Hi guys need your advice. ................Took the car into the shop and they could not get it to run right so they checked for compression and number two cylinder was low (only about 40 psi). The shop recommended taking off the heads and checking for a burnt exhaust valve.
The question I would have is, has any of the process as had been indicated by others above been executed? If the diagnostic effort stopped with solely the "compression test", and post that singular observation you have been advised to begin disassembly, I would advise you to quickly extricate your vehicle from this shop, and go find another, or do it yourself.
Just bought a 68 Shelby gt500 with a 428 police interceptor engine that was rebuilt less than 1000 miles ago but about 18 years ago.
Now, if I were to gander as to the issue (utilizing the all knowing crystal ball.......
), at 40 p.s.i. one would be lead to believe the the valve is not "stuck", but if the vehicle has been sitting without operating for a period of time (you didn't indicate clearly), then particularly the exhaust seats will tend to corrode and the rust does not provide a good seating surface, hence will demonstrate leakage. If this were the possibility, then I would advise one to just drive the vehicle for a couple of weeks and then retest. But this procedure is only to be attempted after ruling out other possibilities where this would be contraindicated.
Maybe a cam issue?
The "cam issue" perhaps should have been answered as part and parcel of the original diagnostic inquiry, and the fact that you are inquiring here indicates that you are have been left attempting to diagnose what you contracted someone else to answer. Perhaps this is just a failure in communication, or as some customers I have encountered state: "I just didn't MAKE them understand" (and I counter with: "the use of the baseball bat has been outlawed".......
), but this also leads one to fear a perhaps unpleasant outcome on the horizon.
Want to do this right the first time.
This "want", does not always mesh well with old cars, and monetary budgets, put I understand the point of view that having to do a task twice in order to get it right isn't economical either. Me.......
, being in the business, witnessing upon disassembly many so called "rebuilt" engines, and being the prima donna that I am, not accepting the "acceptable" or what is described as "the industry standard", that puppy's coming out-a-there, for a complete tear-down, inspection, and thorough rebuilding. But, also note, that's why my projects are never finished.
Scott.