Topic: cam change problems

[duckeman]

ok first let me say Hi to everyone,I am new here. Heres my problem I recently swaped my cam,this is the second time the first one walked forward and the block ate the dist drive gear,I have since installed a new cam but it,will not fire up and run keeps back firing though the carb.heres my problem how do I know for sure that I am on the compression stroke, and not the exhust stroke,I placed a finger over the # 1 spark plug whole,but it pushes air on the exhust stroke as well as the compression stroke? thanks in advance for all your help!!

[Soaring]

The compression stroke is when the piston is all the way to the top.  If you are firing when the piston is at the bottom of the stroke, you won't get it to fire.  Turn your engine by hand, and use a screwdriver to feel when the piston is all the way to the top.  Then check your rotor and see if it is pointing  to 1:00 o'clock.  If not, then you are most likely 180 degrees out.  When you are 180 out, you will get backfiring out the carb as you have described. 

[duckeman]

I thought the rotor was suppose to be pointing at the #1 spark plug

[Soaring]

It is.  Maybe your 73 has a different firing order than my 65.  Yes, the rotor must be pointing at the #1 plug wire.  What engine do you have? 

[duckeman]

sorry I did not tell everyone it is a 351w,now I thought that I bring the engine to compression stroke #1 pistion and point the rotor at the #1 spark plug,in the cap not the motor.

[Soaring]

Ain't English a fun language?   Confusing as hell isn't it, expecially after you have had a few beers.  Your rotor must be pointing at the #1 where the #1 wire hooks up to the distributor cap.  Your firing order is 13726548 for all 351's. 

[jethat]

If the disrtibutor has never been moved (taken out and replaced) all you gotta do is line up the mark on the crank pulley when it come to the #1 cylinder on the distributor. To place the distributor correctly after its been removed and the engine has been turned you need to bring it to the mark on the compression stroke. A finger in the spark plug hole is one way the other is with the valve cover off you watch for the valves to close when it comes to the mark on the crankshaft pully (damper actually)... if one of the valves or rocker arm is down its not on the compression stroke..

[holdover]

"The compression stroke is when the piston is all the way to the top"  AND both valves are closed. The exhaust stroke also has the piston at the top, but the exhaust valve is open.

[Soaring]

"The compression stroke is when the piston is all the way to the top"  AND both valves are closed. The exhaust stroke also has the piston at the top, but the exhaust valve is open.

That's true.  Is there an echo in here?