quick90rs

iTrader: (3)

I've spent hours researching a question here, I've never felt like I've gotten the timing right on my vortec 350, I use a timing tab that bolts to the right side of the stamped chrome timing chain. I used the harmonic balancer from my original engine which was a 305 TBI, this engine is gone and I now have a vortec 350 from a 97 1 ton gmc can The only solution I've found was from a post about 14 years ago that read

"The balancer for a 350 that will put the timing marks at about 2 o clock is Pt # 6272222. You can use a regular timing tab that bolts to the timing cover with this one.

This will move the marks from the location behind the water pump."

I have no problem buying that balancer and using the two bolt timing tab (could someone recommend a tab?) if I'm sure I can be confident in timing my 350 carbed vortec with the LT4 Hotcam that I currently run.

So, is this true and can I run this balancer and normal tab ? Thanks all

bigal55

iTrader: (1)

You should always verify TDC using a positive stop with the heads on the engine. Search "find TDC" and you will get details on how to do this and what tools you will need (the stop made from an old spark plug or something equivalent). HTH!

quick90rs

iTrader: (3)

Alright thanks, my heads will be off this weekend and taking a trip to the machine shop. While I have them off could I visually set TDC and then match the timing mark on the balancer with 0* on an aftermarket timing tab? If it matches up I'm good ? Is there more to it ?

cardo0

U want to use a piston stop. Tools dont lie. I dont know how many try to do it visually. Are your eyes more accurate than a degree wheel and piston stop?

I posted a method in this thread post #12: https://www.thirdgen.org/forums/tech...-true-tdc.html.

Im finding most owners are in denial finding the actual TDC for the timing tab. Truth is truth and sometimes it hurts. Maybe i shouldnt even make this post as it more than likely flames a few. But it doesnt hurt to have an accurate timing tab.

Hope this helps more than it hurts.

bigal55

iTrader: (1)

Yes, while you have the heads off, you need a positive stop. A strap with a bolt threaded down through it, to contact the piston as it approaches TDC, across the cylinder works great. Just follow the post referred to by cardo0 and you should be fine. Eying TDC or using a dial indicator on the piston is not as accurate due to the "dwell" of the piston at TDC. This dwell is not very long but can be a few degrees or more, depending on accuracy of gauge and the crankshaft stroke and rod length of course. So.......