Oh dear. I am afraid that that is precisely the symptom of main bearing
damage. At least that is how mine manifested itself. Clunking or knocking
sound, rapidly growing louder, until performance was significantly
reduced. In my case one of the main bearing caps was cracked through, so
I just found another engine; but it is possible to do just the bearings
(not the bores or the head), if the condition of the rest of the engine
Sorry this had to happen to your new purchase. I had suspected mine had
some such problem due to the low price, and wasn't surprised when it
showed up. Good luck.
Robert Haigney had this to say:
>I'm a new MG owner, I purchased a 69 MGB-GT, I'm having a problem and was
>wondering if anyone knew what it might be, there's a knocking noise, it
>just recently, I haven't driven the car since it started, the noise seems
>coming from the behind the engine and in front of the gear box, their is no
>problem changing gear and the car turns over fine, if you rev. the engine
>knocking noise starts, and it's there when the car reaches a higher rev
>in any gear (you can't go over 35 mph), you can't hear the noise when the
>is idling, I had a mechanic look at it (not an MG man), he seems to think
>the rod's in the engine, but I'm not sure, the sound doesn't seem to be
>from the engine, anybody have any ideas....?
'66 MGB GHN3L76149
If you're near Mountain View, CA,
it's the red one with the silver bootlid.