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I bought a "beater" 1975 Stingray about 6 months ago and I'm just now getting around to setting the timing on it. I'm no expert but what I ran across I've never seen before and I can't even imagine how it would work with a timing gun. The timing tab extends over the width of the balancer. Therefore, I can't see the timing mark on the balancer because at the time I need to see it I can't because it's obscured completely by the timing tab. Is this a legitimate timing mark configuration? If so, is it possible to set the timing using a timing light? Please see the picture below and thanks!
From: At my Bar drinking and wrenching in Lafayette Colorado
You either have a damaged balancer or an incorrect balancer or timing tab. Inspect the balancer and verify that the outer ring has not shifted back towards the engine. If it has not shifted, you either have an incorrect balancer installed or an engine with the right balancer but with an incorrect timing tab - check your engine ID numbers and casting dates to see what you really have. If the balancer is correct for the engine but not correct for the tab, do a TDC verification check and install a timing tab you can read at the correct location following the TDC check. If it's a "beater" car, chances are good it's some odd-ball non-Vette engine that's not a '75, and they slapped an incorrect timing tab on it when they hacked it together.
Lars
Thanks Lars! I didn't think it was a legit setup but I really needed someone to confirm. I'm going to go through the checks you mention and find out what I'm truly dealing with. I'll post what I find out here (just incase you're interested). Thanks again.
Timing tabs for 1975 were spot welded in 3 places to the timing chain cover. Hard to tell, but it looks like your tab has the correct 3 reinforcing ribs. Five (5) teeth on the tab are indicative of an L-48. L-82's tabs had six (6) teeth. As best as I can tell your timing tab appears to be a correct 5 tooth tab . A better picture without the shadow would help to make a proper determination.
Your harmonic balancer is another story. That huge gap between the first pulley and the edge of the balancer is a concern. You seem to have no gap between the HB and the timing chain cover. As stated by Lars, it is either a defective balancer (shifted rearward) or it is an incorrect balancer. Below is a pic of a timing tab and balancer from a '75 L-48. Compare your gap to the gap in the pic below.
my 75 beater. but it is a numbers matching beater. OP's car looks to have the correct timing tab. it matches mine and 73-75's pic. has no gap behind the balancer. the gap between pulleys and balancer looks like a spacer built into the pulley. but i guess it could be the balancer outer ring shifted back and what is showing is the OD of the inner hub. my take is later model balancer designed for long water pump. do you have a set back timing light? if so, add 7 degrees to the timing and the mark should just show at the bottom of the tab. so timing will be 7 deg less than set back dial says.
Last edited by derekderek; Sep 1, 2021 at 05:18 PM.
Thanks to all of you for the pics, advice, etc. As Lars original stated, and you all confirmed through pics and/or your experience, the balancer did slide back. With my novice eye I thought it was all one casted piece. I confirmed that you guys are right be getting under the car and tapping the balancer with a hammer. Sure enough it moved a bit forward. I continued for a few and am up to a 1/4 gap now. Do you guys think it's even worth getting forward? Should I replace it? Or, can I leave it as is and use an alternative approach to getting the car timed? i.e Derek's suggestion, etc.
From: At my Bar drinking and wrenching in Lafayette Colorado
You cannot "repair" a balancer by tapping a slipped outer ring into position. The balancer is junk. Don't drive the car until you replace it - there is a good chance it can actually come apart, causing significant damage to car and anyone standing in its explosion zone. It's as dangerous as a hand grenade.
That damper is 100% shot and must be replaced right away. The outer inertia ring was originally bonded to the inner hub by a rubber ring. That rubber ring has failed. I would not drive it that way.
Wow. This is really a bummer. I don't want to cause more damage or hurt anyone so it's going to stay parked until I get it repaired. I really do appreciate your help. Thanks.
Damper doctor in California can rebuild the balancer they are one of the largest balancer rebuilders in the country. I believe it is $200 or so for the rebuild and about 1 week turn around.
Odd Timing Marks
