Author Topic: APT Smart Carb Testing today 40mm Billet Sphynx 363 (Read 33498 times)

Pumashine · « **Reply #60 on:** October 10, 2014, 02:14:22 PM »

Quote from: Burns363R;44339

New Run.

Yep, thats they way mine looks

Burns363R · « **Reply #61 on:** October 10, 2014, 02:18:06 PM »

The pic doesnt do it much justice, it was pretty white at the base of the electrode.

jcs003 · « **Reply #62 on:** October 10, 2014, 05:25:32 PM »

might be time for newer technology. seems plug chops are misleading and are far from a precise science.

john

Jerry Hall · « **Reply #63 on:** October 10, 2014, 05:48:03 PM »

Quote from: Burns363R;44339

New Run. New plug B9ES slightly leaner setting, but not much, 3 clicks leaner. Same 1/2 mile down and back run, motor was warm before the new plug was installed and ran.

Now look at the porcelain with a magnifying glass and look for any microscopic specks that may look like microscopic pepper specks. The specks are aluminum from the outer edges of the head and piston. Detonation erodes the outer edges of the piston and head and collects on the porcelain surrounding the center wire of the spark plug . Specks that look like fresh aluminum were deposited on the spark plug in the last 30 seconds or less of engine operation. Black or brown specs are older aluminum specks that been coated with a film of carbon, turning them to a darker color.

Burns363R · « **Reply #64 on:** October 10, 2014, 05:52:38 PM »

I noticed at WOT in 6th gear i can hit top speed at half throttle, any more throttle and it bogs, or doesnt pick up RPM per say.

Jerry Hall · « **Reply #65 on:** October 10, 2014, 06:38:28 PM »

Quote from: Burns363R;44344

The pic doesnt do it much justice, it was pretty white at the base of the electrode.

You have to remember that a spark plug is NOT an instrument that measures power, acceleration, air/fuel ratio, throttle position, RPM or combustion pressure or temperature.

We can only observe the operating temperature of the spark plug and any deposits that accumulates on it. That is all were can conclude from looking at a spark plug.

Reading sparks plugs requires a lot of painful and expensive past experience with a particular engine. Every engine package produces spark plugs that have their own unique look. We have to associate what the spark plug looked like on that engine package when all of the conditions are duplicated when that test or reference engine produced it best power and was tuned so that it would not hurt itself.

The soot ring being present, absent or how long the soot ring is at the base of the porcelain does not tell us anything about the state of tune (power or Air fuel ratio) the engine is experiencing. It only tells is that the spark plug is operating at a temperature that will burn off or not burn off most of fresh mixture that is coming in contact with this very hot surface on the porcelain. If a soot ring is present at the base of the porcelain it is only because that portion of the spark plug is not hot enough to keep the soot burned off.

Summary:

Tune the engine so that if runs well and monitor the spark plug for detonation. An engine that is a highly developed (a design that has all of the bugs worked out) will not usually hurt it self as long as it does not experience detonation. If you are having problems seizing pistons and not experiencing detonation you need to find the design flaws in your engine package. Getting the bugs worked out is usually the responsibility of the engine designer or engine builder. If or when changes are made to the engine package, the person making those changes is responsible for getting the new bugs worked out.

Jerry Hall · « **Reply #66 on:** October 10, 2014, 06:45:45 PM »

Quote from: jcs003;44350

might be time for newer technology. seems plug chops are misleading and are far from a precise science.

john

Reading spark plugs has never been a science. Only those with limited tuning experience believe it is a science. Spark plug reading is an art if anything. You only acquire an eye for spark plug art or can be critical of the art after many expensive art lessons.

Jerry Hall · « **Reply #67 on:** October 10, 2014, 06:58:08 PM »

Quote from: Burns363R;44352

I noticed at WOT in 6th gear i can hit top speed at half throttle, any more throttle and it bogs, or doesnt pick up RPM per say.

It sounds like a carb that has too big of a main jet or a carb that is too large of the engine. I doubt that the carburetor is too big. A healthy 363 needs a carb in the 40 to 44 mm range.

Do you have any needles that have the same mixture at all the other settings but leaner at only WOT. When you turn the clicker doesn't the whole needle move up or down? If this is so, you are leaning or enriching the needle at all throttle settings. It sounds like you may be experiencing some of the same problems that I experienced when attempting to tune the new Lectrons 35 years ago.

RyanWsly · « **Reply #68 on:** October 10, 2014, 07:21:55 PM »

Jerry how accurate is reading piston wash in your opinion? Like sticking a bore scope in the plug hole and looking after some operation or simply pulling the head? Would something like this give him a better idea of what is going on after short runs like that or does it need to run for longer periods of time? Not something I am real familiar with other than looking at the piston when I have had mine apart so I am interested to see what your thoughts are. Please keep this updated Kyle it is interesting following the process and reading Jerry's input also.

Pumashine · « **Reply #69 on:** October 10, 2014, 09:15:06 PM »

Quote from: Burns363R;44308

Cory has been really helpful for me. He recommended me going back and trying the 76 now that i have proper fuel flow.

Today when I went to the mailbox I got a new FMR from APT. SWEEEEEEEEEEET. They sent me a 76. Is that leaner or richer than the 74?

Burns363R · « **Reply #70 on:** October 10, 2014, 09:17:47 PM »

Leaner. I ran a 76 today and it was lean. I'm going back to a 74 for more testing tomorrow. Corey told me they have a 72 now so I may end up there. We'll see. I want to dominate the harescramble sunday.

Pumashine · « **Reply #71 on:** October 10, 2014, 09:25:51 PM »

Quote from: Burns363R;44363

Leaner. I ran a 76 today and it was lean.

I asked for a richer FMR. I told Tom I was making around 80 HP. I must have been shipped with a 78 then? What size FML was your 40mm SC sent with Kyle?

Burns363R · « **Reply #72 on:** October 10, 2014, 09:28:58 PM »

It had the standard sma one on the other scale they used I think. Mine came with a 78 and 76 rod to. My carb was used and the previous owner gave up. I ran the stock needle and then went straight to the 76

Burns363R · « **Reply #73 on:** October 10, 2014, 09:31:28 PM »

Honestly just try the needle. I think that your engine combo will respond differently than mine. There's a lot more going on here than straight flow and orifice low pressure draw like a standard carb. It uses pressure signals from the engine to determine fuel demand. And I dont fully understand it.

Burns363R · « **Reply #74 on:** October 10, 2014, 09:34:51 PM »

Quote from: Jerry Hall;44356

It sounds like a carb that has too big of a main jet or a carb that is too large of the engine. I doubt that the carburetor is too big. A healthy 363 needs a carb in the 40 to 44 mm range.

Do you have any needles that have the same mixture at all the other settings but leaner at only WOT. When you turn the clicker doesn't the whole needle move up or down? If this is so, you are leaning or enriching the needle at all throttle settings. It sounds like you may be experiencing some of the same problems that I experienced when attempting to tune the new Lectrons 35 years ago.

My understanding is this is alot like a Lecton. But there is no jet. You slide the FMR up or down to control idle to 1/2 throttle. 1/2 to full throttle I determined by the FMR itself.