C2redcoupe

I have bumped #1 to TDC and I now notice that my timing mark on balancer is at about 12 o'clock (looked at from front of engine) it is nowhere near where it should be relative to the timing tab on the cover. It should be at about 2 o'clock. I guess whoever put the engine together last did not index the cam and crank properly or else the timing chain has jumped. I runs just fine as long as I keep the mark around 12 oclock or so.

Anyone else have any other explanations or recommendations?

Thanks,

Mike

67L36Driver

Outer ring on dampener slipped? Check witness mark.
Maybe wrong combination of timing cover/tab and harmonic dampener. Find TDC using a piston stop and mark outer ring is the short cure.

JohnZ

You may have a '69-up passenger car balancer - they had the timing index line ten degrees counter-clockwise from the pre-'69 position to accommodate the new long-water-pump accessory drive system. Your index line shoud be EXACTLY in line with the center of the keyway slot in the hub - that's the correct C2 position. If your index line is in line with the keyway and a piston stop TDC exercise puts the index line at 12 o'clock, you have a problem inside the timing cover.

SWCDuke

The other issue is the timing tab. Early SBs had it spot welded to the timing chain cover. The change in balancer mark clocking was accomanied by a switch to a "bolt-on" timing tab. If the timing tab broke off the cover, the "quick fix" was to replace it with the bolt on timing tab, which won't show true readings with the early balancer. The two acceptable combinations are:

1. Pre-'69 balancer, timing tab spot welded to timing chain cover.
2. '69-up balancer, bolt-on timing tab.

If you co-mingle a combination of pre-'69 and '69-up balancers and timing tabs everything will be off about ten degrees as stated by John.

Duke

C2redcoupe

Thanks Guys, I am suspecting that the balancer damper has rotated. I see a bit of rubber protruding from the inner and outer sections of the balancer. I guess I'll pull off the balancer, check it and get a new one if necessary.

Thanks as usual for the sanity checks.

Mike

67L36Driver

Before you drag out the dampner puller, check the witness marks with a mirror.

Seaside63

Check with Damper Dudes before you cast off your original damper. They can rebuild it.

SWCDuke

What's a "dampner" [sic]?

Duke

67L36Driver

Duke.
Pikie Pikie Pikie.

C2redcoupe

I'm gonna check the marks on inner and outer tonight and will let you know. If if needs rebuilt, I will send it off Damper Dudes

Mike

lars

C2 -
I've seen 3 balancers with rotated outer rings recently (including on my own car), and I've seen 2 balancers explode the outer ring recently (one causing serious injury, and another causing serious vehicle damage). Chances are it has slipped - very common problem.

C2redcoupe

I pulled tne balancer today and posted pics at the links below. I see that the keyway on the inner ring is aligned roughly with the timing mark on the outer ring. Anyone have any ideas whay I am so far off the scale? I am at 12 oclock when it should be at ~2 o'clock to line up with the tab on the timing cover.

I don't see any other alignment marks on the inner ring.

Thanks as usual for your help,

Mike

http://i4.photobucket.com/albums/y13...e/DSCN0073.jpg

http://i4.photobucket.com/albums/y13...e/DSCN0074.jpg

JohnZ

The balancer looks OK; how do you know you're at #1 TDC when the timing index line is at 12 o'clock - did you verify TDC location on the balancer and timing tab with a piston stop?

C2redcoupe

John,

When I get #1 to TDC, using both methods of turning over till #1 blows and also using a piston stop, the timing mark on the balancer is straight up at 12 oclock.

This really has me puzzled...

Thanks,

Mike

Allcoupedup

Mike,
You need to use the piston stop TWICE to find TDC. You found the first mark by waiting for the compression stroke and rotating until the piston his the piston stop. Now rotate your engine the opposite direction until the piston hits the piston stop again. If your balancer is OK, the index mark should be right in between your two piston stop marks.

The key here is that the piston is not at TDC when it hits the piston stop.


Brian

C2redcoupe

Brian,

Thanks for the response. I think I am really close to TDC but the problem is: My balancer timing mark is a full 45 degrees off from where it should be on the timing cover tab, it is at the 12 oclock position.

When I get back home this weekend, I am going to run through the whole process over again using the piston stop and see what happens. Before I took off the balancer, the car was running great but when I time it the only way it will run decent is if I have the balancer timing mark at 12 oclock position.

I have checked the balancer keyway and C/shaft key and I see no signs of wear or slippage.

I will update when I have any news to report.

Thanks,

Mike