MGB quad carb mgb???

[erniecaptr7]

ive seen people quad carb triumph spitfires before but does anyone know if it is possible to quad carb a 1980 mgb???

 

[elvacar]

Not practical as the Head has only two inlet holes as in one hole for two cylinders

they are bi-furcated or split . The cross flow head (Pierce, Derrington) that allow for separate ports

and 2 twin choke webers - I have not seen a 4 SU application

(The neatest deal is the SU they made to work like a weber - twin chokes twin dashpots

https://retrorides.proboards.com/index.cgi?board=general&action=display&thread=88353

Triumph Lemans cars - Maybe others)

And there is rumors misty and mysterious of a Weslake head for the engine that had intake over exhaust on the same side - special cam cover - 4 holes in - 4 holes out

Could have been used on an ill fated Elva Courier Lemans run - but who knows

Hush Hush on the QT no one in the MG world knows about this

It is an Elva secret only - Weslake and Elva were right next door in Hastings and Rye - or so I was told



Weslake - Oh yeah those were the guys with all the patents listed on your valve cover

 

[erniecaptr7]

those look awesome....is there any way i can get my hands on a pair of them and where would i look?

 

[elvacar]

Rare as hens teeth I am afraid - I want to recreate these in Billet using 1.25 Dampers and needles

float bowls

https://www.morris-minor-conversions.co.uk/#/weslake/4534824178

Here is something most MG Guys never knew existed an A Series Weslake head

an active program prior to the all consuming Gurney Weslake effort for Formula 1

(Was there a more beautiful car - ever made than the Gurney Eagle)

This head design keeps the spark and fuel separate as BMC intended

and the fuel swirling as Weslake intended - utilizing the same combustion form.

Note: Weslake designed the MGA Twin Cam Head

The valve cover would be shallower on the Weslake Head - carbs a little higher

if using a Weber - it would the MGA OK - no Issue MGB

Or maybe the usual teardrop bonnet bulge ala TR4 to indicate a subtle hint of power

https://www.elvacourier.com/story/part2.html

Or why would Derrington have to make a special manifold for this car - B series heads are B series heads after all - it would have been tooled years ago at the dawn of the MGA & Magnette

Intrigue

The real MG aficionados are apoleptic - how could this go un noticed - who was paying attention
why were there no factory notes - Where is Eric Boreham to set this straight - imagine BMC guys lifting special blocks and know how out the back door -

Was there a better design available - did Pierce tool up the wrong head for MOSS to sell to us.

Anxious readers

a 10K rev MG engine for LeMans and it was never used in anger - built by students using a BMC special block and Buick V8 followers - 2 liter -- Interesting

Where did this motor go - what power did it make to push the car to 150 mph

I have some of the story - maybe somebody has another piece of the puzzle

 

[elvacar]

Oh another little clue

----

Harry Weslake and Frank Nichols of Elva were good friends - Shops very close together in Rye

England in 1964 - i was there in 1983 - flow benches all intact

Harry designeds the IOE Head conversion for the flathead ford (4 cyl english)

that Elva sold and used on a few customer sports racing cars

but the head did better in sales to Nigel et al to hop up the family Ford Prefect

https://www.elva.com/story2/ioe-conversion-zoom1.jpg

Interesting how small England was in 1954

 

[Hap Waldrop]

More carb than given engine needs never makes more HP, and almost always run crappy. I seen the guy in Oregon who uses motorcycle carbs on Triumph Spitfires engines, I think it's more bling than anything else. You have make a bunch of HP mods to a street MGB engine before you would every need any more carbs than the twin HS4/HIF4 SUs on a MGB 1800. I'm currently building my own personal MGB street engine, 1900cc big bore, exetensively ported head with 1.7" gas flow intake valves, 10 to 1 compression ratio using a APT VP12 billet cam and vernier to dial in the cam timing in. Now this engine woud be a canidate for twin HS6s, but the truth is why the bigger carbs only offer me wee bit more top end HP, the smaller HS4s with a few mods will be a faster responding carbs for sporty drivng, and not give the car that big carb intial bog almost all MGBs have with too large of carbs.

 

[elvacar]

Hap:

Don't you also mod the HS4's for flow to improve the top end. A big Weber on a B never made much sense. Flowed carbs got the job done

What no bite on the Weslake B series head

Also running APT's billet VP12 cam, Vernier - Early ported B Head 1600 40 over, high ratio lift - running H4's so that the car is original to it's build. - and I have no issues with airflow - just dialing the right needle/mixture - too rich at altitude

 

[billspohn]

I've owned these and fiddled with them on TR and MG (crossflow) engines.

The SU DU6 was used on several cars including the Climax FPF used in the Cooper Monaco, the Triumph TRS, and prototype MGA Twin Cam racers. They were discarded in favour of Webers in the Twin Cam development program. Nice historical curiosities, but not all that useful.

I rebuilt mine and finally sold them for use on one of the TRS cars a number of years ago. FWIW it is incorrect to say that they are a quad carb, any more than a Weber DCOE is a quad. They are both two barrel carbs, so two carbs total. I much prefer the Weber option and would probably have stuck these on my wall as display had not a guy that really needed them popped up.

I do keep a few Webers going:

 

[elvacar]

Bill:

The Islero is beautiful - i remember it for having the slowest turn signals and windows (shared with Aston) - What car and where did the finned valve cover come from - I assume the Jamaican

THE webers are nice - but I think the single DCOE on the non- cross flow looks out of place

while the Quad setup on the twin cam looks absolutely correct - aesthetics wise

I friend in Rye England is tracking down the drawings from Weslake - they really should be archived

like the Henry Miller ones in the US.

 

[billspohn]

The finned valve cover is on an MG engine in my TVR Grantura Mk 3 race car, on an HRG Derrington crossflow head.

The Jamaican uses a 3.4 GM V6 which is injected.

As I pointed out, the Webers on the Twin Cam engine are in no way a 'quad set up. There are only two carbs. Would you call an American 4 bbl Holley a quad set up?

 

[Hap Waldrop]

Hap:

Don't you also mod the HS4's for flow to improve the top end. A big Weber on a B never made much sense. Flowed carbs got the job done

Yeah I open up the stock MGB velocity stack to 1.5", do so lathe work on it as far as putting a wider angles on it to get more air in, counter bore the mounting hole to run a KN RU-4410 cone air filer like we do on the SCCA race car, then port match the carb to velocity stack, so it get opened to 1.5 on the front side as well, thin the shaft a bit, and also put a knife edge on the butterlies, and radius the piston edge a bit to help flow at aprtial opening. Here's a set that will be similar to my street cars I doing for vintage race car, he waned built so if if ever wanted to put them back on street car he could, so we didn't thru bore them, they are still fully bridged.

 

[Hap Waldrop]

Here's set of Huffaker HS4s I restored a few months ago, they were thru bored.

 

[Hap Waldrop]

here's a close up of the stack and carb throat, notice the Huffaker jet wing, it was upposed to guide the air flow over the jet, which sticks up in a thru bore carb, also notice the bridge is completely gone, these were the hot ticket for track, but don't idle real good, so horrible for the street.

 

[elvacar]

Thanks

I saw another set that had extensive mods - soldered butterfly- reduced shaft - knife edged

and not thru bored - but a vestige of the bridge

the brass piece provided enough of an impediment in smooth flow as it almost forms a virtual bridge



In trying to keep my car looking exactly like the a period article I have kept the MGA air cleaner

housings hiding K&N filters & minuscule radiused plates - no room for stacks

Hap - the guy that does all the Nascar/Indy/F! heat shielding lives in Central Oregon

he is ex McDonnell Douglas and supplied McLaren with the Gold stuff under the hood on the F1

Looks better than the red stuff on the bowls and not too expensive



Could even keep the Blower cool on the SC cars

 

[Cottontop]

does anyone know if it is possible to quad carb a 1980 mgb???

Given enough MONEY and TIME, nearly anything is possible...

Here is my attempt to quad SU the SBF in my 1959 Healey.

It has cost MUCH more than I should have spent and taken MUCH longer than it should have taken and when I finally push the "fire" button, I hope it will all work.

I have also removed the up-front distributor in favor of a crank timed computer system.

Tim

 

[elvacar]

Got to admit it took some guts to do that, so do two carbs feed one bank - the manifold looks split

At first I thought it was photo shopped - got to like it though

Re adds the British element back to the car

Aircon - you don't need no stinking aircon

The only thing better would be the 4 bore webers

Scott Philiben

 

[billspohn]

Jensen tried exactly that on the 361 in the early 60s on the first CV-8s but ended up getting better service from an American 4 bbl carb.

 

[Cottontop]

so do two carbs feed one bank - the manifold looks split

Scott,

No... The intake plenum is like a hollow cigar box mounted on edge and is bolted atop an Edelbrock 4-barrel manifold.

EACH carburetor dumps its fuel/air into the box where it swirls around and is then sucked down to the Edelbrock and distributed to the cylinders by the fuel runners. It is just like a big 4 barrel carburetor on a single plane intake manifold.

There should be no "balancing" (e.g. adjusting to make sure that 1-2, 3-4, 5-6, & 7-8 all the the same fuel/air mixture) required because each cylinder will see the same fuel/air supply as every other cylinder and as the SUs are vacuum operated all cylinders should see the same vacuum source.

THAT is the theory! Theory looks good on paper, but I am curious to see how it all REALLY plays out.

My car has a 4 speed automatic overdrive transmission and has an arm that must be advanced at the same rate as the throttles are opened. This arm tells the transmission how much "load" there is. Similar to the vacuum advance on a distributor.

The tricky part was figuring out how to pull that arm with the throttles. My solution was to put another anuminum pulley on the BACK of the intake plenum connected to the front pulley by a stainless steel shaft.

Now, when the accelerator cable pulls and rotates the front pulley to open the butterflys, the rear pulley rotates and pulls the transmission cable.

I hope it works that way also

Now that I have the ignition computer working with the laptop that is used to set & tune the ignition advance curve, I should be days away from lighting it up.

Here's a zoomed-out view.

Tim