Ok im really screwed. I was gonna adjust my timing, but my mark is almost halfway on the other side of the fly wheel. The timing plate is on the driver side yet when i mark the groove it shows on the passenger side!! I put it on the front driver side spark plug which is supposed to be #1. but how can my timing be off by 4 inches?!?! What could be really wrong? are the plug wires be all wrong?? can some one help me!! BTW can someone show me a diagram of the spark plug seq. ?? help fast i wanna get this problem fixed!! thanks!

 

Just a few questions first....Is it running like that or did it run like that?

If so, have you disconnected the vacuum advance before setting the timing? (You may have to tweak up the idle to keep it running when you disconnect the vacuum advance)

It is also possible, if it's running, that the ring has slipped on the harmonic balancer and the mark on the balancer is no longer TDC.

Good luck!
Joe

 

I had the same reaction the first time I checked my timing. Then, I read the instructions a bit closer. Remove and plug the vacuum line to the vacuum advance. That should bring your mark around to where it looks more reasonable.

 

ok, it runs fine and i havent adjusted anything. but i went to adjust the timing and the light wasnt picking anything up. so for kicks and giggles i put the light on the passenger side of the car and saw the mark on the wheel. its off by about 4 inches! so what could be the problem? you think it could have slipped? if it has, fow do i adjust the timing now? can anyone tell me how to find post #1 on my distributor? where is this power plug thing?? 78' vette

OHH and i DID have the thing plugged with a golf tee

 

Do you have your timing light connected to plug wire #1? Just guessing. If not that will throw the flash way off and could be the reason for the confusion.

 

I agree, recheck it, I check my timing frequently and just the other day I put the sensor on the wrong wire. I was wondering WTF was going on.

 

It is almost a certainty that the ring has slipped on the balancer. With the sharks it is most common. You will need to locate TDC and check where the mark is, but I would bet thats it.

 

ok #1 is the front driver side piston and the front driver side distributor pin. i put the timing light on the spark plug itself, and then conected the power to the battery. way way way off ( it shows 4 inches off in the advanced direction, or counter clockwise looking at the front of the vette. 4 inches to the left of the timing plate is where the mark shows if you where to look at the engine block from the front of the car. ) but here is one thought, can i just put the light on a different plug? put it on different plugs untill it lines up where the adjustment plate is? if not, and it HAS slipped, hod do i fix it and/or get it back to normal. and even if you cant tell me how to fix a slipped ring, i need ideas on how to get this timing right!! lol HELP!! 911!!

PS here is whats wrong with my car --> http://forums.corvetteforum.com/showthread.php?t=913615

 

Step #1: Make sure that your timing marks are giving you TDC. The only way to do this is to remove the #1 spark plug, you are right it's the front driver's side plug. Next, you need to turn the engine until you can get the #1 piston to TDC. Many ways to do this...I usually try using a fan belt and fan at first...or try to reach around the fan and place a socket on the harmonic balancer bolt and turn it with a ratchet. Don't even try cranking the engine to get it to TDC, you will probably get hurt somehow and you won't be able to get as precise movement as you would by hand. uhmm...make sure it's out of gear, in park, emergency/parking brake set. The engine is hard to turn, so you may need to remove all the spark plugs just so you can turn the engine properly.

Step #2: After getting the #1 piston to TDC look at the timing mark and make sure that the groove on the harmonic balancer lines up with the TDC on the timing marks. If it does not line up...and it's like 4" off like you say it is then you have sheared the key (small rectangular piece of metal which locks the inner groove of the harmonic balancer with the crank shaft) and will need to remove the harmonic balancer, clean up any messes it made, install a new key and re-install.

Step #3: If you got here then your timing marks are correct and there is no mechanical problem with your timing marks. Make sure your timing light is set to read TDC (some lights allow adjusting the light for advance). It is not possible for the timing to be 4" toward the passenger side cause that would be around 90º BTDC and the engine would not run.

 

how hard is it to replace the key you speak of?

 

You will have to remove the fan belts, fan, water pump pully, water pump, crank pully, harmonic balancer, timing gear cover, timing gears and chain. It will then be obvious where the key is since the crankshaft has a slot and so does the crank timing gear and harmonic balancer. That's why it's a good idea to double check your timing point to make sure that the key is indeed sheared before tearing into replacing it. After you get the harmonic balancer out you will easily see whether the key is sheared or not. You will need a harmonic balancer puller to get that far. You will need a 3-jaw gear puller for the crankshaft gear. And you will need 1 3/8" and 1/2" torque wrenches to get the bolts back in properly, as well as assorted SAE sockets. Plus, a timing cover gasket, timing cover to oil pan seal, and (if necessary) a timing cover crank seal. It would also be a good time to replace your fan belts and thermostat. Be sure to inspect the timing gears and chain to see if they should be replaced.

You should get a repair manual and study it before tearing everything apart if you haven't done this kind of stuff before. An alternative is of course to take your vette to a mechanic.

 

It's possible just the outer ring on the balancer has slipped. This is a semi-common problem. If this is the case, then you just have to replace the balancer with a new one. This is much simpler than having to fix a sheared key. There would be no need to remove the timing cover and gears, just pull the balancer and replace it.

Mike

 

Yeah, I didn't think of that. The harmonic balancer is two pieces with the outer piece bonded to a rubber cushion which in turn is bonded to the inner hub which has the slot for the key. If someone rebuilt the engine and cleaned the harmonic balancer with solvent, or if it's just badly used, then it's very possible that it's just the harmonic balancer that needs replacing. If there's an Autozone near you then you can borrow a harmonic balancer puller with a deposit which you can get back when you return the tool.

 

Firing order is 1-8-4-3-6-5-7-2. The only way I know of determing TDC is to pull the left valve cover, pull the #1 spark plug, and rotate the engine until you get near the timing mark. Put your finger over the spark plug hole. If you feel the air coming out, and both rockers are loose, then you are on the compression stage. If not, you are on the exhaust stage, and the exhaust rocker is tight (exhaust valve open). So, to recap, you want air coming out of the spark plug hole and both rockers loose. That should be TDC. From there you can start to look at how the wires are routed.

I don't know about 78's but on my 72 sb, the #1 plug is tower just to the right of the center of the dwell window, standing at the front of the car looking towards the firewall. That is the center of the #1 spark plug tower is the right hand edge of the dwell window. When I had timing issues on my newly acquired 72 I took nothing for granted. I pulled all of my shielding off and physically checked and tagged each wire. Then I put the wires in the right place and re-did the timing. You can also buy the book "How to Rebuild Your SB Chevy", available at the NCRS store at www.ncrs.org, and it will walk you through the distributor, timing, and spark plug orientation issues. Well worth it, especially if you are an electrical moron like me.
Gary

 

just look at my picture above. That is a view of the distributor from above. The front of the car is labeled, and you can see the orientation of the wire pack on the HEI distributor.
so, find your number one tower, then go down to where the cap meets the body of the distributor. Draw a line on the distributor body right under the terminal of the #1 terminal. Then when you have the cap off and are installing the distributor you want the rotor to point to that line when you have the distributor fully seated in the engine and the engine is set to top dead center. Know that when you are installing the distributor the rotor will turn as it goes into the engine, so you need to set the rotor ahead a little. If you did it right, the rotor will line up with #1 when installed.


HEI distributor correctly installed in car, front of car on left, viewed from drivers side. Note #1 terminal.



Under the #1 terminal make a mark on the distributor body. See black mark on distributor body, under the #1 terminal.
Now remove the cap.


Start installing distributor body in engine. Note that rotor is not pointing at the mark for number 1 on the body, but is turned pointing more at the fender. That is because as the distributor drops into the engine and the gear engages the cam gear, the rotor will turn. The objective is to have the rotor point to the mark for #1 when the distributor is FULLY SEATED.

As such.



If the distributor will not full seat in the engine it is most likely because the oil pump shaft slot is not lining up with the notch at the end of the distributor shaft gear. You will have to take the distributor back out and with a very long flat screwdriver turn the oil pump shaft. You need to turn it so when the distributor drops in the engine fully it lines up with the inside of the distributor shaft gear. This takes some practice.

If all is seated well the rotor should be pointing very close to the #1 mark when fully seated. If you have the crank set at 0 degrees timing it should point right at it. If you want to set your static timing, turn the crank to about 8 degrees before top dead center and then turn the distributor body so the mark lines up with the rotor. You will then be able to secure the distributor, install the cap, wires and fire it up. Time with a timing light after that.

Hope this helps.

 

My timing is still way off but my baby is running excellent now! It was Air Spring adjustment and Choke adjustment. But thanks for everything, Hopefully someday Ill figure out why the mrk is so off whack.

 

Congratulations on fixing your car!

Just for fun, take a look at your dampener to make sure it isn't coming apart. The outer ring should be reasonably flush with the back of the pulley. If it is off by more than 1/4" you are on the way to disaster. More than 1/2" and you are on borrowed time already. Most just slip around and stay put, but you should check to make sure. Joe

 

He will find out why it is off soon enough, when the oil is running out of the front of the engine. As I said in my first post, this is a most common problem with these cars. Almost all of them do it sooner or later. The ring will eventually slide back onto the timing cover and wear a hole in it. Dont rely on the timing mark that is on the damper. You may be in for trouble if you do so without verifying that it is correct.

 

you need to

 

If your timing chain and gear are worn they could have jumped a tooth.
If that has happened your mark will be off.

If you don't have too radical a cam.....
... get useself a vacuum gage and tee it into the system...with engine running at idle, adjust your points to get your highest vacuum. Then adjust your dist. timing for highest vacuum. You can also adjust your carb with this gage. You can look for a timing mark if you want but when engine is running its best it is pulling the most vacuum and the needle will be steady. An unsteady needle could be burnt valves, vac leak, loose timing chain or ?. If you can see your mark and it is drifting back and forth suspect bad timing chain.