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Discussion Starter · #1 ·
Hello guys, first time poster here and I hope someone on here can help me with a certain issue.

Basically , the timing was way off on my Nova(350ci). I plugged the vacuum port going to the distributer, hooked up my vacuum gauge to manifold vacuum.

At first I was only getting about 13hg on the gauge. In adjusting it, I was able to get up to about 19.5hg which is my highest recorded and the engine sounded quite smooth. I locked the distributer , hooked up the advance again and went for a drive. I maybe should note, I adjusted the fuel mixtures screws and idle.

When driving with little to no load, it drives quite well however, when I put my foot into it, it starts to ping like crazy.
I feel like the engine is more alive and quick when on the throttle but it does ping when I give it more load. The only way I was able to get it to stop pinging is to turn back the distributer so I am registering about 15.5 hg but, it does feel a bit more sluggish.

Any advise or help is appreciated.

Thanks.
 

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Mike - 74 Nova Baltimore, MD
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You should not set your timing by manifold vacuum alone.
You need to set your timing by using the marks on the timing cover and balancer... plus you will need a timing light.
  • Disconnect and plug the vacuum line going to your Distributor's VA canister.
  • Set idle speed.
  • Using a timing light connected to the #1 spark plug, point the timing light at the timing tab and balancer.
What is your timing at idle (VA disconnect)?
What is your total mechanical timing when you rev the engine ((VA disconnect)?
 

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Chances are that if you advanced your idle timing your total timing is too far advanced. Often there is too much mechanical advanced built into the distributor (stock distributors) to allow nice advanced idle timing and proper total timing.
 

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Hello, and welcome to SNS! First, do you have any specifications on your motor such as components? Is it all stock? What year? 2/4bbl, cam, headers, compression ratio, aftermarket ignition/spark box, coil, HEI, hot ignition module for the HEI, (it's a 350 so you're in good company no matter what!) any aftermarket go-fast goodies? Did this timing issue just suddenly begin out of nowhere or did something occur that prompted you to mess with it? Depending on the engine and other components, there are many things which could be causing this. As @RifRaf and @matt777 stated, and a lot more. Did you/have you changed anything other than turning your distributor CCW and CW to change your base idle timing? What fuel do you run in it? Lots of questions but with a few answers, I'm sure we can help... Or at least get you headed in the right direction to correct the issue. One thing you need to make sure of is that your entire ignition and fuel system is fully-functional before you go messing with your timing. Good plugs gapped correctly, good/clean dist cap and rotor (no carbon arcing under the cap), good plug wires with no shorts (Bermuda, clam-diggers or otherwise), clean air filter, correct air/fuel idle screw adjustment (lots of youtube videos on that one, depending on the carb you're running), etc. Let us know and again, welcome to the site!! :)

~Andy
 

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Sometimes even the mark on the balancer can be off a few degrees. Among all those replies is the solution, and I'm guessing too much total advance. When you accelerate and hit the throttle, you gotta guess too much advance, so there are ways it can be limited: use a piece of wire or fab a small tab that will limit the vacuum advance travel under full throttle. Gas is really bad these days, so 16-18 degrees a stock vacuum advance could add will likely be too much. If you can find a way to limit the vacuum advance to 10 or 12 and see how it performs, try that. Also, you might try a higher octane fuel depending on the CR you are running. You'll get the ping back down.
 

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Discussion Starter · #7 ·
First off "Riff Raf" Thanks for the response,

I guess I will have to go out and purchase or see if I can borrow a light. Also, I noticed that there was no timing marks or a timing tab on the balancer. What Idle should I be aiming for when doing this?

"Stroker"

Its pretty much a stock 350 from what I believe is a C10, probably 70s model. Have not had a chance to look at the casting numbers yet. Its a 4bbl quadrajet, its got an RV style cam, stock heads I believe. Has an RPM performer intake. The distributer is stock I believe. Compression ratio is unknown.

It was not so much an issue before, i just realized it was sluggish off the line and when I installed power disc brakes I did not feel like the vacuum was sufficient. Upon putting a guage on it, it was registering only 12.5hg or so. I turned the distributer CCW slightly and I was up over 17 or so. The highest number I could achieve was 19.5 or so with a 850 rpm idle.

I run 87 octane , which it ran fine with before. I have tried to adjust the fuel mixture screws etc. This carb could use a rebuild but I do have a quadrajet that I am rebuilding right now to go on the car and should work way better as It will be brand new once I am done with it. Im used to building motorcycle carbs so I am somewhat familiar with carbs. I can tell that the right mixture screw on the car now does not seem to be working perfectly.

I have not gone through the whole car completely yet(time constraint right now). Just doing what I can for the time being.

AllyMcreal, thanks for the tip. I will def consider the higher octane fuel. I am curious now to see if it will still ping on the higher rated fuel like 92 or 94.

I really appreciate you guys advise thus far. This is a great forum from what I have seen.
 

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Mike - 74 Nova Baltimore, MD
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Also, I noticed that there was no timing marks or a timing tab on the balancer.
Look down at the balancer (towards the drivers side of the water pump) and you should see a timing tab that is attached to the timing case cover that looks something like the image below (red arrow).
420382

... And somewhere on your balancer, there should a single line engraved into the outer ring of your balancer (yellow arrow). This engraved line could be located anywhere on the circumference of the balancer, so you need to look for it.

If your timing cover does not have a timing tab attached to it, you will need to measure the diameter of the balancer and purchase a "bolt on" aftermarket timing tab that matches the balancer diameter.

Once you have your timing tab installed on your engine, it would also be good idea to confirm that the timing mark on the balancer lines up with the "0" mark on the timing tab at #1 cylinder TDC. There are several youtube video that explain how to do this.

What Idle should I be aiming for when doing this?
When setting your initial timing, an idle speed of about 800-850 rpm should be fine.

The distributor is stock I believe.
Stock points distributor (with remote coil)?... or stock HEI distributor (with coil in the cap)?
 

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I have had a balancer have the wrong timing mark on it. It was off by 3-4 degrees, and I don't know if it was made that way or the rubber was compromised, but it was definitely off. You can check your timing mark against TDC (there are a few ways to find true TDC on your #1 cylinder) and go from there. End of the day, sounds like you are getting too much advance under load/low vacuum.
 

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It sounds like you advanced the timing to get the vacuum up, now it's way to high. Have you adjusted your valves? Valves out of adjustment can cause low vacuum readings. I would start there, then work with the ignition.
 

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I've timed plenty of motors before but I never bothered timing for TOTAL advance (before owning h8ful) which requires a timing light with offset and a helper. If you've got one of these cars, you're going to need a timing light and buying a decent one that has an adjustable offset is worth the money spent. SBC's like mid-30 degrees of total timing when you're on the gas so the idea is to set the timing light to say 35 degrees, have a helper hold your RPM's at 3500 shoot at your timing mark and turn the distributor until the line lands at 0. Then set your light to 0, let the car idle and shoot at your timing mark and see what your initial timing is.

I heard that guys back in the day would set their initial timing and then take the car up onto the highway and keep adding timing until the motor started pinging, then back it off a little.
 

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Discussion Starter · #12 ·
Thanks everyone for your help and messages.

RIFFRAF , yes its an HEI with coil in the cap. There is no timing tab so I will have to get one and put a couple of new notches on the balancer as I do not see any marks there either. It may have had the stick on timing tape at one point.

It looks like I may just to have to go back and start from the beginning, find TDC and go from there as far as mounting a new timing tab etc. I need to find time to go through the motor, swap out the plugs and adjust the valves. Should be good to do that all in one day. After that, I can be sure of timing the motor correctly.

UNSTABLE.. I really like the idea you put forth. That's seems like another good technique I can use in the future.

I have a feeling at some point the PO did not set in the distributer correctly or initially pointed properly and may be way out.

Thanks again guys for all your help and I will update as I go along!
 

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Unless you have a solid lifter cam, I would skip adjusting the valves until you ensure your fuel/ignition system is all working correctly. Unless you suspect the PO had their hands in the valvetrain, there's really no reason to go diving into the adjusting of your valves unless you suspect a reason they're out of adjustment. Here's the thing... If your car doesn't backfire out of the carb on acceleration, you need to look elsewhere for the detonation issue. Loose valves has a significantly different sound than detonation and while it could be an issue, you would hear the noise even at idle and if your car did not detonate before you messed with the timing/vacuum, then your issue is most likely fuel or timing/ignition related. Start small and work your way up, eliminating all things small before diving into tearing your valve train apart. As for your balancer timing mark, I implore you to keep looking around the circumference of the balancer for a line. Even aftermarket balancers all have some sort of mark for TDC. Plugs, wires, cap, rotor, rotor button, air filter, fuel filter, egr, vacuum leaks, coil, HEI ignition module, all things to check before you dive into the mechanics of the motor internals...

We're all here to help,

~Andy
 

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Discussion Starter · #14 ·
:D:DThanks Andy... haha like that end rant/advise. That's awesome... ok sounds like a plan.

The cam that is in it is a COMP Cams High Energy 260H Hydraulic Flat Tappet. I know the PO had his hand in it and I do hear something faint either a lifter or rocker or something if I rev it up slightly and back off but its not very intrusive and you really have to pay attention. Its almost like a rhythmic tic that you can hear that will go up and down with RPM but its under the driver side valve cover.

I will take another look for the marks Andy.

Thanks again.
 

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If you don't see a timing pointer off to the side of the waterpump like what was shown in the pic above, then look straight down behind the water pump, between the waterpump and the timing cover, in the late 70's the timing pointer was moved to that location. There should be a groove in the ballancer like the others have said, and shown in the same pic above, if the ballancer is dirty it might be hard to see, unless it was changed with an aftermarket one when the cam was installed, and the timing pointer might have been left off at that time also. If the pointer is missing, make sure you get the right one for the ballancer you have, there are different timing mark locations on the ballancer and different size ballancers. You can google the different timing locations and how to check your ballancer.

Also you can read through this old post from here on timing and vac. advance, it's kinda long read but explaines it very well.
 

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Hello guys, first time poster here and I hope someone on here can help me with a certain issue.

Basically , the timing was way off on my Nova(350ci). I plugged the vacuum port going to the distributer, hooked up my vacuum gauge to manifold vacuum.

At first I was only getting about 13hg on the gauge. In adjusting it, I was able to get up to about 19.5hg which is my highest recorded and the engine sounded quite smooth. I locked the distributer , hooked up the advance again and went for a drive. I maybe should note, I adjusted the fuel mixtures screws and idle.

When driving with little to no load, it drives quite well however, when I put my foot into it, it starts to ping like crazy.
I feel like the engine is more alive and quick when on the throttle but it does ping when I give it more load. The only way I was able to get it to stop pinging is to turn back the distributer so I am registering about 15.5 hg but, it does feel a bit more sluggish.

Any advise or help is appreciated.

Thanks.
Go to Home Depor or Lowes buy a gallon of Acetone and a gallon of Ethylene. Mix them 50/50 in a metal container do not use plastic cause each will dissolve plastic and wear rubber gloves. Add 2-1/2 ounces to 5 gallons of gas, this mixture turns regular gas into high test. Do not ex
Hello guys, first time poster here and I hope someone on here can help me with a certain issue.

Basically , the timing was way off on my Nova(350ci). I plugged the vacuum port going to the distributer, hooked up my vacuum gauge to manifold vacuum.

At first I was only getting about 13hg on the gauge. In adjusting it, I was able to get up to about 19.5hg which is my highest recorded and the engine sounded quite smooth. I locked the distributer , hooked up the advance again and went for a drive. I maybe should note, I adjusted the fuel mixtures screws and idle.

When driving with little to no load, it drives quite well however, when I put my foot into it, it starts to ping like crazy.
I feel like the engine is more alive and quick when on the throttle but it does ping when I give it more load. The only way I was able to get it to stop pinging is to turn back the distributer so I am registering about 15.5 hg but, it does feel a bit more sluggish.

Any advise or help is appreciated.

Thanks.
Buy a gallon of Acetone and a gallon of Ethylene, wearing rubber gloves mix a 50/50 mix and then add 2-1/2 ounces to 5 gallons of regular gas. This slows the burning of the fuel so it behaves like hi-test. Use the ratios given no more no less... when you adjust the carb using a vacuum gauge make sure to roll the mixture screw in until the engine stumbles, then screw it out until it stumbles again, but be sure to count the number of turns... then turn the mixture screws in for half the value counted.... it is extremely important to preload the mixture screw springs so they dont shift and mess up the mixture. Also if you have points and condensor, then put matched condensers on each side of the coil, set the dwell to 24 to 25 degrees and set the timing 2 degrees above factory spec... Dont use Champion plug cause the thread is not rolled into an Apex configuration and the sharp edge will eventually tear up the plug bore. USe use NGK,plugs and gap them .050 above spec, clean the plug bore with carbon cleaner using a brass brush like those from a gun cleaning kit and Torque the plugs. Run an extra ground from the distributor to the neg post of the battery and run a double pigtail ground wire to the block and frame. Wipe the distributor out with rubbing alcohol, put a dab of molycote on the distributor cam and a drop of non - detergent oil on the felt insert underneath the rotor..... dont mean to sound like I'm preaching to the choir but I started in this business over 50 years ago and had a 58 ford with a 312 Merc engine with ECZG heads and used to go over 40,000 miles on a tune-up fitted with a Borg-Warner t-85 with O/D wired to a toggle switch and ran it like a 6 speed. Just wish I had a 411 rear instead of the 358. I was getting 19 to 20 on the highway the engine was turning 1700 RPM at 75 MPH.... .
 

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Buy a gallon of good, Polish Vodka (Real potato Vodka, not that corn crap they pawn off as vodka... that's garbage) and sit in a lawn chair outside in the sun and start drinking.

By the time you're finished, EVERYTHING will be pinging and you'll know exactly which end is up/down/sideways!

Again, all good ideas throughout this post but you really need to start thinking about getting to your baseline first... making absolutely certain everything is functioning correctly before you go playing with experiments that can damage rubber parts in your carb, fuel pump, tank, lines, your lungs... the environment, your home, the works! ***Acetone is volatile and is immediately absorbed into your liver through contact with your skin and can cause all sorts of nasty issues health-wise, as well as being extremely flammable, and sometimes explosive, depending on circumstances. there are UEL and LEL which I will not go into here but I'm a fire marshal and I promise, you need not mess with that to make your car function properly. Acetone is one of the single most flammable liquids we have with the broadest range of flammability in % of air right there with gasoline. It's not good stuff. While old-timers used these things regularly, they also had less information about MEK, lead (TEL), mercury, DDT, plenty of things once thought benign like washing car parts with their hands in gasoline (leaded or not) and siphoning gas by sucking on a hose... which are now the reason so many have cancer or other major health issues. Save yourself the trouble and find out what's wrong with your ignition and fuel system first before experimenting with chemistry. You don't need two problems when you only started with one. Keep us posted
 

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Thinking he meant ethanol... E85 comes to mind. or E95. I do mix a couple gallons of it with my 91 octane here in CA (we only have 91 at the pump here in N CA unless we opt for the race gas, but that's not for a daily here as the CARB fuel requirements jacks the price sky high) to milk out a few extra ponies in my Lightning for the blower. It likes the cooling of the ethanol a lot and the limited mix I use boosts the octane over 98-100+ so the timing maxes out even at 10 psi of boost without so much as a single ping from the motor. You can tell the motor is running just fine but I caution anyone running O2 sensors, you likely will get a lean mix on a bank or both using this method as ethanol burns differently than gasoline so the O2 sensor's resistance is different in the mix, pre and post cats... depends on how your trims are set. Have not experienced any issues with the fuel systems I use ethanol mix in... just gotta watch out for the aluminum corrosion... and evaporation from your carbs if you use it in a carb app. Also, don't try it with an Edelbrock... they don't like the ethanol at all and aren't built to tolerate more than the small bit CA already mandates in the pump gas here anyhow... if even that...
 
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