Quote Originally Posted by petrified.rabbit View Post
The keyway would be holding the timing gear in place, not the balancer. So if the keyway broke, the timing belt would not be turning in time with the crank = bent valves.




it does have an oil pressure switch on the back of the engine near the timing cover, this if oil pressure is not present it cuts spark (i believe).

about the backfiring on starting fluid, i think you need to do a cylinder leak down test, if you have a better compression tester that has the airline style fitting in it, then you can cheat and use that, put a cylinder at top dead center, put the line onto it and pump in some air (not 90lbs, start with just a little). listen to the intake, and exhaust for air movement, if the cylinder is sealed, then you should not hear anything. Where did you get the head and valves? 140 psi compression is good, but you should not be able to backfire.

the only things i can think of at this point are archaic at best, but could work, like pulling the plug and cranking the engine so see it gas blows out of the cylinder, pulling plugs and testing them against the block for spark, etc. Not that you haven't done those test proper. But sometimes the wrong way shows more. Im still leaning toward no gas, personally.


I bought the cylinder head from Odessa cylinder head off of their ebay store.
GM Chevy Aveo 1 6 DOHC Cylinder Head vals Springs Only | eBay

The backfire happened after I had sprayed quite a bit of starter fluid into it. The same thing happened when I pulled the injector manifold off the car so I could see if the injectors were firing any fuel. They are--but the car backfired at me again. Can't keep making fireballs under the hood. Things are getting scary.