Replaced the cam and lifters and heads on a 87 turbobuick because of a bad #3 lobe. Also replaced the coilpack, plugs and wires.
Finally got the car running smoothly and made some short trips to shake the car out.
BLMs 139 at idle, 115 at constant speed, 128 when coasting. Compression test on cylinders showed 165 to 170 in all cylinders. New oil, EOS, coolant and fresh gas.
The car seemed fine enough to return to the owner. Drove 125 miles at 65 mph and 2800 rpms for almost 2 hours. Water temp 170 F and oil pressure 40 psi for most of the trip. Never went over 10 psi of boost.
The last two blocks from the owner's house, the engine sounded like something inside was hitting another part, but this only occurs when the engine is heat soaked and above 2000 rpm. Car idles fine with no strange noise and also runs fine with no strange noise until heat soaked.
Checked #3 exhaust rocker, and it's moving up and down.
Don't think it's a lifter because it's not a ticking sound, and there is no sound at idle.
Unlikely to be a head gasket as there is no "fftt" sound.
Don't think it's a bearing as it's not really a knocking sound, and it doesn't happen at idle.
Hope it's not a burnt valve because the engine idles well and it doesn't sound like an exhaust leak.
Any ideas?
As well, the valley between #3 and #5 manifold starts to glow when under load for an extended period.
Finally got the car running smoothly and made some short trips to shake the car out.
BLMs 139 at idle, 115 at constant speed, 128 when coasting. Compression test on cylinders showed 165 to 170 in all cylinders. New oil, EOS, coolant and fresh gas.
The car seemed fine enough to return to the owner. Drove 125 miles at 65 mph and 2800 rpms for almost 2 hours. Water temp 170 F and oil pressure 40 psi for most of the trip. Never went over 10 psi of boost.
The last two blocks from the owner's house, the engine sounded like something inside was hitting another part, but this only occurs when the engine is heat soaked and above 2000 rpm. Car idles fine with no strange noise and also runs fine with no strange noise until heat soaked.
Checked #3 exhaust rocker, and it's moving up and down.
Don't think it's a lifter because it's not a ticking sound, and there is no sound at idle.
Unlikely to be a head gasket as there is no "fftt" sound.
Don't think it's a bearing as it's not really a knocking sound, and it doesn't happen at idle.
Hope it's not a burnt valve because the engine idles well and it doesn't sound like an exhaust leak.
Any ideas?
As well, the valley between #3 and #5 manifold starts to glow when under load for an extended period.