Finding Top Dead Center

[OldGrayII]

O.K. , before I removed my Timing Cover (Timing Chain Job), per the Instructions on Gnttype, I rotated the engine to what I "Thought" was Top Dead Center Compresion-I rotated the motor until the Valves were CLOSED and the balancer mark was approaching 0, I then rotated the rest of the way until the white Balancer Tic Mark was exactly at Zero -- When I pulled off the timing cover the marks on the sprockets DID NOT LINE UP, they were about a 3/4inch turn backwards until they lined-up! Now when I put the cover & Balancer back-on, won't my White Tic Mark be OFF!!!! Do I now Re-Mark the balancer before I put my tape on to set the Cam Sensor??????????????????

 

[Chuck Leeper]

TDC

DO NOT remark the balancer. Has the car been marked for the cam sensor setting? If so, there may be another mark on the balancer that is NOT actually TDC. It would be AFTER TDC.
Be sure the engine is:
BOTH #1 valves are closed.
Balancer mark for TDC is matched to the ZERO point on the cover.
Install the new gear and chain set so that the marks LINE up.
NOTE: the old chain is either stretched, the gears worn out or both to allow the cam to lag behind the crank position, causing the need to turn the crank to line up the marks.
Do not turn the crank. Instead turn the cam so that the marks line up. This will allow you to bolt it up, and then set up to reinstall the cam sensor, once the rest of the pieces are put in place. [At that time, you will have to rotate the engine about 25* AFTER TDC and then put the cam sensor in.]
DO NOT forget the crank splash deflector. [the dish shaped disc]
DO NOT forget to loc tite the cam bolts.
DO NOT forget to line up the pins when putting the cover on... Doing so WILL crack the cover!!
DO NOT forget to add sealer on ALL the cover bolts. Some of them go into the water jacket.
DO NOT forget to set the crank sensor clearance.
DO NOT forget that the balancer bolt HAS to be torqued to OVER 200#!! LOCTITE too!!

HTH,

 

[John Larkin]

An old idea that's cheap to truly find TDC. Take an old sparkplug and knock the center out of it. Find a pencil, dowel rod (something about 6" long) or whatever that will slide through the hole for an insert (sand it good and oil it so no debris will get in the engine). Bring the engine up to what you think is TDC and screw the sparkplug shell in the hole. Slide the insert down the hole until it sits on the piston. Then run a rubberband down it to keep it from falling through the sparkplug shell. Note where your mark on the balancer is (zero probably) on the compression stroke and then rotate the engine backwards. When the engine comes back to the mark, watch for it to rise and reset the depth or if it doesn't rise, push down on the insert and see if there is any slack. It may take a few rotations back and forth to sneak up on it, but in the end you will have true TDC. From there you can assess the timing marks or you can spend $20 on a nicely manufactured TDC checker and do the same thing.

 

[OldGrayII]

Thanks Guys,

Chuck, if I understand you correctly, you are saying that I should turn the motor BACK to where the sprocket marks were that DID NOT line up, Remove the NEW Chain, and then turn the CAM to exactly 6 o'clock. But how do I then turn the Crank (currently at 1 o'clock position)????

By the way, I "Thought" the V shaped indentation mark, painted white, currently on the balancer was a factory mark!! If that mark was put on for a CAM sensor setting, wouldn't THAT explain why I had to turn the motor BACK with the chain on to get the dots to line up??????

 

[MSDGN]

Yes...if that white mark is for the cam sensor setting you would have to turn the motor backwards to line up the "dots"...if that is the case then there should be a square groove(TDC) cut into the balancer about 1.5" counterclockwise from the white mark...

 

[OldGrayII]

Arrrggggg...I'm at work, soon as I get home I'll check the balancer, THEN we'll get this straight!!

 

[TurboTR]

OldGray you can verify your TDC mark pretty easily just by feeling the #1 piston top with a long screwdriver through the plug hole while you turn the crank by hand. Just takes a few minutes, at least if you have a front mount IC that is

Verify TDC 1st, then set the cam properly like "OldGeezer" says. Don't forget the crank oil slinger

TurboTR