75 Maverick with a 302 I'm getting no compression on 5 cylinders and I can't get the car started. When I bought the car 2 years ago it was not running and the previous owner said he just redid the heads and that it was an electrical issue. I did find an issue with the Duraspark wiring and fixed that. I have a long weekend to pkay with it and... A few minutes ago I hook up a compressor to the number 1 cylinder via a compression tester adapter and air came out through the carb. I rotated the engine by hand 180 degress and tried agian(just to make sure I was at TDC) and air came out through the carb. Does this mean a valve is stuck? The front valve on number 1 looks lower that the one next to it by laying a straight edge between them. If I back off all the rockers should that close all the valves so I can check each cylinder? If I can physically see that some valves look lowwer does that mean they are bent or stuck? Could this many valves be bent or stuck at the same time?? Other information the nusts holding the rockers on a bright and look new, but the push rods on a few of the front cylinders( 1 and 2) were a little rusty at the top. Thanks a lot and Happy 4th of July!!! Bob
turn the engine and see how many do not move. tap the ones that dont with a mallet or block of wood and hammer. removing the plugs first will make this easier...:Handshake i had this happen with a 6 cyl. it was one valve. i started the engine and found the one stuck. tapped it with a hammer and that took care of it.
I wouldn't try...the valves are in the open position and could hit the piston... air comming back through the carb. means the intake valve is open, that will let raw gas wash out the cyls. ...and if the valve is only half open, you could also bend a pushrod... ......
You could also bring #1 up on compression stroke, and take your distributor cap off to see if your rotor button is pointing to #1 on your cap. Take a magic marker and mark the distributor base or the bottom half of the two piece cap and see if the rotor button points to your mark, Just to rule out jumping time.
Looking back through what emails the seller sent me , the seller said the timing chain was replaced, but I'm not sure if it ever ran after that.
If you have 5 cylinders where you get no compression.............I'd be pulling the heads to see what the issue is. You said one valve looked lower than the other...............if there is rust on the push rods there could be rust on the valves/seats............etc. You mentioned trying to start the car, if you spun the motor over what happened............anything? As someone said, you run the risk of damaging something if the valves are open/stuck at TDC. If it were my car I'd be pulling the top end down for a much closer look. IMHO
