thoughts on Alusil cylinder's
Long story short this could possibly save $3,500.00 dollars in the end if I don't sleeve the block and buy pistons.
Any thoughts??




When you say plasma the pistons, are you talking about tin coating the piston or is this the Swain Tech process? Tin coating the aluminum is what is typically recommended in the Alusil bore. Your options if you keep the stock bore is to coat the bore or coat the piston. I have heard many with good results from Nikasil on the piston walls.
Having built some engines with Alusil bores and having done my share of experimentation, I can only recommend the OE piston suppliers or sleeving your block. If you sleeve, you can run a cheaper piston and more boost without fear the cylinder walls will mushroom under high boost. If you keep the Alusil, you will get much better longevity. Do you want the engine to last 400k miles or 150k miles before you need to rebuild or are you doing this for maximum hp?



Wossner forged pistons with wrist pins and rings. Four of the eight.
Coating for Alusil block
When I rebuilt my M117 AMG engine (5.4L SOHC), I had the block slightly bored to remove some scratches in the cylinder walls. Had new modern pistons/rings made due to the 0.5mm increase in bore. Wossner made my pistons and coated the skirts so they would be compatible with Alusil.
When you say plasma the pistons, are you talking about tin coating the piston or is this the Swain Tech process? Tin coating the aluminum is what is typically recommended in the Alusil bore. Your options if you keep the stock bore is to coat the bore or coat the piston. I have heard many with good results from Nikasil on the piston walls.
Having built some engines with Alusil bores and having done my share of experimentation, I can only recommend the OE piston suppliers or sleeving your block. If you sleeve, you can run a cheaper piston and more boost without fear the cylinder walls will mushroom under high boost. If you keep the Alusil, you will get much better longevity. Do you want the engine to last 400k miles or 150k miles before you need to rebuild or are you doing this for maximum hp?







Last edited by W126AMG; May 12, 2019 at 10:56 PM.
You know then again here we have Eurocharge running 9 second times with a 160,000 mile M113 stock engine so one has to wonder LOL !!!
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The durability of the coatings for pistons in alusil bores is spoken of all over the interwebs. No real objective data I have found in years of looking (for other alusil platforms before this one).
The wossner is clearly a sprayed on coating. Depending on the roughness of the bore surface in your engine, and the clearance of the pistons, you will or will not succeed. Not to mention, I am not even sure what you are showing us, as those are for 4 valves per cylinder, and the M113k is a 3 valve engine.
The post talking about "OE" or steel sleeves is mostly correct. Technically, Mahle is OE, but their "gold" skirt coating is also hit and miss if you spend more than 10min in google. The thing that works is an ORIGINAL iron or ferrous coated piston (like the ones that come out of your engine) in an alusil bore.
I am rebuilding my engine now. I have done what I have done before with alusil - An30 paste, felt pads, 60 seconds up and down at 200rpm, and new rings on original unworn pistons (since they don't seem to wear much anyway). Yes, I then have swain coat my pistons, but that is above the iron coating, and it is not sacrificed on the skirt (at least I sure hope not).
The ONE OPTION that I have not seen is the Line-2-line coating that is made to wear in. Again - since alusil is so sensitive, its an expensive test.
Piston clearance with the aftermarket forged pistons is quite the pivot on this. Too much or too little, it doesn't matter what coating you have. Ask yourself why no german oem uses an iron sleeve in the last 30 years, but all of our American V8s have them.



The durability of the coatings for pistons in alusil bores is spoken of all over the interwebs. No real objective data I have found in years of looking (for other alusil platforms before this one).
The wossner is clearly a sprayed on coating. Depending on the roughness of the bore surface in your engine, and the clearance of the pistons, you will or will not succeed. Not to mention, I am not even sure what you are showing us, as those are for 4 valves per cylinder, and the M113k is a 3 valve engine.
The post talking about "OE" or steel sleeves is mostly correct. Technically, Mahle is OE, but their "gold" skirt coating is also hit and miss if you spend more than 10min in google. The thing that works is an ORIGINAL iron or ferrous coated piston (like the ones that come out of your engine) in an alusil bore.
I am rebuilding my engine now. I have done what I have done before with alusil - An30 paste, felt pads, 60 seconds up and down at 200rpm, and new rings on original unworn pistons (since they don't seem to wear much anyway). Yes, I then have swain coat my pistons, but that is above the iron coating, and it is not sacrificed on the skirt (at least I sure hope not).
The ONE OPTION that I have not seen is the Line-2-line coating that is made to wear in. Again - since alusil is so sensitive, its an expensive test.
Piston clearance with the aftermarket forged pistons is quite the pivot on this. Too much or too little, it doesn't matter what coating you have. Ask yourself why no german oem uses an iron sleeve in the last 30 years, but all of our American V8s have them.
If you read my post, I said my pistons are for an M117 engine, SOHC. The valve reliefs are on both sides of the piston so the pistons could be used on either side of the engine. The discussion in this thread is about Alusil coated pistons.
"Roughness of the bore surface"?? What are you talking about? My block was properly lapped and honed with the correct lapping paste and technique that is mandatory and specified for Alusil blocks. The clearance between the coated piston and cylinder bore was specified by Wossner and my block was bored to within .00019" of Wossner spec. My engine was built correctly by me and my brother. You build your engine your way.
Last edited by W126AMG; May 14, 2019 at 10:23 PM.




Great. So you are in the wrong forum. And you are talking about “alusil coated pistons”. Which don’t exist.
All my comments other than about your valve reliefs stand. Piston coatings for alusil bore walls other than oem are unproven and data is not objective.
Last edited by BC928; May 14, 2019 at 10:23 PM.

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At the dealer people would rebuild engines with no measuring of anything at any point in time. The new 2.0 turbo engines have so much piston to wall clearance that you can rock them in the bore. I was amazed by that, but no one else even seemed to understand what I was trying to show them.



