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How critical is the timing?
I have a 64 F100 with a 292. It hesitates and stalls when pulling out from a stop, say at a stop sign or a light, or when making a left turn.
I have just rebuilt the carb, replaced the fuel pump, replaced the distributer, installed an electronic ignition unit. The hesitation seems to be at least in part a function of the timing. I set the timing to 6 deg BTDC as the manual says. Still does it. I just reset it to 10deg and I am about to test drive it. The question is how critical is the timing setting if the engine is not pinging? Will it in general run better if the timing is set closer to TDC? or will it run better advanced as far as possible without pinging? Thanks. |
Originally Posted by wfon
(Post 14422290)
I have a 64 F100 with a 292. The question is how critical is the timing setting if the engine is not pinging?
Will it in general run better if the timing is set closer to TDC? or will it run better advanced as far as possible without pinging? Thanks. |
The 292 has a two part rubber-lined vibration damper that is prone to slippage, this makes the markings on the damper impossible to read accurately. A second issue is that a stock distributor advance curve is pretty stiff.
Setting the (initial) crankshaft timing is just part of the engine tuning. A vacuum gauge is a good way to set the initial timing until the damper can be replaced. |
That's really a vague question. I'd say as long as you have no driveability problems, it is not critical. However, if it is not tuned, you leave economy, performance, and overall enjoyability on the table. So it is absolutely worthwhile to tune the timing.
In general, any engine will like more initial advance, like around 12 degrees and maybe more but it should run fine at a factory setting if the engine is stock. On top of that, the amount and rate of mechanical and vacuum advance are important. The part about stalling at a left turn doesn't sound like timing, though. That sounds like a fuel distribution problem. For most people, rebuilding a carb is buying a kit, cleanup, replacing stuff and throwing it back together. That's not what I would say is rebuilt but it's not necessarily bad, either. We diy-ers often miss things that seasoned experts might see. I might have a second look at the carburetor, particularly the accelerator pump since it occurs from a stop. All these parts that you have changed, were they done in an attempt to fix this problem? Or, did the problem occur after installing one of them? I'm with Tedster. Forget your timing marks unless you are certain that the damper is good. Advance it and see if the problem goes away. |
Originally Posted by charliemccraney
(Post 14423012)
That's really a vague question. I'd say as long as you have no driveability problems, it is not critical. However, if it is not tuned, you leave economy, performance, and overall enjoyability on the table. So it is absolutely worthwhile to tune the timing.
In general, any engine will like more initial advance, like around 12 degrees and maybe more but it should run fine at a factory setting if the engine is stock. On top of that, the amount and rate of mechanical and vacuum advance are important. The part about stalling at a left turn doesn't sound like timing, though. That sounds like a fuel distribution problem. For most people, rebuilding a carb is buying a kit, cleanup, replacing stuff and throwing it back together. That's not what I would say is rebuilt but it's not necessarily bad, either. We diy-ers often miss things that seasoned experts might see. I might have a second look at the carburetor, particularly the accelerator pump since it occurs from a stop. All these parts that you have changed, were they done in an attempt to fix this problem? Or, did the problem occur after installing one of them? I'm with Tedster. Forget your timing marks unless you are certain that the damper is good. Advance it and see if the problem goes away. |
Back when dirt was new, we had, or my oldest sis had a '57 Victoria 2-dr hardtop with a 292 & Ford-O-Matic. It would hesitate and stall upon acceleration unless you really tromped on the gas pedal.
The cure was to add some washers in the vacuum advance behind the spring, making the vacuum advance a tad slower. It didn't take many flat washers to have the desired effect. tom |
Originally Posted by Tedster9
(Post 14422993)
The 292 has a two part rubber-lined vibration damper that is prone to slippage, this makes the markings on the damper impossible to read accurately. A second issue is that a stock distributor advance curve is pretty stiff.
Setting the (initial) crankshaft timing is just part of the engine tuning. A vacuum gauge is a good way to set the initial timing until the damper can be replaced. What does stiff mean in terms of advance curve? Does that mean it is likely to stall? |
Originally Posted by charliemccraney
(Post 14423012)
That's really a vague question. I'd say as long as you have no driveability problems, it is not critical. However, if it is not tuned, you leave economy, performance, and overall enjoyability on the table. So it is absolutely worthwhile to tune the timing.
I do have a problem with what you call "overall enjoyability" It just isn't fun to drive when it bucks, hesitates and sometimes stalls In general, any engine will like more initial advance, like around 12 degrees and maybe more but it should run fine at a factory setting if the engine is stock. On top of that, the amount and rate of mechanical and vacuum advance are important. The part about stalling at a left turn doesn't sound like timing, though. I meant when you come to a stop waiting for traffic before making a left, not just any left turn. The condition is that same as a stop sign, just even more dangerous to stall in front of oncoming traffic. That sounds like a fuel distribution problem. For most people, rebuilding a carb is buying a kit, cleanup, replacing stuff and throwing it back together. That's not what I would say is rebuilt but it's not necessarily bad, either. We diy-ers often miss things that seasoned experts might see. I might have a second look at the carburetor, particularly the accelerator pump since it occurs from a stop. I bought the truck about 6 years ago and I was having more of less this problem then. I have spent the entire time since then hunting for an answer. I replaced the Carb as one of my first tries. I just got back from my test drive after setting the timing to 10 deg. No ping, but I still get hesitation, except when the the choke is applied. With the choke on, it runs better. All these parts that you have changed, were they done in an attempt to fix this problem? Or, did the problem occur after installing one of them? I'm with Tedster. Forget your timing marks unless you are certain that the damper is good. Advance it and see if the problem goes away. |
Originally Posted by tomw
(Post 14423997)
Back when dirt was new, we had, or my oldest sis had a '57 Victoria 2-dr hardtop with a 292 & Ford-O-Matic. It would hesitate and stall upon acceleration unless you really tromped on the gas pedal.
The cure was to add some washers in the vacuum advance behind the spring, making the vacuum advance a tad slower. It didn't take many flat washers to have the desired effect. tom The service manual has this image showing a spring and "calibrating washers" https://cimg3.ibsrv.net/gimg/www.for...86cb15c734.jpg My distributor does not have those parts on the vacuum advance. Do I have the wrong advance mechanism? https://cimg1.ibsrv.net/gimg/www.for...5b9b67546b.jpg |
There are a whole bunch of threads here at FTE in the archives to digest if you're willing to spend some time getting up to speed on timing, as well as other webpages devoted specifically to ignition timing/distributor curving and such.
And a stock setup 292 Y block will respond really well to this. But it takes a methodical approach. At least you can eliminate this as the source of the problem and have a lot more fun too, better fuel economy (such as it is) and the Y block engine exhaust note is basically ear candy. Really! Run it up to 3000 RPM or so with vac adv. disconnected and plugged, observe marks with a timing light. Report what the total timing is in degrees. Should be "all in", 36 to 38 degrees. Since you replaced the distributor itself it should be in good shape, but the mechanical advance may be too late. When the advance kicks in is more important than how much to some... degree. |
Since you have a rebuilt distributor, it probably does not have a stock vacuum advance unit so it probably cannot be adjusted with washers. It probably can be adjusted with an allen wrench. I can't tell which one you have from your picture. It's very blury. However, vacuum advance is not a necessity. It is for economy and that's about it. You can disconnect and plug the vacuum line to see if the problem goes away.
The stock "stiff" advance curve would not cause it to stall. It sounds a lot like you're not very familiar with diagnosing problems and you need to learn how to do that. A great place to start is with a shop manual. The factory shop manuals are excellent. If you don't already have a factory manual, either original or reprint, get one. And do what Tedster says to learn about stuff. |
Plus one on the above.
I will add that your report that adding choke makes it less hesitant to stall may indicate that your accelerator pump may be set to lean or inoperative. If you watch down the venturi of the carb, does the carb put squirt of gas in when you first push on the throttle lever? If not, check the accelerator pump. If so, you may be able to adjust the pump to come into play earlier or more strongly. When you step on the gas pedal, the air is moving and will accelerate and get sucked into the intake rather quickly. The fuel, on the other hand, will NOT accelerate as quicky as its mass is more dense. The accelerator pump adds a squirt of extra fuel to help make up for the slow acceleration of the liquid fuel through the carb passages. It 'bridges' the time it takes for the fuel to catch up to the air flow. If weak, you will get stumble on acceleration as the mix is not rich enough to burn. tom |
Originally Posted by tomw
(Post 14424484)
Plus one on the above.
I will add that your report that adding choke makes it less hesitant to stall may indicate that your accelerator pump may be set to lean or inoperative. If you watch down the venturi of the carb, does the carb put squirt of gas in when you first push on the throttle lever? If not, check the accelerator pump. If so, you may be able to adjust the pump to come into play earlier or more strongly. When you step on the gas pedal, the air is moving and will accelerate and get sucked into the intake rather quickly. The fuel, on the other hand, will NOT accelerate as quicky as its mass is more dense. The accelerator pump adds a squirt of extra fuel to help make up for the slow acceleration of the liquid fuel through the carb passages. It 'bridges' the time it takes for the fuel to catch up to the air flow. If weak, you will get stumble on acceleration as the mix is not rich enough to burn. tom I have also tried this morning to advance the timing as far as it will go. The vacuum advance keeps it from moving any further clockwise. That did not solve the problem. |
Originally Posted by Tedster9
(Post 14424158)
There are a whole bunch of threads here at FTE in the archives to digest if you're willing to spend some time getting up to speed on timing, as well as other webpages devoted specifically to ignition timing/distributor curving and such.
And a stock setup 292 Y block will respond really well to this. But it takes a methodical approach. At least you can eliminate this as the source of the problem and have a lot more fun too, better fuel economy (such as it is) and the Y block engine exhaust note is basically ear candy. Really! Run it up to 3000 RPM or so with vac adv. disconnected and plugged, observe marks with a timing light. Report what the total timing is in degrees. Should be "all in", 36 to 38 degrees. Since you replaced the distributor itself it should be in good shape, but the mechanical advance may be too late. When the advance kicks in is more important than how much to some... degree. |
wfon said: I have also tried this morning to advance the timing as far as it will go. The vacuum advance keeps it from moving any further clockwise. That did not solve the problem.
Note rotor and bowl positions, remove distributor hold-down & bolt. Pull distributor and rotate the bowl so there is more room for the vacuum advance, and turn the rotor in the same direction a tooth or two. Put distributor back in place, and add some tension to the hold down {slight}. Adjust plug wires one spot in the proper direction in the cap to get the pointer back at the plug/wire it was pointing at when removed, or turn the bowl. Crank engine a few turns to seat the distributor hex on the oil pump drive. The distributor will drop in place as the load of the oil pump causes a bit of slippage. Set timing. |
Originally Posted by charliemccraney
(Post 14424407)
It sounds a lot like you're not very familiar with diagnosing problems and you need to learn how to do that. A great place to start is with a shop manual. The factory shop manuals are excellent. If you don't already have a factory manual, either original or reprint, get one. And do what Tedster says to learn about stuff.
I am pretty pleased with how it runs when it is hot, and I guess I could just leave the choke engaged until the engine gets up to temp. That would solve it. I wish I had one of you guys around to come and listen to it and take it for a test drive. I am guessing for someone who knows these engines and how they should sound and perform, the answer would be obvious. I am not really sure what is "normal" for this truck. It seems to me that I should get much more power out of this engine. When the truck is empty, I think it should jump out of my hands and fly, but maybe they aren't set up to do that and never did. Maybe I expect too much. But I also have a '32 Ford Model B with a 4 cylinder engine that just purrs. I can't understand why this sweet V8 should not have its own throaty purr, not just at idle, but as I roll out and onto the highway. It should accelerate smoothly and then push me back into my seat. Shouldn't it? |
If you have driven a new F-150 with a 302, they should have comparable performance. Your truck is likely lighter, but the 292 is a smidge smaller. It should move well, and if you press the gas pedal, you should get pushed back into the seat a little by acceleration.
Have you checked the timing advance mechanism? You should set the timing at hot idle with the vacuum line disconnected. Leave it off, start the engine, and watch the timing marks as you raise the rpm. If the centrifugal advance works, the timing should advance. Re-connect the vacuum advance, and it should also advance as the rpms increase. Your distributor may not be working properly. Have you checked the thermostat for working properly and getting the engine up to working temperature? tom |
A '64 292 is not even remotely any kind of performance engine to begin with. Further, it's 50 years old and most definitely has a problem because even if the acceleration is not brutal, it should not hesitate and stall so you're certainly not experiencing what you should.
I've never experienced a '64 292 but with the low compression, small cam, typical factory advance curve and single exhaust, I don't think you should expect much. Those things can be overcome and it can be made into a very strong performer, though. |
Originally Posted by wfon
(Post 14426280)
...I am not really sure what is "normal" for this truck. It seems to me that I should get much more power out of this engine ... I can't understand why this sweet V8 should not have its own throaty purr, not just at idle, but as I roll out and onto the highway. It should accelerate smoothly and then push me back into my seat. Shouldn't it?
Drove my truck for years with it all kinds of whacked out. (Frugal is good. Cheap is expensive? Something like that. Used a junkbox carb and dizzy and golly knows what for timing because the crank dampers on these engines are trashed by now.) Here's how to fix that kind of thing.. Get yourself a manual, no way around that if you want to own stuff like this. Motors" manual, 1950 is a real good one for these vintage engines, next a vacuum gauge, and then a timing light and a tach. Usually even if you haven't done a procedure before by reading through these forum archives will set you up just fine. Another problem If the truck isn't driven much like many "classics"; the battery will sulfate up, wiring connections and grounds will corrode and eventually fail, ignition and lighting and everything else won't work right. Brakes will start to stick, leak at seals. Tires and belts and hoses start to take a set, etc. Fuel starts to sour and gum up in the carb, valves tend to stick. Read the manuals and webpages that apply to these engines, YT videos and the gazillion web pages - esp. for oddball stuff. Y block 292s have low compression in stock form and allows for substandard fuels. This is not a bad thing necessarily these days because they can have a lot of advance dialed in without detonation or pinging. If you want to run better octane fuel timing can be advanced some more. Take the time with your truck and you will be very happy with your Y block. I can see by your photos that your distributor is right in there where it needs to be (or clocked correctly). Just a smidge in one direction is 1-2 degrees, a vacuum gauge works great for timing but have to use a light to see what's what from 500 rpm to 3500 or 4000. Mine is at ~ 14 deg. initial or so, and have deduced the weights are on the 10L slot. That means there is about 34-36 degrees of "total timing" brought in, before the engine exceeds 3000 RPM. The vacuum advance will add another 10 or 15 degrees at steady freeway cruise for a grand total of about 50 degrees BTDC, that's what you want to verify. |
I guess I titled this thread incorrectly. I should have asked is matching the timing in the specs critical. I have gone back and rotated the distributor as far as it will go clockwise, and it runs much better. I have not gone back to check to see what the number of degrees before TDC is, but it has to far exceed the 6 degrees in the manual or even the plus 5 more mentioned in the manual. But it does not hesitate and does not ping. But why does this adjustment work when the spec is 6 deg.? I am thinking there must be something else not to spec, something else out of wack for a much higher that expected advance to work.
Any ideas as to what causes this? I know I should leave well enough alone, but I want this to run more or less as it did when it rolled off the line. Am I crazy? |
You didn't mention anything about how you tuned your carb.
Hook up a vacuum gauge and see what your vacuum is at idle and under load. I set the idle speed, then adjust the carb by vacuum, recheck the idle speed, then set the timing. |
I don't have a vacuum gauge, and I don't know how to tune the carb other than to adjust the idle fuel screws, but I thought they had nothing to do with how the engine operates at any speed above idle.
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Unless you have a shop nearby that specializes in older and antique vehicles and are willing to pay for that service, you are going to have to acquire tools and knowledge in order to keep your truck in good order. Or maybe find some local clubs so you can meet people who can help and teach.
After 50 years, any number of things can be worn enough that the factory timing setting does not work. One of the most common problems with timing has been mentioned 3 times already. The crankshaft damper ring slips which renders the timing marks useless. If this has happened, you simply cannot know where your timing is Matching to the spec in the manual is not critical and many people actually do alter the timing because it does make the engine run better, even on a freshly rebuilt, like new engine. Factory settings are safe and guarantee a reliable engine but at the sacrifice of performance and economy. You're not crazy to want it to run as it did off the line but it will take willingness on your part to learn how to diagnose and fix problems. Asking questions on a forum like this is great and does help to get to the bottom of a problem but at the end of the day, you are the one looking at diagnostic tools, making decisions and making adjustments. I'm not being mean so don't take it that way. I'm just being sincere. When suggestions are made, don't say "I don't have this" or "I don't know how to do that." You need to learn how to fix your truck. Get a vacuum gauge, learn how to tune all aspects of the carb. Learn how to tune and diagnose ignition advance. etc. If you aren't willing to follow through with suggestions, then that is where our ability to help ends. Ultimately, only you can fix your truck. |
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