Timing check

[David Brady]

I replaced my front timing cover last weekend and the new one from GM didn't have a indicator for TDC on it. I want to have the timing checked by the dealer - do they need this indicator or is it all done by the tech2? My review of the timing issue is that the TDC offset will not have changed but the base timing should be checked. Is this right? Is one base timing better than another? Thanks for the input.

[charliepeterson]

As long as you didn't take the gears off, the timing will be good. The Tech II is what changes the timing numbers. The dealer will set it to -.25 to -.50 TDC. As long as you have a pyrometer installed you can go as far as -1.94 TDC. The dealer might not recommend this. I personally like this number.

[David Brady]

Wtih 195,000 miles on it I ordered the gear set and replaced the timing chain while I had the cover off. The chain was still like new, but I replaced it anyway. I used the same cam/pump drive gears. I put the HO pump and newer thermostat housing on it. It has run fine but I would like the dealer to check it out. When I replaced the IP 2 years ago I had a dealer set the TDC offset to -1.60 and I have been happy with it. My recollection of the TDC posts was that the software will takeover as long as the pump is within a reasonable range of correction.