Backup Generator

[BioHazard]

Did you check the cylinder face and bore with a magnet?

Henry

Yeah, same as the outside, kinda sticky but that's it. I did notice a very slight "rainbow" color in the cylinder, sorta like stainless steel that has been heated. I wonder what it is?

[billswan]

Try a spark test, if you have a die grinder put a stone in it and try grinding off some metal on one of the fins. If it was non ferrous  like aluminum or mangnesium their would be no sparks.

Of course if a magnet sticks I guess their would have to be some Iron in it, so of course their will be some sparks to one degree or another.

I believe pure stainless steel is non magnetic. And some lesser grades are magnetic.

You could use the spark test to compare the sparks to known metals.

Billswan

[Randybee1]

There are a lot of different grades of stainless steel. The "basic" stainless steel  (martinsitic) is magnetic, as you keep adding chromium/nickel you change the structure of the steel making it non magnetic           ( austenitic).
Being magnetic or nonmagnetic is not a reflection on the quality of the steel. Its more of a reflection on the end use of the product. More chromium and nickle increases the cost. I'm guessing that you have martensitic stainless steel, which is fine for the application it is used in.

Randy B

[Crofter]

I think the slight magnet draw is to the nickle which is part of the nicasil bore plating process. Nickle is quite magnetic. There are different plating processes and some seem to plate only the bore and manage to mask off the outside of the casting (aluminum here I bet). Others I have seen are shiny all over the outside and still others are left with a flat black dull surface. I have had my hands on quite a few stock and aftermarket chainsaw cylinders and that is what I have seen.

[cgwymp]

I think the slight magnet draw is to the nickle which is part of the nicasil bore plating process. Nickle is quite magnetic. There are different plating processes and some seem to plate only the bore and manage to mask off the outside of the casting (aluminum here I bet). Others I have seen are shiny all over the outside and still others are left with a flat black dull surface. I have had my hands on quite a few stock and aftermarket chainsaw cylinders and that is what I have seen.

If that's the case, then a magnet should stick well to the bore, yes? Should be an easy test to perform....

[Crofter]

I wouldnt predict it to stick well since the nikasil is only a few thousandth thick commonly and the bore also may be a chrome plating with the usual thin nickle plate that goes under chrome plating. In any case I bet a nickel it is an aluminum casting.

[cgwymp]

I wouldnt predict it to stick well since the nikasil is only a few thousandth thick commonly and the bore also may be a chrome plating with the usual thin nickle plate that goes under chrome plating. In any case I bet a nickel it is an aluminum casting.

But if the magnet will be attracted <i>through</i> the cylinder casing to the cylinder plating, shouldn't it stick much better to the plating itself (even if under thin chrome plating)?

[Crofter]

I wouldnt predict it to stick well since the nikasil is only a few thousandth thick commonly and the bore also may be a chrome plating with the usual thin nickle plate that goes under chrome plating. In any case I bet a nickel it is an aluminum casting.

But if the magnet will be attracted <i>through</i> the cylinder casing to the cylinder plating, shouldn't it stick much better to the plating itself (even if under thin chrome plating)?

From looking at the picture, I feel the shine on the entire casting is a thin flashing of nickle plating which  is slightly magnetic rather than the core material of the casting which is most likely aluminum. If it was cast iron it would be unquestionably  magnetic and obviously heavier. I dont think it is anything exotic but I havent had it in my hands either.

[mobile_bob]

the whole jug may be nickel plated, it would make sense to me that this would be the case
as it would be quicker and easier to just plate the whole darn thing rather than figure how to plate
the cylinder walls alone.

if the whole jug is plated, i would expect a mild magnetic attraction if done in nickel

i suppose one could drill a test hole in one of the fits, to see if curls of aluminum come up from the bit?

bob g

[BioHazard]

Hmmm...I guess I'll take a chunk out of one of those fins and see. I will say that in person, the color difference between the cylinder and the crankcase/head is much different than the pics look.

I'm just guessing here, but the casting on the cylinder is much rougher than the rest of the aluminum castings - they're either made in a different place or out of something different.

Stupid question - do they hone a cylinder after they plate it? Factory hone marks are clearly visible....

[mobile_bob]

yes they would hone it after the plating process i would think, reason being the rings have to have something
to wear into and seal.

mack and detroit liners were never plated,  but were induction hardened to near glass in hardness, afterwhich they
were honed.

it takes a very hard grit hone to cut into a hard surface and leave a crosshatch

bob g

[BioHazard]

After taking this thing apart I can't help but think how cool it would be if this engine was a little V twin. Probably wouldn't add more than 10lbs to the generator and you'd be looking at 2kw and probably less flicker. I've seen the RC guys make twins out of weedwackers. I can hear the EPA screaming now.....

[BioHazard]

I forgot to mention, I did find what look like two adjustment screws on the carb. I didn't really want to play with them, carbs aren't my thing....

I just had a crazy idea, I'll ask the MFG what it's made out of. 

[mobile_bob]

ask the manufacture?

where is he fun in that?



bob g

[BioHazard]

I finally got some info from the manufacturer today. The base units are only $49 each! CARB approval adds $10. This could be a typo but it says the recommended oil is SAE 10W/30.  Still have a few technical questions to ask them...