While driving back from the fun car show in Kent on Sunday, June 26th, I started to hear a noise like noisy valve tappets coming from the old L24, (now with just under 200K miles), especially when the engine is running at 2500 RPM or higher. Since I adjusted the valves not that long ago, I was surprised to hear the noise from what I thought was coming from under the valve cover. So after getting the car home without incident, I removed the cover and proceeded to adjust the valves as I normally do, wishing I had three hands to do this delicate procedure; one hand for the lock nut, one hand for the adjusting nut and one hand to slide the feeler gauge. Somehow, I seem to manage to get this job done with just two hands.
After buttoning up the valve cover and wiring, I started car and took it for a short test ride, only to find out that the noise was still there. BUMMER! So, I did the same procedure again, this time carefully checking to make sure all 12 of the valve stem "caps" that are between the valve stem and rocker arm were in place and all 12 of the tension springs were in their proper locations. All were in place and looked good
. Finally, I looked down into the front end of the engine checking to see if the timing chain was very loose or if anything was down there that didn't belong. Everything looked OK but I did notice that the arm of the mechanical fuel pump seemed a bit loose. I was able to move it front to back more than I thought it should move 
. Sure enough, after starting the engine up again, the noise was still there 
.So now, I figured it might be the mechanical fuel pump, which, if you remember, I have had many problems with before. This Airtek model pump has the single piece stamped top on it that I found worked a lot better than the "original style" screwed top pumps that I tried previously (see my old posts on this). However, after removing the pump, the arm and spring basically fell out of the of the engine in individual pieces!
After a more detailed inspection, I realized the pivot pin which holds the arm into the pump casting was not securely fastened to casting. It should have had the casting peened over the shaft to properly secure it. This, I suspected, was the cause of the noise that I was hearing. After replacing the pump with another which seemed to have a pivot pin better secured than the other pump, I finally got the car started and running again. Yippee! My main concern now is it appears that the quality of these aftermarket parts are really bad or questionable at best.
Drive on!
