Basic Tuning of Carbureted Performance Engines November 24, 2023 03:01AM
The steps of tuning basically any carbureted internal combustion engine, particularly those used in competition, should be done in a specific order. This applies to the firing of a new engine, installation of a new component having to do with the ignition or fuel systems on an engine that has been running, periodic checking of normal tuning adjustments, or searching for the cause(s) of an engine performance problem. Checking and adjusting , done in this specific order, should help you get them all right without having to go in circles on your tuning adjustments. This helps determine if engine problems are due to improperly adjusted basic adjustments, or to some issue having to do with other variables.

Before making final adjustments to the carburetor, ignition timing must be properly set. Ignition timing affects how the carb works through the entire rpm range of the engine. This applies not only to when the engine is in the competition event, but also to its idle speed and part throttle running before and after the event, in this case , a pull. Determining the proper amount of initial timing(at idle), and the advance curve as the rpm's go up, is determined by many factors, including compression ratio, valve timing, and fuel octane, just to name a few. If you are uncertain about the ignition timing, consult with someone who has adequate knowledge of your engine combination. Getting the timing right is critical to the rest of the tuning adjustments. Next, are adjustments to the fuel delivery system and carb.

Before making carb adjustments, fuel pressure must be set to a pressure that is suitable for the size of the needle and seat size that your carb uses, and for the power that your engine makes. Assuming that you have an adjustable fuel pressure regulator(recommended), set the fuel pressure to the proper level, always with the engine running(idling). Next is setting the fuel level("float level") in the fuel bowl, if you have the type of fuel bowl with an externally adjustable needle and seat height. On the tractor carbs that I build , I use a Holley fuel bowl that is commonly used on their performance and racing downdraft carbs. This bowl type has an adjustable needle and seat height feature at the top of the bowl. Set the fuel level to the middle of the sight window, or the bottom of the sight hole, depending on which type of Holley bowl you are dealing with. This, as with fuel pressure, must always be done with the engine running, with the fuel pressure already at its proper setting. Fuel pressure regulators(conventional restriction type regulators), and needle and seat/float mechanisms used in carburetor fuel bowls, both require a small amount of fuel flow to function properly. The amount of fuel flow that an engine uses while it is running at idle speed, is enough to satisfy that need, assuming that the regulator, needle and seat, and float are all in proper working order. Your fuel pressure gauge should be mounted where the driver can easily see it during a pull, so he can monitor it closely. The next adjustments are to the idle speed and idle mixture.

Now that the fuel pressure and fuel level in the bowl are set, then the idle speed and idle mixture can be set. You may need to go back and forth between the two a couple of times, to get both where you want them, to achieve your best idle quality. These two adjustments should be done with the engine fully warmed up.

To recap, here's the proper order :

1)ignition timing, 2) fuel pressure, with engine running, 3) float level, with engine running, 4) idle mixture and idle speed, with engine fully warmed up.

Another system that can really help with fuel related tuning, is having a wide band O2 sensor system that tells you what the air fuel ratio is in real time, having the readout gauge located so the the driver can easily read it during a pull and during all other situations when the engine is running. The kind I like to use is called the AFR500, available from Ballenger Motorsports. This system, used with an upgraded NTK exhaust sensor, can be used with heavily leaded racing gas, without fouling the sensor. I have two on my engine dyno that I've been using for years, and have never fouled a sensor, and have run many engines with leaded racing gas. I suggest that you investigate the AFR500. Other similar systems that do not or cannot use the NTK exhaust sensor, typically have sensor fouling problems, giving you unreliable air fuel ratio readings. On pulling tractors, I usually look for air/fuel ratios around 12:1, both at idle and under power.

If you are dealing with an engine performance problem, and all your basic adjustments are correct, including your air/fuel ratios, then additional investigation will be necessary. Things like faulty spark plugs and plug wires, fuel contamination or stale fuel, too much fuel pressure drop from idle to full power, dirty air filters, and clogged fuel filters can cause problems. and this just to name a few. Determining engine performance problems can be a frustrating process, because frequently, they are caused by more than one factor. Eliminating one factor at a time, as a possible contributor to the problem, is the process needed to solve the problem. It can be frustrating and time consuming, but in most cases will solve the problem. Norm Schenck/Competition Fuel Systems/Birch Run, MI/520-241-2787/normanschenck@juno.com



Edited 1 time(s). Last edit at 11/24/2023 03:07AM by Norm Schenck.

Re: Basic Tuning of Carbureted Performance Engines November 24, 2023 11:53AM
Usefull info , Thanks for heads up on FAM for leaded gas ,

Re: Basic Tuning of Carbureted Performance Engines November 25, 2023 01:28AM
You're welcome. Until I discovered the AFR500 system with the upgraded NTK sensor, using wideband O2 systems with racing gas was a frustrating deal. The key to making this work, is to make sure that the NTK sensors are fully heated up(Sensor system powered up) before firing up the engine, and leaving the power to the sensor system on, after the engine is shut off. This minimizes deposits that could foul a sensor, and burns of any that do deposit. This procedure can help a little with other brands of sensors, but only for a while. Been there, tried that. The NTK sensor design is obviously superior to the others. Norm/CFS

Not Antiques Anymore November 25, 2023 02:33AM
Quote
Norm Schenck
You're welcome. Until I discovered the AFR500 system with the upgraded NTK sensor, using wideband O2 systems with racing gas was a frustrating deal. The key to making this work, is to make sure that the NTK sensors are fully heated up(Sensor system powered up) before firing up the engine, and leaving the power to the sensor system on, after the engine is shut off. This minimizes deposits that could foul a sensor, and burns of any that do deposit. This procedure can help a little with other brands of sensors, but only for a while. Been there, tried that. The NTK sensor design is obviously superior to the others. Norm/CFS

Why are electronic devices and non-oem carburetors allowed in antique tractor pulling? Kind of takes away from the whole antique thing doesn't it?

Re: Not Antiques Anymore November 25, 2023 02:47AM
Because the original carburetors that the tractor factories used back in the day, were, for the most part, very poorly designed, and were in many cases barely adequate then, on the farm. With the typical vintage era tractor engines that are being used now in pulling competition, with stroker cranks, bored cylinders, ported heads, special cams, and fabricated headers and intakes, those old carbs are totally inadequate, sometimes dangerously so. These engines are, with all these modifications, quite expensive, and to put them at risk with a carb design from 65,70,75,80 years ago, is like playing Russian roulette, with a fully loaded pistol.

Re: Not Antiques Anymore November 25, 2023 03:01AM
I respectfully disagree with you. I know of many big cube antique tractors that are running conventional updraft carburetors and are very strong running competitive tractors even at the Tunica type pulls anywhere in the country. Obviously you have a product that you are trying to justify its existence and are trying to market it. I have no problems with that. I just believe that it should not be allowed in antique pulling, unless they have a modified open class available where there is no speed limit or restrictions on engine modifications. Just my opinion. Best wishes on the marketing of your product.

Re: Not Antiques Anymore November 25, 2023 03:19AM
And I disagree with you. There are many tractors that are being held back by poorly working and undersize carbs, that were never intended to make the kind of horsepower that these modified tractor engines are capable of now. The boring/stroking/porting/ camming thing has been allowed to happen, and I'm trying to fill a need for carbs that can handle the HP potential safely. For the purist, yeah, it has gotten way out of hand. But it is what it is now, so things progress into more technical components, as they have and still do, in all other forms of motorsports.

Re: Not Antiques Anymore November 25, 2023 08:15AM
If electronics are allowed, then EFI should be as well. Why stop at ventures? In your argument muti-port EFI is justified. Just sayin. Best wishes.

Re: Not Antiques Anymore November 25, 2023 08:17AM
Venturi not ventures.

Re: Not Antiques Anymore November 25, 2023 10:31AM
Yeah, EFI should be legal. The only kind of EFI that would outperform a good carb, is the type that would have independent tuning of the air/fuel ratio for each cylinder, though the entire rpm range of the engine. That type of EFI system would be able to compensate for the typically unequal distribution that most intake manifolds have. The tuning process for a system that complex, is not particularly easy, and would best be done on a heavily instrumented dyno. More technology, which it appears you’re against .

Re: Not Antiques Anymore November 25, 2023 11:09AM
No I'm not against technology. However, that being said, some technology is good, and some definitely are bad! It appears that you are all for, Make weight, make hitch and pull. No need for anymore rules than that. Because technology has generated better tires, better fuel, better hitches and whatever else they have rules established for in various classes.

Re: Not Antiques Anymore November 25, 2023 11:45AM
So, you’re saying that the technologies used to make pulling tractors more competitive. are BAD? And that other technological improvements are good? Is this because you are having trouble being competitive ? And you want other pullers to be denied access to technologies that can be used to make their tractors more competitive? It appears that way. Then what are those GOOD technologies?

Re: Not Antiques Anymore November 25, 2023 11:52AM
If a group of pullers want to get together and form a class modern technology antique chassis tractors, let them have at it, doesn’t mean everyone has to par take in the festivities, but it sure would bring some new eyes to the sport.

Re: Not Antiques Anymore November 25, 2023 12:05PM
It appears that there is an old saying that applies to you. It goes....
“ If you can’t run with the big dogs, stay on the porch”. In other words, “those that don’t want to make the effort to be competitive, should go do something else”. And not try to drag others back to his level.

Re: Not Antiques Anymore November 25, 2023 12:19PM
Also, hey folks. Have you noticed that WHY has no profile, and is not in the Users List?

Re: Not Antiques Anymore November 25, 2023 01:04PM
Mr Norm, 1st off I can assure you that we have no problems being competitive and we more than get our share of wins. So no need to play the can't run with the big dogs crap. I have pulled tractors most of my life and know of many extremely competitive tractors with common updraft carburetors. Have these carbs been tinkered with? Absolutely!! But when you start spewing jibberish out ya mouth about a common carburetor not being safe, then I have to wonder what your motives are and tells me that you don't know what you are talking about. Please give one example of a common updraft carb causing any personal injury or harm to others with their game of "Russian roulette"?
2nd, I don't know of any of these "Purists" that are holding anyone back from getting better or dragging anyone backwards.
3rd, just because one chooses not to buy your "Special gadget", why should he or she get out of pulling?
4th, I Never said "technologies used to make pulling tractors more competitive. are BAD?" I said, I was not against technology! I said some technologies is good and some are definitely bad. Example, when they invented the telephone over the telegraph, that was good. When they invented many of the social media platforms this was bad, and proven that this has harmed our society, especially our younger generations.
There have been many "Technological advances " that have been bad ideas. There have been some good.
5th, I don't want to deny anyone access to anything that they would like to spend their money on. I agree with Bbailey 100 percent. Let someone create a open anything goes class and let them at it. But let the antique classes as they have been established alone. Obviously they are working. I was to an antique pull in Northern Ohio this summer and they had huge numbers of competitors there, and I didn't see a single one with goofy homemade carbs or EFI. If I remember correctly Bbailey was there pulling too!

Re: Not Antiques Anymore November 25, 2023 01:23PM
Yep
I seen some pvc toilet flanges run real well !

Re: Basic Tuning of Carbureted Performance Engines November 25, 2023 01:33PM
You and Why The Hacker, might consider joining the 21st century. Toilet Flanges no longer cut it. And don’t you wonder why WHY feels the need to hack in and stir the pot?
Did you notice that WHY has no profile, and is not listed on the Users List? Why does he feel he needs to hide his identity completely?



Edited 1 time(s). Last edit at 11/25/2023 01:41PM by Norm Schenck.

Re: Basic Tuning of Carbureted Performance Engines November 25, 2023 01:44PM
Now I'm a genius!!! Hackers are very intelligent Norm. Just FYI Norm, Bailey and I both are right here with you in the 21st century. As hard is it is for you to realize! Bring on the EFI and allow v8s or whatever else wants to run. I used to think less rules were better, however I see now why they are in place. Think....

Re: Basic Tuning of Carbureted Performance Engines November 25, 2023 02:13PM
First off Mr Norm, I have not "Hacked" into anything! All I have done is shared my honest opinion which is not false in any way, only my honest, true, opinion on the subject of electronic and exotic systems on antique tractors. You are the one who gets all defensive and offended just because one has a difference of opinion, or does not agree with your ideas. Again this makes me wonder "Why", oh excuse me, Hacker as it is now??? Just because one chooses to remain anonymous, does not make their opinions or ideas any less valid than yours or anyone else's. Bbailey, ya better get 2 commodes to keep up with the electronics! Lol Hacker

By the way, I'm still waiting for you to answer how a carburetor is a safety issue, or a game of Russian roulette???? I sure don't want to endanger anyone with my old carburetor. Please do tell!
Regards, Hacker

Basic Tuning of Performance Carbureted Engines November 25, 2023 02:11PM
Goofy homemade carb?


Re: Basic Tuning of Carbureted Performance Engines November 25, 2023 02:20PM
Thanks again , appreciate the follow up info on having system powered up .

Re: Basic Tuning of Carbureted Performance Engines November 25, 2023 02:31PM
That’s a detail that makes it all work. Like so many endeavors now, its the details that make or break them. You’re welcome.

Re: Basic Tuning of Carbureted Performance Engines November 26, 2023 06:58AM
First off carburetor guy you do make some nice pieces, I’ve seen them before and I have much respect for someone who has that ability BUT you definitely lack people skills, I come on here and make a plain and simple statement and get thrown under the bus along with a friend who does all of his own work and his ride runs real good, so you might think before you type
As far as the making fun of the toilet flanges,you need to take a trip down to north central Ohio next summer and see for yourself, that ol boy whipped up on a lot of good tractors this year and he could care less what anyone thinks
As far as me getting into the modern times I was running 2 750 Holleys and trigger wheel ignition 25 years ago on an antique
Maybe the page needs a new section for don’t take pulling so serious, kinda like setting in the shop or setting on a weight rack at a pull, just BS conversation, I have much respect for the technical information and all knowledge that is presented, but man it gets intense
Now I think I’ll go stink up the 5.0’prostock thread since I seem to be good at that !

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