Why not? Please
Bad piston = $4500
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From: SCV SoCal
2002 CLK430
I would be interested to know what type of pistons the stock factory NA 55 motor are. The blown ones are likely forged. I would like to know if the regular ones are cast or hyperutectic or what???? I would also magnaflux the piston or whatever to see if you can see any fissures or whatev which might give you a clue, or for that matter check all the other pistons. If I were you with it already apart, I would replace all of the pistons with some forged ones if they are not forged etc. bumping the compression down would also be a great idea but that's a function of piston and rods etc. but you could effectively and more safely make more power then.. hence not worrying about issues.
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From: City with Tall buildings!
C43/55,2k11 Volvo S60 T6AWD,2k Audi B5 S4,95 Eagle Talon Tsi AWD 500+awhp
I think it's the piston dome. Because the rod length would affect the bore and stroke if it were diff. Where the rod pins are in the 5.5L motors has not changed. Would not be a 5.5L motor anymore from what I understand. The heads on the 5.5L motors are all the same N/A and F/I. Read Vic's (Vrss)thread about the 5.5L heads in the w211 E55 forum.!
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LS7 powered Corvette
True what was said about examining the piston, I just meant it would be difficult to say what caused the issue... lack of fuel, poor timing, excessive heat etc.
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From: Ga.
All of them!
Stroke and bore define the displacement. You generally don't touch these to adjust compression ratio. You generally use the piston and combustion chambers in the heads to determine and adjust the compression. Ie. dished pistons will lower compression if all thing remain the same.
Smaller volume at tdc=higher compression. Make more room and you will have lowered the compression ratio.
Last edited by mbenzman; Apr 9, 2007 at 10:56 PM.
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From: City with Tall buildings!
C43/55,2k11 Volvo S60 T6AWD,2k Audi B5 S4,95 Eagle Talon Tsi AWD 500+awhp
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From: Ga.
All of them!
A little more on rods, the rule most engine builders go by is to use the longest rod you can as this allows more dwell time for combustion pressures to build. You typically shorten rods when you increase the stroke to compensate for the installed height of the piston, But you will lose some efficiency due to the higher piston speeds and thus the pressure has less time to act on them. A lot of serious builders will cheat by having the piston pins relocated higher on the (custom) piston to use a longer rod and offset the losses of an increased stroke by achieving a longer rod length.
Hope this helps before this gets too off topic.
Last edited by mbenzman; Apr 10, 2007 at 04:16 PM.
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From: S.E. FLA.
05 ML-500 , 03 CLK5.5 AMG has left the Garage
1 Bad Piston ?
Way Cool Rich. 
Can we said Rod angle ! or Offset Grudgeon pin Bore in the pistons. ,
God, I'm so happy That my Computer is up and running again
If you guy keep asking Questions, I'll never get my motor back together. I 'll take some picture of the pistons , In the engine block. I've got the motor part , {but not all apart} The pistons have a small Dish , no relief pockets for the valves . I will also c'c' the combustion chamber this week end also. JUST FUNNIN .I get it all to you guys. Thanks ___PTE___
Can we said Rod angle ! or Offset Grudgeon pin Bore in the pistons. , God, I'm so happy That my Computer is up and running again If you guy keep asking Questions, I'll never get my motor back together. I 'll take some picture of the pistons , In the engine block. I've got the motor part , {but not all apart} The pistons have a small Dish , no relief pockets for the valves . I will also c'c' the combustion chamber this week end also. JUST FUNNIN .I get it all to you guys. Thanks ___PTE___
Last edited by PTE; Apr 10, 2007 at 04:31 PM.
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2007 cls63 AMG
Have you checked your plugs for that particular cylinder yet? any abnormalities on it as compared to the rest of them, is the electrode tan in colour? any silver speckles? Is the gap different than the rest. Are all the plugs the same heat range? I find it difficult to imagine that your piston cracked under high boost pressure and the plug survived.
You need to post pictures up of the piston itself, did it scuff the cylinder wall? does it need to be bored or can you get away with a hone? Pistons just don't crack, if it happened once , it will happen again unless you find the root of the problem.
Maybe it is a bad tune, when you get it all rebuilt, take it to a dyno with a wideband and do a couple of full throttle runs to see that your mixture is ideal.
As somebody already suggested here that get all your injectors flow tested to see if one has gone static. If you are really worried that compression is too high, you can stack two head gaskets to effectively lower your compression or see if somebody makes a thicker head gasket.
There are a lot of good suggestions by people all throughout the thread, take your time and try to get to the root of the issue.
You need to post pictures up of the piston itself, did it scuff the cylinder wall? does it need to be bored or can you get away with a hone? Pistons just don't crack, if it happened once , it will happen again unless you find the root of the problem.
Maybe it is a bad tune, when you get it all rebuilt, take it to a dyno with a wideband and do a couple of full throttle runs to see that your mixture is ideal.
As somebody already suggested here that get all your injectors flow tested to see if one has gone static. If you are really worried that compression is too high, you can stack two head gaskets to effectively lower your compression or see if somebody makes a thicker head gasket.
There are a lot of good suggestions by people all throughout the thread, take your time and try to get to the root of the issue.
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2007 cls63 AMG
mbenzman is exactly right. Some people might be having a little hard time understanding i will try to make it a little simpler. There are two kinds of compression dynamic and static.
Your static compression is the ratio of air that can be squeezed into the cylinder when the piston is all the way down to the amount of air that can be squeezed in when the piston is all the way up. Ofcourse we all know that air is almost compressible. Thus if a configuration is 9:1 it means that you can squeeze 9 times more air in when the piston is at its lowest possible position in the cylinder to when it all the way to the top.
Even though you have a static compression number there are too many variables inside a variable combustion engine as in rod stroke, rod length, dwell times cam duration and lift, especially timing. You can pack air in through the intake valve but if the exhaust is bleeding before combustion occurs, you loose compression.
Rod lengths are not adjusted for increasing or lowering compression, although the dwell will affect your dynamic compression, rod lengths are adjusted to increase/decrease your rod-stroke ratio. Ofcourse you can change crank stroke too, or a combination of the two. Rod to stroke has a big effect on what rpms you can wind up your motor to and where your power band will be. HTH
Thanks
Your static compression is the ratio of air that can be squeezed into the cylinder when the piston is all the way down to the amount of air that can be squeezed in when the piston is all the way up. Ofcourse we all know that air is almost compressible. Thus if a configuration is 9:1 it means that you can squeeze 9 times more air in when the piston is at its lowest possible position in the cylinder to when it all the way to the top.
Even though you have a static compression number there are too many variables inside a variable combustion engine as in rod stroke, rod length, dwell times cam duration and lift, especially timing. You can pack air in through the intake valve but if the exhaust is bleeding before combustion occurs, you loose compression.
Rod lengths are not adjusted for increasing or lowering compression, although the dwell will affect your dynamic compression, rod lengths are adjusted to increase/decrease your rod-stroke ratio. Ofcourse you can change crank stroke too, or a combination of the two. Rod to stroke has a big effect on what rpms you can wind up your motor to and where your power band will be. HTH
Thanks
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From: Clearwater, Florida
2002 CLK55 Kleemann
Have you checked your plugs for that particular cylinder yet? any abnormalities on it as compared to the rest of them, is the electrode tan in colour? any silver speckles? Is the gap different than the rest. Are all the plugs the same heat range? I find it difficult to imagine that your piston cracked under high boost pressure and the plug survived.
You need to post pictures up of the piston itself, did it scuff the cylinder wall? does it need to be bored or can you get away with a hone? Pistons just don't crack, if it happened once , it will happen again unless you find the root of the problem.
Maybe it is a bad tune, when you get it all rebuilt, take it to a dyno with a wideband and do a couple of full throttle runs to see that your mixture is ideal.
As somebody already suggested here that get all your injectors flow tested to see if one has gone static. If you are really worried that compression is too high, you can stack two head gaskets to effectively lower your compression or see if somebody makes a thicker head gasket.
There are a lot of good suggestions by people all throughout the thread, take your time and try to get to the root of the issue.
You need to post pictures up of the piston itself, did it scuff the cylinder wall? does it need to be bored or can you get away with a hone? Pistons just don't crack, if it happened once , it will happen again unless you find the root of the problem.
Maybe it is a bad tune, when you get it all rebuilt, take it to a dyno with a wideband and do a couple of full throttle runs to see that your mixture is ideal.
As somebody already suggested here that get all your injectors flow tested to see if one has gone static. If you are really worried that compression is too high, you can stack two head gaskets to effectively lower your compression or see if somebody makes a thicker head gasket.
There are a lot of good suggestions by people all throughout the thread, take your time and try to get to the root of the issue.
The injectors are going to KLEEMANN to be flow tested.
No cylinder scuffing, the block will not be honed. The piston shows no signs to any of the usual suspects (lean, detonation, or oil starvation). There are no signs of scoring (block or piston), no discoloration, no pitting, no anything. If you didn't see the cracked ringland you would swear it is a perfect piston.
As far as the tune, if it had gone lean you would have seen it in the piston. The tops of the piston, or pistons, would show the telltale signs. Mine do not. I do plan on dynoing the car once it is back together, whenever that ends up being.
KLEEMANN has no problems with the compression and neither do I. I am one of 2-3 KLEEMANN cars with any type of failure. That is less then .1%. I am still leaning towards a defective piston. I have been in contact with MAHLE, the manufacture of these pistons to get them involved. I am hoping they will inspect the piston and offer a more educated guess as to why it broke. What I am really hoping for is that they want all the pistons and will work me out some kind of deal. Unfortunate Mercedes still owns the rights to this casting number, so its not available aftermarket.
The pictures are posted at the top of this thread. https://mbworld.org/forums/clk55-amg-clk63-amg-w208-w209/188486-pics-bad-piston.html They are very low quality. I hope to have better pictures tomorrow.
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From: So.Ca.
E55
Thank you mbenzman and c240classic,I did not have time to explain the bore,stroke and rod deal.
Many people get confused and think by changing the rods length,you are changing the stroke.You can take the rod completely out of the motor and the bore and stroke will still be the same.
Many people get confused and think by changing the rods length,you are changing the stroke.You can take the rod completely out of the motor and the bore and stroke will still be the same.
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Posts: 784
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From: Ga.
All of them!
Way Cool Rich. Can we said Rod angle ! or Offset Grudgeon pin Bore in the pistons. , God, I'm so happy That my Computer is up and running again
If you guy keep asking Questions, I'll never get my motor back together. I 'll take some picture of the pistons , In the engine block. I've got the motor part , {but not all apart} The pistons have a small Dish , no relief pockets for the valves . I will also c'c' the combustion chamber this week end also. JUST FUNNIN .I get it all to you guys. Thanks ___PTE___
Can we said Rod angle ! or Offset Grudgeon pin Bore in the pistons. , God, I'm so happy That my Computer is up and running again If you guy keep asking Questions, I'll never get my motor back together. I 'll take some picture of the pistons , In the engine block. I've got the motor part , {but not all apart} The pistons have a small Dish , no relief pockets for the valves . I will also c'c' the combustion chamber this week end also. JUST FUNNIN .I get it all to you guys. Thanks ___PTE___
Nice teaser Patrick!! Ok you got dished pistons to drop compression, so more boost is happening or what? I'm sure you have some coatings on the pistons as well. Is the bore and stroke untouched? It should be wicked, a modified Kleemann S4. You are making me want to play too!
Thank you mbenzman and c240classic,I did not have time to explain the bore,stroke and rod deal.
Many people get confused and think by changing the rods length,you are changing the stroke.You can take the rod completely out of the motor and the bore and stroke will still be the same.
Many people get confused and think by changing the rods length,you are changing the stroke.You can take the rod completely out of the motor and the bore and stroke will still be the same.
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From: So.Ca.
E55
If you are set on using Mahle's then yes,but if you can live with a different manufacture(which I suggest you do so)then you can have that EXACT piston copied.1 complete set of pistons(8) for the price of 1 AMG factory Mahle piston.
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From: Clearwater, Florida
2002 CLK55 Kleemann
The problem is that they can copy the design but not the material. The pistons in this motor are not a standard run of the mill piston. They are designed so that they are very quiet on start up, and can take the abuse of pulling around a 3600 lb car at high rpms. I have talked to JE, CP and Mahle. JE and CP say that they can copy the piston, but suggest that I stick with a stock piston. That is right from them. KLEEMANN also suggests sticking with a stock piston due to the processes by with the stock piston is made. The M113 motor is a very complex motor. Mercedes spent lots of money designing every piece of it. I do not think that I can get a better piston from JE or CP.
