Valve Rattle?

[88STANGMAN]

Help i have noticed what sounds like valve rattle when the engine is under a load and RPMs are above 3500. The car is a 1988 GT 5.0. It has just had a tune up also.

 

[stang22]

Is it pinging or detonating? What do you have your timing set to?

Tim

 

[88STANGMAN]

Sounds like detonation-just bought the car so i havent checked the timing yet. Just seems to do it under load. Also backfires some going up hills.

 

[stang22]

If it does it under load, that could be a sign on detonation. What type of fuel have you been using? Double check your timing as well.

If you are not sure how to do it, here is a little write-up I did to help out.

http://www.leemotorsports.com/stang22/timing2.htm