M156 Rebuild Possible?
12-20-2020, 04:13 AM
#1
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2007 Mercedes E63 AMG
M156 Rebuild Possible?
hey guys,
I haven't done much resarch into this, but how are people dealing with rebuilds and the TWAS or nanoslide coating? Are people rehoning or do you just drop new pistons and rings in? I read that the TWAS treatment leaves a mirror like finish that is very hard but also thin. I'd assume this finish if honed would require a specific honing tool?
I haven't done much resarch into this, but how are people dealing with rebuilds and the TWAS or nanoslide coating? Are people rehoning or do you just drop new pistons and rings in? I read that the TWAS treatment leaves a mirror like finish that is very hard but also thin. I'd assume this finish if honed would require a specific honing tool?
12-20-2020, 03:27 PM
#2
Senior Member
hey guys,
I haven't done much resarch into this, but how are people dealing with rebuilds and the TWAS or nanoslide coating? Are people rehoning or do you just drop new pistons and rings in? I read that the TWAS treatment leaves a mirror like finish that is very hard but also thin. I'd assume this finish if honed would require a specific honing tool?
I haven't done much resarch into this, but how are people dealing with rebuilds and the TWAS or nanoslide coating? Are people rehoning or do you just drop new pistons and rings in? I read that the TWAS treatment leaves a mirror like finish that is very hard but also thin. I'd assume this finish if honed would require a specific honing tool?
Sounds like a good question for a machinist.
whatever AMG calls it, basically it is very similar to HVOF. High Velocity Oxy Fuel Thermal spray. Or tungsten carbide spray.
Honing it would indeed require special stones, diamond.
You’d also need to step up all the way through 4,000 grit to get a mirror finish.
Really, though- you shouldn’t need to touch it unless there was a mechanical failure causing mechanical damage to the cylinder wall.
If you see lines on the cylinder wall, but can’t catch your fingernail in them, I wouldn’t worry about it.
You should check for out of roundness and cylindricity. Yes that’s a word according to the GD&T manual. Check out of round and cylindricity with a torque plate bolted to the top deck, especially if it’s mounted to an engine stand.
If the measurements are out of spec, the thermal spray needs to be stripped, reapplied, and reground.
They grind these coatings with diamond wheels, as opposed to cutting them like you would with a cast iron bore.
Respraying and grinding 8 bores is a very expensive proposition, because almost no one has the equipment. Back when I was working for a rally team, we looked into getting a block redone for another vehicle and we were quoted $1,000 per hole. I don’t know if that is still the case.
If I were going to do this, I would attempt to sleeve the block with a traditional cast iron sleeve.
12-20-2020, 03:50 PM
#3
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yeah, so that leaves the question which I believe is the answer...do you just drop in new pistons and new rings?
with standard iron ductile sleeves or iron bores it's a absolute requirement to rehone at the minimum when installing new rings.
with standard iron ductile sleeves or iron bores it's a absolute requirement to rehone at the minimum when installing new rings.
12-20-2020, 04:28 PM
#4
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Pretty much, yeah. Just pistons and rings.
Make sure you get correct rings for coated cylinder walls. The side profile (looking edge on) is slightly convex, as opposed to a ring for a cast iron bore which is square.
Make sure you get correct rings for coated cylinder walls. The side profile (looking edge on) is slightly convex, as opposed to a ring for a cast iron bore which is square.
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hachiroku (12-20-2020)
12-20-2020, 07:31 PM
#6
Senior Member
Did you get your Mahle’s?
