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Timing issue-still missing something
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Author:  vanmansl6 [ Sun Jul 28, 2013 7:45 am ]
Post subject:  Timing issue-still missing something
Ok,
I have used the piston stop tool as instructed, but the intake valve opens every time I crank the engine
Now, when I use the new timing mark created by the piston stop tool, I look for the intake valve to open, and when it does, I line up the new mark to zero (TDC) Each time, I feel for the piston, and it is not at TDC and the exhaust valve rocker is tight.

I know I am still missing something here, but I'm at a loss-

What step in this process am I missing?
Author:  jhdeval [ Sun Jul 28, 2013 7:57 am ]
Post subject: 
I used this video to help me understand the piston stop tool.

http://www.youtube.com/watch?v=PD0ZRc7Dy28

When using the piston stop tool turn the crank clockwise till you hit the tool. Mark the spot lined up with the 0 Degree timing mark. Then turn the crank counter-clockwise. Again mark the spot lined up with the 0 Degree timing mark. Then measure the 2 marks and dive by two. VERY VERY carefully mark on the crank the center mark. That is true TDC.
Author:  vanmansl6 [ Sun Jul 28, 2013 8:39 am ]
Post subject: 
Thanks, I understand the procedure, but what I need to know is is there an initial reference point that I need to begin with? Or do I just put the tool in at any part of any stroke? Do I have to establish appx. TDC on the #1 compression stroke? One issue i'm having is finding that point.
Author:  Reed [ Sun Jul 28, 2013 9:25 am ]
Post subject: 
No, there is no initial reference point for verifying the timing mark with the piston stop tool. The piston stop tool does not care what part of the four stroke cycle the crankshaft or camshaft is in. The piston stop tool will stop the piston as it approaches the top of the piston bore no matter what the valves are doing.

I think you are getting the two operations confused. You only need to worry about watching the intake valve open AND CLOSE when you are trying to find TDC on the compression stroke and verify that your rotor is pointing at the #1 plug tower. Finding TDC (either TDC) on piston #1 (or 6) does not involve watching the valves in any way or verifying that the engine is at any particular point in the four stroke cycle.

I will walk you through the steps again.

To verify that the timing mark on the vibration dampener is correct, do the following:

(1) remove the #6 spark plug since you are working on a van and the #1 spark pug is a PITA to get to.

(2) install the piston stop tool in the #6 spark plug hole with the center "stopper" portion of the tool screwed all the way in.

(3) by hand, and not by using the starter motor, rotate the crankshaft clockwise until the #6 piston hits the tool and stops the crank from turning any more.

(4) make a make on the vibration damper next to the TDC mark on the timing tab.

(5) rotate the crankshaft counterclockwise until the #6 piston again contacts the piston stop tool and stops the crankshaft from turning.

(6) Make a second mark on the vibration damper next to the TDC mark on the timing tab.

(7) remove the piston stop tool and replace the #6 spark plug.

( 8 ) rotate the crankshaft until the two marks you just made are easily visible and accessible. On a van you probably want to rotate the crank until the marks are pointed towards the ground.

(9) Using a tape measure, measure the distance between the two marks you just made. The middle of the distance between those two marks is the true TDC for your motor. Make a mark at the midpoint between the two marks you made when you used the stop tool. This third mark is your new timing mark and will accurately indicate TDC on the #1 and #6 pistons.

FOOTNOTE 1: When you are searching for TDC in relation for verifying your timing, you are actually looking for TDC on the #1 piston since that is the piston the timing gun is hooked to when you set the timing. The reason you can use the #6 piston on a slant six to find TDC for the #1 piston is because the #1 and #6 pistons in a slant six travel up and down the cylinder bores as a pair, but at opposite points of the four stroke cycle. In other words, when piston #1 is at TDC on the compression stroke, piston #6 is at TDC on the exhaust stroke and vice versa.


Once you have made a mark on your vibration damper that accurately reflects true TDC on the #1 piston, you can then verify that your base timing is roughly correct by doing the following:

(1) remove the valve cover

(2) rotate the crankshaft by hand while watching the movement of the #1 intake.

(3) rotate the engine until the #1 intake valve opens and then closes again.

(4) once the intake valve has closed, keep rotating the engine while watching the vibration dampener.

(5) Watch for the timing mark you just made using the piston stop tool to come around and reach TDC.

(6) Stop turning the crank over once the timing mark has reached TDC on the timing tab.

(7) your motor is now at TDC on the compression stroke of the #1 piston.

(8) pull your distributor cap and look where the rotor is pointed

(9) if the rotor is not pointed directly below the #1 spark plug tower, rotate the distributor until the rotor does point directly below the spark plug tower. This may require removing the distributor completely from the block and rotating the distributor shaft and then reinstalling the distributor


If you do all of the above, your motor will now be properly timed with the timing roughly set to TDC on the compression stroke of piston #1. This is a rough ballpark setting and you will still need to set the timing with a timing light once the motor is running.
Author:  vanmansl6 [ Sun Jul 28, 2013 11:02 am ]
Post subject:  Ah Ha!!
OOOOOk

Timing mark is set- the truck fired right up! set base timing to about 7deg BTDC and took it on a test drive.

This truck now runs perfect and is a rocket!

Thanks Reed for the explanation I got it now, so i'll fine tune it from here , finish up the minor details ( grill bumper exhaust system) and she will be ready for the road again

Thanks to everyone on the board who helped me out
Author:  Reed [ Sun Jul 28, 2013 11:27 am ]
Post subject: 
Hooray! Glad it worked out for you.
Author:  walpolla [ Sun Jul 28, 2013 2:19 pm ]
Post subject:  typo
Reed, is your point (7) a typo?
"(7) your motor is not at TDC on the compression stroke of the #1 piston. "

Should read "is NOW at TDC?

regards,Rod
:?:
Author:  Reed [ Sun Jul 28, 2013 2:30 pm ]
Post subject: 
Yep, you caught me. That is a typo. It should read "Your motor is NOW at TDC". Sorry about that. I am in the middle of drafting some complicated legal pleadings and my mind is not 100% focused on proofreading. Sorry about that.

EDIT: I went back and fixed it. Thanks for pointing it out.
Author:  walpolla [ Sun Jul 28, 2013 3:18 pm ]
Post subject: 
It wasn't meant as a criticism, just that if a "learner" read it some time in the future, confusion might result. All good.

regards,Rod :D
Author:  Reed [ Sun Jul 28, 2013 4:40 pm ]
Post subject: 
No no, criticize away! I want my posts to be as accurate as possible, yet I recognize that I often type quickly and leave typographical errors. If you ever spot something like that in one of my posts feel free to smack me on the head and remind me to fix it. :wink:
Author:  crater [ Sun Jul 28, 2013 8:45 pm ]
Post subject: 
I flip NOT and NOW constantly. I find myself having to go back and re-read tons of my work emails lately to make sure I haven't done it.
Author:  walpolla [ Mon Jul 29, 2013 12:17 am ]
Post subject: 
Quote:
... feel free to smack me on the head.. :wink:
OK, if I ever feel the need to bash someone, I will check out a post or two from you. :lol:

regards,Rod :lol:
Author:  wjajr [ Mon Jul 29, 2013 5:01 am ]
Post subject: 
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