So I am attempting to set the timming on my 350. I borrowed an inductive timing light from my uncle that is from the 70's but has been hardly used. Until now I had just timed it by ear and the car runs pretty well. So upon setting everything up, with the engine running well, the mark lights up way towards the passenger side of the vehicle. Like as if the initial timing is like 50 degrees advanced or something. My harmonic balancer is about 15 years old, but I havn't ran the car a hole lot since I built the engine. I know factory type balancers can shift, but my question is how common is that. Does anyone know. I didn't think it would happen to mine, but that's all I can figure at the moment. Thanks.

 

I don't know on your model, but I have a 91 and on the passenger side near the heater and ac dryer there is a brown/black stripe wire coming out of the harness. This put it in bypass. You disconnect it.

 

I am just running a regular HEI. It's not computer controlled, and I have the vacume advance disconected, and the hole pluged, so I think the timimg mark should be fairly close to my timimg tab.

 

"Shifting" (the outer ring breaking loose from the layer of spooge and wandering around) is VERY common.

If the motor runs right but the mark is out to lunch somewhere, ignore the mark. The engine does not whup out a timing light and check the mark, and run according to that; all it cares, is when the spark occurs. As long as it's right, it's happy.

IOW, if I may paraphrase one of The Great Ones in another unrelated field:

"If it RUNS good, it IS good".

Don't worry about some number; let THE ENGINE tell you what it wants.

It's not rocket science. Put it somewhere that it runs. See how it is. Move it. Better/worse? Better: move it some more the same way. Worse: move it the other way a little farther than you moved it the first way. Better/worse? Better: yadda yadda yadda until no further movement in either direction makes it any better.

Don't outsmart yourself, especially with a non-stock motor and unknown distributor; you have ABSOLUTELY NOT THE FAINTEST CLUE what the "right" timing IS, so what good is a light going to do? Just give the engine what it wants.

 

Just make sure it is not too loose and about to fly off

 

Thanks. I knew it could happen, but just wasn't sure. Thanks for the advise.

 

Either that or your dist. is a tooth off.

 

Doesn't matter if the dist is 1 or 4 teeth off. It doesn't matter to the engine or the balancer. It fires when it fires. If you are off one or more teeth it just means you must rotate the top of the distributor so the #1 plug terminal is lined up with the rotor at TDC. If the mark is in the wrong spot I would suggest replacing the balancer as it has spun once and it will take less for it to spin again. One day it will fail and ruin your engine.

 

LIL..............Your incorrect !

If the dist. is in a tooth or 4 off the timing mark will NOT line up with the
scale.

 

It can be off by 1 tooth or many, it will just require twisting the distributor to a very odd position to get the timing back to the point it will run properly.

Is this the original balancer on the motor? Like was said above, the outter ring can slip and throw off the timing reading (balancer is shot). OR.....

You could have a balancer/timing tab mismatch. GM put the timing tab in one of two positions: 12:00 (straight down behind the water pump) or 1:30 (peeking out under the driver's side leg of the water pump). The line on the balancer was in a different position to match the timing tab location. The difference between the two is about 40*. Very common when somebody swipes the balancer off an original 70s/80s era 305 carbureted or TBI engine (usually 12:00 postion balancer) and then shoves it on the front of a motor with a timing tab over in the 1:30 position. You end up reading about 50* advance when it's timed for good performance. It's not actually that advanced it reality, but that's how it reads when you put the timing gun to it.

 

I had a 77 Corvette years back that required putting the light on the number 2 (passenger side front) cylinder to get proper time... no clue why, it just worked that way. Engine was stock top to bottom, dist. Was in correctly plug wires on correctly everything was right but it threw the mark to the passenger side just like mentioned above... try it on the number 2 and see what happens

 

Thats really interesting. I had no idea they even made balancer marks/timing tabs for any small blocks that weren't to the right under the drivers side output of the water pump, or the "1:30" position as you call it. I wonder if the parts guy grabed the wrong balancer for me or something. Although I think the timimg mark was in the right position (aproximatly) when I first built the short block. I didn't have a timing tab at the time because I orderd an aluminum timing cover from summit and discover a stock one wouldn't work because the cover is so much thicker. Years later I've made/modifed a Mr gasket one from the parts store to work with my cover.

 

Thats interesting. I try it for the heck of it and see where the lights at.

 

I have to agree with the other guys. I'm asuming your talking about the distributor gear at the botom of the shaft where it meets with the cam and oil pump right? I think you may have misunderstood the conversation - because if your dist was off a tooth I guess your timing could be off.

 

most common reason for timing marks to not line up.

 

i was waiting on someone to point this out.it DOES matter where your timing marks are if it didnt GM wouldnt have put them there

 

GM put them there for THEIR OWN convenience, not yours (ours). Makes it faster for them to build and set up motors.

Does it make em run "perfect"? "ideal"? "optimum"? REALLY???