One thing to remember is that anything much over 2 psi will flood DCOE carbs. It just pushes past the needle valve and goes mega rich at idle. Second, one thing I always do on those Webers, particularly if they are old, is block off the cold start devices. The plungers often fail to seal, passing fuel and air into the venturi. You can buy blank starter jets from Webcon, and tap the gallery with a 6mm thread and Loctite in a grub screw to eliminate the issue. Weber do a deletion kit but it is a bit dear. Obviously your incorrect jetting needs to be sorted as well. Float levels are critical too. Progression jetting can be the most awkward thing to fine tune on a DCOE, but once they are right, the Weber DCOE is a superb instrument that rarely gives trouble. I love them!
@@Urchfab Be sure to use vibration isolation mounts on the carb or you might end up with float issues due to the vibration. I cracked a couple of brass floats, which leads to them sinking and leaving the needle valve wide open. I learned my Weber lore from John Passini's books on theory and tuning of Weber carbs; he goes into a lot of detail on the design of the progression circuits and the 'families' of emulsion tubes that you might use to fine tune the transition from idle to main jet operation. But it looks like the Haynes book also has at least some of that information.
I used Tipton garage for all of my a-series and Weber carb tuning, back in the day. The old man worked for Downton back in the day and the son Steve worked for Janspeed. They really really know what they are doing and they are relatively local to you. Highly recommended. Oh and that Weber manual and the colour tune takes me back over 20 years. A trip down memory lane 😅
I 'inherited' my dad's 'Colourtune' along with all his other stuff. Never used it but have looked at it a few times. Only have one petrol car at the hosue to try it out on..a 'lowly' Fiat Seicento...
@@malcolmyoung7866 it may not work because most colour tunes are designed for the older engines with bigger spark plugs. Very cool piece to keep though, nice bit of automotive history 😊
Matt, I would try to get some shielding for the sensor cables, and earth it at one end, also make sure the earth for the ECU is heavy gauge wire and goes direct to the battery, not via any connectors.
Magnificent, Matt ! What a riveting story about learning the intricacies of Webers. When they're sorted, can't wait to hear then rorting away and hauling you along. :-)
Hi Matt, I fell foul to those spray bar screws falling out many years ago and ended up drilling them and lock wiring them for peace of mind, the vibration is there nemesis 🤣 lovely looking car btw, you are very inspiring so keep it up, ps gonna buy some tickets now 🙌
One thing to check first is the throttle return, make sure it returns to closed position every time you blip the throttle , otherwise the progression jet is operating. Next is the fuel level in the float chamber. It would be useful to have a lambda sensor in the exhaust manifold with a dash mounted gauge to allow you to check the mixture at a glance .
45F9 idle jet, F2 emulsion tube, 180 main jet, 200 air, 45 acc jets, 0 bleed back valve, 38-40 choke, adjust idle mixture screws to get highest rpm. this is starting point for 1293cc.
Car looks fantastic. Will keep an eye out for you next year? Make sure crank trigger wire is shielded and keep it away from the electric water pump supply too.
Great to see the Mini going at last even though you had problems. The carb issue sounds similar to the one I have on my crossflow powered Westfield. I had to wind the idle screws out a lot to get it to idle but it boggs down if you try to accelerate at anything more than light throttle openings. I will have to try some different jets if it ever stops raining !
The best thing you can do is make yourself up a wideband lambda exhaust reader that you poke up your exhaust, Iv just done my mk2 golf and once you get your head around it it does make a lot of sense
@Urchfab iv ended up adding fuel to the idle jets on my 32/34dmtl weber and taking out about 4 jets worth on the top end, refer to lambda of 1, not afr it's easier to understand then
I used to run a 40DCOE on a 1275 A series with Kent Megadine cam many years ago and took it to a rolling road dyno in Ipswich (witchtune) and the operator got the idle and mid range sorted by drilling the jets musing a small hand chuck and a set of tiny drills. Unfortunately it was running hot so had to terminate before he could get to WOT. If you find yourself in a similat position, make sure to find out what drill sizes they use😕
Having just fixed similar symptoms with my Mini’s A-Series, I would check for vac leaks at the carb and exhaust manifold flanges. That shared bolted joint design is difficult to achieve even clamping force between hot and cold flanges of the two manifolds. Making the flange thicknesses equal is critical. I had vac leaks on cyls 3 and 4 but not 1 and 2. Even with the wideband gauge fitted it was impossible to get it run consistently well. Found the vac leaks, fixed those and it was like flicking a switch…engine ran better than it ever has and no more soaked plugs.
Those scales are trick,, the advantages of very small cars. Is that a genuine Weber or a China Weber. I believe the cheap ones are very hard to sort out. And too few understand them now. 3psi is what they need, no more. No less either or they lean out. While I have never used a return system it is a very good idea. With a triple Webered 6 I discovered I needed two generic Mazda RX3 pumps. Would starve over 5000. BUT to drive around the pits it would go fluffy rich at 2000 rpm. 2 pumps 2 switches Buy yourself an in dash fuel pressure guage. I have found one very good for checking things as you go. Every carb is pressure sensitive and more pressure = more volume within reason.
Carb setup I can only advise getting ahold of Vizard's book on tuning your a-series, I raced minis back in the day (very very long time ago) & was never near a dyno... Vizard's dcoe settings for various builds are pretty near dead on balls accurate and a very very good starting point. I never suffered an issue and made only fine tweaks to his baseline settings...
try a long inlet manifold, I used to have a full race 950 with a 45dcoe which ended up where the original speedo was but which gave no trouble at all, engine built by Mo Mendham
Maybe you already know, but the new Webers (series 151 from Spain) require different settings than the old ones (from Italy). The book you mention refers to the old ones. Setting the float height for example is different as the new ones have plastic floats. they need 12.5mm distance from the cover, not 8.5 mm as the old, brass ones need. Same goes for the number of turns the idle screws need to be turned. There are different types of idle screws (pointy and less pointy) around, some need 1.5 tuns, others up to 5. This info will probably not solve all your problems, but it might help a little. I'm not an expert but I'm (just like you) learning by doing :)
Change the inlet manifold gasket as they have a habit of blowing in the middle of them, i had the same issue as you are having and I took the inlet manifold off and discovered it was blown so I put a new one on and the car was fine.
colortune is not enough. You definitely need wideband sensor. Colortune can use only on idle. More RPMs may cause damage "plug" - blows glass :). With wideband check at idle, at mid rpm's and at MAX engine speed - If the head gasket is going to fail, this is where it will fail
G'day, Weber carbies, I run dual 40mm idf weber carbies on my 63 vw beetle, and they are really a learning curve. But for me anyway, it's all part of the car having fun with it. 🥴 Q. On the welder. I'm looking to buy a mig welder that will weld 23 gauge sheet metal. This one, you are raffling, is it able to mig weld so thin of a metal. And the mini has really come up a treat she looks awesome out on the track. ✌️ Peace.
Don't know if it applies to Webers or not, but from memory of the Dellorto carbs, the float height setting was critical to it's performance and there were several positions it could sit, it would give you similar conditions as to what your experiencing.
@@Urchfab It was a very long time ago but from memory it was a simple steel rule measurement, from the bottom of the bowl to the top of the float. I think it was a wet measurement but don't quote me. I swapped out the carbs on my Lotus Cortina, the Dellorto's were so much better but to be fair the Webers were pretty much knackered.
John at SC supplied me my engine components which I assembled myself (It's great stuff). What spark plugs are you using? I use NGK BP9EV and they never fail up. Using a 45 DCOE and distributor ignition. I'd recommend Atspeed racing in Essex for rolling road calibration. I guess Essex is a bit of a journey for you though. Hope you get it sorted soon 👍🏻
Hi Matt Are you running any vacume advance,If not and if you are using unleaded fuel.That could be it.I went though,exactly the same problem,When i worked at a driving school.here in Australia.When we had to move to unleaded when avgas was being fazed out.The old lead Kent engined Formula Ford cars .would foul up plugs,As the unleaded burns much slower than good old lead petrol.cheers kym
Is it too late to throw those relics in the bin and set up an EFI system? I think you need to flip the sensor on the other side of the block and wrap it in tin foil or something. Modern fuel kills carbs. No matter how good you tune it, leave it for two weeks and you can start the whole process all over again with new parts. EFI is able to clean itself, due to much higher line pressure and modern materials.
if its running on 2 and 3 does it not rule out fueling as your main issue for the missfire as 1&2 are paired as are 3&4 does your ecu come with a coil test mode to bench check it
@@Urchfab That is _way_ too big, as you suspected. For a 1275 in race tune it'll need to be around a 50F11. A standard or mildly tuned 1275 would be in the ballpark of 50F2. David Andrews has a decent page on DCOE tuning, I can't link it but look for "Selection and tuning of Weber DCOE carburettors" and you'll find it.
@@Urchfab The F number relates to the size of the bleed hole in the side of the jet, it's effectively a fine tuning parameter as going up or down a whole jet size makes a big difference. The lower the F number the leaner.
Too heavy for a mini. I put a Suzuki swift engine in mine back in the day. But these days I'd choose a Micra engine. Although this car is for a specific race series and most likely needs to retain the a-series engine
@kevinfromdevon The Honda engine only weighs in about 345 L.B.S.. That is just as heavy as the iron block Austin engine in the car and is an aluminum engine block. Plus it has more horse power.
@@richardbrowne3641 yeah you are probably correct. I know that it had an adverse effect on the handling of my Micra when I swapped from 1.3 turbo to k20 turbo. Now my Micra has a k24, a rear subframe and AWD. So hopefully the balance will be better and it will handle okay. I will find out soon
So you built the car, the engine, transaxle/gearbox and electrical systems, and you've not known the basic principles of carburation. All carburetors do the same basic things. How they achieve that is determined by the manufacturer to get final results. Its basic Physics applied, not guess work and magic. Reading the manual is always helpful don't you think?
carbs are old school, if the regs allowed it it'd be on fi. And the number of people who understand webers gets less each year, so makes perfect sense to me why he's never had to learn them before.
![GT-R Powered 240Z [Dyno Disaster]](http://i.ytimg.com/vi/844PvOyhv0g/mqdefault.jpg)
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One thing to remember is that anything much over 2 psi will flood DCOE carbs. It just pushes past the needle valve and goes mega rich at idle. Second, one thing I always do on those Webers, particularly if they are old, is block off the cold start devices. The plungers often fail to seal, passing fuel and air into the venturi. You can buy blank starter jets from Webcon, and tap the gallery with a 6mm thread and Loctite in a grub screw to eliminate the issue. Weber do a deletion kit but it is a bit dear. Obviously your incorrect jetting needs to be sorted as well. Float levels are critical too. Progression jetting can be the most awkward thing to fine tune on a DCOE, but once they are right, the Weber DCOE is a superb instrument that rarely gives trouble. I love them!
Thanks for the info, I will check all that. Its a new carb on there and I think I'm just under 3 psi so I'll drop it back a bit. Cheers
@@Urchfab Be sure to use vibration isolation mounts on the carb or you might end up with float issues due to the vibration. I cracked a couple of brass floats, which leads to them sinking and leaving the needle valve wide open. I learned my Weber lore from John Passini's books on theory and tuning of Weber carbs; he goes into a lot of detail on the design of the progression circuits and the 'families' of emulsion tubes that you might use to fine tune the transition from idle to main jet operation. But it looks like the Haynes book also has at least some of that information.
I used Tipton garage for all of my a-series and Weber carb tuning, back in the day. The old man worked for Downton back in the day and the son Steve worked for Janspeed. They really really know what they are doing and they are relatively local to you. Highly recommended. Oh and that Weber manual and the colour tune takes me back over 20 years. A trip down memory lane 😅
I will look them up 👍
I 'inherited' my dad's 'Colourtune' along with all his other stuff. Never used it but have looked at it a few times. Only have one petrol car at the hosue to try it out on..a 'lowly' Fiat Seicento...
@@malcolmyoung7866 it may not work because most colour tunes are designed for the older engines with bigger spark plugs. Very cool piece to keep though, nice bit of automotive history 😊
Matt, I would try to get some shielding for the sensor cables, and earth it at one end, also make sure the earth for the ECU is heavy gauge wire and goes direct to the battery, not via any connectors.
Lovely car Matt! Nice job. You will get the tuning sorted!
Look up the book written by David Vizard "how to modify minis". Written in the 70"s huge section on Weber and Delorto tuning and jetting
Another brilliant informative video. Please keep them coming.
Glad to see your still wrenching..
Great explanation of the Weber idle workings Matt. I find it all a black art, but you simplified it for me. Thanks.
Never realised there could be so much involved- extremely interesting video Matt, you’ll get there! 👍😊
Cheers
Magnificent, Matt ! What a riveting story about learning the intricacies of Webers. When they're sorted, can't wait to hear then rorting away and hauling you along. :-)
Looks awesome. Looking forward to seeing it dialled in. Best of luck with the gremlins, everything will be obvious with hindsight 😂
Great content, God speed in your continued tuning the bugs out of this beauty - Keep at it Mat success will come soon.
Matt find a good carb man it’ll save time and temper great build there’s nothing like a quick mini fun and enjoy 👍🇬🇧
Hi Matt, I fell foul to those spray bar screws falling out many years ago and ended up drilling them and lock wiring them for peace of mind, the vibration is there nemesis 🤣 lovely looking car btw, you are very inspiring so keep it up, ps gonna buy some tickets now 🙌
One thing to check first is the throttle return, make sure it returns to closed position every time you blip the throttle , otherwise the progression jet is operating. Next is the fuel level in the float chamber. It would be useful to have a lambda sensor in the exhaust manifold with a dash mounted gauge to allow you to check the mixture at a glance .
Great work, knowledge is power
Fantastic Mini, superb video!
Cheers
45F9 idle jet, F2 emulsion tube, 180 main jet, 200 air, 45 acc jets, 0 bleed back valve, 38-40 choke, adjust idle mixture screws to get highest rpm. this is starting point for 1293cc.
Car looks fantastic. Will keep an eye out for you next year? Make sure crank trigger wire is shielded and keep it away from the electric water pump supply too.
Will do! cheers
Awesome job mate.
Love the Mini.
Thanks 👍
Wow, they still do the Colortune? I don't think even the packaging has changed - that takes me back a good 40 years.
Looks a clean build, very nice.
Great to see the Mini going at last even though you had problems. The carb issue sounds similar to the one I have on my crossflow powered Westfield. I had to wind the idle screws out a lot to get it to idle but it boggs down if you try to accelerate at anything more than light throttle openings. I will have to try some different jets if it ever stops raining !
Great to see it up and running, cant wait to see it at full send on track
Me too. Cheers
The best thing you can do is make yourself up a wideband lambda exhaust reader that you poke up your exhaust, Iv just done my mk2 golf and once you get your head around it it does make a lot of sense
👌
Its on the list!
@Urchfab iv ended up adding fuel to the idle jets on my 32/34dmtl weber and taking out about 4 jets worth on the top end, refer to lambda of 1, not afr it's easier to understand then
Great video, really interesting about the carbs. 👍🏾
Great video Matt 🙌🙌
I can't wait to see the car dialled in
Me too mate
I used to run a 40DCOE on a 1275 A series with Kent Megadine cam many years ago and took it to a rolling road dyno in Ipswich (witchtune) and the operator got the idle and mid range sorted by drilling the jets musing a small hand chuck and a set of tiny drills. Unfortunately it was running hot so had to terminate before he could get to WOT. If you find yourself in a similat position, make sure to find out what drill sizes they use😕
Having just fixed similar symptoms with my Mini’s A-Series, I would check for vac leaks at the carb and exhaust manifold flanges. That shared bolted joint design is difficult to achieve even clamping force between hot and cold flanges of the two manifolds. Making the flange thicknesses equal is critical. I had vac leaks on cyls 3 and 4 but not 1 and 2. Even with the wideband gauge fitted it was impossible to get it run consistently well. Found the vac leaks, fixed those and it was like flicking a switch…engine ran better than it ever has and no more soaked plugs.
I did check that but will have another look. Cheers 🍻
Once you get the idle mixture right, so you don't need to keep blipping the throttle squirting fuel in, it will probably be fine.
Those scales are trick,, the advantages of very small cars.
Is that a genuine Weber or a China Weber. I believe the cheap ones are very hard to sort out. And too few understand them now. 3psi is what they need, no more. No less either or they lean out. While I have never used a return system it is a very good idea. With a triple Webered 6 I discovered I needed two generic Mazda RX3 pumps. Would starve over 5000. BUT to drive around the pits it would go fluffy rich at 2000 rpm. 2 pumps 2 switches
Buy yourself an in dash fuel pressure guage. I have found one very good for checking things as you go. Every carb is pressure sensitive and more pressure = more volume within reason.
Great to see the mini finally driving. What Is that app your using with the scales??
Gunson Colortune was the only way to balance the mixture of twin carbs. Turn the garage lights off first though 😊
Carb setup I can only advise getting ahold of Vizard's book on tuning your a-series, I raced minis back in the day (very very long time ago) & was never near a dyno... Vizard's dcoe settings for various builds are pretty near dead on balls accurate and a very very good starting point. I never suffered an issue and made only fine tweaks to his baseline settings...
alternatively just google: "Vizard Tuning the A-Series Engine"
try a long inlet manifold, I used to have a full race 950 with a 45dcoe which ended up where the original speedo was but which gave no trouble at all, engine built by Mo Mendham
Great looking car. The guys round at the garage at Coombe could of helped with your carb problem, they even have a dyno.
Maybe you already know, but the new Webers (series 151 from Spain) require different settings than the old ones (from Italy). The book you mention refers to the old ones. Setting the float height for example is different as the new ones have plastic floats. they need 12.5mm distance from the cover, not 8.5 mm as the old, brass ones need. Same goes for the number of turns the idle screws need to be turned. There are different types of idle screws (pointy and less pointy) around, some need 1.5 tuns, others up to 5. This info will probably not solve all your problems, but it might help a little. I'm not an expert but I'm (just like you) learning by doing :)
and fuel is different than before :)
Change the inlet manifold gasket as they have a habit of blowing in the middle of them, i had the same issue as you are having and I took the inlet manifold off and discovered it was blown so I put a new one on and the car was fine.
19:25 might also be number of progression drillings... the progression cct worked on a combo of jet and body drillings as i recall...
Love the cheap corner weights but, you should build some frames to sit them in that you can level L to R, F to R.
Its on the list of jobs. Cheers
If the crank ignition trigger wheel has worked loose, that will give you erratic ignition timing, especially at tick over.
Nice to see you again gvnor..... LAG...
colortune is not enough. You definitely need wideband sensor. Colortune can use only on idle. More RPMs may cause damage "plug" - blows glass :). With wideband check at idle, at mid rpm's and at MAX engine speed - If the head gasket is going to fail, this is where it will fail
ps: crank sensor distance to trigger - you need less than 1 mm. Steel shrinkage??
G'day,
Weber carbies,
I run dual 40mm idf weber carbies on my 63 vw beetle, and they are really a learning curve.
But for me anyway, it's all part of the car having fun with it. 🥴
Q. On the welder. I'm looking to buy a mig welder that will weld 23 gauge sheet metal. This one, you are raffling, is it able to mig weld so thin of a metal.
And the mini has really come up a treat she looks awesome out on the track.
✌️ Peace.
Yes it will weld it, it does tig as well which might be better suited when you going that thin. Cheers
@Urchfab
Thanks ✌️
Don't know if it applies to Webers or not, but from memory of the Dellorto carbs, the float height setting was critical to it's performance and there were several positions it could sit, it would give you similar conditions as to what your experiencing.
I will check that. Cheers 🍻
@@Urchfab It was a very long time ago but from memory it was a simple steel rule measurement, from the bottom of the bowl to the top of the float.
I think it was a wet measurement but don't quote me.
I swapped out the carbs on my Lotus Cortina, the Dellorto's were so much better but to be fair the Webers were pretty much knackered.
John at SC supplied me my engine components which I assembled myself (It's great stuff). What spark plugs are you using? I use NGK BP9EV and they never fail up. Using a 45 DCOE and distributor ignition. I'd recommend Atspeed racing in Essex for rolling road calibration. I guess Essex is a bit of a journey for you though. Hope you get it sorted soon 👍🏻
I have a few different sets, might even have those. I'm sure it will be ripping soon. Cheers
Hi Matt Are you running any vacume advance,If not and if you are using unleaded fuel.That could be it.I went though,exactly the same problem,When i worked at a driving school.here in Australia.When we had to move to unleaded when avgas was being fazed out.The old lead Kent engined Formula Ford cars .would foul up plugs,As the unleaded burns much slower than good old lead petrol.cheers kym
Is it too late to throw those relics in the bin and set up an EFI system? I think you need to flip the sensor on the other side of the block and wrap it in tin foil or something. Modern fuel kills carbs. No matter how good you tune it, leave it for two weeks and you can start the whole process all over again with new parts. EFI is able to clean itself, due to much higher line pressure and modern materials.
Tickets bought..
if its running on 2 and 3 does it not rule out fueling as your main issue for the missfire as 1&2 are paired as are 3&4 does your ecu come with a coil test mode to bench check it
It does yes, I can test all the plugs are firing. I also swapped the outputs on the ecu to verify both sides of the coil were working.
It looks so right!!
Cheers 🍻
Your roller rockers need spacing. They are not central on top of the valves.
Interesting stuff..
standard weber
Rolling road deffo..... Pay someone who dies this day in day out... You won't regret it
Kswap it if your not keeping originality Evan a dseries Honda is pretty good with rods and pistons
Its gotta be A series.
I totally get it especially that thing it’s why I kept my car a d series
Nostalgia 😎
👍💪
What size are your current idle jets?
F860
@@Urchfab That is _way_ too big, as you suspected. For a 1275 in race tune it'll need to be around a 50F11. A standard or mildly tuned 1275 would be in the ballpark of 50F2.
David Andrews has a decent page on DCOE tuning, I can't link it but look for "Selection and tuning of Weber DCOE carburettors" and you'll find it.
Ok thanks, I will look that up. What's the F number a reference to? I have some 45f8, 50f8 and 55f8 to try tomorrow. Worth a try? Cheers
@@Urchfabf number is air hole size
@@Urchfab The F number relates to the size of the bleed hole in the side of the jet, it's effectively a fine tuning parameter as going up or down a whole jet size makes a big difference. The lower the F number the leaner.
Do you have a fuel pressure regulator fitted? ... set too high? ...
Yes, set to 3.5 psi
Timing chain rattle
Honda K24 Swap the engine!
Too heavy for a mini. I put a Suzuki swift engine in mine back in the day. But these days I'd choose a Micra engine. Although this car is for a specific race series and most likely needs to retain the a-series engine
@kevinfromdevon The Honda engine only weighs in about 345 L.B.S.. That is just as heavy as the iron block Austin engine in the car and is an aluminum engine block. Plus it has more horse power.
It wouldn't get in the Race Series he wants to Race in
@@richardbrowne3641 yeah you are probably correct. I know that it had an adverse effect on the handling of my Micra when I swapped from 1.3 turbo to k20 turbo. Now my Micra has a k24, a rear subframe and AWD. So hopefully the balance will be better and it will handle okay. I will find out soon
It had a honda engine in it when I bought it.
Oh Matt, you washed your newly painted mini with a broom 🤦🏻♂️
I thought that might trigger a few people.
ditch the music !!!!
like number 144? gross!
?
@@Urchfab a dozen dozens is a gross - 144
Ahhhhhhhhhhhhhhh
So you built the car, the engine, transaxle/gearbox and electrical systems, and you've not known the basic principles of carburation. All carburetors do the same basic things. How they achieve that is determined by the manufacturer to get final results. Its basic Physics applied, not guess work and magic. Reading the manual is always helpful don't you think?
Ok thanks Albert
carbs are old school, if the regs allowed it it'd be on fi. And the number of people who understand webers gets less each year, so makes perfect sense to me why he's never had to learn them before.
Always a good show
Good to hear you’re helping out Home built Jeff down under
Had a pair of moddied hif 6 on my 1430... great mpg on motorway.. and a ripper on track...? Bit easier to set up i believe.. !