blackbenzz

Since I have 55k rods/pistons and NA 55 rods/pistons I decided to share with the board what I've found.

Both rods are crack forged. The biggest difference is the oiling port in the NA 55 rod (bottom) which weakens the rod



Notice the difference in wrist pins (NA 55 on top)



The NA 55 (bottom) has higher compression as expected.



NA 55 on right



The 55k pistons look to have really low compression. I have an 06 E55 engine on it's way to me and I will tear it down and put higher compression forged pistons, ARP head studs, and rod bolts in it. This should beef it up a bit. I want higher compression than stock because I want more power per psi and off boost power. I can post differences in the heads, blocks, etc if I get the time. The NA motor was able to hold over 650whp and in my CLK55 was able to trap 138.71 before letting go. I would expect the 55k motor to be able to hold more power but I'm not willing to put the stock 55k motor in my car and risk it blowing up and putting me and the car into the wall.

Quicksilv3r

Cool post, thanks.

cm60k

Thankss for sharing bro...

ZAYED,,

blackbenzz

You're both welcome. I will post pics of Mahle forged "SLR" pistons later as well as some other pics like ARP rod bolts and ARP head studs. I no longer have the Mahle forged pistons so I don't have many pictures of them and they were already in a 55k block. But it's better than nothing. I will have side by side pics after my custom forged pistons are made comparing them to the NA 55 and 55k pistons.

55fanatic

what do you think the cost on building your new block will cost?

also was the 55K piston used? Why so much discoloration between the two?

blackbenzz

I've decided to go with a very mild "build". I want to keep it a street car and don't want to tie up much more money into it. This should be able to hold what this blower can make but only one way to find out. I already have ported heads and ARP head studs to use so all I'm really buying is forged pistons, rod bolts, and all necessary gaskets, bearings etc. So not including the price of the new block it should be around $3k. Unless I have to buy extra stuff which I may have to since my last block broke alot of stuff and the 55k engine requires a hybrid oil pump to fit my car. I will probably need to buy a new upper oil pan for my car because I threw my last one away and this one is missing a huge chunk in the middle now lol. Labor is free cuz I'm doing all the work.

Yes 55k Piston came out of my old E55. Had ~82k miles on it. I cleaned it up and it has been sitting in basement for 2 years or so. The NA 55 is fresh out the block and not cleaned up (~102k miles). Probably should have cleaned it up, sorry.

Gadget

Will the upper oil pan from an S55 fit?

I still have to drop that used S55 into my E55 and I think that parts gets taken off.

G

sk8erjosh09

Very cool man. I would be totally interested in seeing the differences in block and head designs if you do end up having time.

Robert AMG

iTrader: (1)

Nice thread, plus you forget to mention the difference in weight between both pistons, as i remember when i built my engine that the n/a 55 piston alone is less weight then those of 55K(580g for 55k and 530g for n/***).
also the heads differ in volumes the 55k ones are slightly bigger.
n/a 55:

55k:

blackbenzz

I'm not sure I would have to look at it. Doubtful. Thanks though.
Ok I will try
Thanks for the adding the additional info! This is more of what this forum needs!

e55amgrocket

The N/A heads and S/C heads have the same combustion chamber volume. The intake runner volume is actually more on the N/A head but I don't remember the exact volumes of the runners but the CC volume on both heads is 60cc's.

stockC43

Can you run na heads on a kompressor bottom end? any advantage/disadvantage?

BlownV8

What pistons are you using? Coated cylinders or pistons or sleeved?

e55amgrocket

Yes the can be run on a 55k bottom end. I actually bought a set of N/A heads for my build thinking they were the same and found out after having them ported and taking the 55k heads off. My head porter ended up porting a 55k set also and then took a spare set of N/A heads and S/C heads and played with several ports trying things on both and said the N/A head was the way to go in his opinion. I think Ahmad might have pics of the intake ports of both to show the difference. The 55k heads have a raised divider that the n/a heads don't.

trackjunky

iTrader: (1)

we need more threads like this! thanks for sharing!!

blackbenzz

Knew you had them measured but didn't know the numbers. Thanks for chiming in
Yes you can. They bolt right up. I think the NA heads flow more. Steve had them tested.
Getting pistons and rod bolts through Weistec. Ceramic coated tops with teflon coated skirts. 9.8:1 C/R is what I decided to go with.
There you go. I do have pics of the differences but they were on my old phone. I will get better pics when the 55k engine come sin and I disassemble it. I will post pics of ported vs non ported NA 55 heads I have on my phone for now.
I agree! You're welcome


Just to add a bit more info and pics to this thread. First off if you plan on running NA heads please make sure you run the shorter plugs because if you run 55k plugs they are too long and will hit!. You will do alot of damage on first start up. This is why I always recommend to hand turn the crank several times before starting the car after doing any engine work.

Pic of NA 55 head ported intake



Pic of unported NA 55 head intake (I will get comparison pics of all 3 when my 55k engine gets here to disassemble)



I promised a pic of the Mahle forged "SLR" pistons so I found a couple on my phone. I bought the block with them in it and was told not to remove them so the pics I took were with the pistons still in the block sorry. There's an obvious difference from the bottom (and they are lighter)



NA 55 piston from bottom in block



From the top they look like a compromise between the NA 55 and 55k pistons... but forged. So the compression is somewhere between the 2.







You'd have to be a detective to notice the minute differences between a NA 55 block and a 55k block. One thing I did run into is that the 06 E55 block apparently has a different crank than a NA 55 (I'm not sure about the other years). The flywheel wouldn't bolt to the 55k crank because of different spacing (55k on left)



This pic gives you an idea of NA 55 pistons vs the Mahle forged ones in the block.



Pic of ARP rod bolts on 55k rod



This pic is a comparison of one variation of the 55k oil pump (I wanna say S55 but can't remember right now. Either way it's different than E55 because of the different oil pans to fit different cars) and a W208 CLK55. It's hard to tell in this pic but they are not interchangeable because of the different bolt hole spacing! Also the pickups are in different locations. Just a nice surprise I ran into when trying to do a 55k block in my car before. I had to buy 2 oil pumps (which wasn't exactly cheap) and use the front half of one and bolt it to the back half of the other in other for the correct oil pan to fit... but it works!



You can see the spacing issue in this pic if you look closely. (Na 55 oil pump on a 55k block)



And just for fun here's a pic of the NA 55 piston that broke and got lodged in the cylinder the first time an NA 55 motor let go on me. I haven't removed the piston from the most recent one since I'm leaving it in the block when it becomes a table. It adds character lol





Hopefully all this info will help some people in the future and save them alot of time and $$$

sk8erjosh09

MB changed the crank bolt pattern in 05 on most models, others earlier, others later. If you need a flexplate for the newer bolt pattern let me know. Thanks for the pics and descriptions though, awesome information.

Gadget

I am going to be installing a used engine from an 05 S55 in my 06 E55. Is this going to cause me a problem with the crank shaft?

The S55 engine does have the flex plate on it.

Looking at the oil pump in the pictures above. Word is I will need to move the oil pump from the E55 engine to the new/used engine. Will that require removing the front timing chain cover to make the swap?

G

sk8erjosh09

The torque converter has to match the flexplate. I'm not sure which models changed and which didn't but I believe S and E both changed in 2005, so you should be ok.

You can change the pump's with just the pans off. Way easier if the motor's out though. I just flipped the whole motor over lol.

Gadget

It is going to get pulled, but I want to have everything needed on hand so I can get the parts swapped over and back in the in short order.

G

sk8erjosh09

Totally understandable, if you can PM the block number on the S and on the E I can check in the EPC to see if their the same bolt pattern. That would be your only issue, everything else can just be swapped over or around if needed.

blackbenzz

Good info. The motor should come with a flexplate but I will take you up on that offer if it doesn't. Thanks. Any idea why they changed?
The converter is different on an 06 too? I was able to bolt my converter to an 06 flex plate.

macko

Cool post +1

sk8erjosh09

No clue why they changed, it's actually very irritating and cost me like $1300 in a useless flywheel and clutch from a newer C230.

Matching torque converters to flexplates is a hit or miss. The converter bolt pattern (as far as I'm aware) did change along with the redesigned crank bolt pattern, but like I said, most M113's changed in 05, where as some changed in '04 and some in '06. So it's hard to say if you got lucky, or if the converter bolt pattern mates to all of the flexplate's... Honestly man I can't tell you 100%, I'm basing this off my experience which is limited for the auto's. I have the redesigned flexplate and an older converter, so I'll see if they mate up and text you.

blackbenzz

Thanks
The converter bolted to the flex plate I had. I have an 01 and it bolted to 06 flex plate.

Here is a pic comparison for those who haven't seen it (06 crank on top. Notice the bolt hole spacing and two extra holes).