Strange Popping noise from Engine (MGA)

[parkerw@juno.com]

Hi listers,
        After attempting to replace the steering rack boots, (*&!%&#@!
jam nut, tie rod, and anything else down there)  I was pulling my MGA
back into the garage when I noticed a strange popping noise, NOT a
backfire, coming sort of between cylinder firings.  It was about 3/4 the
volume of the engine running, and seemed to be coming from the engine. 
Two questions:
        What is it?
        How do I fix it?

TIA,
Parker Whiteway
57 MGA that could end up with a for sale sign if it dares throw any more
freaky problems at me.