General engine tech -- Drag Racing to Circle Track
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Matt80
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by Matt80 » Thu Nov 21, 2019 2:13 pm
Hi, I recently saw a Nikasil plated steel alloy block that had the cylinder deck awfully looking.
I was told the deck it was ok and it just got that looking for the plating
Is that normal?

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bentvalves
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by bentvalves » Thu Nov 21, 2019 3:06 pm
those marks are from a rotary abrasive tool of some sort, used to "prep" the deck for HG replacement.
they prepped it alright... for a trip to the resurfacing machine!
edit: looking closely I am seeing no circular marks as would be left from a rotary tool, but it looks very similar in nature. almost looks like a belt sander was used on it to be honest.
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exhaustgases
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by exhaustgases » Thu Nov 21, 2019 5:42 pm
Looks like someone just sanded that area with something unsupported, like hand held emery paper or?
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Roundybout
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by Roundybout » Thu Nov 21, 2019 6:30 pm
In those pictures the cylinders have been Nikasil plated and the deck looks like that after Nikasil treatment but before any cutting of the deck, correct? If that’s the finished product (decking included) that’s just plain wrong. A MLS gasket is not going to like that finish. If it’s ready for decking I’d be suspect on what procedures they used to clean the deck. That looks like someone with a chisel worked on that. I work on a lot of Nikasil coated Kohler tractor engines and the only think touched is the bores. I’ve never seen anything like that after treatment.
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peejay
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by peejay » Thu Nov 21, 2019 7:25 pm
Looks like when someone hits a deck with sandpaper or a "cookie" because they don't like the look of the stains in the metal from where the old gasket was or wasn't.
It can be ugly as long as it is smooth and flat... and that deck is now neither!
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MotionMachine
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by MotionMachine » Thu Nov 21, 2019 8:29 pm
If the nikasil goes all the up to the deck, it probably should not be surfaced or the nickel will chip off. Maybe that's why it got cookie dusted.
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Matt80
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by Matt80 » Mon Nov 25, 2019 2:12 pm
He just told me that the block deck is perfectly flat, but he isn't able to understand if it needs any machining on it.
If yes, is the Nikasil really going to chip off??
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MotionMachine
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by MotionMachine » Mon Nov 25, 2019 7:39 pm
I do some blocks using iron Mahle nikasil sleeves. They warn to do no machining after installation for this reason.
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Matt80
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by Matt80 » Tue Nov 26, 2019 9:27 am
MotionMachine wrote: ↑Mon Nov 25, 2019 7:39 pm
I do some blocks using iron Mahle nikasil sleeves. They warn to do no machining after installation for this reason.
Sorry, are you referring to machining the block deck? Have you any email address to directly contact them about this? Thanks
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MotionMachine
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by MotionMachine » Fri Nov 29, 2019 10:53 am
Yes, they say to not deck the top of the sleeve because the nickel goes all the way up and it might fracture if machined. I hone them of course but no decking. This was through engineers I do work for and their contact at Mahle Germany so I do not have any direct contact info for them.
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midnightbluS10
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by midnightbluS10 » Sun Dec 01, 2019 1:02 pm
peejay wrote: ↑Thu Nov 21, 2019 7:25 pm
Looks like when someone hits a deck with sandpaper or a "cookie" because they don't like the look of the stains in the metal from where the old gasket was or wasn't.
It can be ugly as long as it is smooth and flat... and that deck is now neither!
What are cookies? Those little Scotch Brite Roloc pads that go on angle grinders?