In short order the cause was found to be low compression in the cylinders; an inspection of the cylinder walls unearthed the problem. The Nikasil liner was failing, which allowed the rings to score the cylinder walls and reduced compression. The question was: Why? There was a two-part recipe for failure.
What is Nikasil cylinder plating?
NiCom (Nikasil) plating is an electro-composite coating – consisting of a nickel metal matrix with hard particulate dispersed uniformly within it. The process involves electroplating nickel in the presence of hard particulates, such as SiC, under conditions allowing the hard particulate to co-deposit with the nickel.
Can you ball hone a Nikasil cylinder?
Nikasil is to hard to actually be honed, unless you’re using a diamond hone. The only thing you’re doing when you hone a nikasil lined cylinder is deglazing it, which is a good thing. Use a ball hone, or a scotch bright pad.
How thick is Nikasil plating?
Coating Thickness of Nikasil®
In practical use the cylinder walls or sleeves are electroplated with a layer of Nikasil®, typically between 80 and 180 µm thick.
Do you have to hone cylinders when replacing rings?
More often than not, you will need to hone your cylinder when replacing the piston rings. That is because honing creates small crosshatches in the surface of the cylinder, to allow the wall of the component to retain oil and provide lubrication for the piston ring.
How do you clean a Scotch Brite cylinder?
I use a green scotchbrite pad, some wd-40 on the pad and on the inside of the cylinder. I just follow the crosshatch with the pad going both ways for a few minutes then wash the cylinder 2-3 times over with warm water, dawn, and a dish scrubber.
Who invented Nikasil?
Nikasil was introduced by Mahle in 1967, and initially developed to allow Wankel engine apex seals (NSU Ro 80, Citroën GS Birotor and Mercedes C111) to work directly against the aluminium housing.
When did Jaguar stop using Nikasil?
Jaguar replaced Nikasil with steel liners after 2000 and therefore vehicles from this year onwards should be relatively safe bets.
Does honing remove material?
Honing removes material from the workpiece via abrasion. Like grinding, honing utilizes aluminum oxide, CBN, diamond and other abrasives to generate the cutting action.
Should Nikasil be honed?
It’s perfect for deburring and deglazing engine cylinder walls. The Flex-Hone can be used on both steel and Nikasil-plated cylinders on either 4-stroke or 2-stroke engines. If your cylinder is in normal condition with no damage, and you’re just changing rings between top ends, honing should be the only thing required.
Does Nikasil wear out?
No with normal wear. More issues with 2t when you lean out and or crack a rings. You should be good to go if your cylinder is in spec.
Does honing increase bore size?
Just running a hone through the cylinder doesn’t remove enough material to make a significant difference in bore diameter. There’s enough tolerance on the piston/rings to account for mild honing.
