Help with late 60s 440 engine?
I have a late 60s 440 engine i just completley rebuilt. And we put brand new spark plugs in it, and still cylinders #1 and #7 arent firing as the others are. Its perfectly timed and everything, they are just misfiring. Anyone know why? Can it be the valve seals?:confused:
|
Bad plug wires? Bad plugs? Have you swapped wires and plugs around to see if the misfire follows?
Number of issues could cause this. |
"The basics"
Compression Spark at the right time Fuel It's likely not fuel, unless there's a manifold leak at the 5 and 7 intake ports So check compression, with both plugs removed or do a leakdown check Valves? Opening closing? adjustment? Have you checked spark at the plug end of the plug wires? (Such things as a defective cap, bad wires, or even bad plugs) |
Plug wire routing can ???? sometimes causes misfire
|
check your distributor and point and condenser
|
Alright so i did a compression test, and compression in the good cylinders are reading around 100 and in the bad 1st and 7th cylinder it is reading around 25. I also did valve leakdown test and none of the valves are leaking. Is this a sign of bad piston rings? what is the problem?
|
Might be a head gasket, cracked head. Ring or piston problems, it should show lots of oil
I assume with your leakdown you listened for leakage in the intake and exhaust? Did you look in the rad cap for bubbles? Run down someone with a coolant chemical test for combustion leakage. |
Squirt a little bit of oil in the spark plug hole, and re test. See if compression raises or not.
If yes: bad rings and possibly more. If no: valve issue, head gasket, cracked head, block, ect as 440roadrunner said. |
All times are GMT -7. The time now is 07:50 PM. |
© 2024 MH Sub I, LLC dba Internet Brands