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Timing Mark Problem

Posted by jerry57 (My Page) on
Sun, Oct 2, 05 at 23:24

Need Help - Had the harmonic balancer and timing cover removed and mechanic replaced oil plugs in chevy 350 engine. Installed engine in my 57 chevy truck, starts and engine runs great put can not get the timing mark to appear to set correct timing. I put the engine on TDC 1 piston and installed the distributor and all spark plug wires. Question - Can the harmonic balancer be but on wrong by mechanic? Can the timing chain have been installed wrong? Any other help would be great.

Thanks

Jerrt


Follow-Up Postings:

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RE: Timing Mark Problem

How about a little more detail on: "can not get the timing mark to appear to set correct timing."

It won't appear using a timing light or what?????

GG


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RE: Timing Mark Problem

Pull #1 back out, and find TDC manually. Now look at your damper and see where the mark is. It's possible that the damper pulley is bad and the outside weight is turning on the rubber portion.

As far as getting things wrong with the chain, or the balancer being missinstalled, those are always possibilities. It is going to be up to you to do the work and find out.


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RE: Timing Mark Problem

the fact that engine runs great assures me that the distributer is in correctly.
there are different timing sets marked on balancers. they have to match up to the timing indicator on the timing cover.
when you do as suggested above, with the sparkplug out, and compression is felt, or even if you just shine a light into the Sparkplug hole and watch the piston rise up to the top. where is the timing mark? if it does not line up with the timing tab on the timing cover, either the balancer is bad,wrong, or the incorrect timing cover is in place.
John


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RE: Timing Mark Problem

IMO, if it runs fine, there isn't an issue...unless the balancer can spin. We don't want that. Time it by ear. Advance timing 2 degrees at a time, put the engine under load. When you hear it start to ping under load, back it off 2 degrees and it's done. That's more accurate than simply adjusting it to 4 degrees BTDC or whatever the spec is and calling it good anyway. BTW, are you sure you're looking for the mark in the right place? Some you had to look down through the gap straight through the top between the water pump and engine block. Some were to the left of the damper. jmo


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RE: Timing Mark Problem

Will guys I guess from time to time you do some stupid stuff. I had number 3 and 1 spark plug wires cross so I was really picking up the time off number 3 cyclinder. This puts the timing mark way way off. Motor has a mild cam so is hard to hear the miss with the wires crossed. Would have been able to tell if I could have driven the truck. Changed the wires and timing is set correcting.

Thanks for all the recommendations

Jerry


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RE: Timing Mark Problem

You can't put the balancer on wrong.Theres a key that lines it up on the snout of the crank.The balancers rubber is not spinning or it would shake your engine apart from not being balanced correctly and you would feel it when you drive.If you did drive it and had wires crossed you would know it.It is hard to tell when there is no load on the engine just from starting it and reving it without a load on it,especially if you put more cam in it that gives your engine that new idle and has your car shaking a bit.


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RE: Timing Mark Problem

It is possible for a balancer to be off and not cause a severe vibration, at least on my Ford Mustang. The timing was almost 10 degrees off because of the old balancer's timing marks had moved. The balancer on the Mustang has an inner piece, an outer piece with the timing marks on it, and a rubber piece in the middle. If the rubber deteriorates, the outer piece can move resulting in the timing marks being in the wrong place.

I replaced it because the rubber piece looked like it was starting to deteriorate.

If you compare your old balancer with a new one, you should be able to see if the same thing happened with yours. The timing marks should be in the same place in relation to the key on both.


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RE: Timing Mark Problem

I am having this same issue on my 77 350 chevy. When using a timing light, on #1 plug, the mark on the damper is at about 40 degrees ATDC??? It runs and pulls great. I bought the car about a year ago and just decided to do a tune up, now I am confused!


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RE: Timing Mark Problem

SPSHAW:

1. About your 350 Chevy engine and far out timing marks. I'll mention this far-out possibility since it happened to a friend of mine.

Check the paint color of the vibration damper (it carries the timing mark) and the color of the top end of the engine. These should match. This engine was made with either red or blue paint, depending on the accessory choices and truck model. On one engine, the stationary timing plate was on the left side and on the other, it was on the right side.

My friend got into this problem when he bought a used pickup. It was running great when he decided to give it a tuneup including spark plugs, spark plug leads, and other stuff. Then he tried to time the engine - trouble. He took it the local authorized Chevy truck garage and they were puzzled to. The zone manager took one look at the engine and spotted the color difference.

On checking back with the previous owner, he had replaced the vibration damper - found one at a slavage yard (of the opposite color, of course). He did not attempt to time the engine since changing the damper/sheaves did not affect timing. He then sold the truck to my friend.

2. Make sure that you are on the no. 1 plug. Look at the two banks of this V-8 and determine which of the two front cylinders of the two banks is slightly forward of the other. The one fartherest forward is no.1.


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RE: Timing Mark Problem

Thanks for the follow up, but I don't think this is my issue either. The vibration damper is the same color. The car is a 50,000 mi, one owner corvette and they confirmed at the time of sale that it never had any major replacements performed. It even had the original plugs in it.

I have resigned to doing a complete timing check. I will pull the valve cover, confirm TDC and see how the mark lines up. I also plan to check wire routing, as it has the plug wires routed under the manifolds I will probably have to check with an ohm meter verses pulling each wire, they really hid them under alot of tin work. Is it possible to have wires switched and still have it run good?

It does start good, runs great and screams up to the red line. I am totally perplexed on this one. It has been a few years since I have had the opportunity to play with a hot rod, now I am feeling like in idiot!


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RE: Timing Mark Problem

If you pull the wires off of the plugs, you increase the chances that you will have a problem with them. The insulation ages and gets brittle, just like the carbon fiber impregnated core does. An ohm-meter will show the resistance of the wire, but does not show you if the insulation cannot prevent the spark from jumping through. That's why today if we touch the plug wires, it gets new. Fail to do that and you usually see the car come back with a problem.

As far as the timing mark problem goes if the engine is running as good as you say it is, then leave well enough alone. The possiblity of the damper slipping is pretty high, but there could also be a much simpler explanation. Number #1 is the divers side front, (LH) accidently using the first plug on the RH side would give you exactly what you described.


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RE: Timing Mark Problem

This afternoon I did a Mechanical check of the timing. First I lined up the timing mark to the timing tab, ensuring #1 cylinder was at TDC.

Next I pulled the cap and confirmed that the rotor was pointing to #1 plug wire on the cap, it was close, but not exactly on it.

I confirmed the wires were in the correct order by pulling the plug end of the wire and used an ohm meter to confirm it was the correct wire on the cap, they were.

In preparation of firing the motor I put the inductive pick up on the #1 wire at the cap, I know this is not the correct way to use the light but I am getting despirate by now.

Fired up the engine....and yes, the mark is still off by a huge amount ATDC. Placed the inductive pickup in the correct location by the plug on #1 cylinder and the timing was verified to be in the wrong place.

Reading the postings above has got me thinking though. My car is an early 77. If I recall correctly it was built in March, still has the key lock security in the left front fender. This was a transitional year for the corvette.

I began seaching through the cob webs of my mind, I told you it has been awhile since I dabbled in the world of the small block chevy. I think the story you told above is the case here.
The timing tab on this engine is high on the damper. If you were to look at it from the front of the engine it would be at about the 1 - 2 o'clock position, welded to the timing chain cover. While the the mark on the damper, when running and the light on #1 cylinder, is at about the 3-4 o'clock position. This is were I remember the timing marks to be on the early chevys.
So...I will be making a trip to the local parts store to buy one of those cheap Mr Gasket bolt on timing tabs to see if the mark lines up better with that one. If that doesn't work.....I will do as you said above and leave well enough alone. It just gets under my skin when I can't figure out an issue with a small chevy. They are practically fool proof, but this one is making me out to be the fool.


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RE: Timing Mark Problem

I note a bit of confusion about the term, "balancer" or "Harmonic balancer", as applied to the ring bonded by an elastomer to the hub on the front end of the crank shaft. It is not a balancer. A better term is "torsional vibration damper". It is there to damp down torsional vibration modes in the crankshaft when the crank is operated near or at a torsional mode of oscillation. The amount of mass fastened on the other end of the crank shaft (clutch assembly / flex plate and drive half of a torque converter) affect the torsional natural frequencies of the crank shaft - and associated masses. Some of these frequencies are not avoidable within the normal operating range thus a control is needed to limit stresses and torsional oscillations.


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RE: Timing Mark Problem

i have the same problem, my timing mark on the damper is at about 12 o clock and the tab is at 2 oclock, i turn the distributor cloclwise to get the mark where it should be but it runs like crap, it hesitates real bad and sounds like its cammin when i dont even have a pro cam.. now when its idling with the timing mark at 12 oclock it still hesitates and kinda runs rough, i put it in gear and again sounds like its cammin, try to power brake it and as soon as i let off the gas it shuts down. whats goin on here?


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RE: Timing Mark Problem

i am having the same problem on my 350 in my ford coupe no matter how many times ive reset the distribator my timeing mark always come up at the 12 oclock position,engine runs good at high idle but when you slow it down it stalls and then diesels and runs backwards and spits out the carb.


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