Bosch Platinum +2/+4
06-07-2006, 12:45 PM
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2001 CLK320
Mulit electrode - side gap plugs
the main issue is what gap these multi electrode plugs have. The Bosch +2 and +4 plugs are not adjustable.
The stock gap for 3.2 V6 and 4.3 V8 calls for 1.0mm
The "phased-spark" type of system appears similar to one of my other cars (non MB) where one side fires from center to ground and the other fires in the opposite polarity (ground to center). What is taking place is one coil is firing two plugs instead of a coil on plug setup that has one coil per plug like Audi and others use on their systems.
The issue with that is a double platinum or iridium plug is a better choice because the non platinum (ground electrode) side will erode and the gap will increase with the miles accumulated. The double platinum style does a better job of resisting the gap erosion.
The multi electrode plugs aren't necessarily better for most applications. It didn't work very well on my non MB car's DIS system.
In fact, they caused mis-fires...took them out and put the single style electrode plugs in and worked fine w/o anything else needing attention. The +4's were black carbon fouled because of the high incidents of misfires - also cause a drop in city mileage.
The stock gap for 3.2 V6 and 4.3 V8 calls for 1.0mm
The "phased-spark" type of system appears similar to one of my other cars (non MB) where one side fires from center to ground and the other fires in the opposite polarity (ground to center). What is taking place is one coil is firing two plugs instead of a coil on plug setup that has one coil per plug like Audi and others use on their systems.
The issue with that is a double platinum or iridium plug is a better choice because the non platinum (ground electrode) side will erode and the gap will increase with the miles accumulated. The double platinum style does a better job of resisting the gap erosion.
The multi electrode plugs aren't necessarily better for most applications. It didn't work very well on my non MB car's DIS system.
In fact, they caused mis-fires...took them out and put the single style electrode plugs in and worked fine w/o anything else needing attention. The +4's were black carbon fouled because of the high incidents of misfires - also cause a drop in city mileage.
06-07-2006, 01:15 PM
#4
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Originally Posted by Hal H
the main issue is what gap these multi electrode plugs have. The Bosch +2 and +4 plugs are not adjustable.
The stock gap for 3.2 V6 and 4.3 V8 calls for 1.0mm
The "phased-spark" type of system appears similar to one of my other cars (non MB) where one side fires from center to ground and the other fires in the opposite polarity (ground to center). What is taking place is one coil is firing two plugs instead of a coil on plug setup that has one coil per plug like Audi and others use on their systems.
The issue with that is a double platinum or iridium plug is a better choice because the non platinum (ground electrode) side will erode and the gap will increase with the miles accumulated. The double platinum style does a better job of resisting the gap erosion.
The multi electrode plugs aren't necessarily better for most applications. It didn't work very well on my non MB car's DIS system.
In fact, they caused mis-fires...took them out and put the single style electrode plugs in and worked fine w/o anything else needing attention. The +4's were black carbon fouled because of the high incidents of misfires - also cause a drop in city mileage.
The stock gap for 3.2 V6 and 4.3 V8 calls for 1.0mm
The "phased-spark" type of system appears similar to one of my other cars (non MB) where one side fires from center to ground and the other fires in the opposite polarity (ground to center). What is taking place is one coil is firing two plugs instead of a coil on plug setup that has one coil per plug like Audi and others use on their systems.
The issue with that is a double platinum or iridium plug is a better choice because the non platinum (ground electrode) side will erode and the gap will increase with the miles accumulated. The double platinum style does a better job of resisting the gap erosion.
The multi electrode plugs aren't necessarily better for most applications. It didn't work very well on my non MB car's DIS system.
In fact, they caused mis-fires...took them out and put the single style electrode plugs in and worked fine w/o anything else needing attention. The +4's were black carbon fouled because of the high incidents of misfires - also cause a drop in city mileage.
06-07-2006, 01:24 PM
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Originally Posted by Hal H
the main issue is what gap these multi electrode plugs have. The Bosch +2 and +4 plugs are not adjustable.
The stock gap for 3.2 V6 and 4.3 V8 calls for 1.0mm
The "phased-spark" type of system appears similar to one of my other cars (non MB) where one side fires from center to ground and the other fires in the opposite polarity (ground to center). What is taking place is one coil is firing two plugs instead of a coil on plug setup that has one coil per plug like Audi and others use on their systems.
The issue with that is a double platinum or iridium plug is a better choice because the non platinum (ground electrode) side will erode and the gap will increase with the miles accumulated. The double platinum style does a better job of resisting the gap erosion.
The multi electrode plugs aren't necessarily better for most applications. It didn't work very well on my non MB car's DIS system.
In fact, they caused mis-fires...took them out and put the single style electrode plugs in and worked fine w/o anything else needing attention. The +4's were black carbon fouled because of the high incidents of misfires - also cause a drop in city mileage.
The stock gap for 3.2 V6 and 4.3 V8 calls for 1.0mm
The "phased-spark" type of system appears similar to one of my other cars (non MB) where one side fires from center to ground and the other fires in the opposite polarity (ground to center). What is taking place is one coil is firing two plugs instead of a coil on plug setup that has one coil per plug like Audi and others use on their systems.
The issue with that is a double platinum or iridium plug is a better choice because the non platinum (ground electrode) side will erode and the gap will increase with the miles accumulated. The double platinum style does a better job of resisting the gap erosion.
The multi electrode plugs aren't necessarily better for most applications. It didn't work very well on my non MB car's DIS system.
In fact, they caused mis-fires...took them out and put the single style electrode plugs in and worked fine w/o anything else needing attention. The +4's were black carbon fouled because of the high incidents of misfires - also cause a drop in city mileage.
06-07-2006, 01:24 PM
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2001 CLK320
Here's one Bosch platinum model
I just got these - haven't installed yet. They are OEM style
Bosch #FR8DPP33 (used in 3.2V6 & 4.3V8 and the AMG 5.5V8)
The cars typically come with Platinum Beru's from the factory - kind of hard to find...the owners manual cross references Bosch and NGK's as alternatives.
I got my Bosch plugs on line at www.alloemautoparts.com - they had a promotion (used them in the past) and got free shipping and a slight break on the price.
Bosch #FR8DPP33 (used in 3.2V6 & 4.3V8 and the AMG 5.5V8)
The cars typically come with Platinum Beru's from the factory - kind of hard to find...the owners manual cross references Bosch and NGK's as alternatives.
I got my Bosch plugs on line at www.alloemautoparts.com - they had a promotion (used them in the past) and got free shipping and a slight break on the price.
06-07-2006, 01:39 PM
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2001 CLK320
Originally Posted by halik
Why exactly would a double/4x electrode cause misfire? I'm sure BOSH make the +4s such that the resistance (and therefore spark timing) is the same. I think the really issue was the gap size rather than the multiple electrodes.
That side-gap setup would be a guess as the center electrode is recessed flush with the insulator tip - I didn't want to mess around with re-gapping 24 settings (6 plugs x 4 each) and risk an electrode breaking off.
I have used the standard Bosch platinums since the mid 80's w/o problems. Those versions are easy to set / check gaps on. These +4's didn't work for me - won't ever buy them again.
Just trying to avoid someone else having this experience. With the M112 / M113 engine, you'll have 12 to 16 plugs to deal with - space is tight around those engines and who wants to remove and install plugs multiple times? I certainly don't want to do that...
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06-07-2006, 04:51 PM
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I just recently had +4 put in my CLK320. I first went to the local dealership and they had the same plugs and wanted $11.00 a plug. I just went to see what kind they would recommend, I than went to the local autoparts store and got them for less than half that price. Seem to work good.
