Timing issue
Thread Starter
7th Gear
Joined: Aug 2009
Posts: 7
Likes: 0
From: Summerset South Dakota
Timing issue
Got a 76 L-48, 83K miles and I cannot get the timing set right. I used a dial back timing light (with vacuum unhooked and plugged) and I have to turn the dial to 55 degrees to get it close to the timing tab. Checked the balancer when I replaced the timing cover seal and it has not separated or anything. I even compared it to another 350 balancer I had and it was the same. The tab is on the driver's side but when the timing is set to 0 the mark on the balancer is at about 10 o'clock or so? When you do try to set it to the factory setting it won't hardly get out of it's own way. This thing has got me puzzled pretty good. When I put the light on the number 8 wire it is a ways before the tab but it is on the driver's side then. Anyone have any ideas? Is this the wrong balancer or is something wrong in the dist? It runs pretty good where I have it right now.
Melting Slicks
Joined: Dec 2009
Posts: 3,164
Likes: 623
From: Thunder Bay
Start with the basics. Make sure the timing mark is correct. Use a TDC checker to determine #1 TDC and make sure the timing mark is lined up. If that checks out, check to make sure the cam is timed correctly. I've seen Chevy timing chains get so loose they can jump a tooth, although your engine doesn't have the kind of mileage I'd expect for that to happen.
Thread Starter
7th Gear
Joined: Aug 2009
Posts: 7
Likes: 0
From: Summerset South Dakota
I have put aftermarket weight/spring advance kit in it. I even checked to make sure that the advance was working just fine. I did the TDC check but used my finger in the #1 plug hole. I have not pulled the timing cover off to check the chain. I do recall having a small block once that had the timing cover at the top of the timing cover but there is no way to see it that way with the short water pump on that motor. Not sure if I should try another timing tab or harmonic balancer. Or try a new dist.
Race Director
Joined: Sep 2004
Posts: 11,874
Likes: 263
From: Arlington Va Current ride 04 vert, previous vettes: 69 vert, 77 resto mod
the harmonic balancer outer ring is pressed on over hard rubber and these slip over time.....when they slip the timing mark is no longer meaningful.....to determine this you find TDC of the number 1 plug and then look to see where the line on the balancer is....if it is at 0* then life is good if not the outer ring has slipped.....
another way to get an idea if its way out ( assuming the car is running well) is to mark the spark plug tower on the base of the distributor of the number 1 plug take off the distributor cap and then keep bumping the car or if the car is a manual push it unitl the rotor is pointing at the this line.....this will mean that the car is relatively close to TDC NOT exact but if when you do this the timing mark on the harmonic balance is no where in sight then you know it has slipped.
another way to get an idea if its way out ( assuming the car is running well) is to mark the spark plug tower on the base of the distributor of the number 1 plug take off the distributor cap and then keep bumping the car or if the car is a manual push it unitl the rotor is pointing at the this line.....this will mean that the car is relatively close to TDC NOT exact but if when you do this the timing mark on the harmonic balance is no where in sight then you know it has slipped.
Thread Starter
7th Gear
Joined: Aug 2009
Posts: 7
Likes: 0
From: Summerset South Dakota
I did match the balancer up with another one I had in the garage and the marks were in the same exact spot. I will have to try the valve cover off, TDC method and see where that gets me. Worked on many small block chevys and never had this issue before.
Le Mans Master
Joined: Dec 2003
Posts: 5,727
Likes: 38
From: Fremont CA
If your balancer is indexed right and these syptoms of bad performance are still present, my vote is for an original timing chain cam gear failing. Chevy OEM timing chain sets come with nylon coated cam gears and it is not uncommon for them to loose teeth and retard cam timing.
Thread Starter
7th Gear
Joined: Aug 2009
Posts: 7
Likes: 0
From: Summerset South Dakota
I have been looking at getting a new balancer for it, but I don't know if it is supposed to have a 6 3/4 or an 8"? NAPA and Ecklers are calling for the 6 3/4 but Oriellys is showing a 8". Could it possibly have the wrong balancer on it? And would changing the balancer hurt anything. The one currently on there now is pretty ate up where the seal sits but I don't think itis leaking.
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Race Director
Joined: Sep 2002
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From: San Diego - Deep Within The State of CONFUSION!
I have been looking at getting a new balancer for it, but I don't know if it is supposed to have a 6 3/4 or an 8"? NAPA and Ecklers are calling for the 6 3/4 but Oriellys is showing a 8". Could it possibly have the wrong balancer on it? And would changing the balancer hurt anything. The one currently on there now is pretty ate up where the seal sits but I don't think itis leaking.
Race Director
Joined: Sep 2004
Posts: 11,874
Likes: 263
From: Arlington Va Current ride 04 vert, previous vettes: 69 vert, 77 resto mod
sure it can have the wrong balancer on it......if its the correct dimensions and weight mostly it effects only where the timing index marker is....
Thread Starter
7th Gear
Joined: Aug 2009
Posts: 7
Likes: 0
From: Summerset South Dakota
Got it solved! Got a replacement balancer, same size 6 3/4 but the timing marks are where they should be. Thanks for all the help guys....appreciate it! Now I wonder why it had the wrong balancer on it? Glad it is right, now to get the timing set right.
Race Director
Joined: Sep 2004
Posts: 11,874
Likes: 263
From: Arlington Va Current ride 04 vert, previous vettes: 69 vert, 77 resto mod
