Melting Pistons

Malc · 07-04-2003, 06:47 AM

The engine had a bit of a problem on Wednesday evening. The right hand piston has melted enough to make the barrel scrap as well. The left piston looks like it had few moments of life left. Fortunately both heads are OK.

I'll post further when I work out what caused it, but as both sides have gone I would say a very very lean mixture caused by a problem with either the fuel filter or fuel pump or engine management. Another chap on the UK forum had a similar problem last week which he put down to the BBPower chip.

Dave Hopkins · 04:46 PM

Said, fortunatly rare. If the cylinders costs are prohibitive it is possable to have them bored and replated. Check the back pages in your local bike newspapers/magazines for a source? One shop in the US is I beleive the turn around is about 3 weeks as he bores the cylinder, sends it out for plating, then he may have to hone it???
That fixes the damage, the big issue is how to fix the cause? At erics web site he talks about exhust temp & mixture sensors. It may be smart to add such while you sort this out?

roger albert · 07-05-2003, 06:32 AM

Why do they put it down the the chip? Just the part they don't understand and so a good place to lay blame? The chip either works or doesn't. It doesn't make things go lean. Whatever the condition, the stock chip would have been leaner.

I can't recall. What's your exact config malc? Which BBPower setting were you running? How was your timing set? What grade of gas to you run? Those latter two are the biggest likely contributor.

Anyway, sorry to hear about the trouble, but do tell us more.

later
roger

Lorenfb · 07-05-2003, 08:23 AM

Have to love those chips, if that's the problem!
Who knows what you get, when you replace the stock chip?

Chris Canning · 07-05-2003, 08:49 AM

Hi Roger

I have to say i'd go for the chip,when Malc put the chip he said the MPG improved, which must have leaned it out,and to burn both pistons at the same time,he was also doing 120 at the time!!,it could be anything but it's a fair bet it's chip related,even though he's had it in for a lot of miles.

Chris

roger albert · 07-05-2003, 08:52 AM

It's pretty obvious what you get, even if you don't know every datatable entry. Why would anyone continue to think its the chip? Chips don't run lean. They run, or they don't , period. Sorry, but you're missing the point entirely. The aftermarket chip is going to be richer in virtually every operating condition. It's ones and zeros; no inbetweens. Whatever caused the overheating, would have done so even faster with a stock chip. There's a problem, but blaming the chip is no more valid than blaming evil spirts for sneezes and pestilence.

Eron Flory · 07-05-2003, 09:50 AM

Malc,

Did you ever hear any detonation also refered to as "pinging"? Detonation is when the fuel "explodes" rather burning in a controlled maner. Combustion pressures rise very rapidly and stress pistons as well as eating away at spark plugs. A careful inspection of the spark plug should show signs errosion on the electrode or spots (melted aluminum) on the insulator if detonation was occuring. This would point towards poor fuel quality or too much timing advance or both, as Roger mentioned. Lean mixture alone probably could not cause your pistons to be damaged. Detonation is more likely to occur when you are running lean but without detonation and without starting out too rich less fuel = less heat.

Was there damage to the top of the pistons? Detonation would damage the top of the pistons and/or the rings and ring groove lands. If it was only on the piston skirts and in the cylinder I would suspect poor oiling or oil quality.

Could you post any photos?

good luck getting it running again.

Eron

Chris Canning · 07-05-2003, 02:54 PM

Hi Roger

Sorry but i think your wrong,there are two bikes in the Uk done exactly the same thing,with one common denominator,spend my saturday night out with my spouse and friend with his,he built Bayliss's factory engines when he won in 99,even he said the chips a dead cert,and he sells after market chips!!!!

How many other people do know who've burned two pistons at the same time on an S???? No me neither but of the guys i know,they all run stock chips,oddly enough mine has always run rich,with a K+N and an open race system and thats the way it's staying.

If you ever wonder how close to the wind the S sails,have a look at the Brisk spark plugs info,they recomend a different spec plug if you use an aftermarket chip.

Chris

07-06-2003, 01:35 AM

The motronic will adjust the amount of fuel injected in response to the information it is receiving from the various sensors and from the information stored in the chip. I would presume with the stock chip, if one of these sensors failed it would switch to the emergency map which runs the bike rich. With the BBP chip, if there is no emergency map to switch to and sensor failure occurs it may well interpret this as needing to weaken the mixture. I can't imagine why a chip would suddenly change its programme for no reason and decide to decrease the injector on time unless it is receiving duff information. If it is the chip then my opinion would be that it was poorly programmed in the first instance, it is after all just an electronic look up table.

Lorenfb · 07-06-2003, 06:52 AM

How about the timing and detonation? Advancing the timing is where
the chips get the performance. There's no knock sensor on our BMWs,
and who could ever here pinging or detonation on a motorcycle?

Loren
'04 Boxer Cup

roger albert · 07-06-2003, 07:02 AM

Well, I'm not there and haven't made any measurements, but I never have bought that anyone's bike is running rich with the stock chip and open exhaust, unless there's something wrong with the bike. The bikes design and physics dictate that, not some sort of weird-roger-conjured-opinion.

Chris, I believe you're either misdiagnosing that yours is rich, or it has a (perhaps fortunate) problem that causes it to run rich. For something else to be true, you'd have to have a different chip than everyone else, which seems fairly unlikely.

It's really tough to burn a piston due to leanness alone. You have to look at something causing detonation. I still think spark advance is most likely. A faulty sensor is an outside chance (two sensors dying is just as likely as two chips having a problem, no)

What I suppose is possible, and chip related, is t he ignition mapping on the BBP chip. I don't honestly know if it's the stock map or not. Some vendors fiddle with fuel only(Vanderlinde, FIM I believe) , and others with fuel and spark (Rhine West) I'm not sure about BBP. So, that could be an issue, and maybe one I've neglected to consider well enough. I'm a lot more interested in figuring out what is happening than in being right, so it has to be taken into account.

In my experience though, most folks have no idea what the chip does, or why it does it, or how the fuel system even vaguely works, so there are a lot of wild theories out there. This includes resellers and users of chips (not developers) so there is a lot of supposedly credible info out there that is just wrong. There are only so many folks who understand computers and programming, and only so many engine management, and a very very small interection of two. I've studied both formally in college and on the job and only have it about half figured (tons to learn yet) so how can any sales guy be expected to have is sussed?

Blanket recommendations smack of marketing too. Since there are many different chips, not all of which even juggle the same parameters, how does Brisk know what to recommend?

As Andrew says, the chip can't just decide to change mixture. I also don't buy that the BBP or any other chip can run without default mapping, as that would require rearchitecting the engine management software, not just updating existing tables.

I guess I have about 3 possibly useless points, which I'll attempt to make anyway:

I'm not saying it can't be the chip, I"m just saying it's a convenient point of blame, especially for those who don't understand what a chip can or can't do, or how the system works, AND, that simple leanness in not the most likely cause of this, AND, that the chip, in the vast majority of operating conditions, and certainly under full throttle, runs richer than stock, and thus offers more safety margin, not less, at least in terms of fuel.

Point 4, We don't know anything about the BBP chips ignition parameters. BIG question mark.

curiously yours
roger

p.s. Malc also listed two other option that both make more sense. The fuel pump and the fuel filter, to which I'll add a pinched line (pinched supply line, that is; pinched return would enrichen - it's a good old injection tuning trick) I'm not recommending anyone do that. Fine for top fuel, but not ideal on the street

sud-z · 07-06-2003, 07:37 AM

Sorry about your misfortune.

Not for nothing but you can hear knocking and pinging. At least associated with low octane fuel. Put in the wrong stuff once on an R1150RT. Only happend in top gear, two up and lugging a little. Feel it too. Down-shifted and it went away. Put in the right fuel and it didn't happen again.

Curious to find out what the problem was/is.

-Shawn

Raven · 07-06-2003, 09:57 AM

"How about the timing and detonation?"

Interesting question.

How do you check the timing on the S?

Is it even possible that it could change on it's own?

Chris Canning · 07-06-2003, 10:23 AM

Hi Roger

The bike runs fine and always has done,i've always excepted that on the basis of the exhuast system,as it is one of only two in existence,i always smile when i read about after market pipes!! well the bit at the back!!mine doesn't even have a balance pipe at the front,although it is very cleverly symesed at the back.

As for the chip,it's not just Malc's there are two!! gone exactly the same way,so your looking for a common denomenator,Yep it could be anything,but you mean to tell me,both have got blocked filters,both have a pinched fuel!!!,i fully realise that this kind of 'If your Aunt had balls she be your Uncle' thread is right up your street,but i know enough about detonation know it's not always instint,it could have taken thousands of miles to eat the crowns of the piston,and may have carried on running apart from Malc panning it at 120!!!

The one thing i can tell you about after market chips,there's no money in them,because after you've bust your ass doing one,Joap Soap phones up orders one and does a copy and sells it to all his mates,which brings me back to the friend i go out with on a saturday night!!! he sticks to doing Michael Rutters factory Ducati with a lap top,it cuts the middle man out!!!

Chris

07-06-2003, 10:55 AM

It could possibly change if the timing plate slipped for any reason(unlikely), but probably even fully advanced it wouldn't be enough to cause detonation unless you were using kerosene instead of gasolene! You can check it by removing the small rubber plug on the r/h engine casing just above the injector.

There have been problems with the Hall sensors but they would generally either work or not. The wrong grade of spark plug might cause detonation if it were overheating, but I can't see Malc having the wrong plugs fitted.

I run mine with a fully advanced timing plate, Laser chip and a 3.5 bar fuel pressure reg. I've not had it gas analysed but it sure runs ok and the plugs look a good colour. I'm pretty sure it doesn't run weak anyway. I always use 97 octane fuel also and never had any pinging under any engine speed/load condition.

It would definately be worth checking ignition timing and the fuel pressure before running the engine for too long again.

roger albert · 07-06-2003, 03:39 PM

Good points all Chris. Who knows how long it's been going on? Know way to know for sure that it's not too lean. I've no measurements, so I can only speak of likelyhoods. Nothing definitive. Would be nice if our own beasts were laptop/handheld updateable. I guess as far as stockers go, only Triumph and Ducati really allow that. I'm jealous.

What the heck is your exhaust config anyway? Just curious.

There are some decent ways of copy protecting chips using a substrate/socket. Keeps the run of the mill riff-raff out of your code anyway.

What do I know anyway. If I could troubleshoot the hacked wiring harness on my newly acquired Hawk more quickly, I'd be sipping an after-track-day beer right now instead of typing and cleaning my messy-ass workbench. ARght!@#$%!!!
Stupid bike puked out right before load out.

Lorenfb · 07-06-2003, 06:21 PM

Like I said, who knows what really gets changed in the
aftermarket chips? I doubt that most chip guys really understand
what they are changing or doing to the maps and how it affects
the overall Motronic system. It's not simple and not a hit and
miss game.

Check out my web site (systemsc.com). I may provide some
insight into basic chip modifications as used on auto Motronic
systems which are basically the same as on the R1100s.

Good Luck
Loren
'04 Boxer Cup

ted andersen · 07-06-2003, 08:51 PM

I used to lean out my r50/2 for maximum fuel milage before leaving for daytona. I could consistantly (3 years in a row) make it from southwestern Virginia to Daytona on one tank of gas (big tank). Averaged about 80 miles to the gallon, and as this was a parts bike cobbled together from pieces/parts I wasn't too worried about hurting it... I was more into a personal "fastest time" record.

The last year I tried it (year 4), I ran stone cold out of gas about 20 miles from Daytona at about 55 miles per hour. Burned a hole in the top of each piston.

Don't know if this is at all applicable, but could sudden instantaneous fuel starvation have caused Malc's problem?

Just a thought.

-Ted

Eron Flory · 07-06-2003, 09:06 PM

I don't think that running out of fuel could have caused his problem. I have seen a lot of vehicle that have run out of fuel without damaging a piston, I've done it a couple of times myself. I do know that an engine that is detonating is less fuel efficient than one running normally and WILL hole a piston, so that may explain why you didn't make it to Daytona that time. I hope that you eventually did made it to Daytona it would be shame to be that close and miss the races.

Eron

Mrmerlin · 07-06-2003, 09:22 PM

Hi ,It would be interesting to find out if the fuel your using has any diesel fuel mixed into it.
I got a bad load of fuel once and it made my OLD Guzzi run like crap , luckily I looked at the fuel to see if it contained fuel oil, get some fuel from the tank and spill it onto a white piece of cardboard , unleaded fuel will evaporate in about 1 min and leave no residue, fuel oil will leave a oily ring on the paper, also you could try to smell it, or check the color of the fuel, unleaded is clear and diesel has a straw color to it.
I did have to replace my exhaust valves as they were running hotter and the ex valves were turning a lite blue around the edges from the extra heat given off from the bad fuel, the fuel was tested by the tank truck company and it wan noted that the gas i got was contaminated with fuel oil also called Diesel fuel.
I hope you can find out what has caused your problem.....Stan