Just bought this 1400 a series! Now what to do...?

[moggymaniac]

Have just won this item on eBay...a 1275 midget engine offset bored out to 1400cc. Description as follows:

"This is an offest bored 1400cc A series in line engine which would fit a Midget or A H Sprite even a Moggy minor or any in line A series car.
The engine was built a number of years ago by Mike Barrett at Lincoln The engine is offset bored with 74mm pistons giving it a cc of 1400. The crank is I believe a Marina crank which is a larger big end giving the bottom end more strength. To help with power the engine uses a 286 cam which gives the engine a big ability to rev and create power.
It should be remembered that the larger the cc the cooler the cam will appear.
Finally the engine has only covered about 1000 miles without issue before I swapped it in my car when I developed a turbo
Please be aware that the engine does not have a cylinder head. I do have a standard Midget head if required although I would be looking to find and modify a MG metro head for the engine"

So...besides all the trans alterations needed for my current 1098 to withstand the extra power which I'm fairly informed on, what is the best cylinder head to go for? I know the cam is pretty lairy for a road car (yes this is going in a road car!) but I'm thinking with a 940 head worked to the right amount I could make this work on the road and get 100BHP (??)without too much issue, what do you all think? Will a 940 head need skimming? If so how much to get the best compression for a street able engine? I'll be running a HIF44 carb and have a 3 branch tubular exhaust manifold, should be fine with the right needle I'm guessing....if so which one? Would I be able to use a standard cast really let assembly from the 940 head?nik guessing the rocker assembly from my 1098 won't do it. I'm relatively inexperienced with calculations with cam lift etc so any advice would be greatly appreciated

[irmscher]

Try and get hold of Tuning BL,s A series engine by David Vizard that will tell you most things

[philthehill]

Well done in winning your 'e' bay bid.

Use the best quality head gasket you can get as there is very little land between No: 2 and No: 3 cylinder bores.
One of my spare blocks (1275cc Midget) is offset bored to 1400cc (74mm bore) and it is surprising how the gasket manages do its job with so little metal to hold it in place.
Just because the Marina crankshaft big end journals are of a larger diameter does not make the crankshaft any stronger. The journals were made bigger to compensate for the use of a lesser grade material in the manufacture of the crankshaft. For 100hp plus you should aim to refit the 1275cc Midget crankshaft.
My other spare 1275cc block (Marina 'A' Plus) is just about to go off to Oselli to be offset bored to 1380cc (73.5mm bore).
The beauty of the 1380cc re-bore is that you still have one more re-bore to go; and the reduction of 5cc per bore down from 1400cc does not make any perceptible difference.
74.7mm bores are possible but not so reliable as the metal remaining between cylinders No: 2 and No: 3 is reduced to 0.065".
The Vizard book will tell you all you need to know and more in tuning the 1275cc or in your case 1400cc especially regarding camshafts. A good all round camshaft (even for road use) for a 1400cc is the Megadyne 286 which I had fitted to the MG 1400cc engine.
Amended note:- You will have to use the 1275cc engine push rods as they are slightly longer to compensate for the taller block as pointed out by bmc below.
There is nothing to stop you using the 1098cc rocker gear but it would be better with the 1275cc rocker gear so as to get the valve gear geometry correct otherwise you could end up with valve guide and rocker wear.
As regards the head I would obtain and fit a standard MG Metro 940 head and see how it goes - then work forward from there.
The Vizard book will give you the standard combustion chamber cc (21.4cc for a unmodified 940 head?) and divide that into each bore i.e. 350cc and that will give you your compression ratio (without taking into account the head gasket volume) of 16.35 - 1 which is way too high for a road use engine. So on the face of it you do not need to skim the cylinder head - more like increasing the combustion chamber size by re-shaping the combustion chambers as per the Vizard book.

Any questions please ask.
Phil

[bmcecosse]

In my view you are heading for trouble... An engine like this is really not for everyday use - the 286 cam will be far too peaky, and the air flow will be limited by the head anyway - so there won't be the possibility of 'revving' the engine to get the best from it. The head gasket will always be a worry.. The longer pushrods are needed because of the taller block - not the 940 head. You can use the 1098 rocker gear - but you must realign the rockers to act directly over the valve tips - especially with that no doubt high lift camshaft... I am suspicious of why the engine is for sale after only 1000 miles - especially when no head is included. Inspect the block carefully for evidence of the gasket having blown. With the thin metal between the bores - if it blows once, it's difficult to recover the block without stripping and refacing - and of course skimming down the piston tops to match... Good luck with it all!

[moggymaniac]

Cheers for the info guys! You can see the listing for yourself:
http://pages.ebay.com/link/?nav=item.vi ... ID=EBAY-GB

It does look slightly darker between the two middle cylinders, what'd you think? I'll find out what conrods are in it when I pick it up on Wednesday. I know the cam 286, not sure of the manufacturer of the cam yet. What's the best type of head gasket to buy?

[bmcecosse]

Has to be Marina/Mini rods - there are various types with different weights.... There may be a special gasket for big bore engines - no doubt at a premium price. Check with the likes of Minisport.

[philthehill]

Put a good quality straight edge on the top of the block between No:2 & No:3 cylinder and see if you can get a feeler gauge between the straight edge and top of the block and report back what you find.
As regards head gaskets here is a reasonably priced cylinder head gasket for large bore engines that wont break the bank and is of good quality and sold by a reputable dealer.
http://www.somerfordmini.co.uk/eshop/in ... s_id=15015
If you find and fit a 1275cc Midget crankshaft you can fit the 1275cc Cooper S rods which are made in EN24 material (later ones had rods made of EN21) and are the strongest production 'A' series rods available but are a bit pricy even S/H.
The early Midget rods were the same as the Cooper S (EN24) but later down graded to EN21.
The early Marina rods were made of EN19 and progressively down graded to EN16 and finally EN15.
If you keep the Marina crank a set of Innocenti rods in EN19 are the strongest production rods to suit your crankshaft.
When you check the con rods see what the forging numbers (which are embossed on the side of the web) are as that will tell you the origins of the con rods.

[moggymaniac]

Thanks again,

1) I'll probably go for a 12g940 head with the 1275 rocker assembly, this is a bolt on job, right? Obviously this will have some work done before it goes on.
2)Are midget/mini/marina rods all the same length? I guess it'll have decent ones if it was built by a guy that knows what he's doing.
3) Inlet manifold - will a standard 1275 mini one do the job or do I need oselli or something similar, much power difference between them?
4)crankshaft - i'll look for a midget one on the cheap if this is best for power but i'm not so worried if the marina one will do the job!

I just want to be clear before I get started on what actually needs doing. I'll check the surface of the block once i've got it!

Cheers guys, all very helpful!

[bmcecosse]

The crank makes no difference to 'power' - just to reliability! Many hundred pounds to fit a Spridget crank and S type rods..... Only justified for competition use... You will need the best alloy inlet manifold you can find and a single HIF44 carb. Do try to find a big-valve 940 head - but any will fit in the short term. Again - make sure it is FLAT. May be worth having it lightly skimmed just to be sure......

[philthehill]

bmc - I agree with you as regards the use of a Midget crankshaft with Cooper S rods and the related cost of using such items. The O/P though is talking about power outputs in the region of 100bhp which is just about on the limit for a Marina crankshaft and if he succeeds in getting that amount of power from the engine he should seriously consider upgrading the crankshaft to maintain reliability.

As regards the length of the rods - the 1275cc rods are all the same length but the big ends can be of different sizes/diameter and appearance.
The Marina rod especially if made of EN15 is not a very good rod for a power engine - so are they good? I personally would not use a Marina EN15 rod. If I had to retain the crankshaft I would go for the Innocenti rods in EN19. They can be identified by the bar across and between the webs about halfway down the rod.
In my experience you will not find a cheap MG Midget crankshaft - even when used & S/H they command a good price. Sometimes it is cheaper to buy a complete engine just for the crankshaft. Been there done that. Do not buy a Midget 1275cc crankshaft that has been reground more than 10 thou without it having been tuftrided again. If you are very very very lucky you may find a 1275cc Midget crankshaft in EN40 which has been nitride from new - if you do you will need a mortgage.
The Marina crankshaft should be good for under 100bhp so long as you cross drill the journals for oil transfer have the crankshaft tuftrided, have the crankshaft balanced both statically and dynamically and fit a crankshaft damper and use good quality crank bearings and engine oil.
Inlet manifold - go for a standard MG Metro alloy one. You can always upgrade to a Maniflow or Oselli one later. Try with and without the water connection to see which suits your engine best.
The 940 head (both 9 stud & 11 stud) will be a straight bolt on job (a 9 stud head can easily be converted to an 11 stud if required). You can either dispense with the by pass hose by blanking the aperture in the head and water pump though you can get a suitable water pump with the transfer passage already blocked.
To bring a sense of reality to the proceedings - any work on tuning a 'A' series and doing it properly is going to cost money no matter how high or low a tune the engine is given.

[bmcecosse]

It will take a very special head (= v expensive) to get 100bhp from that engine... And yes - it would all need to be upgraded, (including centre main strap) lightened and balanced to allow the necessary revs.....and perhaps twin HIF44 carbs - or a Weber 48 DCOE.. DEEP pockets required!

[moggymaniac]

OK then, so now you guys have informed me that I don't have enough money to get 100BHP...

If I leave as is with the marina crank, have it balanced etc (perhaps not dampened due to cost), 286 cam, decent (not marina) rods, HIFF44 with the right needle and K&N cone filter, Stage 2 janspeed or something similar big bore 940 cylinder head, MG metro inlet, lightened flywheel, 3 branch exhaust manifold with SS Big bore system...what power can i expect from this 1400? And what compression should I expect to see from this engine?

I need to be realistic on budget and therefore power, plus i don't want to blow it up after 2 minutes...

I had a listen to david vizard on youtubetalking about tuning, and he kept saying 'detonation' - is this just to describe the moment of explosion in the bore?

Cheers again

[liammonty]

I think Vizard is referring to pinking, or pre-ignition, by detonation. If I'm not mistaken it's the American term, and he's lived there for a long while!

[philthehill]

I do not know how much money you have budgeted for your 1400cc to get 100bhp but you should be under no illusions that tuning an 'A' Series to get in the region of 100bhp can be done on the cheap. It cannot.
Having built and used several performance 'A' Series engines including a 1400 cc unit (and about to start a new 1380cc unit) I am more than aware how much it costs to build and tune a 'A' Series to get a good increase in power.
You will need the damper on the front of the crankshaft whether you have it balanced or not.
This is what a well worked 1400cc 'A' series looks like to get at least 100bhp and comprises of a 1400cc Midget block, Oselli stage 3 race head, 649 cam, 45DCOE carb, large LCB etc. etc. It has a lightened flywheel but that does not add to the power only engine pick up/acceleration.
As regards determining compression ratio:- your modified head should have a known compression chamber capacity (say 30 cc including the volume given by the thickness of the head gasket and the dish (if that is the type fitted and which is preferable in a 1400cc) in the top of the piston. Therefore you know the swept volume of each cylinder (350cc), so 350cc divided by the total combustion chamber of 30cc will give a compression ratio of 11.6 to 1. The actual compression ratio for your engine will depend upon the final combustion chamber volume, the dish in the top of the piston and/or if they are flat topped pistons, how far the top of the piston is from the top of the block on TDC, Head gasket thickness are much the same.
Detonation is the point that the fuel/air mixture in the combustion chamber can and will ignite and can be effected by many things so it is important to get things right. Pre-detonation is the air fuel mixture being detonated before the preferred detonation point i.e. timing setting. So I would recommend that you obtain (if not already obtained) the Vizard book on tuning the 'A' Series.[frame][/frame]
Even my current 1380cc has a damper on the front of the crankshaft to help hold it all together.[frame][/frame]

[moggymaniac]

Ok then, well thank you for shredding some light on an area of the car that I'm relatively new to! I'll inspect my engine when I get it, and figure out what the best way to go is. Is 80bhp more realistic for the setup I suggested above?
In the meantime...I'll start a piggy bank... :p

[Kevin]

Don't forget Swiftune when deciding on a camshaft.

[bmcecosse]

To avoid expensive lightening and balancing costs you should aim to stay below 6000 rpm. The 1400 engine will have great torque capability - which the 286 cam will not provide. You should consider the AC Dodd RS+ cam which gets excellent reviews for providing a very torquey power curve. With a decent head (again see AC Dodd for a good head at fair price) you will easily get genuine 85 to 90 bhp without exceeding 6000 rpm and without wrecking the engine. The Marina crank and rods will be fine with this - although a centre main strap is always advisable....