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How to stop engine pinging


Tom M
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My bike sometimes pings from about 4900 to 5100 rpm under load in higher gears above half throttle. It's not a big deal, I can ride around the problem (downshift to pass on the highway), but I wonder if this could be completely cured? FWIW I run the 93 octane gas as that's the highest available in my area.

 

Background: When I first bought the bike the it had a custom PCIII map done for the bike with the following setup: Ti ECU, MG Ti exhaust, stock crossover, K&N air filter. It pinged very badly at 5k with this setup. Once I manually tweaked the map in the problem area it got a lot better but the problem did not completely go away.

 

My present bike setup is stock '02 ECU, MG Ti exhaust, Ferracci crossover, K&N air filter, Phil A airbox mod, PCIII with downloaded map from a fellow board member who has essentially same bike setup. The guy who sent me the map reported no pinging at all on California pump gas which I believe is the same formulation as the gas we get here in Massachusetts. The bike runs great except for the aforementioned pinging. I haven't tried richening up the map in the ping zone yet, but it is richer than stock there now. I'll give this a shot when I get back on the road.

 

In some ping discussions I remember reading on this board I believe it was said that the squish band and the piston crown have a lot to do with detonation. Some folks who went to FBF high compression pistons reported more pinging, some reported none. I don't recall ever seeing a Mike Rich high comp piston buyer ever mentioning pinging one way or the other. So after all that I guess my questions are...

 

Has anyone got rid of a pinging problem by installing aftermarket pistons? FBF, MR, or other?

 

Has anyone got rid of a pinging problem by machining the cylinder or head to adjust the squish band?

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Has anyone got rid of a pinging problem by installing aftermarket pistons? FBF, MR, or other?

 

Has anyone got rid of a pinging problem by machining the cylinder or head to adjust the squish band?

 

 

Tom,

My bike does not ping with Mike Rich pistons. It didn't before them either. Mike says the squish area is better with his design so perhaps they may help. Certainly it is a lot more complicated than that. Your mapping can be way rich in some areas and way lean in others.

It is likely you are too lean in the range where you are getting the pinging. If you want to play with your map and don't have access to a dyno, figure what rpm & percentage of throttle opening you are getting the ping and enrichen your map in that area - you can always go back. Also, if there is a lot of carbon in the chamber, that can cause some ping as well. A build up of carbon creates two problems. If it is thick enough it will raise the compression ratio, (doesn't seem too likely here) plus bits of carbon can stay red hot causing the mix to ignite prematurely. Pull a plug, look around the edge at the base of the threads and see if it is black & sooty. There are products to clean out the carbon. We have had good results with Seafoam.

:2c:

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Pinging can be caused by mixture or timing. Unfortunatly the pc3 can only adjust mixture. If the issue is due to timing(as it is on my wifes v11), you can band-aide the situation by adjusting the mixture to be overly rich. Not the best solution, but it can work. If you could retard the timing slightly, that might help(and it can improve power as well). But that is not easy to do.

On a final note, Improving squish is a good idea and it can help get rid of pinging, but it is a fine line to walk since most ways to improve squish also increase compression, which can add to the pinging issue. Usually the improvement in squish out weighs the increase in compression, but not always.

Good luck. One way or another it can be done.

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On a final note, Improving squish is a good idea and it can help get rid of pinging, but it is a fine line to walk since most ways to improve squish also increase compression, which can add to the pinging issue. Usually the improvement in squish out weighs the increase in compression, but not always.

Good luck. One way or another it can be done.

 

 

Definitely. Thing to remember though is that squish is set not by the dimensions of the head so much as by the height of the barrel. You can set it either by using differentially thicknessed gaskets, (As with the new 8V motor.) or machining the base of the barrel.

 

The thing to remember is that no two engines are ever going to be the same. While generally an overly lean mixture will be the chief cause of detonation if the CR is OK and squish is close to correct an overly rich mixture will also tend to contribute for the reasons Dan listed. I'd tend to think that that the timing is one of the least likely culprits simply because the timing component of the map is shared between all bikes, those that detonate and those that don't, and I assume it would be fairly immutable? I may be wrong there of course. If your plugs are very dark try the 'Gloop up the ETS with anti seize' trick and see if it improves things. Mind you doing that will probably require another dyno-tune for the PCIII.

 

Other than that? Use an octane booster? If 93 is the best you can get I'm not overly surprised it pings.

 

Pete

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(3 octane in the USA is not the same as in Austalia. I believe we use an average of RON and MON, and you just use one or the other(correct me if I'm wrong). As far as timing goes, you're assuming the Guzzi is capable of machining all thier bikes the same as far as things like sensors for the crank and/or cams. I don't have that kind of faith in Guzzi from what I've seen. Minor differences in the mounts for the sensors could and would make for noticable variences in timing from one bike to another. But that is just speculation on my part. I do know for sure that on my wifes v11, if the mixture is set for optimum power it pings, and if I richen it up a bit it stops. Your mileage may vary.

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Octane booster's the cheap way. Try DurAlt to clean out the deposits that may contribute to the problem.

 

I plan on messing with the quish on my V11 to try to get rid of pinging because this worked fabulously on my Eldo. I set the squish pretty tight, and whereas previously it would ping sometimes on premium, all the time on mid-grade and viciously on regular gas, I cannot now (or at least haven't been able to yet) force it to ping, even on regular.

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[i thought the ping problem was only on the 2000-2001 bikes at 3000 rpm. My 2000 Sport only pinged when it was in the summer time in hot weather. Tried adding fuel with the PCIII but could not completely eliminate it. It only happened when the weather got hot and dry. Now my Ghezzi Brian with FBF high compression pistons with ping badly at 3000 rpm when the air is dry. A cool day, it never pings. I tried riching up the fuel mixture via the PCIII but it does nothing. I feel it is more in the ECU which gives it too much advance at 3000 rpm. Humm, my 03 Rosso has never pinged. Wonder if it has a different advance curve? Yep, I am going to switch the computers between the bikes to see if the problem goes away.

 

Mike

 

 

 

quote name=Greg Field' date='Jan 25 2008, 12:19 AM' post='136324]

Octane booster's the cheap way. Try DurAlt to clean out the deposits that may contribute to the problem.

 

I plan on messing with the quish on my V11 to try to get rid of pinging because this worked fabulously on my Eldo. I set the squish pretty tight, and whereas previously it would ping sometimes on premium, all the time on mid-grade and viciously on regular gas, I cannot now (or at least haven't been able to yet) force it to ping, even on regular.

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To get a squish area in the V11 combustion chamber, you have to mill off 1 mm from the heads gasket surface to get rid of the chamfer on the outside of the hemispheric chamber.

Furhtermore I had to shorten the cylinder barrels by 0,45 mm on the base gasket surface to bring the pistons on top of the cylinder. In this area every engine might be different.

Then you get the head gasket thickness (1,2 mm) as squish area.

Valve to piston clearence has to be checked after these mods have been done!

 

My KR pinged at 3000 under full throttle due to a very lean condition (A/F ~ 17). This almost disapperared when the mixture was richer in that area. I use 95 Eurosuper.

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To get a squish area in the V11 combustion chamber, you have to mill off 1 mm from the heads gasket surface to get rid of the chamfer on the outside of the hemispheric chamber.

Furhtermore I had to shorten the cylinder barrels by 0,45 mm on the base gasket surface to bring the pistons on top of the cylinder. In this area every engine might be different.

Then you get the head gasket thickness (1,2 mm) as squish area.

Valve to piston clearence has to be checked after these mods have been done!

 

My KR pinged at 3000 under full throttle due to a very lean condition (A/F ~ 17). This almost disapperared when the mixture was richer in that area. I use 95 Eurosuper.

That's pretty much what I did as well. Had the local Guzzi shop do it for me while they were porting the heads. The whole time the kept telling me what I was doing woudn't work. Some people don't understand the difference between squish and compression.

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Thanks for the great input guys! I should have mentioned that I did do a de-carbon procedure and it didn't help. I wonder why my bike pings at 5k when others have problems at 3k? Anyway, it looks like I have a few solutions here that I can try when I get the bike back on the road. From easiest to harde$t:

 

1. Add octane booster

 

2. Add fuel with PCIII (even though I don't think it's lean there based on the A/F chart that was done with the custom map by the previous owner)

 

3. Install Mike Rich pistons?

 

4. Have head and/or barrel machined to adjust squish band. This is beyond my capability but I'd be willing go this route if there was a local shop who knew how to do this for a reasonable amount of money.

 

Guzzimoto,

How happy are you with the machine work that you had done? Were you setting your bike up for street or track?

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3. Install Mike Rich pistons?

 

 

Tom,

 

My bike has similar modifications to yours, no TI ecu though. I tend to do things in stages so I have a handle on the degree of improvement (or decline :o ) from each mod. The last thing I did (a year ago) was the MR pistons. The only other thing I did at that time was drill the air box lid. I was using an off the shelf map for the bike with the mufflers and crossover and left that unchanged to see how things would be. Seat of the pants, the bike makes more power across the board but especially in the upper rev range. Now I'm fully aware that seat of the pants is just that and often times hopefull thinking will make a bike/car/garden tractor feel more powerfull ^_^. My acid test was on a particulary long straight with my best riding mate on his S2R 1000. The season before the pistons he would pull away from me through the lower gears and I would barely make up ground above 100mph. After the pistons we're neck & neck in the lower gears and I have a couple of bike lengths on him by about 125. So if for no other reason than to edge out my old pal, the mod was worth the money.

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I would like to determine what you guys are calling Squish.

Are you setting the deck height?

I'm sure there is a optimal cylinder height, measured from

the bottom gasket surface to the top gasket surface. The point

of using various thicknesses of base gaskets and head gaskets

is to be able to get the deck height set properly.

What this magic number is, I don't know. Havent been able to cipher

guzzi's manual yet.

I'm putting my engine back together(while I'm still waiting on tranny parts)

55,000 miles...what I consider well taken care of.....

Valve guides shot....valves shot...seats shot....heads have been

hot ....slight warpage....

Heads are done now and look fantastic....can't wait to put it together..

Hope I opened up a whole nother can of worms

 

andy

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Tom,

 

Thanks for the info Dan, and congrat's on making your bike as fast as your bud's S2R! I thought a custom map would be mandatory when you install high comp pistons. Not needing to do that would help keep the initial cost of that upgrade down. Hmmm. On what shelf did you find the map you're using?

 

I'd really like to hear if somebody out there cured a pinging problem by installing the MR pistons. More power from a piston swap would just be a bonus for me.

 

FWIW I went back to the stock ECU after I added the crossover and drilled the airbox because I couldn't find a map for the Ti ECU with my other mods. The custom map that I had for the Ti ECU was definitely lean after the intake and exhaust changes. My seat of the pants (there it is again ^_^ ) comparison between the two is the stock ECU is stronger and smoother from low end to midrange but the Ti ECU seemed to pull a bit harder from 5k to redline.

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Thanks for the info Dan, and congrat's on making your bike as fast as your bud's S2R! I thought a custom map would be mandatory when you install high comp pistons. Not needing to do that would help keep the initial cost of that upgrade down. Hmmm. On what shelf did you find the map you're using?

 

I'd really like to hear if somebody out there cured a pinging problem by installing the MR pistons. More power from a piston swap would just be a bonus for me.

 

FWIW I went back to the stock ECU after I added the crossover and drilled the airbox because I couldn't find a map for the Ti ECU with my other mods. The custom map that I had for the Ti ECU was definitely lean after the intake and exhaust changes. My seat of the pants (there it is again ^_^ ) comparison between the two is the stock ECU is stronger and smoother from low end to midrange but the Ti ECU seemed to pull a bit harder from 5k to redline.

 

According to Mike there is not that much difference in actual compression ratio with his pistons. The whole idea is better shape for a more efficient burn. So the mix should be the roughly the same. I intend to have him port the heads next month. Then I'll certainly have to change the map. I've already found one that should be a suitable place to start then tweak from there. When I bought my PCIII from Todd E. he had several maps available. One of them pretty much matched my mods.

PM me with your e-mail and I'll send you the maps I have.

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Thanks for the great input guys! I should have mentioned that I did do a de-carbon procedure and it didn't help. I wonder why my bike pings at 5k when others have problems at 3k? Anyway, it looks like I have a few solutions here that I can try when I get the bike back on the road. From easiest to harde$t:

 

1. Add octane booster

 

2. Add fuel with PCIII (even though I don't think it's lean there based on the A/F chart that was done with the custom map by the previous owner)

 

3. Install Mike Rich pistons?

 

4. Have head and/or barrel machined to adjust squish band. This is beyond my capability but I'd be willing go this route if there was a local shop who knew how to do this for a reasonable amount of money.

 

Guzzimoto,

How happy are you with the machine work that you had done? Were you setting your bike up for street or track?

I happy in that it runs better then before. You get what you pay for, though. And I did not pay a huge amount for the work. The bike is my wifes street Guzzi. 37,000 miles and she rides it in all kinds of situations, from touring to parking lot racing( like autocross). It is easy to do work like that on a Guzzi. The heads and cylinders pop off so easy. No water cooling to deal with. It's cake. There are many opinions on how to set up your squish, but as stated before by some one else I think you just mill off enough of the head to get rid of the beval( you'll understand it when you see it). then set the piston height to be flush with the top of the cylinder by milling of the cylinder(I milled off the top of each cylinder). The head gasket will give you clearence between the piston and head. But you do need to be sure that you have piston to valve clearence by putting clay on the piston tops where the valve pockets are and spinning the motor over a couple of times.

The squish and porting work helped with the pinging, but it will still ping if I run it lean (not really lean, a/f ratio13/1-13.5/1). It lilkes about 12/1-12.5/1. But it doesn't ping much and with gas prices what they are...

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