/10 min. to 95C, 98C and i even had 103C.
The 103C was a bit scary!
Gonna try a bigger fan, new thermosthat and if that doesnt help perhaps even a new waterpump when the engine comes out AGAIN this winter.
And hopefully finally hook up the heater again.

Gonna build in an electric oiltemp gauge too.
temp sensor on top of oilfilterhouse.
I wanna see as much info of the engine as possible only problem is: where do ya leave all the gauges? :)


Arie de Best

Why is 103 scary?

Was this 103 with the fan on also?

Missing the cowling that routes air from the bonnet to the rad and chasing my way up mountain passes the engine got quite hot, but never so much so that the fan didn't bring the temp down as soon as it switched on.

I have an LED for the fan, and that reassures me that the temp is going up only when the fan is off
Will Munns

I had an idea that the 2 pairs of white dots were there as calibration marks - and assumed that the upper pair were probably where the needle should sit when the water was at 100/ 212 degs. But I am not sure about this. Someone must know!

Second point 103 degrees shouldn't matter. The whole point about having a pressurised cooling system (+ 7lbs rad cap) was to raise the temp at which water boils. So 103 degs is likely to still be below the actual boiling point. And the higher temp of the water as it heads off towards the radiator, the more efficiently it will dissipate the excess engine heat - assuming of course that your rad is working efficiently and can handle that sort of heat input so that a steady state is achieved.

Guy
Guy Weller

Guy,
That has always been my understanding as well. If the bulb is in boiling water (at sea level, etc), the needle should be between the two white dots. Not sure that I have seen this in print, however.
David "not too hot" Lieb
David Lieb

Thanks David.
And what about the other 2 dots? They must represent another set temp in order to provide the scale calibration.

Guy Weller

This thread was discussed between 17/09/2008 and 22/09/2008

MG Midget and Sprite Technical index

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