86Shelby
12-31-2007, 02:54 AM
Starting from the beginning of what happened and what I've found, sorry it's long:
Friday I took a trip to my parent's place in the R/T and came back home, about 90 miles round trip. About 35 miles into the trip I come to a stopsign and the car doesn't idle right. No noise that I noticed, but the idle is crap, misfiring real bad. The idle stayed bad for the rest of the trip.
Throughout the trip there were times that the engine felt low on power, and others that it ran just fine. Still got 27-28 mpg overall.
I get back into town and there is a noise from the top end of the engine. Definitely not a good noise. Much, much heavier than a lifter tick, but at 1/2 engine rpm like a valvetrain issue. Doesn't sound like a bottom end knock since it's obviously coming from the head, under the rear valve cover.
I took the valve covers off to inspect everything there. I did find some damage to the intake cam caused by the pins I used to try out my rocker arm fix. I found the issues there and corrected them by moving a few rockers into different positions. I also found that my exhaust cam sprocket had slipped and was now fully retarded. Figuring that those rockers were causing the noise and the bad exhaust timing was causing the bad idle I buttoned everything back up and fired it up. Noise and misfire are still there.
I pulled the valve covers back off, laid out some towels to catch oil and started it. I was able to track down the noise to the exhaust cam, right near the sprocket. It was loudest when I would put my stethescope in the small hole at the end of the head by the rocker shaft, or right behind the cam sprocket. During this I also unplugged the knock sensor thinking the SBEC might be pulling a lot of timing due to the noise, no change after it was unplugged. After this test I saw the sprocket had slipped again, fully retarded timing on th exhaust. I'm getting some washers tomorrow to put under the screws so hopefully it won't slip again.
I am simply at a loss for what could cause a noise like that in that area.
The hole I heard the noise from is the small one, just to the left of the rocker shaft.
http://i225.photobucket.com/albums/dd65/86Shelby/IMG_7362.jpg
Friday I took a trip to my parent's place in the R/T and came back home, about 90 miles round trip. About 35 miles into the trip I come to a stopsign and the car doesn't idle right. No noise that I noticed, but the idle is crap, misfiring real bad. The idle stayed bad for the rest of the trip.
Throughout the trip there were times that the engine felt low on power, and others that it ran just fine. Still got 27-28 mpg overall.
I get back into town and there is a noise from the top end of the engine. Definitely not a good noise. Much, much heavier than a lifter tick, but at 1/2 engine rpm like a valvetrain issue. Doesn't sound like a bottom end knock since it's obviously coming from the head, under the rear valve cover.
I took the valve covers off to inspect everything there. I did find some damage to the intake cam caused by the pins I used to try out my rocker arm fix. I found the issues there and corrected them by moving a few rockers into different positions. I also found that my exhaust cam sprocket had slipped and was now fully retarded. Figuring that those rockers were causing the noise and the bad exhaust timing was causing the bad idle I buttoned everything back up and fired it up. Noise and misfire are still there.
I pulled the valve covers back off, laid out some towels to catch oil and started it. I was able to track down the noise to the exhaust cam, right near the sprocket. It was loudest when I would put my stethescope in the small hole at the end of the head by the rocker shaft, or right behind the cam sprocket. During this I also unplugged the knock sensor thinking the SBEC might be pulling a lot of timing due to the noise, no change after it was unplugged. After this test I saw the sprocket had slipped again, fully retarded timing on th exhaust. I'm getting some washers tomorrow to put under the screws so hopefully it won't slip again.
I am simply at a loss for what could cause a noise like that in that area.
The hole I heard the noise from is the small one, just to the left of the rocker shaft.
http://i225.photobucket.com/albums/dd65/86Shelby/IMG_7362.jpg