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Quote:
Originally Posted by psykotech
That's the similar lines that the Honda service department told me - F*ckers. They have the nerve to call me a month ago to ask me how my car is going and would I like to book in a schedule service with them!!
I gave them a piece of my mind about the pinging and also told them that they put swirls marks on my car when they gave the car a wash.
wtf... 2008.. 2009.. 2010.. 2011.. 2012 and now 2013.. and Honda still hasn't fixed this infamous pinging issue?
back in 2008, i remember that only automatic transmission CU2's were affected. but now we have one dude with the same problem on his 2013 6MT??
It was always both transmissions. It's the engine not the transmission that pings champ.
Nah mate, first reports it was only AT CU2's. Not saying your wrong as your 100% correct that pinging has nothing to do with the transmission, but at the start it seemed to only come from Auto Owners on OzHonda.Quote:
Originally Posted by CU2 Euro 09
I still have doubts about it being the Oil Visc causing pinging, but you never know!
I'm still betting on a electrical/ECU problem as it's intermittent.
I'd also like to ask Honda what the 'Operating Conditions' are that would make the vehicle ping?
Guys, please make note that the original pinging in the auto version of the CU2 is not the same as the post combustion sound (PCS) described at length in this thread.
The ping fix incorporated the replacement of the knock sensor with a more sensitive unit and the upgrade of software to the ECU and the automatic transmission.
My 2009 manual CU2 never suffered from pinging but had bad PCS after the so called ping fix.
My CU2's PCS issue was cured after I moved to UK in 2010> accidently may I add, by using Mobil 1 0W-30 ESP - Thank you BigBen for isolating this for all of us.
The fuel that I use is 95 octane supermarket cheapo (which is obviously sourced from a major fuel supplier).
Listed below are the specifications for a few oils from the same manufacturer - in this case Exxonmobil. The data shows that there are variations in the viscosity at 40ºC and 100ºC.
I have also included the specification for Amsoil 0W-20 as this oil is mentioned in this thread.
Assuming that most of the engine wear occurs at startup, we want an oil that is thin enough to flow fast at startup and have enough viscosity at normal operating temperature to keep the metal parts lubricated.
The ideal number seems to be 10. So, we should select an oil that is close to 10 @ 40ºC and 100ºC respectively.
The above holds true for vehicles under normal operating condition with the exception of racing, where a racing oil should be selected.
* The oils listed below are all Synthetic oil. If you are using Mineral oil or a Synthetic/Mineral blend, the properties will vary considerably.
Typical Properties
Mobil 1 ESP Formula 0W-30
SAE Grade 0W-30
Viscosity, cSt at 40ºC ASTM D445 67.8
Viscosity, cSt at 100ºC ASTM D445 12.2
Typical Properties
Mobil 1 0W-40
SAE Grade 0W-40
Viscosity, cSt at 40ºC ASTM D445 71
Viscosity, cSt at 100ºC ASTM D445 13.5
Typical Properties
Mobil 1 ESP Formula 5W-30
SAE Grade 5W-30
Viscosity, cSt at 40ºC ASTM D445 72.8
Viscosity, cSt at 100ºC ASTM D445 12.1
Typical Properties
Mobil 1 0W-20
SAE Grade 0W-20
Viscosity, @ 40ºC, cSt (ASTM D445) 44.8
Viscosity, @ 100ºC, cSt (ASTM D445) 8.5
AMSOIL Signature Series Synthetic Motor Oil
Typical Properties
Amsoil 0W-20
Viscosity, @ 40ºC, cSt (ASTM D445) 46.7
Viscosity, @ 100ºC, cSt (ASTM D445) 8.8
It seems that the CU2 (K24Z) engine’s oil specification is to be changed as mentioned in this youtube clip from Honda. At 50 seconds, Jeff Jetter, mentions Honda’s plan to move to 0W20 oil retroactively to 2001 for most of it’s vehicles.
http://www.youtube.com/watch?v=OAYkigNbzgs
The new Group 5 oils are rewriting history it seems and I plan to fill with 0W20 at my next oil change and have the added bonus of better fuel economy.
So what about the post combustion sound (PCS) problem?
It seems that the low viscosity numbers allow the engine to rev more freely without labouring and the cooling effect of a lower viscosity oil as it flows more freely.
The new GF5 (Group 5) oils are now becoming available in UK & EU. I would think that they can be found in USA too. As you can see from the spider chart below there are many advantages to using GF5 over GF4.
Both Amsoil and Total have GF5 oils in UK but you need to check the specification of the formulation as GF4 is still being sold.
Note: Engine oil cannot be shipped overseas due to it being a flammable liquid.
I will be changing to GF5 in April (12 month interval) and plan to use 0W20. It is also a good idea to do the oil change in Spring as very cold weather can be pretty tough on an oil (separation of waxes etc).
My CU2 has just 28,000 kms on the clock.The current long term fuel efficiency is 8.3 ltr/100km. Which I think is pretty good considering the traffic over here. I expect some improvement with 0W20.
So, from my experience with 0W30 Synthetic (which I have been using since late 2010), the engine revs more freely and it does not PCS or ping. As seen from the viscosity numbers, I would expect 0W20 to be better....especially for low milage CUs and then, you may want to consider 0W30 and then 0W40 (in that order). Also, I would suggest synthetic oil over mineral oil or blends. Note that some oils I have mentioned may not be 100% synthetic as there seems to be some argument as to what exactly constitutes a synthetic oil.
Bear in mind that most of the engine wear occurs at startup (especially cold) and an oil with a low viscosity that flows fast is able to lubricate the engine more quickly than a Tar like oil that is hard to pump! So, try to get a 0W-X oil if you can.
The PCS problem with my CU2 is now a distant memory..... no a nightmare, that I am happy to put behind me.
Attachment 24125
I agree with Irving 100%. After running close to 25,000km on Amsoil 0w-20 I'm happy to say that I hear no pinging at all. I'm really enjoying the car the way the engineers design it to be.
Even in the +45 Deg C heat with the aircon switch on stuck in Sydney traffic that we had last month I had no pinging what so ever. I remember that day because there were a number of traffic lights out of commission. Cars we broken down in the middle of the road which overheated which made traffic coming home one of the worse commute I ever encountered - but no pinging!!! Woo Hoo.
The K24Z engine either has a design flaw or was intended to be lubricated by a low viscosity oil (0W-20, 0W-30 or 5W-30). Note: I have tested Mobil 1 5W-30 and 0W-30 in UK with good results and Ben has tested Amsoil 0W20. I have not tested 0W-40 and cannot say if it will eliminate PCS.
The viscosity of an oil ideally should be around 10 bearing in mind that a lower viscosity fluid is easier to pump and travels more easily through oil passages. It has to flow at the correct rate in order to lubricate and extract heat from critical components. If the oil flows faster or slower, it wouldn’t be doing it’s job properly. So, the correct flow rate is important.
The engine oil temperature is generally higher than the coolant temperature in cars by 10ºC to 15ºC. Also, the oil temperature will generally take longer to come to operating temperature than the coolant temperature. This is probably the reason that PCS was more prevalent when the engine was cold. Even if the engine coolant temperature showed ‘normal’ it is unlikely that the oil temperature was at operating temperature. Therefore, the oil had a higher viscosity and was harder to pump and flowed less freely, dissipating less heat from the engine’s cylinder head and allowing more heat to build up. Thermal runaway (in electronic terms). Until the driver eased up and less load was put on the engine. The engine then cooled sufficiently so that post combustion did not occur until the peak load was again demanded of the engine.
Interestingly, the PCS in my CU2 started at around 3900 rpm and was most prevalent as the engine approached peak torque. The CU2’s peak torque is quoted at 234Nm@ 4300-4400 rpm - Is this a coincidence? I think not!
Below are viscosity values generated through extrapolating from the known figures @40ºC and 100ºC (based on ASTM341) together with it's related graphical representation of Temperature vs Kinematic Viscosity:
Mobil 1 0W30 ESP
Temperature ºC Kinematic Viscosity cSt
0 ----519.39
10 ----281.18
15 ----213.17
20 ----164.51
25 ----129.03
30 ----102.74
35 ----82.93
40 ---- 67.8
50 ---- 46.89
60 ---- 33.75
70 ---- 25.14
80 ---- 19.28
90 ---- 15.17
100 ---- 12.20
110 ---- 10
115 ---- 9.12
More temperature - Kinematic viscosity values have been added to show real life temperatures and it's effects on viscosity. Obviously, in real life one would not expect to see such high numbers at low temperatures due to the additives used to minimise this effect.
The chart represents 40C to 115C for greater clarity.
Attachment 24126
As we can see from these results, Mobil 1 ESP 0W30 looks like a pretty good oil when the engine is at operating temperature.
Figures are based on ASTM 341 extrapolated from known calibration data @ 40C and 100C
How does that relate to pinning is what I'm interested inQuote:
Originally Posted by Irving
What part of the engine is causing this.
PCS or Post Combustion SoundQuote:
Originally Posted by Fredoops
After the initial ignition of the air/fuel mixture, the sudden combustion drives the piston down. During this event (on the downstroke), the hot gases are further ignited as smaller explosions - ***due to the excess heat trapped in the cylinder head before the gases are vented by the exhaust valves.*** This is the pinging noise that we could hear.
[QUOTE=Irving;3662749]
//Therefore, the oil had a higher viscosity and was harder to pump and flowed less freely, dissipating less heat from the engine's cylinder head and allowing more heat to build up.//
Some say that this is infact a good thing, as you are getting further smaller explosions during the downstroke which they claim may help generate more power.
However, as many of us know, it is not a desirable characteristic in the CU2.