Ask an Engineer

[ducatilover]

Which is why I said earlier i wouldn't give much for the cush drive in the Kawa clutch's chances of survival...they don't have a good reputation as standard.

It's a 22 year old shit heap, so it's going to explode anyway (incidentally, my 2nd gear is mint. Seems to be the only one ever to not run second, it never will with my nana riding...)

I'm hoping the one large pulse won't be too hurtful.
I could always experiment with the ZZR400K cams, but it'll take some huge mongrel shims to pull the clearances to spec...
Unless I have a set of 400 buckets still, but I'm pretty certain the 600 ran bigger springs.

[Canis G.]

It also cold-welds to itself, you have trouble with nuts siezing onto bolts with SS unless you use the right lubricants. It's also not as strong, (generally) as most modern fasteners materials. Having said that I've never been happy with the common OE practice of using cadnium plated screws in alloy cases, and I've used SS replacements before now.

Edit: good thread lubricant and general all-round corrosion preventitive is Prolan, (lanolin) available from most fasteners suppliers.

So given issues of strength (how much weaker than equivalent sized HT steel?) and corrosion (I assuming galvanic - what's in the alloy that reacts with ali? and what works as the electrolyte?) could you use stainless studs with plain steel nuts to prevent the seizing?

I hear what you are saying about Prolan - thanks for the tip.

Cheers

[pete-blen]

So given issues of strength (how much weaker than equivalent sized HT steel?) and corrosion (I assuming galvanic - what's in the alloy that reacts with ali? and what works as the electrolyte?) could you use stainless studs with plain steel nuts to prevent the seizing?

I hear what you are saying about Prolan - thanks for the tip.

Cheers

If you are putting stainless bolts in alloy use "lanocote" it stops seizeing & electrolysis
stainless & alloy are the two worst metals to put togeather..
Over tighting stainless bolts & nuts can cause the stainless to pick up & lock togeather..
DON"T use a stainless bolt in alloy for a earth strap ..

[Ocean1]

So given issues of strength (how much weaker than equivalent sized HT steel?) and corrosion (I assuming galvanic - what's in the alloy that reacts with ali? and what works as the electrolyte?) could you use stainless studs with plain steel nuts to prevent the seizing?

I hear what you are saying about Prolan - thanks for the tip.

Cheers

The corrosion is usually galvanic, not nescessarily electrolytic, it's enough that the metals are in contact and significantly seperated on the table.

Without looking it up I'd say stainless's tensile performance is typically a fair bit better than mild steel and maybe 80% of an 8.8 fastener. It varies quite a bit as it work hardens and the production process, (particularly rolled threads) often produces bolts a bit stronger than normal.

As for mixing nuts/stud material, stainless in close contact with ferrous oxide behaves exactly like ferrous materials. It rusts.

Prolan not only lubricates and excludes atmospheric oxygen and other chemicals, it actually prevents galvanic corrosion. No idea why. A friend is a very senior chemical engineer, he's got no idea either.

[koba]

No idea why. A friend is a very senior chemical engineer, he's got no idea either.

Cool. I like that.

[husaberg]

Cool. I like that.

He'd still charge you for the report though

[Ocean1]

He'd still charge you for the report though

Bit of a specialist, can tell you anything you want to know about materials. Once fitted a radio to his car, bit of a tight fit and it stuck out from the dash a bit but he was dead proud of it. I got a call next morning, he'd started the car to go to work and... couldn't get first gear.

[koba]

Bit of a specialist, can tell you anything you want to know about materials. Once fitted a radio to his car, bit of a tight fit and it stuck out from the dash a bit but he was dead proud of it. I got a call next morning, he'd started the car to go to work and... couldn't get first gear.

Hammer?

[speights_bud]

Year one of Apprentiship paperwork, don't fit steel to alloy where vibrations occur, something about galvanic corrosion as mentioned earlier... or something... its too late to think hard. example was aluminium tv aerial on a tin roof blowing in the wind.

[Ocean1]

Year one of Apprentiship paperwork, don't fit steel to alloy where vibrations occur, something about galvanic corrosion as mentioned earlier...

Generally try to avoid having materials from too far apart on this list in hard contact:

Active (Anodic)

Magnesium
Mg alloy AZ-31B
Mg alloy HK-31A
Zinc (hot-dip, die cast, or plated)
Beryllium (hot pressed)
Al 7072 clad on 7075
Al 2014-T3
Al 1160-H14
Al 7079-T6
Cadmium (plated)
Uranium
Al 218 (die cast)
Al 5052-0
Al 5052-H12
Al 5456-0, H353
Al 5052-H32
Al 1100-0
Al 3003-H25
Al 6061-T6
Al A360 (die cast)
Al 7075-T6
Al 6061-0
Indium
Al 2014-0
Al 2024-T4
Al 5052-H16
Tin (plated)
Stainless steel 430 (active)
Lead
Steel 1010
Iron (cast)
Stainless steel 410 (active)
Copper (plated, cast, or wrought)
Nickel (plated)
Chromium (Plated)
Tantalum
AM350 (active)
Stainless steel 310 (active)
Stainless steel 301 (active)
Stainless steel 304 (active)
Stainless steel 430 (active)
Stainless steel 410 (active)
Stainless steel 17-7PH (active)
Tungsten
Niobium (columbium) 1% Zr
Brass, Yellow, 268
Uranium 8% Mo.
Brass, Naval, 464
Yellow Brass
Muntz Metal 280
Brass (plated)
Nickel-silver (18% Ni)
Stainless steel 316L (active)
Bronze 220
Copper 110
Red Brass
Stainless steel 347 (active)
Molybdenum, Commercial pure
Copper-nickel 715
Admiralty brass
Stainless steel 202 (active)
Bronze, Phosphor 534 (B-1)
Monel 400
Stainless steel 201 (active)
Carpenter 20 (active)
Stainless steel 321 (active)
Stainless steel 316 (active)
Stainless steel 309 (active)
Stainless steel 17-7PH (passive)
Silicone Bronze 655
Stainless steel 304 (passive)
Stainless steel 301 (passive)
Stainless steel 321 (passive)
Stainless steel 201 (passive)
Stainless steel 286 (passive)
Stainless steel 316L (passive)
AM355 (active)
Stainless steel 202 (passive)
Carpenter 20 (passive)
AM355 (passive)
A286 (passive)
Titanium 5A1, 2.5 Sn
Titanium 13V, 11Cr, 3Al (annealed)
Titanium 6Al, 4V (solution treated and aged)
Titanium 6Al, 4V (anneal)
Titanium 8Mn
Titanium 13V, 11Cr 3Al (solution heat treated and aged)
Titanium 75A
AM350 (passive)
Silver
Gold
Graphite

End - Noble (Less Active, Cathodic)

Note that the terms "stainless" and "alluminium" are very broad descriptions.


The vibration thing may be more to do with what's called fretting corrosion, where the surfaces actually rub together, it produces fairly distinct corrosion patterns. It's not unheard of on headstock and swingarm bearing surfaces.

[Canis G.]

Thanks for your time and answers Ocean (and others) - much appreciated. Guess I will stick to steel studs and prolan.

[husaberg]

iron sleeves in Two strokes
Niksil is a much better option i realise this of course.

The early japanese engines have cast in iron sleves right.IE MB100's RD250's/400 plus many others

The sleeves appear to be corrugated i guess to aid surface area and to make sure they don't move.

With a pressed in interference fit iron sleeve and a aluminum cylinder the heat transfer is not so good.
A few people have mentioned carbon builds up behind them further impeding the heat transfer.

Has anyone ever done a thread in sleeves where a thread would be formed (on the sleeve and bore)and the sleeve held in this way?
putting aside the difficulty lining up the ports (i think this would be no worse certainly less fraught with a misalignment or jam)

Would the increased surface area aid transfer of heat is it achievable, would it be cost effective?

As an aside i see the new Yamaha 150 or 125 four stroke road bike has a non coated alloy cylinder with i believe a very high silicon content.

[Kickaha]

With a pressed in interference fit sleeve and a aluminum cylinder the heat transfer is not so good.

You mean with a cast sleeve? would an alloy sleeve and nicasil be any better? close to $1000 when I asked about it being done

[husaberg]

You mean with a cast sleeve? would an alloy sleeve and nicasil be any better? close to $1000 when I asked about it being done

yes I mean with a cast iron sleeve.
And yes i think a aluminum alloy sleeve coated would be preferable but bloody costly.

Sometimes a sleeve is unavoidable like when attempting to make a smaller bore engine.

I actually wondered about filling the entire cylinder with alloy weld and then machining and plating, but was laughed at for the suggestion (note that's how some cylinders are repaired)

[Grumph]

yes I mean with a cast iron sleeve.
And yes i think a aluminum alloy sleeve coated would be preferable but bloody costly.

Sometimes a sleeve is unavoidable like when attempting to make a smaller bore engine.

I actually wondered about filling the entire cylinder with alloy weld and then machining and plating, but was laughed at for the suggestion (note that's how some cylinders are repaired)

There's been a lot of things tried - read the old books.

The neatest one I know of was Herman Meier when he was developing the Royal Enfield 250. He did a chrome plated alloy sleeve which was of a different alloy to the cast barrel - get the right interference fit and temperature differential and it dropped out. Slip fit at room temp but stuck fast when hot....easy to change things.

Most continental and british sleeved cylinders are a plain parallel wall sleeve. Unfortunately most Jap cylinders since 1970 have been odd shaped liners cast in.....