LT1 Based Engine Tech 1993-1997 LT1/LT4 Engine Related

Got my valve BACK UP... now how do I find TDC?

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Old Mar 30, 2003 | 01:50 PM
  #1  
grendal's Avatar
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From: Houston, Texas, USA
Talking Got my valve BACK UP... now how do I find TDC?

Hi guys,

I want to say THANK YOU THANK YOU THANK YOU to all the respondants to my thread regarding my fallen valve....

With the help of a non-car-savvy friend with fingers ready to grip, I spun the crank and got that valve back up!!!!!!!

Now on to the next problem, which is obviously that my crank hub balancer's arrow is DEAD WRONG.... There's no way it can be right given as far as I had to turn the bloody crank to get the valve back up... apparently I was just plain LUCKY on cylinders #1 and #8 and the valve guide/seal must have kept it from falling.....

This car has 108k miles on it, and I'm the third owner, and there's an aftermarket clamp on the waterpump, so I get the impression that it may have had work done down there before, which means there's a good likelihood that the balancer is in the wrong position as I've found out....

How do I find TDC given the following:

The rockers are off on cylinders #1, #8 and #4, and I have new springs already on #1 and #8.

Also, I'm not particularly good with the "stick a wire in and figure it out" method... I have tried this on #4 already in this valve issue and for the life of me I can't tell jack sh*# from that wire in there.

Thanks,

Michael
Old Mar 30, 2003 | 02:23 PM
  #2  
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From: Little Rock, AR
If you are still at #4 and have a spring off, let the valve sit on top of the piston. Have someone watch or hold onto that valve as you move the crank. Turn the crank in very small increments until the valve is at it's highest position. Then make a new mark on your pulley at 6 o'clock (pointing down). That should be your new indicator.
When you move on to the next cylinder and remove the spring, hold onto the valve and push it down until you feel it rest on the piston and you will know that you have it right.
Old Mar 30, 2003 | 02:25 PM
  #3  
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From: Upstate New York,USA
several methods exist. A no-cost way is to pull out the spark plug on cyl Number one. Now, either with a finger over the plug hole in the head or a friends finger over the hole, turn the motor over with a breaker bar. As the piston comes up to the top, the wind pressure will cease pushing against your finger tip. That's approximately top dead center.
Next method: Take out all spark plugs to remove compression resistance. Take an old spark plug and knock the center out of it so that it just has a hole in the metal part and no porcelain. Once cleaned, place this 'tool' in plughole number one. Find a phillips screwdriver that fits in the hole of the tool and push it 'gently' into the hole. Gently turn the crank clockwise till the piston gently stops against the phillips screwdriver blade. Make a pointer out of a clothehanger wire or something suitably stiff. Mark the harmonic balancer with magic marker/finger polish/etc where the point er is positioned against the H.B. Now gently rotate the crank it the Opposite direction untill the piston again gently stops against the phillipa screwdriver blade. Mark the location on the Harmonic balancer where the pointer indicates on the Harmonic Balancer. Now the mid point between those two marks is the top dead center EXACTLY. As far a the orientation of the HB on your car, since we don't have keys in our hubs, it's quite easy to orient the HB in virtually any orientation if the person installing the hub doesn't care to align the crank/HB.
Old Mar 30, 2003 | 02:34 PM
  #4  
grendal's Avatar
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From: Houston, Texas, USA
Thanks Sounds like sensible advice. I will ponder my options and go back in as soon as I can recruit my helper again....

-Michael
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