QuestionQUESTION: Barrie,
Its a 1977 MGB (single carb)number #175-cd-2 (the zenith carb co.)
the vacuum port you show in the photo has the EGR valve hooked to it. Is this the wrong set up??
The unit that I described that I feel my be the controller is #59 part # 145-740 vacuum advance valve; I think this is what controls the vacuum to the vacuum advance? (2 wire hook up one black one yellow & red).
Another problem ...went to start the car and I cannot seem to get it into gear (gears grind) if I turn the car off put it into gear it will go. I'm puzzled...hopefully something broke loose??
It shifted great up to this time with no problems!?
I checked the clutch fluid (low)& its piston sleeve appears to be rough or dirty. I will try filling & purging the system to try to remedy the problem. Is there something else I should be looking for?
thanks much as always for your expertise
pete
ANSWER: Hi Pete. The first part of your question refers back to a previous answer. You refer to part #145-740, which is described in my workshop manual as a `Transmission control spark advance solenoid valve'. It connects the vacuum pipe from the single carb to the vacuum advance unit on the distributor. It is basically a shut-off valve that only allows the vacuum pipe to operate when it is energised. The wires to it are Yellow/Red (energiser) and Black (earth). It is energised via a micro-switch, and apparently it only operates when the overdrive is engaged. It looks very complicated, and it is only on USA cars, not UK cars, so I have no experience with this setup. I hope my information is of some use to you.
The clutch problem sounds like a leaking hydraulic system. You are losing fluid, probably at the clutch slave cylinder underneath the car, or possibly the flexible hydraulic pipe attached to the slave cylinder. Get underneath and have a look. There will probably be a puddle of fluid under the car. Replacement flexible hoses and slave cylinder repair kits are readily available from Moss Motors.
---------- FOLLOW-UP ----------
QUESTION: Thanks for your prompt response.
This vehicle has no overdrive that I aware could this be bypassed as the lines are not hooked up & damaged?
I still do have the distributor vacuum problem? Where should the vacuum be pulled from? Can I tee off the vacuum port that the EGR valve is pulling from?
regards
pete
AnswerHi Pete. All MGBs made after 1976 have an overdrive as standard. What gearknob do you have? There should be a tiny switch built in to the top of the gearknob.
As regards the vacuum, you should connect it to the correct union on the carburetter, not the EGR takeoff. Look carefully underneath the carburetter with a small mirror. The union should be visible.
