Fixing Junk, Aftermarket cylinders

[Paul Fithian]

Super cool, thanks for posting this!

 

[Al Smith]

IMO plating was used as a less expensive method of making cylinders .It might have worked for small engines like a chainsaw but so far has never worked well on automotive engines . Then again it all goes back to the oil which is the life blood of an engine 2 cycle,4 cycle, steam or turbine .All that said it's all about formed opinions which everybody has .

 

[farminkarman]

IMO plating was used as a less expensive method of making cylinders .It might have worked for small engines like a chainsaw but so far has never worked well on automotive engines . Then again it all goes back to the oil which is the life blood of an engine 2 cycle,4 cycle, steam or turbine .All that said it's all about formed opinions which everybody has .

In a 4-stroke engine where you want the rings to rotate during engine operation, cast iron is hard to beat for a cylinder surface. In a 2-stroke with pinned rings, cross-hatch isn’t needed, and thus the cylinder wall can be very hard & smooth like nikasil or chrome. If you tried to use nikasil on a 4-stroke engine, and had the cross-hatch needed to cause ring rotation, I believe the rings would wear out very fast.

 

[Al Smith]

On that just for reference Briggs and Stratton on the old flat head 8 HP engines had three options .The lowest quality was plated cylinder using just the aluminum case as bushings .Next up the IC iron cylinder with brass bushings .Then comes the IC industrial .It had bearings instead of bushings .The pistons , rods etc. interchanged .

 

[Al Smith]

--here ya go---
Cross-hatching is a process of creating a pattern of intersecting lines on the surface of the cylinder wall. The primary purpose of cross-hatching is to create a surface that can retain oil and provide lubrication to the piston rings 123. The angle of the cross-hatch determines how much oil is retained on the cylinder wall. If the angle is too horizontal, the rings could never seat, always floating over an oil film. If it’s too steep, the oil all drains off, and the rings and cylinder wall erode away quickly 1.

The cross-hatch pattern also helps to break in the piston rings by providing a surface for them to wear against. The grooves created by cross-hatching help to hold oil and distribute it evenly across the cylinder wall, which helps to reduce friction and wear on the piston rings 23.

In summary, cross-hatching is an essential process in engine cylinder preparation as it helps to retain oil on the cylinder wall and provides a surface for piston rings to wear against, reducing friction and wear on them.

 

[NateSaw]

IMO plating was used as a less expensive method of making cylinders .It might have worked for small engines like a chainsaw but so far has never worked well on automotive engines . Then again it all goes back to the oil which is the life blood of an engine 2 cycle,4 cycle, steam or turbine .All that said it's all about formed opinions which everybody has .

I'd always wondered if it were a weight issue. I mean, these saw manufacturers have shaved every gram, within reason. I realize sleeving a cylinder has its labors... But I wonder what the manufacturers cost offsets really are.. I mean plating is quite the process. In fact, I think if hyway used sleeves they'd be able to get that right. I think it's quite difficult to achieve proper adhesion, and most likely requires a surgical environment and special equipment... they have to hone the bore after plating anyway. I feel like holding a tolerance for the piston, isn't too far off from holding a tolerance for a sleeve. Or, perhaps they're just happy to be within 0.005", rather than 0.0005". I've pondered all this before. What IS the weight difference @Red97 ?

 

[mrxlh]

In a 4-stroke engine where you want the rings to rotate during engine operation, cast iron is hard to beat for a cylinder surface. In a 2-stroke with pinned rings, cross-hatch isn’t needed, and thus the cylinder wall can be very hard & smooth like nikasil or chrome. If you tried to use nikasil on a 4-stroke engine, and had the cross-hatch needed to cause ring rotation, I believe the rings would wear out very fast.

All Can Am, Polaris 4 strokes are nikasil. Yamaha SHO and Mercury Verado outboards are also Nikasil.

 

[farminkarman]

All Can Am, Polaris 4 strokes are nikasil. Yamaha SHO and Mercury Verado outboards are also Nikasil.

I guess my thinking is wrong

 

[Ketchup]

The angle of the cross-hatch determines how much oil is retained on the cylinder wall. If the angle is too horizontal, the rings could never seat, always floating over an oil film.

Any idea what the optimal angle range is?

 

[mrxlh]

I guess my thinking is wrong

Not necessarily, both 2 and 4 stroke cylinders have cross hatch in them to hold oil, the cross hatch does turn the rings as well.

Any idea what the optimal angle range is?

30 degrees