Bike runs great when cold, but pings when hot

[panomania]

48 pan, s&s 80 stock bore stroker kit,new cylinders, new s.t.d. heads, S&S E carb (jetted 70 main/ 29.5 medium), new coil and wires, new crank,rods,pistons and rings, andrews a-grind. stock style manual advance unit. I have tried a mallory unilite and an j- grind camshaft. same problem...PINGS WHEN HOT...I cant understand whats going on. When the bike is cold it runs great, but when hot, if its under any strain what so ever, it pings like crazy. 93 octain always. I have ask everybody and everybody states the obvious, retard the timing a bit. I can retard it untill it wont hardly run and it still pings. There is nothing else to replace, and nothing else to adjust. Ive taken it to 2 pan experts in my area and neither can crank it or ride it due to bad knees , backs and so on. All my marks line up in the side cover and I have static timed and jetted a million ways and no luck. I feel sure what ever the problem is it isnt obvious. Please guys, give me some ideas, this thing is driving me nuts. (and broke) thanks in advance, pano

[Jonderson]

Hmmm...

What I would do at this point Pano is get a soundscope (one of those things that looks like a doctor's stethoscope, but with a straight end on it), and see if you can pinpoint *exactly* where the ping is coming from. Once you have done that, you can eliminate a bunch of things and hopefully give yourself a more focused direction. Maybe even ID the problem directly.

I had an old speedo cable that would start making a chirp/click noise once it hit 50 and wouldn't stop til I got down to 15 or so. Took me 2 years to figure out what was making the damn noise. I hope it is something as unimportant for you! Good luck!

[66tintop]

When adjusting the air mixture on the S&S E carb, one has to be careful not to fully bottom out the screw into the carb body, I have heard that you can cause irreparable damage to the carb body. Sounds like it could be a possibility for yer pan....I had the same problem with my shovelhead this year, and converted to a S&S B with a Super Bowl. Cleared up the problem. I'm not saying that this is your problem, it could be a possibility.

[darkjuju]

Pans just ping... stick some shovels on there and the ping stops..

when i first got my pan it was a panshovel... after i put the pans back on, i heard that racket and it scared the bull snot outta me. the older pan riders just laughed at me.

13 years later i love that sound

[dirtpandan58]

I put an s&s super E on my pan in the spring, Ran great. In the summer when it started getting hot and after about 40 miles the thing would ping if not knock pulling away from a light. Took it down to the shop and they put a thunder jet on it. He said somethin' about more fuel to keep it cool. They're a little harder to tune but once they're dial in they're tits. After we put it on I ran about 100 miles to check it out. Too fat. Took it back and let him rejet it and bingo, runs strong,plugs look good,starts easy and no more ping.
Must be somethin' to them 'cause he had 3 others sittin' on the bench that costomers braught in to have them installed.
I run a mallory unilite too and like it alot.
Later and good luck,
Dirt

[57stroker]

Don't know if this helps, but I usually run a fuel octane booster in the summer. Usually solves my pinging problem. Last summer, when the motor was stock stroke, the motor would always ping when riding 2 up even with octane boost. I have been using Lucas fuel additive and injector cleaner, but only because it's cheaper than the rest. Some members here say that they run 105 octane racing fuel mixed 50/50 with pump gas, but it is expensive (and addictive!)

[dereborn]

Here's another angle to the problem... You say it's not obvious - and I think that just might be the problem!
In the beginning of this season I had this really loud pinging noise when warm and idling. Checked EVERYTHING over and over, until i found the rear/lower dragpipe was a little loose and when idling the vibes made it touch the brake setup - ping!

Good luck!

[panomania]

Well, it seems to emit this pinging from the front cylinder. My plugs are burning perfectly tan. It will only do it when hot. My oil guage says my oil is at about 175 to 200 degrees when hot. Has anybody seen a pinion gear mis-marked? I dont know...Im drawing straws at this point. I have tried 2 different s&s-e carbs all jetted everyway possible. What is a thunder jet and whats involved in installing one? worth a try. thanks again, pano

[panhandler]

notice you say you have new std heads. How long have you had them and who set them up cause it sounds like you have a loose valve seat which would account for the pinging (or ringing)
when it gets hot. Everything expands and the seat , if not tight will jingle, sometimes it doesn't drop out all the way and the valve interacts with it to cause a pinging like sound. Don't want to sent the heebyjeebies at ya but it may be yer problem. Good luck.

[panomania]

Had a ol' timer tell me yesterday to try the 1980/1981 shovel plugs. He said the electrodes were a little longer, and if they didnt conflict with my pistons, that they may work. He said they were introduced for a pinging issue with those models. Ever heard of or tried these plugs? The std heads I just put on are straight out of the box. They are the complete assembly. It did the same with my old heads. Thanks, pano

[Cotten]

We better define "pinging".
Usually the term refers to octane "knock" that is audible when the motor is under load.

If your machine makes a clacking sound when you leave a stoplight, or when lugging around a parking lot, that's octane knock.

If you have a metallic ringing out of only one head, I would suspect a mechanical problem. And yes, a loose valve seat is not uncommon.

Seats come loose from overheating, as it causes hardened steel to shrink. The most common cause of overheating is a manifold leak.

[panhandler]

with regards to the plugs, I have built up stock heads and use the longer throw 14mm plug. I was using the champion N11yc and have recently switched to the Autolite 64. I have no pinging. Run the stock 74, .050 over with auto advance timer gapping at .018, shorty E and andrews j.

[kell]

Pano
I also have STD heads and a stock manual advance breaker, and have overheating probs and ping on very hot days. Part of the problem may be that with that breaker we are always running at full advance.
I had converted my ignition system to electronic single-fire, which didn't eliminate the overheating... and it was still manual advance after the conversion. So I may put on the Mallory breaker just to get some retard at the low revs.
Another thing, any bike that puts out more power (i.e., stroker) puts out more heat. So you may have a systemic problem (unfortunately).
Also my guess it's a little early to have a loose valve seat already. The heads are pretty new right? Better made than the original too. But that's an opinion. Pinging is kind of like a dieseling sound, not a chiming. Carbon deposits can make pinging more likely just because they can have hot spots that will pre-ignite the mixture. Plugs of too hot a heat range, or sharp edges on the valves (they glow), are other causes of knock. You can get rid of carbon deposits with an additive like Seafoam (also called Deep Creep, available at NAPA), but go easy on it. For some reason my bike was hell to start for a couple of weeks after dosing it heavy through the carb with the stuff. And change the plugs afterward if you do use it.
The obvious: support bracket to the air cleaner.
That's my .02 for now, wish I had the solution. I'm looking for it too.

[panomania]

Hey Kell, here in Alabama, its very hot and humid everyday this time of the year. My bike does do alot better earlry in the day or nights. If Im sitting in mid-day traffic, I would be better off to push it to the side of the road and wait till winter season to resume.
Im gonna put the mallory back in now that I have these new heads on there and see if that makes a difference. Also Im gonna try some of those longer electrode plugs. They dont conflict with the pistons while rolling the motor thru by hand, but I wander how much difference there may be at 3 or 4 thousand rpm's? Will the crank/rods assembly flex very much during riding? Also, might you know your oil temp when hot? Mines running about 180-200.
And last question, my flywheels have 3 marks on them. I have been rolling the motor over untill my front intake closes and then watching the timing hole. 1st is the rear mark, then the F mark with a straight line, and then the tdc mark. I have been putting the F mark in the hole, and and advancing my advance untill my test light comes on. Then I lock it down. Other words when full advance, the light comes on when the f line is center in the timing hole. Ive heard some people say I need to be using my tdc mark instead of the F line. The strobe light aint working on this bike. 3 people has tried to see the line, my wife being one of them, and it bout caused me a divorce. Anyhow, thanks for advice, pano

[kell]

You don't time on TDC, I know that. You time on the advance mark (timing mark). The S&S flywheels have different markings than the stock flywheels I have. The stock flywheels have a dot for TDC front and a slash for advance timing front, which is the mark that has to be visible in the hole for timing. So for static timing put the advance mark, whatever it looks like on your bike's flywheel, in the hole. For a breaker that has automatic advance (like the Mallory), twist it into advance position and make it stay there with a piece of folded carboard stuck in the little hole by one of the springs or something. That's if you're doing static timing. With a strobe obviously you just rev it up and see if the mark comes into the hole.
My oil temp always reads real cool for some reason, even on the days when she gets real hot under the collar. It goes through the cooler and an external filter on the way back to the oil tank, maybe that explains it. Speaking of oil, when I ordered the STD heads I had them make them so that I can convert to external oil lines later. That could help, because the internal passages go through the cylinders maybe an eighth of an inch or something from the pistons and combustion, so the oil's way hot before it even gets to the heads. If yours are convertible there will be a little allen type screw plugged in a hole on a flat boss at the top of each cylinder.