MG Car Repair: weber carb and distributor problem, spic and span, psi max

Question
Hi Howard, I have a 69mgb, bought it from a auction few years ago. The car runs pretty good but smokes like a freight train, not oil burning but running to rich. Plugs soot up bad and sometimes foul out. The weber carb which sits on a piece manifold has no I.D. tag. I took off the carb clean it spic and span still running way to rich. I found numbers on the bottom plate 38dgev, does this sound like the right carb for this car, from what i read most common weber used is the 32/36. I don't know whats been done to the car. The car is in good shape and i love  driving it,I have no problem spending money on this car to get it running right.Someone put a cheap ecco all plastic fuel pump on it and it leaks from a crack in the housing.The points distributor is weak.SO after all that my question is what weber carb, fuel pump, and new distribitor would work on this car. I am familar with all the websites for parts, moss has a electronic distributor called the flame thrower.I know fuel pressure is key. Also the motors compression test was about 180 on all cylinders dry,210 wet. Oil pressure about 50 at idle 75 road speed. Does this sound right. I know iam asking alot but any help will greatly be appreciated. I love my mg.


Answer
Hi Mike,
Smokes? meaning black smoke? I have no info on a 38 DGEV Weber carb. However, the number is usually the venturi size and the letters mean the configuration and features.

The carb could have been taken off of some car that it was jetted for and is too rich for your car. I would first check to see that the choke system is not dumping fuel in and if that is ok, check the fuel pressure from the pump to see that the pressure is not making it flood. (1.5 to 3 PSI Max) If all that seems ok you should contact a company like Red Line in CA or any other Weber parts company (A search on the net should net you several) to see what jets should be used in an 1800 cc engine with that carburetor on it. They may be able to tell you what kind of car it was meant for. It does not matter what car it was meant for as long as it is jetted for the engine. You may have to buy some jets in a range to get it correct. The only thing a larger bore carb will do is possibly make it have low RPM power problems but might gain a little power at high RPM.  

Your compression is a little high for a 69 but it may have had the head resurfaced or excess carbon build up. The oil pressure is also a little high but that can be the weight of oil used or difference in oil pressure gauges. Check it at the block with a hydraulic gauge to see if it matches. If the engine were recently rebuilt all that could just be the result of that. I normally see 69s in the area of 135 to 165 compression and 35 PSI at idle and 45 to 65 PSI oil pressure with 10w 40 oil warm.

As long as you don't have thick oil in it I would not worry too much about the readings.

You do have to watch an overly rich mixture as it can cause the oil on the cylinders to be washed of oil and cause piston and ring problems. Even though a slightly rich mixture does give you extra horse power (up to 40% above stoichiometric) but above that it starts causing problems.

Howard