350/400 SBC Timing Tabs

[dfarr67]

Bolt on stamped steel style- any model for 8 inch balancer better than the rest for accuracy or all so-so. Looking to test fit one against a welded on tab to see if is in the ballpark- welded cover looks to be hand welded not factory spot welded. Can do the piston stop later.

[dannobee]

Don't trust any of them. Do the piston stop method if you want real accuracy. Otherwise they're only "in the ballpark." Sometimes the balancer ring moves or is off from the factory. Sometimes the keyway isn't in the right spot, sometimes the crank indexing is off. They all matter.

[F-BIRD'88]

I compared true tdc to a oem 350 sbc timing cover tab. It was of by 4 degrees.

[6.50camaro]

When I stop verified a 8" pro products damper and bolt on sheet metal timing tap it was off 2 degrees.Dan

[dfarr67]

I can live with 2 deg.

New 400 SBC Power Bond 1050ST balancer, rebalanced to match old Pro Products balancer. Disappointed with the timing markings- they will go away, hack sawed a groove at TDC, dremeled a reference mark if ring slips in the future. I've marked tabs when I've had the heads off with a dial indicator- this piston stop BS is a PITA.

[FC-Pilot]

Timing tabs are a crap shoot at best. Of the pointers I have checker on engines that were already assembled the closest I have seen was 4* off and the furthest was 10*. I know it stinks, but you never regret taking the extra time to do it right. But we all to often regret the shortcut we took.

Paul

[dfarr67]

/\

10 deg is extreme- Mismatched parts, poor quality?

[Walter R. Malik]

Timing tabs are a crap shoot at best. Of the pointers I have checker on engines that were already assembled the closest I have seen was 4* off and the furthest was 10*. I know it stinks, but you never regret taking the extra time to do it right. But we all to often regret the shortcut we took.

Paul

SBC dampers have more than one TDC location and from before 67 to later was about 10 degrees different.
Then there are also ones with straight-up marks; off about 30 from a bolt-on tab.

[Cris]

Dfarr67:

Use the “ball meter” technique outlined by Larry Meaux in this post. I’ve never been comfortable running a piston against a stop. The sensitive ball style flow meter works very well and you don’t have the danger of damaging anything.

viewtopic.php?t=41140&start=15

[chevyfreak]

I try to use the original gm tabs. Some are off but not as much as those chrome aftermarket units. And the chrome reflects the timing light just so you cant see where the line matches up.

Over the years and tracing numerous oil leaks, i stay with gm timing covers as well. The backing for halfmoon seal is welded all the way, and not just a couple off spots like aftermarket. Was a real head scratching on trying to find the oil leak, as it weeps past the halfmoon, only leaked when engine was hammered, normal driving nothing.

Chevyfreak.

[dfarr67]

There are three 8in combo's of balancer and tab- 12:00, 2:00, and something else up to 1969. This is a late model 5.7L roller block with one piece rear seal with Scat stroker crank and oem style 400 balancer. I've been told the balancer should work with the original 1992 timing cover.

[dfarr67]

Dfarr67:

Use the “ball meter” technique outlined by Larry Meaux in this post. I’ve never been comfortable running a piston against a stop. The sensitive ball style flow meter works very well and you don’t have the danger of damaging anything.

viewtopic.php?t=41140&start=15

That was one weird thread.

[FC-Pilot]

/\

10 deg is extreme- Mismatched parts, poor quality?

Many were those terrible chrome stamped deals. Those can easily bend to be way off. When I finally get those right I use cheap silicone sealant between it and the timing cover to keep it held still. One was a friend who wanted the timing pointer closer to the timing cover so he bent it back not thinking at all about what that would do for his timing marks.

Paul

[6.50camaro]

The problem I've had with those cheap sheetmetal pointers was they covered the damper so you can't see the timing marks on the dampers . I cut them back and leave one point that lines up with TDC as found with degree wheel when setting the camshaft. Dan

[dfarr67]

So today the piston stop went in with the factory timing cover with hand welded tab test fit. ran it back and forth three or four times to confirm things (what u see is a stop adjustment to try to narrow things up).....so what am I confirming- I marked against the '0' notch on the timing tab which when I measured with calipers worked out pretty well considering my eye and angle-----> does this also confirm '0' on the timing tab is good against TDC on the balancer? This is with the new rebalanced 400 damper partially installed. This is EFI and my interest is setting base timing to Zero.