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Lurching or trailer hitching is often a symptom of too much advanced timing,... turning the timing up at idle just to get a smooth idle is a mistake ......without knowing the rest of the story.

These cars will run great at in a range of numbers including 24 degrees of timing at idle generally, but you must be grabbing at least 10 of that from vacumn timing.

If not and your base timing is 24, your centrifigal timing must be 12 or so. Most distributors are way over that, so make sure too much timing will cause detonation.

Don’t just turn up idle timing until it “Feels” good or “sounds” good,.....it should feel good and sound good and be correct throughout the power band.

You can make it feel and sound good at idle,...and it will lurch ping and detonate throughout the power band.

So make sure.
Thanks Lemans Guy.
Logic would dictate that if I have some low speed lurching and no pinging and within 36 degrees total timing, that I should be able to pull the vacuum advance off to stop or minimize it-no go.
So I'm going to continue to retard the timing to see if I can time it out. My car is amazing in that I can't make it ping but can get to that other warning sign of a strained starter on startup but she still lurches:x.
 

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Red do you have 24 degrees of base timing and 36 total?

You can get too much timing too early and or to fast and you get the problems on acceleration as the springs may be so weak they pull centrifigal timing in on top of your base timing.

Or they just advance the weights so fast it lurches or pings etc.

I am sure you know your springs are on correctly.

Just make sure you know when centrifigal starts and stops and how much,..lurching could be other things as well.
 

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Discussion Starter #44
So no one seems to be sure what causes the timing to be off two inches. So correct me if I am wrong. As long as I set it where it runs its best, I should set a timing tape on the balancer and get total timing from there? So all I would need to know is where is there? Hard to mark it while its turning lol.
 

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So RM,...you have it mechanically at TDC, dead on......

So if you balancer is OK....Zero is at the Mark on the balancer

Put the timing tape starting there and make a corresponding mark on the engine.

So you have all three at zero.....The number one piston mechanically, ......

the balancer mark is now at zero with the piston..

Start the timing tape at balancer mark

And mark the engine next to to zero on tape and balancing mark....

Now try it and see where the timing light strobe falls........

You are setting the Advance timing light correct, right?.......

..if you set it for 10 degrees advance it will hit the strobe at zero on the balancer mark but read 10 degrees on the light......

Zero on the light should be zero on the balancer.
 

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So no one seems to be sure what causes the timing to be off two inches. So correct me if I am wrong. As long as I set it where it runs its best, I should set a timing tape on the balancer and get total timing from there? So all I would need to know is where is there? Hard to mark it while its turning lol.
If you have verified you are at TDC on #1 , then I would just mark the balancer with some white paint (paint pen works well) and then check what you are dealing with initial and total timing. That said, I suspect the dampener was installed incorrectly.
 

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Didn't read all the posts, but seemed to get the gist that with the piston at TDC Compression, the timing pointer on the cover is not aligned to the balancer mark. The mark is '2 inches' off from TDC. If this is the case, the only cause is the balancer itself: either the wrong one or the outer ring has slipped (common, especially on Chevies). The harmonic balancer hub is keyed into the crankshaft snout, and cannot be installed incorrectly. It WILL be in the right location on the crankshaft, and if not slipped or incorrect, it WILL have it's indicator meet TDC at the pointer if, indeed, the engine IS at TDC COMPRESSION. (not exhaust).
My bet: wrong or slipped balancer.
 

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Discussion Starter #48 (Edited)
Didn't read all the posts, but seemed to get the gist that with the piston at TDC Compression, the timing pointer on the cover is not aligned to the balancer mark. The mark is '2 inches' off from TDC. If this is the case, the only cause is the balancer itself: either the wrong one or the outer ring has slipped (common, especially on Chevies). The harmonic balancer hub is keyed into the crankshaft snout, and cannot be installed incorrectly. It WILL be in the right location on the crankshaft, and if not slipped or incorrect, it WILL have it's indicator meet TDC at the pointer if, indeed, the engine IS at TDC COMPRESSION. (not exhaust).
My bet: wrong or slipped balancer.
The balancer is a new one from butler, and only installs one way on the crank. When I used a piston stop and I mark it on the balancer at stop both ways, and split the difference the mark on the balancer is dead on with the tdc mark on the timing cover. The issue is, when set the distributor to run well or use a vacuum gauge it is about 2" from tdc. If I try to move it near tdc it wants to die.I only have a 068 cam, nothing crazy. So why would it read that way? I have two timing lights and both read it in the same place. It runs well which is not the issue. I would just like to be able to read it on the #s or at least find out what causes this. So far searches only tell me if it runs well yada yada yada... no real answer.
 

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The balancer is a new one from butler, and only installs one way on the crank. When I used a piston stop and I mark it on the balancer at stop both ways, and split the difference the mark on the balancer is dead on with the tdc mark on the timing cover. The issue is, when set the distributor to run well or use a vacuum gauge it is about 2" from tdc. If I try to move it near tdc it wants to die.I only have a 068 cam, nothing crazy. So why would it read that way? I have two timing lights and both read it in the same place. It runs well which is not the issue. I would just like to be able to read it on the #s or at least find out what causes this. So far searches only tell me if it runs well yada yada yada... no real answer.
Who installed your cam? And have you verified it was properly degreed? Since you know the balancer is correct, that tells me your cam timing is off....

Here is a good video :
 

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If the balancer is at the zero mark on the timing cover when the piston is at TDC....it is correct

When it runs correctly the timing advances to 10, 15, 20, degrees before TDC that moves the mark away from zero...

The correctly running timing is not zero, but a significant number of degrees before zero.

Put timing tape on balancer starting at zero....

Then shoot it with the strobe and read the number on the tape that is your timing advance.....should be a number of degrees before TDC or 2” as you describe...leave the timing light at 0 no advance.....

Then try.
 

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One other test (didn't read where it was performed). I always get to TDC by putting my finger (or a compressor gauge) in the spark plug hole. That way you can tell where the valves are when the piston is coming up. Using your finger will cause it to be blown out just b4 TDC. Just a thought.

Agree with the previous post; can you tell us what the advance in degrees is re the 2" gap?

Nick
 

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Discussion Starter #52
One other test (didn't read where it was performed). I always get to TDC by putting my finger (or a compressor gauge) in the spark plug hole. That way you can tell where the valves are when the piston is coming up. Using your finger will cause it to be blown out just b4 TDC. Just a thought.

Agree with the previous post; can you tell us what the advance in degrees is re the 2" gap?

Nick
I installed the cam. Did not degree the cam. So if this swap meet find timing light is proper for a 8cyl application. Because it has 2/4 stroke on it. I advance to 31 for the timing mark to be on tdc. Is this a correct timing advance light? When it's on 0 it reads the same as my base timing light. 2" off.
 

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What cij911 said. If you're bothered by it, time to check the cam timing...could be retarded 4 degrees. If it otherwise runs fine, I would be inclined to time it by ear/vacuum and drive it. Normally a retarded cam will run soft on the bottom end and strong on the top end. How does your engine RUN?
 

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I'll also add this: I wonder where the mark would be if you installed a factory original balancer assembly? Aftermarket parts, no matter who makes them, tend to have 'issues' that original parts in good condition do not. Cranks, balancers, head bolts, ignition systems, and on and on.
 

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I'll also add this: I wonder where the mark would be if you installed a factory original balancer assembly? Aftermarket parts, no matter who makes them, tend to have 'issues' that original parts in good condition do not. Cranks, balancers, head bolts, ignition systems, and on and on.
Totally agree with the above; the part could also be for another engine???
 

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When you have the timing light on 31 and the strobe hits zero....That is 31 degrees of timing advance....

That would be very possible with a hot cam

Can you turn it to 20 and still run?
 

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You are just reading the advance....

At 31 it would be about 2” off zero...

Nobody reads timing by inches....so it is confusing....use the timing tape you already have and verify your light with the tape...

Then you will know that your timing light is right

Sounds like it is all ok, but don’t drive it with 31 degrees base if you don’t know what your Centrifigal timing is...
 

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I installed the cam. Did not degree the cam. So if this swap meet find timing light is proper for a 8cyl application. Because it has 2/4 stroke on it. I advance to 31 for the timing mark to be on tdc. Is this a correct timing advance light? When it's on 0 it reads the same as my base timing light. 2" off.
Well if you did not degree your cam, there lies your problem....Sorry but you cannot just drop the cam in.
 

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Discussion Starter #59
Readjusted my valve lash this weekend and took it for a spin. seems to run run really well, both top and bottom end. Tho it seems to hold back some at wot before shifting gears. I guess I should of seen at what rpms. But the question I had is, after using a piston stop turned both ways to stop. The lower of the two factory type marks is my tdc. So is that where I should put my 0 on the timing tape then while doing the initial timing as in the pic should I fab a pointer to hit at the zero. Hope I am making sense.
 

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Right put your timing tape at the lower mark which you know is TDC #1 Compression......that is zero, no need right now for a mark....

Disconnect and plug vac advance...

Now don’t move the dist start it up and with timing light with no advance, at zero, read your timing advance at the tape. If it is 30’ see if you can get 20 then 10....that is your base timing.

As you increase say to 30 you also increase RPM and may be adding centrifigal timing, so at 30 what is rpm? At 20. At 10....

You also then use the advance on the timing light to check it, set the light to 10......it should hit the mark at zero with 10 showing on the light,

Same with 20 or any number, the light will strobe the zero mark and show the advance on back of the light

Your timing tape and light should be the same or very close.
 
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