Any MGB 1800 engine mechanics out there....

[bandit67]

First cousin calls me, he bought a 1974 MGB with a locked up motor. Owner drove the car for years, parked it for years, and now motor won't spin using a big breaker bar. PO had pulled the plugs and filled cylinders with Marvel Mystery Oil, and still won t budge. Cuz pulled the valve cover and nothing busted/broke. The PO said there was nothing wrong when parked so we don't think a timing chain or rod/main bearing seized . No busted block from a rod hanging out. We don't think it is a tranny or clutch lockup problem either. I have zero knowledge of this engine , whats the quickest way to determine if it's a ring or valve train lock up. thanks...

 

[1 Wild R/T]

Sounds like the easy stuff has been tried... I wouldn't do a whole lot more before pulling the head... Hate to do any serious damage trying to save the work of taking it apart.. It's an inline four... Not like it's hard to pull the head...

 

[69a100]

We don't think it is a tranny or clutch lockup problem either. I have zero knowledge of this engine , whats the quickest way to determine if it's a ring or valve train lock up. thanks...

I'm no MG mechanic either. Did you try the breaker bar trick with the tranny in gear or neutral? Makes a big difference!!! Are you super sure that the clutch is disengaging when the pedals pressed? If the clutch is fine, why not get a good push start and then dump the clutch to break it free? If the PO said that it was fine when parked is either lying or withholding information! I got nuthin else. Good Luck

 

[bandit67]

The PO is an older gentleman and has no reason to mislead us. He had already pulled the plugs and loaded up the cylinders with oil in attempt to unstick the motor. Most folks that would KNOW the motor is locked up because of a loud pop, such as something internal breaking loose, would not lube up the cylinders in attempt to break em loose. We got it on a rack, in case it was not in neutral, and tranny is not locked , it all should have turned. Needless to say, it could be possible clutch/tranny is the culprit, as I have not disconnected [yet]. I have had motors with pistons/rings so locked up, I had to take a piece of rebar and bust the pistons out from the backside. But those were opened yard motors, not garaged enclosed engines. thanks

 

[1 Wild R/T]

Stored indoors helps, Maybe worth trying more soaking... But the thing is MGB's have scrawny relatively long connecting rods.... The loads generated by cylinders firing is completely different than trying to un-stick the engine...

Personally I'd pull the head & be ready to drop the crank out so you can deal with each piston individually...

 

[1 Wild R/T]

I'm no MG mechanic either. Did you try the breaker bar trick with the tranny in gear or neutral? Makes a big difference!!! Are you super sure that the clutch is disengaging when the pedals pressed? If the clutch is fine, why not get a good push start and then dump the clutch to break it free? If the PO said that it was fine when parked is either lying or withholding information! I got nuthin else. Good Luck

See my above post... Spindly connecting rods is why not....

 

[1 Wild R/T]

Do you have access to a bore scope?
Those MGB's were prone to blowing head gaskets, if coolant got into the cylinders.....

 

[bandit67]

I just bought a bore scope, but not used one yet. This is a good idea, I will check them out. But, I agree with you , prolly time to start with a head pull.

 

[1 Wild R/T]

They are fun cars, and have a following... It's worth putting some effort into depending on the condition of the rest of the car.... But if you get to aggressive in breaking it free you culd easily make it not worth fixing... Finesse is the key.... Good luck with it...