Rather than join some other Fbody or LT1 forum, I figured I could get some sound advice here. I'll try to give pertinent details without writing an epic novel. Here we go.
My dad picked up a '94 Trans Am (118K miles showing) earlier this week hoping to make it a flip. The ad disclosed a "noise in the engine more than a valve adjustment". According to the seller, he picked it up as a project, had a "mechanic" adjust the valve and the noise remained. He looked at the car and said it sounded like a collapsed lifter. I went back with him the next day. It sounded like a lifter to me too but it had a dead miss with it. A deal was struck and he drove it 40 miles to my house. As I followed him home there were no problems. He said it ran fine, the miss would come and go, oil pressure was great (50psi cruising and 25 idle when hot). I thought about it overnight and checked it out in the morning. Bad valve spring maybe? The next morning I fired it up. The noise was slight at first but as the car warmed up it got louder. It is ticking at valvetrain speed - not engine speed. Sounded like it was coming from the passenger side front. Pulled injector plugs one at a time to see if it ran or sounded any different. #4 made almost no change. Pulled the passenger side Valve cover. In the process found the intake boot rolled at the bottom there it connects to the throttle body. Installed my "windowed" VC and proceeded to check valve adjustment and see if I could find any damaged parts. These are the things I know:
-The dead miss all but went away once I fixed the boot and readjusted the valves.
-At some point a push rod on #2 and #4 was bent and wore the hole in the head oval shaped. Appeared to be an old injury.
-Many of the springs were shinier (no carbon) between coils. Done but the last guy during valve adjust?
-No bent push rods.
-No broken springs.
-No broken or cracked rockers. A couple were shiny on the guide rails. Touching the retainer?
I removed the driver's side and found the same things. I proceeded to remove the intake. Some had obviously been there before in the past but not too recently. I removed all the lifters and checked for any rough rollers or soft plungers. None were found. They were suspiciously cleaner than all the other parts. Next I pulled all the lifters out of a spare LT1 in the corner ('95 Impala). They look a bit different than the newer set in the T/A. Was there a production difference between the iron head and aluminum head LTs? Maybe just aftermarket instead of GM parts? Put everything back together and have the exact same noise in the same area. Readjusted all the valves hot and running. No change. My next step will be to buy a new set of rockers since the shiny rails were suspect.
Whew! Now that I've got all that out...am I missing something? Have any of you guys run into this? Any suggestions are welcome. Thanks for looking.
My dad picked up a '94 Trans Am (118K miles showing) earlier this week hoping to make it a flip. The ad disclosed a "noise in the engine more than a valve adjustment". According to the seller, he picked it up as a project, had a "mechanic" adjust the valve and the noise remained. He looked at the car and said it sounded like a collapsed lifter. I went back with him the next day. It sounded like a lifter to me too but it had a dead miss with it. A deal was struck and he drove it 40 miles to my house. As I followed him home there were no problems. He said it ran fine, the miss would come and go, oil pressure was great (50psi cruising and 25 idle when hot). I thought about it overnight and checked it out in the morning. Bad valve spring maybe? The next morning I fired it up. The noise was slight at first but as the car warmed up it got louder. It is ticking at valvetrain speed - not engine speed. Sounded like it was coming from the passenger side front. Pulled injector plugs one at a time to see if it ran or sounded any different. #4 made almost no change. Pulled the passenger side Valve cover. In the process found the intake boot rolled at the bottom there it connects to the throttle body. Installed my "windowed" VC and proceeded to check valve adjustment and see if I could find any damaged parts. These are the things I know:
-The dead miss all but went away once I fixed the boot and readjusted the valves.
-At some point a push rod on #2 and #4 was bent and wore the hole in the head oval shaped. Appeared to be an old injury.
-Many of the springs were shinier (no carbon) between coils. Done but the last guy during valve adjust?
-No bent push rods.
-No broken springs.
-No broken or cracked rockers. A couple were shiny on the guide rails. Touching the retainer?
I removed the driver's side and found the same things. I proceeded to remove the intake. Some had obviously been there before in the past but not too recently. I removed all the lifters and checked for any rough rollers or soft plungers. None were found. They were suspiciously cleaner than all the other parts. Next I pulled all the lifters out of a spare LT1 in the corner ('95 Impala). They look a bit different than the newer set in the T/A. Was there a production difference between the iron head and aluminum head LTs? Maybe just aftermarket instead of GM parts? Put everything back together and have the exact same noise in the same area. Readjusted all the valves hot and running. No change. My next step will be to buy a new set of rockers since the shiny rails were suspect.
Whew! Now that I've got all that out...am I missing something? Have any of you guys run into this? Any suggestions are welcome. Thanks for looking.
