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MG Midget and Sprite Technical - 1275 partial re-build - comments please...

I would appreciate any comments/suggestions/advice regarding my intentions to start work on my 1275 engine next weekend.
Since I got the car on the road, it has suffered from low oil pressure when hot (~10psi at tickover, 40psi at speed) and burns a fair bit of oil when being driven and I hope to be able to fix both without taking the engine out....
My plan is to drop the sump and take the head off. I believe this will allow me to remove the big end bearings and pull the pistons out of the block. My plan is then to de-glaze the bores, fit new rings to the pistons and get the head skimmed and new valve stem oil seals fitted (possibly new guides and seats too depending on condition). Might even get the head gas-flowed too but that will depend on the cost and how much other work has been found necessary to rob my precious savings :(
When I put it all back together, I will fit new big end bearings.
Does the above make sense and do you agree my approach?
Glynn (not Glenn) Williams

You don't say how many miles you have on this engine?
But, if you're going that far I would just pull the engine, do the mains and replace the oil pump as well. Depending on mileage you may need to consider a new cam and followers and possibly a crank regrind. I wouldn't be putting more power from a flowed head into a less than robust bottom end.

All this will add up and I appreciate savings are precious.

Best of...

M McAndrew

Thanks Mike. Truth is, I don't really know what the mileage is - speedo indicates ~85,000 miles but no way of knowing if this is correct or not. Was trying to find (lazy) way of doing something to help, without taking the motor out of the car...
I do realise that by not taking it out, one of the main suspects of low oil pressure cannot be addressed i.e the oil pump :(
Glynn (not Glenn) Williams

I have done similar myself in the dim and distant past.

At best, it could be considered a short-term fix...or long-term, depending on how many miles you cover.

You may reduce the oil consumption/smoking and improve oil pressure, but if the big-ends are that worn, chances are that the crank will be scored, too.

If you pull the head and check for wear in the bores, you might get an idea of whether you could get away with re-ringing.

If you're planning on keeping the car for a long time, just pull the engine and do a proper rebuild.
Dave O'Neill2

Cheers Dave. That's pretty much the way I was thinking. If anything significant comes to light when I see the bores and the crank, then I'll have to go the "full hog".
Glynn (not Glenn) Williams

"I do realise that by not taking it out, one of the main suspects of low oil pressure cannot be addressed i.e the oil pump :("

I don't agree. I'm using an oil pump that's years old, and re-used at least twice. I've got near to 100psi when cold.

If your big ends aren't knocking, then the mostly likely cause of the low oil pressure is the mains. Pull the centre cap and take a look at the bearing/journal. That will at least give you an idea of whether or not you can get away with not pulling the engine.

If nothing is scored, just whack in new shells.

I've rebuilt my engine in exactly the way you propose, and have since done over 100k miles. It's now knackered and does need pulling for a "proper" job.
Lawrence Slater

I too think pulling the engine will save you a lot of time and enable a much better job to be done; access to everything is easier and you are more likely to fix marginal problems rather than say 'that'll do' if access is difficult. Unless it's your daily driver and you need the car back on the road asap, what's an extra few hours for taking the engine out and putting it back? Oil pumps are not always the culprit and your feeler guages will tell you if it's ok or not.
Nick Nakorn

Thanks for your input - never a straight forward answer to anything I ask! There's no knocking at the moment and hence my intention to try the easier fix. Will take your approach Lawrence and if worst case, I find scoring then I'll do as Nick advises. (good to hear a positive view re. the oil pump too)
Glynn (not Glenn) Williams

If you want to just be lazy, then leaving the block in place and working around it, is NOT, the solution

Ive done it both ways....there is nothing lazy about rebuilding an engine in stui ... its alot of time consuming physical work, if you dont have the body of a bronzed greek god, or your the age of less then 24, and you want to do this the lazy easy way...pull the engine put it on a tire on a work bench

Provided of course that you have access to the space and tooling....if not, then destroy your body and do the hard work and massive time doing the rebuild in the engine bay

Prop and the Blackhole Midget

Hmmm....Ill have to consult my friend Denys....he knows way more about getting work done on a 1275!
Steven Devine


ROFLMAO....Yepp, deny would certianly know who to ask

Hahaha gez,

Prop and the Blackhole Midget

I knew you would like that one....Ha ha ha.
Steven Devine


I think your approach is reasonable, but don't start pulling it apart unless you are willing to do a full rebuild if you find it needs it. Once you start taking it apart, you have lost your "ignorance is bliss" advantage. I would suggest that you do a dry and wet compression test before you take it apart.

Be aware that if you have too much ridge at the top of the bores, the ridge can break the new rings. Try to cover the crank as best you can with oily rags when you do the glaze breaking, and then flush it down when you are done. One of those air nozzles with a suction line for solvent works pretty well for this. If you don't have a compressor a garden sprayer might work.

I don't think you can do it on a 1275, but check, because on some engines you can replace all the main bearings with the engine in place and without removing the crank.

Does having the head "gas flowed" mean "porting" it on your side of the pond? To me that would just mean testing what the existing flow is. If you mean testing it, I don't see the point. If you mean porting it, that doesn't sound like a very good idea unless you are going all the way with the rebuild.

C R Huff

Thanks Charley for your advice. I fully accept that I might find have to take on a full re-build once I've started and I will take the precautions you suggest.
I believe I can change the main bearings with the crank in-situ but will find out once I start...

Regarding the head, yes I meant porting of the head. Why do you think that would be a bad idea? Is it because it might put additional stresses on the rest of the engine?

Glynn (not Glenn) Williams


Peter burguss is your best friend... you wont find a better head guy as a man or as a professional

A good modified head in my opinion is to remove the blob of metal that holds the valve guild, remove the sand casting crap on the port walls and racing valves and the same over size as the 69 mini cooper head, and hardened exhaust seats, and new competion springs

If you really want some jesus juice performance, go with a high lift 1.5:1 roller tipped rockers, that will make you feel like you got a new racer boy cam

Now you got something to smile about

Prop and the Blackhole Midget

It isn't possible to change the front or rear mains without stripping the engine. It is possible to change the centre main and thrust washers.
Dave O'Neill2


I just completed a 1275 engine pull this weekend on a friend 71 midget... It took exactly one hour and thirty-five minutes from turning the first bolt, to having the engine on the floor... It really isn't a big job at all...
Tom Crause

Ok Tom - thanks for the info. I'll post on here on Saturday evening how I got on and what I actually managed in the end....
Glynn (not Glenn) Williams

Eat your weatties, your going to need them ! ( a popular break fast ceral here in the states)

Youll be fine doing going the direction your going, its just very labor intensive, once your done, it will feel like you have spent the night in a military boot camp gym, lots of up and down.unde and over the car.

Prop and the Blackhole Midget

Please do 2 things....

1. Keep a cell phone under th car close by

2. Make sure the car is WELL supported on blocks and jacks, you going to be under over the car alot and with alot more grunt and rocking safty for this needs to take a bigger priority then in normal operations. So the car falling is a bigger risk then just when.changing oil or bleeding the clutch


Prop and the Blackhole Midget

Good luck, Glynn.

Your neck muscles will seize up solid, and the engine will drip on you long after you thought it had stopped - but if you are a bronzed greek god, that might be a good thing.
Nick and Cherry Scoop


There are several reasons why I think getting the head ported and not rebuilding is a bad idea. One is that based on your symptoms, your engine is tired. Since your engine is tired, I don't think it is going to respond to the benefit of a ported head the way it should, and if it does offer more power you will probably use that extra power to hasten the demise of the rest of the engine.

Then it sounds like you are trying to patch up the engine on the cheap. Having the head ported is probably one of the single most expensive things you can do. So, you would spend a lot of money on the fancy stuff and penny pinch on the basic stuff? Doesn't make sense to me.

I believe Dave on the mains. That was my recollection, but it has been a long time since I have dug into one.

C R Huff

Thanks everyone for your input, tips and advice. I'm just about to start taking it all apart so I'll update later. (Prop - I feel that I should reveal that I will be benefiting from the luxury of working under a garage ramp!)
Glynn (not Glenn) Williams


I would do compression tests now, so you have a clearer idea on the condition of the engine. I would also get the engine running best you can now - so adjust the tappets, timing is set properly, points and plugs set and in good condition, air filters new, air filter breather pipes not leaking/perished, make sure carbs are set up properly and are the oils and filter newish and clean. Plus noting state of rad and heater and hoses, making sure working OK with clear cooling fluid.

Do you have mayonnaise in your rocker cover?

Why all this? Well this gives you a stronger baseline for rebuild in terms of knowing the condition of other components, possible impacts on how well the engine was running and helping you on the condition and set up for putting it back together (if not modifying...)

You will need to take these things off and put them back on, and these will impact how well the new engine runs, how quick you can get it running well, as well as identifying things to fix beyond shells etc and giving clues/bigger picture on general health of engine.

Simple things - was timing OK? When you get round to taking off the valve gear is the rocker gear work, and when head off do the valves look close to burning out (and A Series speciality). Was the car running hot?

Good luck. And if you get the chance clean out the oil ways in the block. And pop in a full new clutch. In the old days of good cheap spares I would also say shove on a new timing chain, but others a can advise if genuine ones are still available and whether the expense of a duplex is worth it (probably not for your build).

M Wood

These engines can take a lot of abuse and keep running. I would not be surprised if you find other issues in addition to the bottom end and oil burning concerns. Not necessarily a big delay, but worth bearing in mind when pulling apart and planning the reassembly - look at the other components/potential issues, not just the problem that you are set on fixing.

Lawrence's story of throwing one back together highlights how to do it when using a careful eye and approach.

I am not suggesting go mad in changing everything, or looking for new problems, just making sure the rest of the engine is serviceable (I.e. old components that are adjusted properly and still working fine). Use good quality gaskets and torque things properly (see earlier threads on torque numbers without coppaslip)

M Wood

Right - back in front of the PC after a full mornings's effort.
I've taken the sump off, removed all four pistons, removed the centre main bearing, taken the head off and stripped it down.
So far, I have found that there is no obvious sign of wear on the centre main bearing nor it's thrust bearings. The four big ends look reasonable too. (both main bearing and big ends are stamped 10 thou' undersize = crank machined in past?).
The pistons are stamped 20 thou' oversize - does this equate to the first cylinder re-bore = 1293cc? The pistons were not loose in the bores bbefore I pulled them out but the rings all felt a little loose once in my hand and I will replace them along with new big end bearings.
The cylinders are all very shiny and I will get these de-glazed before re-building.
NICE SURPRISE - I discovered the head has been previously gas-flowed! Looks very well done too :)
Valves all look in good order and the valve guides look fairly new. Valve guide oil seals were only fitted to the inlet valves - I will replace with new and add four more to the exhaust valves. The valve seats appear undamaged but I will be getting the cylinder head checked over by a specialist (and friend!) next week hopefully.
Will keep this post updated as I make progress and will also report whether I manage to make any difference to my oil pressure (?) although very confident that new rings plus new valve stem oil seals will reduce the oil loss via the exhaust....
Glynn (not Glenn) Williams


With that oil pressure I would definitely not do anything that will increase the load on the crankshaft, i.e. new rings, lapped valves etc.

Engine out, measure the crank journals, regrind if necessary, new shells/thrusts, NEW OIL PUMP, and then do things with pistons and valves.

New valve stem oil seals on inlets only, none on the exhaust.

Richard Wale

Sounds like a high performance engine...

the trick now is to figure out what pistons you have in order to the proper rings

Id say probably no to the valve seals on the exhauste because they dont have them currently, the reason is it allows the exhaust valves to run cooler .... the only time oil will flow down the valve guild on the ex. Is when the engine is shut off

As to the low oil pressure, its probably just needs a new oil pressure spring and/or ball bearing...remember, the more pressure the hotter the oil, the thinner the oil becomes

They make an adjustable oil pressure spring and ball bearing, for no more then it cost ive got one...but I had to use the old spring as the kit I got the spring was to long for my engine

With this engine... id use arp hardware, and get the big ends re-trued to round

Good luck to you

Prop and the Blackhole Midget

This weekend I will be re-building my partially dismantled engine with new big end bearings and new rings (bores have been de-glazed).
I will also be replacing the oil pressure control valve in the belief that this might have been the cause of my low oil pressure.
I have had my cyl head cleaned up and the valves re-ground and also had 7 thou skimmed off, just to true up the face. I am advised this is the very last skim this head can take and so next time it will be scrap:( . On advice from an experienced engine builder, I have made the controversial decision to fit all eight valve stem oil seals.
It is my hope that by the end of the weekend, the car will be up and running again, but with no blue oil smoke and good oil pressure. I will keep you posted.....
Glynn (not Glenn) Williams

Sounds like you got a good plan, with the head checking out okay with no issues, its all down hill from here

Just remember... dont use oil that reduces wear or made for high milage engines and dont baby the engine....those rings only work if they get bed into the cly. And that only happens with friction, metal on metal wearing into each other, for a nice tight comfortable seal ....if that fails, the blue smoke out thr exhauste will come back

Good luck to you

Prop and the Blackhole Midget

new oil pump? competition high-volume version?
David Smith

Update as promised = good news and bad news :(
Good news is the pistons are all back in the block complete with new rings and the head is re-fitted, torqued down and ready to go, as are the manifolds and carb.
The bad news is that the big end bearings that had been supplied were wrong! Apparently, the Midget crank is different to other 1275 BMC cars??? I'm told that I actually need the same bearings as fitted to 1000cc minis? Will get them by next weekend.
Otherwise, everything is ready to go except the big end bearings and re-fitting of the sump. Will have to wait until next weekend now for the big test.....
(By the way, the old oil pressure control valve looked to be in a bit of a state in terms of poorly defined seating plus several score marks. Fitted the new one after thoroughyl cleaning out the recess and then bedding it in with some grinding paste - really hoping that this will fix the low oil pressure at tickover)
Glynn (not Glenn) Williams

The Midget big-end journals are different to *most* other 1275 engines.

They are the same as the 1275 Cooper S, however.
Dave O'Neill2

I2 huge problems

1st grinding paste to do what ??? Im not a fan of this idea at all, this needs to be cleaned to perfection, with no hint of paste anywhere before you fire the engine up....if not, then you might as well stop and pull the engine and do a full rebuild, now, even a small trace amount can have a devastating effect on the life of this engine

2nd.... your supplier says you need bearings for a 1000 cc engine.

Im thinking you need a new supplier, or a new engine....if your (actually are) running a crank shaft for a 998 A series inside a 1275 id say your problems are just beginning, I guess thats doable, but I cant see any advantages

I guess they would have a simlar sized journal

Are you sure that the crank hasnt been resized in its lifetime it may just need oversized bearings

Prop and the Blackhole Midget

Prop - thanks for your concerns. The amount of paste used was minimal and yes, it was thoroughly cleaned away when I finished.
re. the crank and bearings sizes, I don't really understand any more than I've already said above but Dave appears to recognise that they ARE different in a Midget to other 1275s so I have no reason to suspect anything untoward (the crank has been ground previously and the bearings are +0.010").
Will keep you informed of progress and hopefully this time next week will just be worrying about "running it in" :)
Glynn (not Glenn) Williams

dave is correct, the big ends of a midget are differant from *most* other 1275 engines

But then so is a crankshaft shaft in a ford 351 Cleveland vs a ford 351 winsor...they look and feel the same, but NOT interchangeable

The bearings you want are for a mg midget A series 1275, or an A+ series 1275 transverse for a austin mini cooper...*most* other 1275 bearings will not fit the A series 1275 for the mg midget or the austin mini cooper

Prop and the Blackhole Midget

Try posing the question directly to the BBS and other midget forums.... (and no I dont know the answer)

Ask if the bearings for a (948) 998 A series is the same for a 1275 A series

They could be the same, but ive never heard anyone doing this before, but i dont pay to much attention to engines out side the A series 1275 norm.


Prop and the Blackhole Midget


A+ transverse engines use the larger bearings, not the same as a Midget.

Midget journals ARE the same size as 998 and 1098 engines.
Dave O'Neill2

Oh thats cool, thanks dave

Anytime we start talking about alternative engine bearings I tend to find that conversation a little un settleing..

Im glad glynn is in good hands

Prop and the Blackhole Midget

Dave - thanks for the confidence boost that my supplier knows what he's talking about, even though he cocked up last week. (He was VERY embarrassed.)
Can't wait till next weekend now to finish it all off....
Glynn (not Glenn) Williams

Engine now fully back together and running sweet :). No sign of oil being burnt at all (yet) and oil pressure looking healthier with 80 psi when cold, 20-30 psi when hot at tickover, around 50 psi when hot at higher engine speeds. All of this during the first 30 mins of start up after re-build AND using "running-in" oil. I expect the pressure to be higher with the normal 20-50 grade oil that I will be using after the 500 mile oil change.

Thanks to everyone that has advised me over the last couple of weeks on this forum. Thus far, I believe that I have achieved what I set out to achieve but the proof will only come over the next few months of driving, including hopefully a trip to France in late June...

Glynn (not Glenn) Williams

Wow...Nice job! Im glad its got a good ending! Goodluck on yout trip!
Steven Devine

"and oil pressure looking healthier with 80 psi when cold, -- "

So much for the operation of the oil pressure relief valve then, which is supposed to restrict oil pressure to 60psi. I wonder if that figure is misunderstood. Pretty much every engine with new or good bearings and a decent oil pump, reads well over 60psi when cold. So what's the relief valve doing at that point if the reading is well over it?

Have so many people got defective oil pressure gauges?
Lawrence Slater

Lawrence - I changed the oil pressure relief valve for new (spring and valve) when I put it all back together so therefore it should work correctly?
Are you suggesting that it doesn't, or that my gauge is wrong, or both? Or, are you saying that cold engines are always above 60psi and that my case is nothing unusual?

(I'm feeling a little sensitive after taking my engine apart for the first time and then putting it back together, as far as I know correctly...)

Glynn (not Glenn) Williams

This thing about oil pressure keeps coming up - when they were newly delivered to distributors they hit 80lb on start up - so no problem.

The book (Haynes) notes for 1275's normal - 40-70lb/sq in
it also notes idle @ 20lb - which I consider low - a good 1275 should be about 40.

Lawrence - the smaller engines had lower pressure ISTR @ about 60lb.

richard boobier

the relevant Driver's Handbook is usually more accurate about the car when it was new but Haynes have copied the figures correctly this time so it's the figures Richard has given for a 1275

the oil pressure does vary depending on the oil, it's type and grade and warm and cold

on normal running oils mine is the same as Richard's, once the engine is fully warmed my gauges (I've had two in this car as the water temp part of the first failed) show(ed) around 40 at idle and around 70 at 2,500-3,000 revs

just had a look in my two Haynes books (the later carries the same mistakes I've noticed in the first) and for the 1275 oil pressure relief is shown as 50 lb/sq" in both books

I've no idea if the gauge reading is different because it's from a different place on/in the engine, is it always open when the gauge shows above 50 (? I can't remember but you will find the info in the Archives)

there's always a possibility that your oil pressure gauge needs recalibrating but I'm told this gauges type with the oil flowing to it (forget the proper name) tend to be more accurate than electric sender type so why not wait until you change to 20w-50 oil

if like many cars it didn't have an oil pressure gauge would you be worrying about it so much (not that I'm saying to ignore the readings)

personally I'd do another oil and filter change at 1k or 2k miles and build up the revs and sustained higher speed use up to at least 1k or 2k-miles then drive as you like and oil and filter changes as per schedule

depending on the engine/build you may find it doesn't fully open up until 6-10k(?) miles personally after it does I'd be on to fully synthetic oils and lower the winter grade for cold weather and winter use
Nigel Atkins


The BMC workshop manual also notes the oil pressure relief spring at 50lb/sq in - so Haynes have not miss quoted.

I can only assume id its correct that it starts the relief and is bore dia restricted as to pressure reduction provided ?

richard boobier

Nigel/Richard, you've lost me now!

Can't make out what point you're both making but for me, but I've got more pressure now than before I started this work AND I'm only running thin running-in oil.

I plan to drive ~500 miles (without holding back) and then change the oil and filter and re-fill with 20/50 oil.
At this stage, I'll report back and let the forum know what happens.

Glynn (not Glenn) Williams


Glad to hear that it seems to be working out for you.

C R Huff

As promised, I can now report back after taking the Midget over to France for the last week.
1150 miles covered door to door. Ran without a single problem the whole trip. Started on the button every time, never missed a beat.

Oil pressure at 40 - 50 psi whilst running, down to around 10 psi when very hot at tickover. Used about 3/4 of a litre of oil in total, but I suspect most of that leaked from the rear seal. No sign of oil being burned (i.e no smell, no smoke).

Lots and lots of attention from other motorists and lost count of the pedestrians that made a full 180 degree turn to watch as we drove past!

Superbe! and magnifique! were commonly heard in car parks and high streets :) :)

Thanks to all that gave advice and suggestions whilst I was carrying out the (partial)engine re-build. I am now so glad I did what I did and feel like it was money and time well spent.


Glynn Williams

What a lovely car, Glynn. How was the performance? And what sort of water temperatures did she get up to?
Nick and Cherry Scoop

Glynn, the car looks excellent in that colour and the stance looks just right too.
Nick Nakorn

Nick (Hereford) - performance was more than good enough to keep up with (and pass!) modern traffic. Water temps were never an issue. I changed the thermostat (again!) and gave the whole system a good flush last year - never had any trouble since.

Nick (Devon) - thanks very much :)
Glynn Williams

I love the photo glynn

Sorry to say this, but im concerned about your oil pressure, its lower now then when you started

Last posting you where at 80 psi running and 30 psi at idle when cold

Now your at ...10psi at idle, and 40-50 psi at speed, hot. That certianly matches the rule of thumb 10psi per 1000 rpm....but for a performance engine you have, id say those are the minume specs

Have you changed up to 20/50, you mentioned last that you where going stay with the running in oil for 500 miles
Prop and the Blackhole Midget

Prop - thanks for the compliment re photo (pity about the driver...)

Regarding oil pressure:
Started from cold and idling ~80psi
When warm ~50psi around 3000rpm
When HOT ~40psi around 3000rpm
When idling HOT ~10psi, quickly picking up to 30, 40, 50psi as engine speed rises

Yes, after running in for 500 miles, I changed to 20/50 as planned.

In addition to the oil pressure, I am now much happier with the lack of oil being burned too :)
Glynn Williams

the car colour is very nice

I'm not sure if the car might be sitting very slightly low or perhaps the driver's door might be hiding a lot of weight :)

like Prop I think the oil pressure readings sound a bit low but that might be the gauge perhaps

personally now you've just done that long run and are coming up to 2k-miles I'd do a thorough oil (and filter) change - getting the oil as hot as possible before draining and then drain for as long as possible to get as much existing oil and muck out of the engine - and use a decent mineral oil

I'd then leave the next oil and filter change until the next scheduled service

depending on what's been done on the engine and how it might not be fully run in until 6k-miles or more

as you know doing that journey was great for the car so to maintain this you need to do regular reasonable length journeys (at least 20-30+ miles before stopping) all year round and of course full and proper servicing, maintenance and repairs on the whole car

in September we'll be doing about 1,100+ miles going around Wales and all over its mountains which is a great test for the car but more importantly great fun especially if driven in a spirited manner :)
Nigel Atkins

Cheers Nigel - will take all you say on board, except the dieting tips!

We live in South Wales and so every journey we make at home is as you describe and I ALWAYS drive "in a spirited manner" ;)

Honestly, I'm really confident the engine is now in pretty good order and I would be happy to undertake any test to prove it. The gearbox, clutch and axle however are much less well known....
Glynn Williams

I'd be the last person to take dieting tips from other than be ill for a month

sorry I didn't notice you're from Gwent, we go to that area but not really that much, we were there on our three day honeymoon though (perhaps that's why) I was thinking of the north, the unclassified roads around the Lake Vyrnwy to Llyn Tegid area and beyond, not the tourist roads but ones where you hardly see another car on the same road with you

I've never really looked at or noticed my oil pressure whilst going up and down the steep bits but I once did notice on a steep long downhill the water temp gauge heading towards the 'C' which seemed very unusual and smelt petrol as the carb fuel bowls couldn't lean enough but all sort itself when went up the other side
Nigel Atkins

those oil pressure readings sound spot on for a car without an oil cooler.
If your car has one then the hot idle pressure is a bit low.

Should you worry?
Nop just drive it and enjoy.
You don't want to be Prop2
Onno K

"""You don't want to be Prop2""

Hahaha... that is a definate, :-), just having only one of me is so true....hahaha

Thats a great point about the oil cooler or the lack of one, with the engine already being probably a little bit hopped up... those spec probably are very spot on and okay

My engine ran good and hot oil also and low psi #s, when I did the oil cooler that solved the low psi stat

But that was 2011. The 2nd hottest year on record... with temps hitting 110 F daily

Yeah... im not conserned any longer

Prop.. ( the real prop )
Prop and the Blackhole Midget

Following your latest posts (and a bottle of red) I'm now feeling really chilled about my oil pressure (and my body size) especially as I can confirm I do not use an oil cooler :)
Thanks all for your input!

Glynn Williams

Maybe im just being an american.. but you look healthy in your photo, if anything, your to skinny

Prop and the Blackhole Midget

sorry but I've got to totally disagree with Onno about readings (and certainly about having an oiler cooler on a fairly standard road going 1275 but that's another long debate usually)

my 1275 readings seem to match others that have posted on here and they're not the same as Glynn's - not that that necessarily matters - I am of course without an oil cooler as my car goes nowhere near a track

(question for tomorrow not tonight)
what does your water temp gauge show when your at about 3,000 in fourth and when stuck in stationary traffic?
Nigel Atkins

Prop - thanks!!!!!

Nigel - Wow! That's a detailed question....
Temp gauge is absolutely, 100% on "N" at 3000 in fourth, slightly above "N" whilst stationary in traffic BUT I do have an electric fan, set to run at just above "N".
Is this of interest? Why?
Glynn Williams

well yes as the hotter the coolant the hotter the engine and the oil

and now very much so, for me more than you if you don't mind as I'm experimenting with heat on my car - formerly my car would show well before the 'N' when on the open road and only go above 'N' when I switched the engine off, same as others I've heard of

if you don't mind answering these please I'd be grateful;

where these water temp readings the same as before the partial rebuild?

what make/model/type of electric fan do you have?

is your engine fan still fitted?

do you know what temp on the fan's thermoswitch it cuts in at?

what temp water thermostat do you have fitted (82 or 88C)?


Nigel Atkins

Nigel - happy to answer your questions as below:

"where these water temp readings the same as before the partial rebuild?"
Pretty much, yes. Not noticed any difference

"what make/model/type of electric fan do you have?"
Can't remember the make/model of the fan but it is only a cheap one from Ebay. I just bought the diameter that would fit the Midget rad, 10" I think? It is mounted on the front of the rad and blows through it.

"is your engine fan still fitted?"
No. When I first got the car on the road, I discovered that the PO had fitted a Mini engine fan (!) and this was causing the engine to overheat every single time I drove it (blowing instead of sucking). Initially, I just removed the fan and drove without any forced cooling and things were much better although of course, whenever it was stationary, I had to be very careful.

"do you know what temp on the fan's thermoswitch it cuts in at?"
The fan came with an adjustable thermostat that I have set switch in at just above "N". I don't know what temp this equates to?

"what temp water thermostat do you have fitted (82 or 88C)?"
The thermostat is an 88C model.

Hope the above is of some use to you? Let me know if I can tell you any more?

Glynn Williams


Glad to hear that your in-frame partial rebuild is proving to work out. I did the same to my 46 Chevy truck back in the mid-70s, and it is still going strong. Good looking car you have there.

I think your idle oil pressure sounds like it is on the low side of ideal. If it is available over there, I would try adding about 10% or so of Lucas Oil Stabilizer to the crankcase. I was able to try this in a large truck in the Mojave Desert of southern California years ago when the oil pressure was getting too low and the oil temp was getting too high. It not only raised the oil pressure, which thickening would do, but it lowered the oil temperature as well. As is common in large trucks, it was equipped with a lube oil temp gauge. It's been too long ago, so I no longer remember the numbers.

C R Huff

thank you, very helpful thanks as I now have a similar set up

your fan would be a 9"

it's the 88C (instead of standard fit 82C) water stat that I'm experimenting with but so far I'm not confident with it, I have set the fan to cut in at about 'N'

on a run the other week I got stuck behind a slower car going up step twisty bit of road so I held back so that I could keep in 2nd at a constant speed but I caught up with the slower car just before the top and had to drop to first gear, glancing at the gauge I saw the needle well past the 'N' and it took a while before I could get a reasonable speed and to overtake to drop the temperature

I don't feel I have enough margin as it was a warm but not hot day and those are the type of roads I like to drive on, many with a lot longer and sometimes steeper climb so I'm guessing the temp would go even higher on those roads
Nigel Atkins

Charley - thanks for the tip.

Nigel - glad to be of some help but I don't think I'd be too worried if my gauge went above "N" during the situation you describe.
I happen to know from personal experience that the engine can survive the gauge reaching well past the "H", and up into the oil pressure gauge region!!!! I forgot to tighten the hose on the water pump the other month and had to limp a couple of miles with no water in the engine until I could reach a garage and a water supply. I was well relieved that the head and gasket had survived...

Glynn Williams

that's the difference I don't have good luck with cars if I'd have forgotten to tighten a hose I'd have lost the gasket and head for certain, I've already had HGF on my present Midget only 7,000 miles after the engine was rebuilt for no discernible reason and the head had to be skimmed from it

you're probably right that I might be a bit over cautious but I've also had four other HGF on four other cars all without good reason, all expensive repairs, and with running fibreglass cars with bigger engines that get very hot you tend to keep your eye on the temp gauge because things can go from normal hot to over hot very quickly

given what you've put I'll stick with this 88C thermostat a bit longer as I'm going to fit an uprated cooling fan

whilst I'm doing that I'm going to follow my own advice and give the cooling and heating system a clean and thorough flushing (again) as when I fitted the 88c water stat I noticed, not to my surprise but disappointment, that they was plenty of small sandy muck in the main waterway
Nigel Atkins

adding in something like Charley recommends may well get you through this patch until you can get many more miles on the engine

just as a comparison only - bearing in mind different cars, different engines (about 40k-miles on mine) - I was checking my oil pressure gauge readings yesterday for you

Started from cold and idling - I forgot to look
When warm - 70 at 3000rpm
When HOT - 70 at 3000rpm
When idling HOT - just over 40

oil for the last 11 months (shock, horror for some) Mobil 1 10w-60 (soon drops into 50 range) Extended life

the running oil pressure was very slightly higher when I first put the oil in

no oil cooler

can't think of anything else
Nigel Atkins

Thanks for the info re. your own oil pressure - does make mine look a little low..

Meanwhile, I didn't realise I could get an oil 10/60. You obviously don't feel concerned about the use of modern synthetic oils with our old fashioned engines? Hmmm - interesting, making me think differently ;)

(Sorry about your tail of HGF woes by the way. Don't suppose my own little tale helps you feel any better - sorry)

Glynn Williams

Are those mudflaps on your front arches, Nigel, or did you run over some waffles?
Nick and Cherry Scoop

today I had a look at the cold start oil pressure, had to start on choke and push choke in to almost stall with both the reading was 60

of course too much oil pressure isn't good too

a few of the classic/racing oil companies do 10w-60 too and in mineral oil

nearly 20 years ago when I had my other MGs I was told I couldn't use Mobil 1 as it would damage my engines and rot my teeth and steal my looks, but my engines were fine and I've still got m teeth and looks

I will say this latest Mobil 1 10w-60 (Extended Life) oil isn't as good as when they done the 15w-50 (Motorsport) but as they don't make that any more I've no choice - there are better oils than Mobil available but it used to be convenient and not too expensive to get Mobil 1

we were also told by some that if we didn't use leaded petrol or an additive we'd have big trouble but we didn't and didn't, same as the ethanol scares and ZDDP in oil now I think

I also use modern fully synthetic oils in my g/box and diff

with those and the 0w-40 (New Life) Mobil 1 (don't use that, too thin, I was warned by Daniel but didn't listen) on Peter's rolling road the car's power losses were very good

with my present Midget I used to use Halford's Classic 20w-50 and Castrol XL 20w-50 on my present Midget but as I use it all year round and it always sits outside I found the 20w part of the oil made starting the car in the very cold winter weather more difficult than it should be (always started though) and I wanted to drop from oil & filter changes every 6 months to 12 months so as my engine was well passed running-in I went back to Mobil 1

don't worry about upsetting me with any tales, if it wasn't for bad luck with cars I'd have no luck with cars :)

in fact I was having trouble with a new part I'd fitted whilst trying to concentrate on the cold reading today - looks like I'm going to have to revert back to the old part which had to be fished out of bin - I *should* know better, road test even the simplest of parts!

if you want some info and links to info on oil, balanced for and against what I put, then just email me
Nigel Atkins

sorry Nick I missed your post

yeap I did have a full set of mud flaps - part of my GT range, map reading light and parcel shelf - but the multi-fit rear ones didn't because of my exhaust and I remove the front ones too, plus I was told that the flaps would reduce my mpg which I certainly can't afford which only a 5.75 gallon tank

the map reading lamp has been used only once but the parcel holds the road atlas and CAMRA Good Beer Guide so is indispensable

I remember paying IIRC 120 for mud flap when I bought a new MX-5 in 1999, they were so expensive because they were only available in primer and had to be painted to body colour, I had them fitted because I like to travel on b and unclassified roads and they can be wet and muddy, first week I had the car I did a three-point-turn on a country road and scuffed one on the verge

I also had a full set of mud flaps on my previous Spridget and my B roadster V8 conversion but funnily enough not on my BGT that I can remember (or in photos)

Nigel Atkins

So, not waffles, then.
Nick and Cherry Scoop

no 's' Nick...
David Smith

er, yes, a good one, made me smile

and in the usual curt style, a man of few words and all of them absolutely correct

... according to him

... and probably very acceptable to Guy Martin we hope :D
Nigel Atkins

Keep an eye on it Glynn. It is pretty common that overheating will fail the head gasket, but not right away. I overheated a Healey 100-6 in eastern Nebraska, and the gasket didn't fail till I was in California. Similar experience with a Volvo. In that case it took about 1000 miles after overheating to fail.

C R Huff

Doesn't seem to me as if Glynn has any problems at all.

It's sometimes difficult to live up to the perfection discussed on this board, Glynn.
Nick and Cherry Scoop

This thread was discussed between 09/03/2014 and 09/07/2014

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