StevieB
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| posted on 2/1/11 at 07:00 PM |
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Any A-Series/Midget experts in the house?
First post of the year, so Happy New Year!
I've been doing some thinking on my BEC midget project and have decided to change direction in a big way and build it as a classic race car to
be used for hillclimbinh and sprinting.
My plan is to use the 1098 that's currently installed and get the chassis and brakes right first before moving on to the power side of things,
after which I will no doubt make my way towards the usual 1380 race engine etc.
However, in the meantime I would like to breath a little bit of life into the engine so it's not completely weak - maybe a set of bike carbs,
better exhaust and maybe a cam (been recommended a metro turbo cam as it'll give low down torque over and above revvy race cams).
I would like to canvass opinion from anyone who knows the cars/engines well (and I'm sure there are plenty who have played with these before) as
to whether there are any easy wins in terms of handling and tuning that offer plenty of perfoamnce per £.
Obviously I will reduce weight where I can, though being a mk1 there's really not all that much meat on it in the first place.
I did have a grand master plan involving a massive project (and associated budget), but I now want to get it on the road and track as quickly and
efficiently as possible and embark on an adventure of developing the car bit by bit.
Any help, hints and tips greatly appreciated.
Cheers
Steve
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MakeEverything
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| posted on 2/1/11 at 07:16 PM |
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Sounds to me like you have had the best advice, though i think id put a bigger engine in it. The 1275 was the race breed, and has the most capability
in terms of power. You can bore these out to 1380 or even 1410 (i think) but not without cost. the 1275 will take the metro turbo camshaft, and
roller rockers and a decent rocker shaft will make a difference too.
Pistons and cranks can be had on ebay for a pretty good bargain, but as with most race engines, beware the race expired items.
If youre going to look at the 1275 (or even keep the 1098) then seriously consider a centre main cap. I have one if you need one, for a reduced
price. Its brand new but will need machining to match the centre main bearing cap which will also need machining.
Con Rods are another weak spot, though only really when youre looking at 1380 upwards, and silly revs.
Kindest Regards,
Richard.
...You can make it foolProof, but youll never make it Idiot Proof!...
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fatbaldbloke
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| posted on 2/1/11 at 07:25 PM |
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Bike carbs pointless as the A-series has siamesed ports. Run either with twin SU's or a single Weber. There's a few horsepower to be had
from a decent exhaust manifold (as well as a better noise), cam and head work quite fruitful although the 1098 is quite a small bore so there are
limits to valve size. However.... the best investment you could make before spending a single penny on the engine is David Vizard's book on
tuning the A-series engine (available from Haynes).
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mookaloid
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| posted on 2/1/11 at 07:25 PM |
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how about supercharging like that yellow one on top gear a year or two back?
"That thing you're thinking - it wont be that."
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StevieB
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| posted on 2/1/11 at 07:34 PM |
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Vizzard's book is top of the list, but I like to research as many avenues as possible.
Bike carbs can be done quite easily by all accounts, you just use 2 instead of 4 - spoke to Bogg brothers ages ago about it and they said it was the
easiest conversion to do as they just adapt the exisitng manifold to suit rather than make a new one. How much performance they give is something
I'm not sure of.
Supercharging is an interesting route - there are some installation kits on ebay to take an Eaton 45. Moss do an off the shelf kit, but at £3k
it's a bit steep - not far off the cost of a 1380 race engine from Peter May Engineering
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plantman
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| posted on 2/1/11 at 07:41 PM |
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buy dard vizards tuning a seris book just about every thing you need to know I beleive he suggests a bit faster cam about 270degrees Plus single su!!
have look a good book
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fatbaldbloke
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| posted on 2/1/11 at 07:48 PM |
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quote:
Bike carbs can be done quite easily by all accounts, you just use 2 instead of 4 - spoke to Bogg brothers ages ago about it and they said it was the
easiest conversion to do as they just adapt the exisitng manifold to suit rather than make a new one. How much performance they give is something
I'm not sure of.
For sure, not saying it can't be done, but more questioning why, there are well proven routes available. What I did see on a Sprite at some car
show last year was two bike throttle bodies with a megasquirt ECU. That might be an interesting project which would give better control of fuel and
ignition.
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StevieB
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| posted on 2/1/11 at 08:03 PM |
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quote:
Originally posted by fatbaldbloke
quote:
Bike carbs can be done quite easily by all accounts, you just use 2 instead of 4 - spoke to Bogg brothers ages ago about it and they said it was the
easiest conversion to do as they just adapt the exisitng manifold to suit rather than make a new one. How much performance they give is something
I'm not sure of.
For sure, not saying it can't be done, but more questioning why, there are well proven routes available. What I did see on a Sprite at some car
show last year was two bike throttle bodies with a megasquirt ECU. That might be an interesting project which would give better control of fuel and
ignition.
It did cross my mind to do that, mainly because I thought it would be a bit more of an interesting project if nothing else - always fancied having a
go with MS, and throttle bodies do look very 
I do think webers are a lot better than bike carbs, but they do cost an awful lot of money by comparison.
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austin man
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| posted on 2/1/11 at 08:04 PM |
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my Austin A35 (Avatar Pic) had the 1098 engine with a kent cam, a 1.1/2 SU metro ehaust manifold and virtually a straight through pipe, The head was
from an automatic which has big valves, the block needed to be pocketed to prevent the valve hitting the block.
I fitted midget race springs to the fron which are shprther and stiffer ( and for sale as I still have them along with a 1 1/2 su and rear
halfshafts)
I also have vizards book on the a series as well if your looking for one . You need to do as much as you can with the head to maximise gas and fuel
flow as this is the most restrictive part of the engine.
One conversion that has been done to the engine of late is the fitting of a BMW motorbike cylinder head which gave significant power hikes
Life is like a bowl of fruit, funny how all the weird looking ones are left alone
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StevieB
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| posted on 2/1/11 at 08:16 PM |
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quote:
Originally posted by austin man
my Austin A35 (Avatar Pic) had the 1098 engine with a kent cam, a 1.1/2 SU metro ehaust manifold and virtually a straight through pipe, The head was
from an automatic which has big valves, the block needed to be pocketed to prevent the valve hitting the block.
I fitted midget race springs to the fron which are shprther and stiffer ( and for sale as I still have them along with a 1 1/2 su and rear
halfshafts)
I also have vizards book on the a series as well if your looking for one . You need to do as much as you can with the head to maximise gas and fuel
flow as this is the most restrictive part of the engine.
One conversion that has been done to the engine of late is the fitting of a BMW motorbike cylinder head which gave significant power hikes
Might well be interested in some of the bits you have - drop me a u2u with prices.
I have a single SU on at the moment but would have to check which one - the engine's been cleaned up at some point so there's no telling
what's been done to date, if anything.
I've loked longingly at the 16v conversion - expensive to buy as a kit, but one day I might spring the £20 for the installation manual that
describes all the machining required and start to pull together the bits needed. Coupled with a set of throttle bodies it's reckoned to be in
excess of 150bhp 
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Mal
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| posted on 2/1/11 at 08:28 PM |
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The half shafts are weak on a Midget. In the dim and distant past I rallied one with a tuned a-series and used to buy second hand shafts 6 at a time
for changing before the splines twisted and then fractured.
I drilled a 6mm hole through the centre of the LSD components so that a rod could be inserted into the axle case to drive out the broken stub of
spline, without needing to remove the differential.
In the mean time someone may have come up with a modification to overcome the problem with the weak deep square section splines.
If not, I would suggest changing the axle to a Ford English one.
Mal
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marcjagman
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| posted on 2/1/11 at 08:29 PM |
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Didn't classic car mag do a how to turbo charge on one of these about 18 month ago?
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skydivepaul
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| posted on 2/1/11 at 08:47 PM |
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first thing to do is check the regs for the class you are going to compete in for hillclimbing.
if you are in modified road going or mod prod you are usually not allowed to change the cylinder head for a different design type, so out with the 8
port head, bike head etc.
as said before use the vizard book for good advice.
cylinder heads need a good reowork to get the best out of them
ditch the twin carbs and either use a single weber or a 1 3/4 SU
decent exhaust and manifold
if you are going to the trouble of taking the camshaft out i would seriously look at swapping the engine at that stage.
once you are competing you will wish you had put the 1380cc engine in as the 1098 is not going to do much.
the 1098 engine gets it extra capacity from a longer crank (same bore size as a 998cc engine) so they do not like to rev as much as the 998 engine.
you will kill the engine if you over rev it.
when swapping engines make sure the A series engine you are changine to will fit.
i am sure there are issues with using the MG metro 1275cc engine in RWD format but cant remember exactly what it is at the moment.
make sure you sort out the brakes and suspension on the midget as they are pants for competition
turbocharging or supercharging will see you move into a different class for hillclimbing. the usual cut off point is 1400cc. forced induction has a
1.4 x multiplier for your engine size. i.e. a 1 litre engine with a turbo would be classed as a 1.4 litre.
cheers
Paul
[Edited on 2/1/11 by skydivepaul]
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austin man
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| posted on 2/1/11 at 09:33 PM |
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the problem with the metro engine is the crank. I believe all the FWD A series engines have an ofset crank there is an adapter that can be sourced
from what I can recall.
The Morris Ital had the 1300 engine as well as the midget
Life is like a bowl of fruit, funny how all the weird looking ones are left alone
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StevieB
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| posted on 2/1/11 at 09:43 PM |
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The series I'm looking at is the Auto 66 championship, which my mate runs his bike in.
I've read up on the class I'd be in and it's the Post War (Pre '73) Classic and Racing Car Class. There is no ref to the MSA
book like there are for other classes so it's no clear what restrictions there are on mods etc. However, there are a couple of mini's in
the class running 1380's.
I suppose the right thing to do would be to ring them up and ask the question on what restrictions, if any, are applicable. It'd be crap to put
together a good spec car that fails the regs and ends up in sports libre against spaceframe Hyabusa mini's and Radicals etc.
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MikeRJ
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| posted on 2/1/11 at 10:49 PM |
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quote:
Originally posted by austin man
the problem with the metro engine is the crank. I believe all the FWD A series engines have an ofset crank there is an adapter that can be sourced
from what I can recall.
The difference is where the flywheel attaches. The RWD cranks have a conventional mounting flange with multiple threaded bolt holes, the mini/metro
cranks have a tapered nose and one large bolt to hold the flywheel on.
Take heed of the advice regarding the long stroke crank in the 1098; they do not like high revs at all, so if you are going to modify this engine
don't go silly with cam choice. That said you can get reasonable power from them.
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britishtrident
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| posted on 2/1/11 at 11:30 PM |
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1275 engine is a lot less reliable than the other A series, very prone to exhaust valve burning on cylinders 2 & 3 and also head gasket
failure between cylinders 2 & 3 also piston ring problems..
[I] “ What use our work, Bennet, if we cannot care for those we love? .”
― From BBC TV/Amazon's Ripper Street.
[/I]
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gator
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| posted on 3/1/11 at 12:20 AM |
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For me definately forced induction. For all round use, a blower...for silly hp numbers an less drivability, turbo. I've attached some (not up
to date) shots of the humble A Series under the photo section. The engine is now distributorless on Megajolt. Good fun at hillclimbs but. Regards,
Alan.
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gator
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| posted on 3/1/11 at 12:22 AM |
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Forgot to mention...Turbominis website is well worth a look. AB
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ianclark1275
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| posted on 3/1/11 at 12:32 AM |
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as per other comments, Check your regs first and work from there.
Vizard book is a good read.
as for the A series,
this is what i would do for a sprint engine:
get a 1275 A+ block - Old Metro blocks are fine -
Use a 1.5 inch HIF ( i use with a 100Tho jet and B needles)
Maniflow steel Inlet and Exhaust system.
12G940 MG Metro head 35mm inlets ----Scrap yard from old 1.3 meastros had them.
Skim to 12 ish to 1
1.5 rollers - try to get full rollers if you can.
Cam would be dependent on use - but dont go mad. MG Metro one is fine. Kent do a replica with very accurate lobe angles which helps (BL's were
a bit variable)
Diff--4.1 gives good acceleration
1275 GT / cooper s gear box with the shorter 3rd gear.
4 pin diff.
rebore +60 with 21253 HC pistons.
Dont bother with:
11 stud drilling - just fit BK450 as long as block and head are flat it will cope.
turbo or supercharge---only if your into A Series engines. ££
Fancy pressure plates - blue standard will cope with most things
High capacity oil pumps - std is fine
Oil coolers- you dont need them, use good oil--Millers CTV 50.
Modifying head--as cast chambers in 12G940 are ok.
Centre main strap--never seen a standard one break.
Fancy Dizzys--Standard electronic lucas is fine---advance curve will need attention with different springs.
Do bother with:
Replace bearings as required -- Cam ones need machining tho
Fit a lighter flywheel---improved acceleration.
Adjustable oil pressure valve-- dont need lots of oil pressure---it limits your top revs.
coolant pipe routes--you can use end core plugs and solder a 15mm copper fitting into it etc..
Decent cooling system - Rover 216 Ali rad fits in front of a mini. (autocool in york is ok for rads)
2 row timing chain
NGK 7 or 8 plugs
Shell V Power fuel + Millers CVL
just my humble ramblings on the A Series.
I would love to build a 16V A Series, im sure theres a few heads out there that will fit!
IC
measure twice, cut once, scrap it, start again.
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MikeR
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| posted on 3/1/11 at 11:09 AM |
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Tried to post this 3 times now from my mobile (msg to Chris on its way about that).
I've been reading up about fuel injecting A series engines over christmas. I've got an idea about how to do it so you don't get
issues with one cylinder stealing the charge from the other. If you'd interested u2u me and hopefully I can reply to that. My idea should work
very well for turbo / super charging at a later date.
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ken555
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| posted on 3/1/11 at 03:57 PM |
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EFI Minis/
Also Canems do a EFI with throttle bodies http://www.canems.co.uk/siameseports.php
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StevieB
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| posted on 3/1/11 at 07:26 PM |
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Hmm, the plot thickens on my engine....
I thought it was a 1098 (because that's what it says on the log book) but I've just been looking at the engine and have noticed it has
'950' cast on the block, and the engine ID states 9-U-L on it. That made me think it's from a mk1 sprite rather than midget, but it
also has a single SU rather than twin.
Piecing together 50 years of history and figuring out what's gone on is a real PITA!
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mid-buggy
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| posted on 3/1/11 at 07:43 PM |
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Turbominis, efimini, minifinity and mlmotorsport for the forums and info.
force-racing, calverst, swiftune for latest developements and people who build fast a35's
BMW K-Head is not a cheap route to go, I was thinking that way and worked out its cheaper to go bike engine (and thats with paying people to sort it
all out for me).
My mate has a k-head mini and the cost so far is scary, but so is his 0-60.
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StevieB
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| posted on 4/1/11 at 01:08 PM |
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OK, got to the bottom of the engine in my car now - it's a 948 from either a Morris or Wolseley, complete with piffly single 1"1/4 SU.
I also now have Vizards book - so cheap power will be from 1275 or Cooper head (if I can find one for not a lot of money!), MG Metro Cam, 1"3/4
single SU with Maniflow inlet, long centre branch exhaust. Anything more than than and I'd be better off buying a 1275 and transplanting.
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