Not sure what is going on here. I tried going to a throttle body EFI system, but never could get it working just right.
At one point while I was driving, the system did not turn on the fan and the motor got to about 240 degrees before I noticed it was overheating. It was only that hot for less than 2 minutes. Turned it off, let it cool, then drove home. While driving home the heat was max 210 since the fan wasn't working but I was moving.
At another point I thought I got some bad gas vs plugged fuel filter but eventually found a bad coil. This caused erratic studdering until I figured it out then replaced the coil.
At some point during all this I noticed the driver's side exhaust pipe seemed to be rotated downward. The support bracket was previously horizontal, now it is angled about 15-20 degrees downward. Immediately after shutting it off a small amount of steam came out the exhaust pipe. Then next morning a few drops of fluid (water from bad gas? coolant? raw, unburned fuel from coil not firing?) had dripped from the pipe to the garage floor.
I inspected the complete exhaust, everything looked fine. Headers to heads had a small exhaust leak, but nothing major. Headers to collectors fine, pipe all intact, just seemed to be rotated. Not front to back angled down, rotation around the centerline of the cylinder, exhaust tip pointing down more toward the ground.
Engine mounts tight and level. No significant geometry changes visible to the entire motor. Compression test of all cylinders shows 170 +/- in all cylinders. Leak down test <10% on cold engine - most were <5%, #7 was about 8%. All valves reset to 1/2 past zero lash (hydraulic roller link bar lifters) and all valve springs/locks/rockers look ok. Head bolts tight. Intake tight. Bell housing to block, transmission to bell housing, transmission cross member bolts all tight.
It doesn't appear to be leaking water or
oil (few drops at the rear of the pan), no air leaks. Idles fine, drives fine.
Problem is that when driving, letting out the clutch, I get a squeaking sound coming from the drivers side pipe. High pitched squeak/squeal. Starts when the clutch first starts to let out and engage (engine power coming on) and continues for 2 seconds after the clutch is completely released.
At first I thought it was the mechanical throw out bearing since it is a squeak/squeal sound - like the bearing was spinning but not greased correctly and potentially failing. I got the bearing with the transmission and wasn't sure who made it. I just replaced the mechanical bearing with a hydraulic one from McLeod. Works great, clutch releases easily but the squeak is still there. Can't be the bearing - completely new style does the same.
Any thoughts on the rotation of the pipe or the squeaking sound? If it got hot enough to melt the heads and deform the head enough to rotate the pipe 15 degrees, I don't think the head would work at all - just a big blob. If the block cracked - same thing. Seems like it would have to be the exhaust but for the life of me I can't find anything wrong with it. I pulled and twisted to see if there were some failing welds but can't seem to get it to rotate back to where it was before. Gotta be the pipe, right?