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 - New Engine!!

Hi everyone,

I've taken the decision to take my car off the road for 6 months whilst I'm at uni to drop out the standard engine (1275) and get it rebuilt; she's been running badly for a fair while now and I need her to be reliable.

My brief to the re-builders would be this:
1. RELIABILITY
2. A bit more power if possible without sacrificing reliability (especially in the bottom end of the rev range).

My questions are:
1. Is a 5-speed gearbox worth it? What are the issues around getting a new one? Cost?
2. Do I upgrade to a stage 2 engine for an extra £1,000? What are the benefits of it? Can you feel the difference? Is it less reliable/have a shorter life expectancy than a standard unit?
3. Would anyone suggest a firm to complete the work in the south-east or south-west? I've heard Classic and Modern are good...?
4. Are there any other considerations I need to take into account when I'm thinking about doing this? Other costs? Other necessary mods (e.g. brakes?)

I think that about covers my questions (!), I'd hugely appreciate any advice you guys can throw my way.

Thanks for your help and hope everyone's having a great 2014 so far...!

Josh
Josh Spooner

Do I upgrade to a stage 2 engine for an extra £1,000?

An EXTRA £1000? are you sure about that?
Lawrence Slater

1. to me not, with a 3.9 diff the ribcase is perfectly usable.

2. There is no sutch thing as a stage 2 engine, any engine builder can make up a spec to call stage 2. so hard to say if it is worth 1000 quid.

3. forget any region just go to a good one. MGOC spares standard engines are good but off course Peter May or Peter Burgess can make a more custom spec to suit your wishes.

4. If you are just going for a mild engine spec there is no need to change other parts if they are in good working order.
But you could always make some cheap sensible mods like mintex 1144 pads and braided brake hoses, poly suspension bushes help with more suspension contol.
And if you want to spend some money a FL front suspension kit or a PM top link kit are always a good investment.


For engine spec I'd advise the following.
-balanced bottom end put together with good rod bolts.
-first overbore needed with good pistons
-mildly modded head with std valve sizes.
- 266 or 276 cam
-10-1 or 10.5-1 CR (higher CR gives more torque!!)
-vizardised std carbs
-and a roling road setup when it is finnished

All in all to tame for me but not everyone wants a non idling road rocket ;)
Onno K

Josh,

You said your engine is running badly, so you decided to have it rebuilt. Concluding that an engine needs to be rebuilt because it runs badly sounds like a very large leap of judgement to me.

Maybe you already know a lot that you are not telling here? Like, for example, it burns a lot of oil, has very low compression or failed a leak down test, has knocking rods, has low oil pressure, etc. Have you actually checked to see that it needs a rebuild?

Charley
C R Huff

Hi Josh,
as has been put Stage 2 is really just a marketing term but wouldn't normally command another £1k on an A-series engine unless things have gone up a lot (which they might have)

I don't think you need go quite as far as Onno suggests on the engine but all things are relative and Onno raises a good point by considering the rest of the car and not just the engine

a "Stage 2 or 3 or more" engine will be held back if all else the engine requires to get its power out is below par because it's either not suited or in poor condition

how reliable the engine is at this level is more about the engine builder and parts and components used and as always with all cars how good or not the owner is at looking after the car and its rebuilt engine

how reliable a Spridget is is not usually down to the engine itself, part of the problem with the likes of Spridgets is that they continue to run despite the abuse and/or neglect of present and previous owners on the engines

most reliability issues to do with the engine relate to the parts attached to the engine rather than the engine itself

whether to have a 5-speed conversion depends on your use of the car

there are no necessary upgrades required for a "Stage 2" engine other than perhaps better induction and exhaust but as you would with a standard engine to get the best from it you need to have the whole car fully and properly serviced, maintained and repaired with all relevant important components and parts in good functioning condition

when setting a car up you sort the brakes, tyres, steering and suspension before fitting an upgraded engine
Nigel Atkins

excellent point there Charley
Nigel Atkins

Im assuming you know for a fact you need a new engine.

Id have a serious talk with peter burguss, he is a good man, and will listen to what your wanting

These little engines are so versatile... you can do anything with them....so the sky is the limit with everything in between

As to a 5 speed...ABSOLUTLY YES!!!

A five speed makes the car so much more drivable and usable on todays roads, cost?....eeeh, it aint cheap, around $2000 usa dollars

For a engine your describing....

The bottom end...new pistons .10-.20 oversized, SW 5-07 swift tune camshaft, a good exhaust header, rebuilt carbs engine balanced

The head, a basic port, valves cleaned up, new springs, hardened seats

Infact... swift tune has several nice kits that includes alot of what you will need

Its a bit over kill, but I really like the new ...high torque staters, its not nessary, but it sure makes it nice when the engine wont start at the bump of the engine

With the engine.your wanting, the rest of the car imho is fine... I would add panhard rod, cause that really makes the cars handling big time... but id recommend that on a bare bone stock midget

But its going to be hard to find a better friend and partner then peter burguss

Prop
Prop and the Blackhole Midget

Totally agree with Charley. Do not attempt to modify something which sounds as if it is not running well as standard anyways.

Ensure that your engine is running corectly first -check ingnition,fuel,compression,etc as per handbook/Haynes and then and only then consider tweaking it a bit.

Easy perfomance mod is to fit a HIF 44 carb, then possibly electronic ignition - for reliability if nothing else - then a decent set of ignition leads, replace rotor arm, the list goes on way before the time where any so-called stage 2/engine rebuild is necessay.

5 speed box - yes recommended, but it costs if you cannot fit it yourself.

I think you need to ask yourself what you want from the car first and consider what you can sensibly achieve withouut chucking money at it.

Mark
Mark O

Josh,
all the above comments have merit and you should be clear on the reasons for a rebuild before you start.

But, on the basis you are...
Onno's spec sounds like a good starting point and Peter's the man for the build.
The reworked head is essential to release the extra power you are looking for in a mild tune engine but the good news is it will do so without compromising reliability.

I would echo Mark's point on electronic ignition but will go one step further and say a refurb/renew of the dizzy will be required. Not cheap I know but I would go with a 123Tune dizzy to get a bespoke advance map for your bespoke engine spec.

Get a copy of Vizard's book on the A-Series for a bit of downtime from Uni stuff and you'll be fully informed on what can be achieved.
Best of....
MGmike


M McAndrew

My personal experience starting with a standard 1275 was that a fresh rebuild with a 266 cam was very mild and driveable engine.

If you're staying std-ish capacity then the cam is really the only change that can only be done with engine out.

The next single best change for a reliable driveable car as a new distributor with electronic ignition. I say new (aldon, 123 etc) as one of my exchange ones was worse than one I replaced.

For mild road you could then simply change exhaust, and possibly to a HIFF carb etc.

A modified head is a reasonable chunk of money and will give you a modest jump if you do ensure the exhaust and carb are sorted to match (but even a standard head with a hike in CR will help)

Think the main thing is to be honest about the spec and the way you drive. If you're not building an engine that you want to rev to 7K all the time...then you dont need a facny bottom that some will recommend. There's no reason a std bottom end wont be fine with a 266 cam and a few bolt on goodies revving to 6300 or so.

You certainly dont need to worry about fancy head gaskets and just the right spec of studs if you're running a low CR and the car will never leave the garage.

I would say there is no reason at all that an ordinary DIY mechanic cant build a solid engine given enough time and the internet ;-) There's a "build your own A series" DVD that shows you there's nothing to be afraid of. The A series definately isn't rocket science no matter how hard some manage to make it look.

Dean Smith ('73 RWA)

This is the DVD...can't quite believe its £20. must be cheaper than that somewhere.

http://www.amazon.co.uk/ULTIMATE-MINI-BUILDER-DVD-A-SERIES/dp/B002HRYFSM

Might flog my copy on ebay !
Dean Smith ('73 RWA)

This bundle on ebay wouldn't be a bad place to start reading ... (not mine, though I do have all those books)

http://www.ebay.co.uk/itm/Mg-Midget-Sprite-A-series-Tuning-Restoration-Performance-Books-/191039301056?pt=UK_CarsParts_Vehicles_CarParts_SM&hash=item2c7ad465c0
Dean Smith ('73 RWA)

Hi Josh, If youre going to drop the engine and have it rebuilt anyway then it shouldn't cost an extra £1000 to have it tweeked. A cam change will be easy as that would be done anyway as part of the engine build and getting some work on the head at a suitable compression ratio makes sense. Dont go mad with the overbore and compression ratio and there should be no real issue with reliability. The 123 ignition systems seem to be the way to go and there is no reason why you need to replace the twin carbs if you dont mind a bit of work modifying them; good for 100bhp.
John Collinson

Josh seems to have forgotten his post. ;).

Anyway, as regards the 123 distirbtor. The best part of 300 quid (vacuum advance model) just for a bit of supposed extra reliability?

It's a myth that points ignition aren't reliable. So the only other reason to spend 300 quid is for extra performance. Fair enough. But how much "extra" performance could 300 quid buy, if spent on the head for example, instead of on the distributor?

Of course money may be no object. Back to you Josh. How deep are those pockets of thine? :)
Lawrence Slater

IF someone was just worried about changing away from CB points they could buy an igniter head which are available for a fraction of £300

if £300 is spent on head work that could be negated when used with a dissy body that is worn, apparently from new they used to be out of order within two to three years so one that's decades old will probably also be out of order

the engine needs to be balanced with what's attached to it as well as balanced to the other more important systems on the car

I've had two Spridgets that started with CB points (one with unreliable CB points) both progressed to igniter heads and my current Midget has a 123 fitted (after an Aldon igniter head)

I've felt the performance improvement of fitting the 123 throughout the rev range from idle upwards - no readouts I'm afraid just just my knowledge and experience of driving two Spridgets for many years over tens of thousands of miles, often in a spirited fashion

as for reliability in the four and a half years I've had it fitted it's been 100% reliable

and note I did not suggest fitting a 123 to Josh
Nigel Atkins

" --- could be negated when used with a dissy body that is worn, apparently from new they used to be out of order within two to three years so one that's decades old will probably also be out of order"

Have you got proof that distributor bodies were "out of order" when 2 to 3 years old Nigel? Where did you read/hear that then?
Lawrence Slater

I ran A series engined cars from 1963 until 1979 for thousands of miles. As I was in my teens and twenties some of these were "hard" miles. During this time they were all mostly self serviced and I never had a problem that could be put down to the standard distributor.
Ray Rowsell

Ray because you were servicing the cars you were preventing some problems and presumably making adjustments at these services to compensate for the variations with the dissys

many classics for decades haven't been fully and properly serviced so possibly making the dissy worse through lack of attention
Nigel Atkins

New simonbbc dizzys are only about £60 including the electronic module and you could get that curved to suit your engine spec. I never realised the 123's were so expensive. Does anyone who has one actually change it once fitted?
John Collinson

>>Does anyone who has one actually change it once fitted?<<

do you mean a 123?

and if so do you mean change its settings or change the unit?
Nigel Atkins

Well..... my original distributor was failing where the plate for the points (that is moved by vaccum advance) pivots on the main shaft. it was essentially "wobbling".

This was giving eratic timing when I tried to time it at idle and occasional eratic performance driving as the plate moved and the points gap varied no matter how carefully/regularly set and serviced.

A recon distributor was actually worse in this regard that the original. So I'm glad they were from fine from 1963 to 1979 - but you probably weren't relying on 30 year old recon parts at that point.

I replaced it with an Aldon Yellow. I certinaly didn't pay £300 - more like £40 from memory via Ebay - inlcuding lumenition electronic ignition.

Same for my twin carbs being replace with a HIFF44. I'm sure the twins were just fine when new - but mine had done 120K miles and 35 years by the time they became difficult to keep balanced/adjusted and had dectable "slop" in several places that new spindles didn't cure. The HIFF44 I replaced it with was both both much younger and probably less than half the mileage.

So regardless of the number of "they're fine if serviced" opinions....I'm afraid moving bits do wear out after 40 years and many miles and introduce both variability and reliability issues that can be cured with replacements. (and I have not for one moment missed either setting a points gap or balancing the carbs)
Dean Smith ('73 RWA)

as Darren has put >>I'm afraid moving bits do wear out after 40 years and many miles and introduce both variability and reliability issues that can be cured with replacements.<<

can I also add and no disrespect to Ray at all and I accept he didn't have problems and that the car ran well but what is the measure of the car running unless test equipment of some sort, even home test equipment which Ray may have used in which case my point might be redundant, how do you know if it could run better

I accept the monetary costs differences but petrol ain't cheap now and performance includes mpg

I also accept that any gain in performance the mpg gain can be lost as you repeatedly exploit the power performance gain - I've been meaning to do a mpg test for two years but not been on long dull roads long enough yet
Nigel Atkins

"- but you probably weren't relying on 30 year old recon parts at that point."

That statement makes a good case for upgrading to modern improved parts. So much bad experience has been shared on here in respect of the quality of new replacement parts that clearly, in many cases, are not as good as those available when Sprites and Midgets were still in production.
Ray Rowsell

With regard to reliable modern electronic ignition, I recently bought a system to replace the 25d4 points. I got a competitively priced well known setup off the net. It fitted easily, all under the dizzy cap and I thought it should be more or less fit and forget, which was a large part of the appeal.
Less than 1500 miles later the plastic moulding holding the signal magnets had become a slack fit on the distributor shaft allowing for irratic timing and poor running.
The chaps at Aldon diagnosed my rough running problem and fitted one of their Ignitor II (pertronix) kits whilst I was at one of their rolling road days.
The Aldon kit seems fine.

Mark

M Crossley

Mark, I read about your problem in Safety Fast. Just wondering did you bother to investigate why it became a loose fit, as if it fitted OK when installed I can't see how it becomes slack as it doesn't move on the shaft? Wondered if it was fitted to close to the unit and rubbed for example.

Trev
T Mason

Hi everyone,

Sorry it's taken me so long - it's been exam time here so I've been a bit pre-occupied!
The engine seems knackered to me, producing a ton of black smoke and burns a shedload of oil (about a new 3l bottle every month...) and has all new ancillaries on it. I literally replaced everything from carbs to electronic dizzy to leads, starter motor, head & rocker gaskets, entire wiring system, solenoid, exhaust manifold, hoses, etc etc etc.
Excuse my language but I'm f***ing sick of the thing now and she's gone from my pride and joy to an embarrassment and I'm falling out of love with her rapidly which I thought would never happen. I don't have the money not to sort it out properly.

I'll report back with any progress; thanks for all your advice - I really do appreciate it. Don't know how I'd ever progress without everyone's help.

All the best,
Josh
Josh Spooner

Josh....

Your last message says alot,

My advice, sell the car and look into purchasing a mazda MX-5

Im assuming your a young man lower half of 20ish ??? And in college ???

Here is why I say this, ... your #1 priority is school, not rebuilding engines, being a student you need reliable transport thats gas and oil changes, not a car thats favored by many for its tinkering personality

An engine rebuild is going to set you back a good $2500 usa when all is said and done...its not just the cost of parts and machine work

Also remember... even with a brand new engine, theres still alot of other parts that can go wrong not engine related. All that money could be better allicated to half naked college girls, pizza/beer with your frat mates, and tickets for manchester united.

Trust me, in a few years, your life will change.... you will have a ball and chain that gets knocked up with just the hint of the word porn, the job will be dead in and you have 1/2 the hair and twice the weight you have now

Thats the time to get a midget to enjoy the rest of your life with

Prop

My hope is y

Prop and the Blackhole Midget

Josh,

I'm not sure if you missed my question about what you did to determine that the engine needed rebuilding, or if you are now answering that you didn't do anything to determine that other than note some symptoms. For my response, I will assume you haven't checked anything. If I am wrong, please correct me.

From your recent description it seems that you noticed some problems, and then started throwing a bunch of parts at the problem without bothering to figure out what was wrong, and some of the parts you threw seem unrelated to the issues that you observed. Now, as a result, you are blaming the car. Perhaps the car is a piece of crap and deserves blame, but if that is the case you should have figured it out before you threw all the parts at it.

You said it makes tons of black smoke, and uses a boatload of oil. The first issue about the oil is to determine if it is leaking or burning or both. You said you have black smoke, so that would indicate that it is over fueling since oil smoke would be blue.

You said you put on new carbs. But, were they installed and tuned properly? It would seem not or you wouldn't have black smoke. If you are over fueling that much, you may be washing down the cylinder walls with gasoline, which can cause poor ring sealing and lead to higher oil burning. Also, associated with the carb and intake system is the crankcase ventilation system. If that is not operating correctly, you may be pressurizing the crankcase and pushing the oil out of the engine, particularly at the rear scroll seal.

When you had the cylinder head off to replace the head gasket, did you take the head to a machine shop to check it, or did you check it yourself by pouring petrol into the combustion chambers to see if the valves leaked? Did you check the valve seals and guides while the head was off?

So, at the moment you don't need to spend a bunch of money for parts, you need to analyze what you have. I would start by checking why it is over fueling. It is probably set too rich or the choke is stuck on. Then I would proceed to a dry & wet compression check and see what that reveals.

Also, you should identify the year of the car. They are not all the same.

Charley
C R Huff

I forgot to mention.... it sounds like its running rich, carbs adjusted for to much fuel ....classic sign of black exhaust smoke

As to the oil... 3 liters, im assuming its leaking out, if so id make sure the hose to the carbs from the timming cover is working properly

I dont think your burning the oil, if it was... the exhaust smoke would be blue

So may just need a carb adjustment... or considering new carbs, it could be the wrong needle....are the carbs duel SU hs2 spec. ??? ....

Id try a compression check and a vacume gauge check those 2 test will say alot about if you need a new engine or not....

Another thought ive got.... you said you replaced the Achilles with new... does that mean a new dissy also ??? If so that can be a real issue as well if its not the correct curve

based on what your saying, im leaning towards you dont need a new engine just alot of adjustment

But i still stand by my orginal comment that this car may not be a good fit for you at this point in your life

Keep us posted

Prop




Im
Prop and the Blackhole Midget

Charly is fast with his fingers today

:-)

Charley,

Considering we said basically the same thing....it might be time to find a new hobbie, hahaha

You have to admit, some days its like shooting dead cleaned catfish in a 1 gallon bucket of water for lunch

Prop



Prop and the Blackhole Midget

Prop,

A new hobby? Maybe like shoveling snow and insulating the plumbing?

Charley
C R Huff

Charley Ohhhh....

Unfortantly... im trading you the snow shoveling for replacing a shower water facet

Im wishing I had taken up the hobby of pipe insulation before 2 days ago

I HATE PLUMBING repair work

Luckly its in the 40 s today, and 60s tomarrow.....but cant wait for a high of 5 on monday

Ive decided im not shoveling snow this winter....just keep running over it with the truck....so far, that plan is ...."golden"

Prop

Prop and the Blackhole Midget

Trev,
I haven't seen the Safety Fast article. I didn't get much chance to investigate nor any suggestions from the Aldon chaps. They diagnosed my problem, supplied and fitted a cure, tweaked the needle on my HIF44, and found an extra few hp all for the price of my entry! Excellent. To be honest I was glad to be driving home to Blackpool under my own steam.
I've just bought one of their Amythyst programmable kits, ready for my replacement motor. (Josh, it will be a 1360 with RE130 cam Calver head 10.2:1)

Mark
M Crossley

This thread was discussed between 19/01/2014 and 25/01/2014

MG Midget and Sprite Technical index

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