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MG Midget and Sprite Technical - Engine choices

Guys,

IM trying to decide what to do with my engine in my midget restoration.
Started off looking at K series conversion but decided against and had decided on a stage 2 road engine
But then i cam across a 16v mini head and am toying with the idea of that , looks a bit complicated as inlet / exhaust are on opposite side to 1275 standard head
Anyone got any thoughts , is there a 16v head available with ports on correct side ?
Also any thought on alu head, will i get any performance advantage other than weight saving ?
thanks
Andy
a chaffey

Andy,
As a converted K series fan I have to say perservere with a K conversion. I promise you won't regret it. Outstanding performance combined with excellent fuel economy and reliability.
Neil (K series)

I'll be devils advocate here, i'll say stick with the A-series in what ever form, otherwise you might as well have a kit car.
So if you want a modern engine, then go for a Judd V10, transaxle & a plexiglass bubble & just have done with it.
Brad 1380

Hi Andy
The first thing to do is turbo that a series engine with a period metro turbo conversion (I just happen to have a complete set up going spare)then once finished buy yourself another spridge and drop a k series in...Best of both worlds...
Sitting on the fence Rob.
Rob Newt

Andy

stick with the a-series

And read up first!
read a lot
read vizard
read Daniel's book
check out the miniforums there are lots of people who have done all with the good old a-series.

My advice
Start with a good fast a-series
Good botom end good head(invest in that that is what makes the power)fast cam, weber good exhaust and good ignition.
And have fun with that.


There are lots of options
-7 port heads
-8 port heads
-DOHC (the 16v you mention and 8V) in several guises
And then you can go and either SC or turbo anny of these options.
All have their benifits and down sides
Onno Könemann

Anything with rubber bumpers: K-series and debumper.
All other Mk's: A-series based (and debumper)
Alex G Matla

Guys,
thanks fr comments so far , bit more to add , would like to use weber 45 with whatever i choose as have one and have just had refurbed .

Onno, the heads you mention where can i find them and anyone you would recommend over others ?

cheers andy
a chaffey

Try this guy:
http://mk1-performance-conversions.co.uk/shop/page9.html


There are more for sale on the site


Alex G Matla

Brad, kit car? I don't think so.
Neil (K series)

Changing the Cylinder head for something exotic is not an easy conversion and is generally very expensive.

I would suggest buying an A Series and tuning that

If you fit it with a great cam Kent 286, with high compression, weber carb you will have an engine that can rev and pull far more than a standard version.

In a couple of years if you get complacent with that then you will be a lot wiser and you can decide on your next combination
:)
Robert (Bob) Midget Turbo

Bob,
thanks i have the original a series and the weber and was 99% set on the a series ... what other mods are worthwhile , i have looked at following

lightened backplate ?
timing gear ?
123 dizzy ?
roller rockers ?
any mods to gearbox ?


appreciate any advice
Andy
a chaffey

Hi Andy

It is all about dosh. :)

If it were me I would do it in the following order until I ran out of money.

286 cam
High CR
1.5 rockers
modified head
weber 45
lightened and balanced engine parts
5 speed gearbox
3.7 diff

most other parts you will hear mentioned are simply nice and will add very little.

IMO.
Robert (Bob) Midget Turbo

Bob,
I would add in a Maniflow or similar exhaust manifold, and better air filters, both quite early on, probably before 1.5 rockers.
Guy
Guy Oneandahalf Sprites

Is it just me then..
Lower the CR, strap a turbo to it, 4.2 diff and have a VERY big smile on your face when your head gets pushed back into the head rest !!!



Rob Newt

Andy

In the first part of my post i mention several books.
All of the questions you ask are in the books and lots more you never thought about!!!

To determine what you want from an engine build you must first understand what all the mods do!
not just list all the posible mods and pick all of them.

we do not want another "Prop" engine build......
Onno Könemann

Neil,
i was hoping Shaun would be along, hence the kit car comment :-)

Rob,
any more photo's?
Brad 1380

Andy

I agree with all comments below... but the real questions might be:

- what do you want from the engine

- how much extra torque/power would fit the bill now (and in future?)

- will you be using it for road, fast road, track days, continental cruising, ...?

If a revvy screamer, fit a 286 cam and Weber

If a torque monster, go for a turbo

Either way, you'll be on a journey and will at some point want some more; easy enough maybe with a turbo (just increase boost is the simplistic answer!) - maybe more involved with n/a engine.

It's worth spending time thinking about the above before you start. If you're only looking for modest increases (say 20-25%), a large single SU, LCB, high-compression head can give reasonable increase in lb-ft and bhp with simple bolt-on mods for a small outlay.

If you're part-way through a restoration, then you should consider a Kseries conversion: my std 1.8 gives 140+ bhp, 160+ lb-ft with 40+ mpg with very docile characteristics - nearly forgot: 0 - 60 in <6s. They are easy to tune for 160bhp; slighly more outlay for 180bhp; and there are other examples up to 209 bhp. For power per £, this conversion can be cheaper than staying with the Aseries (e.g outlay for a mid/top-spec 1380).

BTW - agree with Bob that change in cyl head to e.g. BMW more complex and expensive than a total engine swap.

Try and get a spin in a number of midgets that have been modified using the different route to experience their different characteristics.

A

Anthony Cutler

Neil K series

Neil saw soem pics of your interior on another thread and have a few questions do you mind posting your e mail address so i can ask you offline

cheers
andy
a chaffey

Andy,
Try: pendinedash (as it is written like this) at hotmail dot co dot uk
Neil
Neil (K series)

Have a look here at Neil's Konversion and Rob's Turbo, I may get my car featured here someday. :)

http://starturl.com/lsjro
Bob Turbo Midget England

Can't really beat a Ford crossflow for cheap. easy, reliable power. I fitted a 1300 with twin Weber 40s for 80bhp at the wheels. Very cheap at £300, plus some work fitting. It can be moved back a few inches for better balance and to compensate for a little extra weight. No electronic nonsense, strong and simple and looks good.... and in period.
D le Versha

Having now sold the porsche and bought my first ever four door car I'm back in the fold after a break of a couple of years - the midge will be my only two seater so the imptus to get it sorted is stronger (and it helps that I have a period of enforced time off starting on thursday - not good with a baby on the way!)

Having gone through a couple of engines in various tunes I would advise the following:

If you want a quick, reliable car with zero maintainence and dont mind losing the period look then a K is the best route open to you. Once you start opening up the 1275 and start bolting stuff on it can get as expensive...

If you want to stick with the a series then seek out Alan Ansted who is in kent for advice; its free!

A series options are as large as your wallet but a decent compression 1330 with a 270/280 cam and breathing well is do-able; depends on what you want out of the engine. Buy a copy of Daniel Stapletons book for a what to fit guide, buy Vizard for a 'so how does it all work' instruction manual..

I've gone down the BMW route (you can see it http://tinyurl.com/56v86l) for this build but since I started there have been a lot of 7/8 port heads come onto the market. Let me know if you want more info but they will not be cheap, certainly one of the more expensive options but you do get to keep the a series...




Toby Anscombe

"but you do get to keep the a series..."

Let me guess the casting of the underblock is only original A-series part on that engine Toby?

Oh wait I can see the front engine plate is original too:-)
Bas Timmermans

Only the head changes....everything underneath it stays the same. But of course you will want to uprate everything that you can Bas :-)
Toby Anscombe

I do not agree with Toby that the K route is trouble free.
Just ask Arie

If you go for a hot A-series all the solutions are at hand.
If you go K there are no standard solutions.
Onno Könemann

4AGE Toyota lump

[/thread] :P
PeterJMoore

Didn't know Arie had had problems Onno?
Robert (Bob) Midget Turbo

Arie has had problems with almost all parts of his K midget!

starter
radiator
ecu
exhaust
etc

he has a verry fast and nice K midget but the road there has not been without bumps.

Going for a fast A-series might not give you the ultimate K power, but it will be a lot of fun and give a fast midget.
A K will be faster but not trouble free and you can ask if it will be more fun.
Onno Könemann

Onno you forget to mention the clutch thing. I said dont mention the clutch:-)

Of and something with the brakes but that wasnt K related.
Bas Timmermans

Andy
As you can see a lot of different opinions about this subject

To change to a K Series is not an easy task and needs engineering skills.

To change to an exotic cylinder head is very expensive and does not reap big rewards by comparison to cost.

Fitting a turbo or supercharger to an A Series gives serious performance and is not very expensive but does require good skills and plenty of advice. The advice however is plentiful and given here freely by those who know how to do it.

Not sure what Toby means about free we all give free advice so no difference there then?

As Onno suggested major rewards can be gained by simply tuning your existing engine as I desribed originally. Relatively cheap and easy to do. Just remember to get a 286 cam and at least 11.25 to 1 CR then the engine will be fine throughout the rev range. The only people who don't like a 286 cam are those who fitted something milder and have no idea of the performance they are missing :
Robert (Bob) Midget Turbo

In around 20k miles with my k I've only had one problem ... broken clutch cable. Now re-designed. Hydraulic clutches most unreliable part. A
Anthony Cutler

Sigh, now I remember why I stopped coming on here..

Bob - free as in Andy lives in Kent as does Alan and many others; Meeting someone in real life would be of greater benefit than a lot of pontificating on here and best of all Andy can have a nose around and probably have a go in a couple of cars with different mods. Some how I doubt if you are willing to drive down to let Andy have a go..
Toby Anscombe

Don't come if you don't want to. it is a free country!

The benefit of the web is that we all give free advice and we all have varying degrees of knowledge. When you try to limit that to only one or 2 local contacts you lose a great deal of what the web gives us.

It is sad that you do not agree with that view and you would prefer individuals to only seek advice from one source.

Robert (Bob) Midget Turbo

Try living in Pembrokeshire. The web is your only contact with the outside world!!!!
Neil (K series)

LOL
Robert (Bob) Midget Turbo

Andy

I'm based in Ashford if you want to meet sometime to talk modified A Series - I'm afraid I have little experience with K conversions though... Have had a bit to do with Arden 8 port Minis in the past...

Regards

JB
James B

Guys,

Thanks for all your advice much appreciated, James i might take you up on that offer in the near future.

With regards to other mods i think Rob Newtons car has many i was looking at and i love the overall look of it , Rob would be gratefule if you could mail me any pics / detail or even have a chat sometime , i too hsve been looking at some Peter May / KAD bits and welcome your opinion.

Cheers
Andy
Andy Chaffey

We are messing about with an MSX 7 port A series head at the moment. In standard form it flows a little more than a small valve standard head. in modded form we are getting more flow with a 1.401" valve than we have ever got from a 1.401" race head. Coupled with the separate inlet ports and webers bolted straight on to inlet ports and I think we have a flyer. I am not sure we will lose too much bottom end power due to largish inlet port, leaving the first portion of the port slightly rougher will discourage mixture separation in the boundary layer flow. This is something we have noticed on TR4 heads...don't lose bottom end bhp like the theories might suggest.
Having the Webers straight on the head is good for tuned lengths, especially at lower rpms. As we are dealing with two valve technology I reckon the torque output will be good at lower rpms, four valve technology lends itself to bhp rather than torque. As they say bhp sells cars and torque wins races.
Time will tell when we get to test the results.

Peter
P Burgess

Hi
Any of you Guys running B series engines in your Midgets
Willy
WilliamRevit

B series? god help us if we were!!

Andy are you thinking of doing a Turbo?
hope so!!!
Bob Turbo Midget England

Peter
Keep us posted
i have always been intrested in the 7ports and wil most likely need a boost to get this engine in the triple power digits ;)
Onno Könemann

Hi Onno

I will keep you informed.

Peter
P Burgess

Hi Andy
Call any reasonable time 07770 965009 always willing to talk Spridgets, if you ever come to Peter Mays I dont live far away so could take you for a blast in the turbo to see what you think.


Rob Newt

Yes ive had a fair bit of badluck on my Kseries conversion because of the bad/lousy way the conversion was done.
Ant did his own with a mate and his car is reliable!
Thats because they knew what they were doing and used their brain.
My K-converter didnt...


I cant believe nobody optioned this: why not build in a 1500?
Standard more torquey then an Aseries and if you call Debbs she can turn the 1500 into a beast.
Arie de Best

Bob
I ran a 2300cc B series in my hillclimber a couple of years ago and was just wondering if anyone else has gone that way. Looking for ideas for my next midget with this same engine/gearbox etc. which I have left over from then. {'m a bit of a B series fan.It's the way to go if you want to go FAST
Willy
WilliamRevit

Willy
I'd rather go for a 6cilinder jag engine if you want a big engine up front.
But that will just stay a fantasy for me
Onno Könemann

Onno
To run in MG National meetings here your car has to be MG powered. A good B series engine in a well set up light midget is a fairy lively package Willy
WilliamRevit

Then it is an intresting option

Though i like the reving nature of the a-series more and think the ribcase is way better than the 4syncro B boxes

A 3 bearing B engine with 3syncro box might win me over ;)

You did put the engine in way back i presume?
cutting the heater tray and probably bashing the hell out of the transmission tunnel.
Onno Könemann

Many many years ago I thought some one perhaps the comps department had put the B series in the Spridget but did not pursue it.

As Onno points out the A Series is a screamer by comparrison

If it was an MG engine (Engines fitted to MGs I assume) then a V8, turbo O Series, turbo A Series or a K Series would all seem a better choice :)
Robert (Bob) Midget Turbo

The factory made a B-engined Midget in 1968, raced inter alia by Roger Enever and Alex Poole. (P112 of 'Mighty Midgets...' - John Baggot.

A
Anthony Cutler

Spot on Ant
I should have gone straight to Baggot's bible when my own memory was found wanting. LOL
Bob Turbo Midget England

Yeah I realise that later engines would/should be a better choice but there is something about B series engines that tickles me - besides I've already been down this road before and really if you can keep a B series motor on the boil in a hillclimb they are quite strong and have a lot more torque over a wider rev range than an A series. My old car had the motor set back and across to the left a bit and had exactly 50/50 weight dist. with me in it With the new car I'm hoping to get about 52-53% rear weight
My motor is a bored and stroked full 2300cc's and is as strong as an ox from 3500-7000.
WilliamRevit

William - what you say is good idea: you can't beat cubic inches... the only negative part is the weight... so why not use the modern upgrade to the B ... aka K Series?

(Sorry, had to say it...)

A
Anthony Cutler

This thread was discussed between 24/09/2010 and 01/10/2010

MG Midget and Sprite Technical index

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