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Sprite single carb

Posted by jewar 
jewar Avatar
John Warlimont
Abbotsford, BC, Canada   can
1971 MG MGB
1973 MG MGB GT

Hi All:
Trying to help a friend get his Sprite licenced. It has had quite a bit performance mod's and has a weber on it.We have emissions test and it won't pass .It is a 1275. He has a parts motor,that is single carb(no carb just manifold). What he is hoping to is put a single su on his motor and detune with the hope of getting a pass,then put his weber back on. Sorry,I know nothing about sprite's so these may not be the brightest questions. Did sprite's progress like the B's and have twin carbs on the chrome bumper cars and single carbs on the later cars. If he does have a single carb s/u manifold on a 1275 engine,what carb should he be looking for and what years used it.
Thanks,John
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Kris Schmidt
Spokane WA, USA   usa

I think a good place to start is why did it fail? Work backward from there. Just 'de-tuning' the motor cold actually put you farther behind. the inspection joint should have given a printout. it will aslo tell you how for out it is. might be just off. also I know some states will let you buy a 'pass'. might be worth the hassle.
7mg2 Avatar
Andrew Hardie
Calgary, Alberta, Canada   can
1969 MG MGC GT "Mr "C""
1972 MG Midget

Since when did B.C air care cars that are 40+ years old?? Seems a little odd, especially if he's going with "collector" plates.

If it is a Sprite ( not a Midget ), it is no newer than '69 and would have had twin HS 2 SU's as standard equipment as did all the 1275 Spridgets. The Weber shouldn't be an impediment to getting it running properly, though it might take an awful lot of setting up depending on which Weber it is.

I'm really puzzled as to why it is subject to emission testing though.



Andy

NAMGBR# 20-7738
AMGCRA# 1678
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jewar Avatar
John Warlimont
Abbotsford, BC, Canada   can
1971 MG MGB
1973 MG MGB GT

Hi Andy:
I believe the car is a 1960. So it follows the same rules as my 71 b did when I got collectors,3 years ago. Must pass aircare initially,but does not have to do a annual reinspection if you qualify for collectors. On top of this the car has to be in a predominately original condition, his car is fairly heavily modified . For some reason,only 1958 and prior can apply for a modified collector plate so not quite old enough. He was expecting air care to get scrapped but at this time it looks like there is a strong lean to keeping it around to 2020. I think that is his problem,he is happy with the way the car runs but it won't pass the way it is. I keep telling him there is people that can make his weber pass,with what u are telling me these cars came with twin HS2's,if they are like my HS4's there is a fair amount of playing around to pass aircare and without collectors would have to be done every year.
Thks,John
7mg2 Avatar
Andrew Hardie
Calgary, Alberta, Canada   can
1969 MG MGC GT "Mr "C""
1972 MG Midget

Hi John,
I have HS4's on my Midget too, so I'd maybe have the same problem as your friend if I lived in B.C. I wasn't aware you guys were subject to the emission police out there with your old LBC's.

If the car is a '60, it's a bugeye and would have originally had a 948 of course. They were fitted with twin H1 SU's which were 1 1/8".
Sourcing a "loaner" set of HS 2's might be his best bet perhaps, as the set up will be pretty close to stock despite the other engine mods.

The HS 4's on my 1380 took a little getting right, but I have the set up for those if you need it. They are on a Maniflow manifold which I know is available here in Calgary. Might even be able to hook you up with a rebuilt set of HS 4's to put on it too. I think it is a superior carburetor set up to a Weber anyway.



Andy

NAMGBR# 20-7738
AMGCRA# 1678
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Alex Wilds
Columbia, SC, USA   usa

My memory is that Weber carbs have no mixture adjustment.... If you want simple clean carburation just for the inspection, how about a single SU hs2 with manifold off a morris minor (cheap and common on ebay or around Vancouver), or SUhs4 single from an Austin America? What sort of exhaust manifold have you?
Bill Masquelier
Santee, Ca, USA   usa

I have lots of HS2's & HS4'4 plus both single and dual manifolds. I am a bit closer than Calgary so if you need parts it would be faster but they should also be available for you up there too.
BillM (in Renton)
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jewar Avatar
John Warlimont
Abbotsford, BC, Canada   can
1971 MG MGB
1973 MG MGB GT

Hi all:
Thanks for the info,I will go back to him and ask more questions. I think I am getting a grasp on a solution.The problem with getting the car through aircare is probably as Alex mentions there is no mixture adjustment,so u have to keep changing jets until u get it into specs, am I right so far. I used to run mini's and I found that a single 1 1/2 on a 1000 worked really well,so I would think it would be the same on a 1275. I am going to try and find out what this single manifold that he has is,probably is for a HS2,but with what Bill is offering, he might be better off picking up a assembly off of him,Renton is only a 100 miles away.
Thks,John
fairmounter Avatar
mike Mike
Pennsylvania, Philadelphia, USA   usa

Moss and Maniflow have a manifold that would work for a single HS6 or HIF44 for about $90 and $300 respectively (it would probably also work for an HS4). The Morris or Mini manifold will basically work, but it might be 1/8" too high for the hood to close. If you buy a Moss manifold and a used HIF44 from a 80's mini metro (ebay.uk), you could probably sell it in North America for close to or more than you would have into it.
59traveller Avatar
Alex Wilds
Columbia, SC, USA   usa

I just pulled single carb manifold off my ride - new maniflow with new SUhif44, (harley eliminator II, vacuum take-off plugged but doable if you put in a nipple), new heat shield, and new KN filter. Bolt on and go. Built from good deals on Ebay. You can see pix of it on the "you show me yours and i"ii show you mine" thread. I'd sell it for $250 (what I have in it) and postage.


Alex - you can PM me if you want
Speedracer Avatar
Hap Waldrop
Greenville, SC, USA   usa
1967 MG MGB "The Biscuit"

I would suggest when you do get a carb on the Midget, for emmission testing lean the fuel mixture out more than you would ever do for street driving for testing, it just a turn of the flats on the carbs, so something you can adjust before testing and then re adjust after testing. I'd say half the LBCs on the road are running too rich.



Hap Waldrop
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Col Avatar
Col
colin renshall
liverpool, United Kingdom   gbr

In reply to a post by Speedracer I would suggest when you do get a carb on the Midget, for emmission testing lean the fuel mixture out more than you would ever do for street driving for testing, it just a turn of the flats on the carbs, so something you can adjust before testing and then re adjust after testing. I'd say half the LBCs on the road are running too rich.
Hope friends of the earth dont read this!Cheating the test station is an art. I should know i've done it many times.
LOL Colin
59traveller Avatar
Alex Wilds
Columbia, SC, USA   usa

DEar John,

Here is the rig I have. SUhif44

Attachments:
59 traveller rig.jpg (35.2 KB) –
59 traveller rig.jpg

surfpea Avatar
Paul Edge
new westminster, British Columbia, Canada   can

Greetings from New Westminster. I've had my dealings with Air Care and british cars. so here's my suggestions. Use SU carbs. It matters little if you use 1 1/4 or 1 1/2 size or a single or dual set up. The engine can only draw in so much fuel air mixture at one time. 1 1/4 and 1 1/2 SU's both have the same jet size so the only variable is your needle size. I had trouble getting a '59 Oxford through, in the end i leaned up the mixtue as much as i could, nut at the top, and went through with it idling at 1250 rpm.It finally passed. Ignition timing didn't seem to matter much. I have all sorts of SU needles if you need any. Good luck.
fairmounter Avatar
mike Mike
Pennsylvania, Philadelphia, USA   usa

What needle are you using?

Very fair price, plus shipping should be less than ordering one from the UK. Perhaps take a video while it is running on the engine if you intend to put it on ebay. Hopefully someone here will pick it up.
mjamgb Avatar
michael anderson
NORTHERN NEVADA, USA   usa

Sounds like John's friend already has a manifold on a parts motor that was likely from some Austin product. I bet Alex has a suggestion as to what car it came from.

Knowing that, build up an HS4 or whatever fits to the specification of that car and Bob's yer Uncle!

Webers do have a mixture adjustment at idle but it is very limited and only intended to "dial you in" that last few bits once the rest of the jets are properly sized.
59traveller Avatar
Alex Wilds
Columbia, SC, USA   usa

Austin America 1100 had a really sweet single casting (intake/exhaust combined) with SUh4. This is for 1098cc and uses that flared header pipe w/ clamp like Mark I midget. Carb has PVC vacuum that goes straight to timing cover charcoal can. I use it on the 1275, works fine. Bound to pass with that sweet set up, just run it a bit lean with the idle set about 1000 rpm.

MG Metro has a fine single carb set up, but kinda rare over here.

Mini Mania has a variety of single carb manifolds for Mini Coopers that sport 1275cc and bigger, usually fitting the SUhif 38 or 44. Bolts right up to the midget with stock exhaust. I have one pictured above. Might have a clearance problem as the stack on the SUhif might
sit a tad taller than stock SU h2.....
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