1974 Oldsmobile Cutlass V8 Two Wheel Drive Automatic 100, 00 miles
I own a 1979 Pontiac Trans Am with a 1974 Oldsmobile 7.4L 455 in it (and a TH-350 auto tranny). I have spent the last year rebuilding bits of the engine in hopes to drive it for my wedding (in 5 days!).
Before it ran fine. I changed the spark plugs, spark plug wires, distributor cap, converted over to an electric radiator fan and a holley blue series fuel pump, installed an edelbrock torker intake and a 800cfm edelbrock performer carb. I also changed the lifters, pushrods, and rockers because I noticed 2 of the lifters were busted (the retaining clips werent even on them). Everything sounded great while driving it around. It would accelerate at WOT with more power than ever and no unusual sounds or hesitation at all. While driving down the highway I experienced a loud "Pop". The positive battery cable made contact with my headers and melted threw giving a direct contact between my battery cable and header. My car died instantly and once I fixed the wire and got my car started again it had a frightening Knock that is RPM driven. The more RPM the louder it gets.
It gets more violent with the more RPM you give it and it is a pretty good sounding knock too (like hitting the engine block with a hammar). I thought it was my lifters so I let it warm up for 20 minutes and then revved it up to 2500 rpm for a while and then brought it back to idle. This didnt solve the problem but when it was at 2500rpm the knock would dissapear for a second and reappear again. (Like the knock was skipping every other knock). The knock The knock occurs at idle about 4 times a second from what I can hear. I changed my lifters just now and changed the oil and filter and retorques my non adjustable hydraulic lifters to 25lbs (factory specs) but the sound is still there.
My Wedding is in 5 days and this has been my dream car that Ive always wanted to drive away in so please any help is greatly appreciated. Im to nervous of driving it to a shop since the closet one is 10 miles away and I dont want to be stranded on a highway.
have the same problem?
Tuesday, December 8th, 2009 AT 9:25 PM