Hey guys I have a 1996 vortec 454. 166K miles on engine was still running great. Did intake manifold gaskets, and a lifter.

While taking out distributor I didn't mark it well enough to accurately put back in. I put engine at TDC, lined up white dot with dimple on distributor put back down, rotor points where it should. Put the cap on, hooked everything up and it ran pretty smooth cam retard was at -4.

I shut engine off adjusted CCW to bring back to spec -1 deg. I swear it is running more rough now.

Am I really off the wall here? or is it because the timing chain (with 166K) has worn out?

I am thinking I may just put cam retard back around -4 until I can change timing chain/sprocket/water pump.

Moving in 3 weeks, not the greatest time for engine trouble. No codes thrown. Thanks guys

 

Chain Elongation and Engine Timing

I just saw this, maybe I'm not that crazy. 166K miles is likely to wear the chain.

 

Not sure why, but truck ran pretty smooth on highway when I put the cam retard at -6 deg. I wonder if my cam sensor is goofy because the degrees didn't change as I expected and didn't always change with rpm. also went to -45 degrees with about a 1 degree change at distributor, then went back down eventually. I feel like I'm shootin' in the dark.

Set at 0 degrees, it ran crappy.

Matco Determinator 2.0 was scan tool.

Planning on changing timing chain/sprockets in the near future.

ANY THOUGHTS?

 

your timing could have jumped a tooth, when you stuck your distributor was you tdc ON COMPRESSION stroke? take your driver bank valve cover off spin your engine "with your cap off the distributor" and watch the #1 cylinders valves after the intake valve opens and closes get your timing marks to tdc and see if your rotor is pointing at number one. you might have your distributor off a tooth

 

I did the method of finger over the spark plug hole, after the puff of air, lined up timing mark. rotated crankshaft clockwise with socket. i set it in so it would point at the right spot. had to rotate distributor slightly clockwise (negative number for cam retard) for it to run better. if it was off a tooth it would be off by a lot (360 divided by 11or13) also would throw a code.