SX Stinger

Okay, my 84 Z28 has a fairly new engine,only 4500 miles on it. Two days ago coming home from the store i heard i knocking in my engine. I figured it needed to be retimed and I was almost home so i just drove slowly so i wouldnt mess anything up. Well shortly after the pinging started the car began to vibrate and shake horribly. It was like i was diving down railroad tracks except tyhe road is flat and no major bumps. I got home checked the timing and it is correct. However the pinging is still there only when the RPM hits around 1500. I cahnged the spark plugs and also discovered my water pump was bad. So i put new plugs and a new water pump in it and guess what no change. What is wrong with my car. I take care of it and check everything every week. It almost seems like the car is trying to tear itself apart is what it sounds like( it is faint though). I love this car but I think she may be killing herself. Please if anybody has experienced or knows someone who has experienced this problem please respond. I need to know what is wrong and what to do.

Thanks Drew

:hail:

Steve89GTA

I'm no expert but I'd bet it's fuel related..

SX Stinger

Checked the fuel, put 5 gallons of good stuff in and made no difference. Vacuum is high and rock steady, Seems to be worse when engine warms up. Havent checked the Cataletic converter yet, could this be a prob? No vac leaks, seems like a few dead cylinders, but we changed all the plugs and checked the wires. This realy has me confused.

Buck268

Have you removede the distributer lately? I put mine in 180* off once...once. It wasnt kewl at all. Sounds a damn lot like your distributer is off a few teeth. Good luck!

SX Stinger

Thought it was ignition at first because thats what it acted like. just did it all of a sudden on the way home, havent pulled the dist, but yes it does act like the timing is all wrong. moving the dist helps a small degree but will not eliminate the problem. Do the HEI coils get weak? or just quit when they are bad? HELP!!

RB83L69

Things to check, from minor to major:

• Carbon tracking in the distributor cap
• Broken or fallen off valve train part (push rod, rocker) on an exhaust valve
• Timing gear sliiped by one tooth
• Head gasket blown, esp. between #5 & #7
• Rolled cam lobe on an exhaust

Good luck!!

SX Stinger

Thanks i will check all of those things....By the way, wouldn't I get an erratic reading on the vacuum gauge if I had a valve train problem??
I will also check the radiator for bubbles (head gasket) although none of the spark plugs looked like they wre in a steaming cyl.. Thanks for the help. Please keep the suggestions coming!!