87 Olds 307 questions

[81Regal]

It appears you checked everything and agree w/ jetsetw31, this will help in case there is a flooding issue. I could also help diagnose a weak pump or trashy fuel. A couple of things that haven't been asked / mentioned are:

1. Did you check the wires for resistance & to make sure they are routed in the correct order. Wires with excessive resistance can cause your weak spark issue.
2. What were the conditions he ran it under at that 285* temp, i.e. in garage idling, changing / flushing fluid, driving on highway, run time at that temp...
3. In terms of the hose blowing off
a. what made it blow off
b. where did the antifreeze go and did he clean up EVERYTHING
c. were any and ALL WIRES & GROUNDS cleaned and or replaced
4. Is cranking speed actually enough the fire engine
5. Has oil been checked for milk-shakishness - not just pulling dipstick but draining some out the pan / filter (also for petrol)
6. Is the carb fuel filter / spring installed correctly? If using a golden sintered-styled filter make sure it's in the correct direction (had an issue on a '66 Impala where I placed it in backwards, engine would start but after a few seconds or so it would sputter / die or shoot fuel out the carb if I tried to increase engine speed. Reversed it and no issue)
7. Have valve covers been pulled to ensure there are no valve train issues, like broken or loose rockers, pushrods

I didn't get any time this last week to look into it anymore and the low compression was my first thought. To try to answer your questions the best I can....
The plug wires cap and rotor are new and routed correctly, didn't check the resistance yet. The previous owner was driving the car 55-60 mph when it blew the hose off and overheated. The water pump was replaced shortly before that like the week before, person that did the work is shady at best, and likes to cut a lot of corners on jobs. No wires were replaced, no work was done to it between the time it overheated and I got it.
The engine cranks over like it should, no milky coloring in the oil, if it is a blown head gasket it could be getting sucked into the exhaust. I took out the fuel filter and didn't make a difference.
I have not pulled the valve covers yet.

 

[81Regal]

OK, I tore into the engine today while it was nice. Pulled the valve covers, didn't show anything, looked like a normal high milage engine. So I went ahead and pulled the carb, there was some gas puddles under the carb. Pulled the intake off only thing I could find was on the tin tray under the intake part of it has corroded away around the rear water jacket, also found a sensor that screws into the front of the intake had coolant in it. Pulled both heads the #6 cylinder has deep scratches in the wall and burnt valves in both heads.
Anyways when it warms up some this engine is going to come out and I have a mid 70's Olds 350 going in. Until then Ill freshen up the 350 with a new timing chain, gaskets and oil pump, will have to reuse most of the brackets and water pump from the 307.

 

[jetsetw31]

Wow deep scratches in the #6 cylinder? That sounds like something got in there. A 350 is a good move. A lot of us did it and won't look back. I'm glad you got to tear it apart. We all would still be wondering WTH?
Thanks for letting us know.
T