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Any suggestions on where to start?

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Simon Hughes

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Hello guys, I'm brand new to the forum. Just bought a 1977 MGB that needs some work so I can get her onto the road for this summer. I'm in Alberta, Canada.

I'm not an MGB expert nor an experienced mechanic so this is going to be a learning journey for me and I hope you'll be able to help me on the way.

In general - she starts but sounds really rough (like a tractor). I guessed running on less than 4 cyclinders but have spark on all 4. Looks like someone has removed all of the emission control systems as I've got no air pump and several cut-off and blocked hoses. No major smoke when running.

My thinking was to start with a compression check or pull the exhaust to check exhaust head gaskets.

Any other suggestions?

Thanks.
 
Welcome, Simon!

Check all vacuum lines. Even though hoses are blocked off, you still could have leaks present.

You have the single ZS carb, no? If so, you might check the diaphragm. It can play havoc if split.

I'm sure others will pop in here soon with more suggestions.

:cheers:
Mickey
 
I would also be suspicious of the missing emissions equipment. Some ports have to be blocked, some have to be left open. Get it wrong, and it won't run well.
 
Mickey, Do you have a copy of Tonys "Waking a sleeping MG" ? I can't find mine. Be a good read for Simon. PJ
 
Good morning Simon,

Welcome to the BCF. If the engine has not been rebuilt in the past and had the cam changed the cam has a very good chance of being wiped out. If the valve are not opening enough there is no way to tune it . Just something to check! Bob
 
Old British vehicle...MG at that...no idea on history....

Pull all the plugs, do a compression test. Period. First do it dry. Then do it wet. Record the readings for a starting point.

Look at the plugs. If wet, caked, huge gap, just get some new ones.
Before you put them in, pull the rocker cover. Crank the engine, observe the movement of the rockers. You will be able to discern if one is moving much less than the others. That would indicate a camshaft lobe issue.
Check the valve lash at this point, just to see if they are close.

If they're good, compression is good, put in the new plugs, check points, cap rotor, I'd be ohmmetering the wires from the contacts in the underside of the cap to the plug ends, but that's just me.
Inspect and clean the cap, in and out, looking for cracks of halos. THEN start is and check for vacuum leaks with spray of your choice or a piece of fuel line up against your ear.
How old is the petrol?
Drain it, new filter, new gas, and try again, running until new fuel is in the carb.
Report back.
 
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Don't forget a big container of patience near the door of your shop so you can grab a handful before working on the car.
Another container, of tolerance, might help you get past the "repairs" any previous owner might have made.
You'll find that the many of the responders are well versed in the topic of MG and often willing to share all the info you want and maybe some you don't.
Many of these members also post on the mgexperience forum, so asking in either location will typically generate reponses from the same individuals.
Welcome to the forum, but more so to your new hobby.
Like any other undertaking, the more you put in it, the more benefit you'll reap.

Regards,

Mike
 
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