MGB MGB Emission Control I Need Help Please

[WJM]

Hi All I have a 72 MGB with twin carbs the ones with the float chamber below the carbs. The emission control system has been taken off before I got the car. They have just joined the carbs with a bit of rubber hose. Any way what I need to know is how to set my carbs up with no emission control syetem so I can get it runnig better. It runs very sick at the moment. Regards John /ubbthreads/images/graemlins/nonod.gif

 

[Guest]

I have a '72 that the smog controls have also been removed before I bought it. There are bowl vents that are joined together with a hose and metal tubing and go to the crankcase vent on the front of the engine. I have taken the metal tubing off mine and made a connection "y" to join rubber hoses together to go to the front vent. Also there is a rubber hose that connect the carbs together between them for fuel to go to the back one from the front one.
The carbs will adjust normally per instructions in manuals with or without smog controls.
Make sure everything else is fine such as points, timing, vacuum, compression and valve adjustment as all these can effect the carb adjustment. Here is a web site that might help.
https://www.wideopenwest.com/~kottage/tech/tuning.html

 

[WJM]

Hi. Thank you for your reply. I am not sure where the crank case vent is. Is it the one that comes from the tappet cover as this the only vent I can find. This vent goes no where just a rubber hose attached to vent pipe and hanging loose. The carbs are connected to each other by two hoses one is rubber the other is a metal pipe connecting the carbs with a open pipe going no where. I hope you understand what I mean. Regards John /ubbthreads/images/graemlins/cheers.gif

 

[Guest]

I just went out and looked at my car and took a couple of photos. Sorry, I made a mistake when I said the bowl vents went to the crankcase vent. Mine used to have a metal tube between the bowl vents and the empty connection you are talking about used to go to the fuel vapor canistors. Mine now are open to the atmosphere. The crankcase vents are another connection and the crankcase vent is in front of the exhaust manifold. See the photos. I have one of them marked so they are self explanitory. Go to my website at the following address:
https://morethanadoor.com/mgcarbcon1.JPG
https://morethanadoor.com/mgcarbcon2.JPG
Bob

 

[WJM]

Bob Thank you for photos that makes much easer to understand. The carb vents on mine some time spits out fuel or if you block the metal pipe the engine cuts out. If I take this metal pie off like you have it should be ok. As for crank case vent mine has been cut and bent over should I have this replaced and do what you have done. Thank You and Kind Regards John.

 

[Guest]

If gas is coming out your vent pipes, then there is something wrong. The floats are set too high or there is a blockage in the needle valve that wont let the gas cut off when the bowl gets full. Another thing that could cause it is one of the floats leaking and gas getting in it and thus riding lower in the bowl and never reaching the cutoff height. Either way, you should look into this and correct the problem.
The crankcase vent might not be a problem if you don't care about originality. Just make sure the cap on the oil fill hole in the valve cover is the venting type. The crankcase needs a vent and oil will come out seals anywhere in the engine if it isn't properly vented. I'm not sure what year had it but older MG's had venting caps. But any place left open to the atmosphere can collect dust and dirt. The best thing to do would be to repair the vent pipe.
The bowl vents should be idealy filtered in some way too but I just haven't done it. I don't drive on dirt roads so this hasn't been a problem.
Bob

 

[WJM]

Bob Thank you I have set up carbs as you have said. I got a second hand side cover with the pipe still on and connected to the carbs via a Y piece. I will pull the carbs apart and see what the problem with the floats is. Will let you know what I find. Regards John. /ubbthreads/images/graemlins/cheers.gif