sleeves/hardness of bores

[abently]

Sam, can you post an approx diameter and length you need for the sleeve ? I try a couple places here and at least give you an idea of what the real cost should be. Automotive sleeves are about $50 if that for quality sleeves...

Maybe call up a couple go-kart places instead if you have no luck with the motorcycle crew ?

http://www.lasleeve.com/master.html (US based but shouldn't be to difficult to order it and get it shipped)

[Sam_Q]

I didnt think of seeing the go-kart guys but they use bigger bores and I thought they where already all two strokes with their rotax engines and the like?

I.D is 47.5mm however if I find another piston I can use up to 50mm.

O.D is irrelevant

I think I need anything 65mm or longer, so again just about anything, and I am happy to machine down a whole 4 stroke barrel to get what I want.

If you could make some enquires it would be really good and I would find it amazing if I get something for as little as $50. Would a car sleeve come in such a small size though?

[oldcorollas]

the first bike place I called just refered me to a custom sleeve place that wanted $300 just for a straight peice of pipe.

a straight piece of centrifugally cast cast iron???

not quite the same as a straight piece of pipe. (if it is cast iron)

[slow laser]

Sam, try using a aluminium barrel and see if High Performace Coatings can cermic coat it?

Thats what i did with my Pit bike, just no sleeve and VERY good oil maintenence. (makes 23rwhp at 13k.)

[Sam_Q]

a straight piece of centrifugally cast cast iron???

not quite the same as a straight piece of pipe. (if it is cast iron)

where do I get that? and wouldnt it have to be a certain grade of cast iron?


slow laser: did you check your bore wear over time? what did it cost you?

[slow laser]

couldnt remember how much it cost me, wear was fine although i had the piston friction coated with the dry film they have also, worked a treat, 3 months of 13k+ dirt bike riding and its still fine.

[abently]

http://www.darton-international.com/mat_spec.htm

Gives you the specs you should be trying to find in terms of raw material. (Centrifugally Cast Nodular Iron ASTM-A536, A-436 Centrifugally Cast Chromoly Class 50 or Centrifugally Cast Gray Iron ASTM-A48 Class 30)

I'll get back to you tomorrow night on what I find locally here. This material shouldn't be more then $50 especially for such a small bit.

[abently]

Okay, firstly after some reading >

http://www.efunda.com/processes/meta...ri_casting.cfm

The properties between Centrifugal casting and normal cast round rods is insignificant.

Call up local metal/steel merchants and ask for 4e (common) Cast iron rod. The cost should only be $20. I can buy it here (only in rod form for that size your after) and send it over if you want... but theres a guy on ebay that also sells offcuts > http://cgi.ebay.com.au/Cast-Iron-40-...1%7C240%3A1318

Hasn't got the size you want at the moment but more importantly check the properties listed and compare it to the other link I listed on the previous post. That's probably as close as your going to get and probably in all honesty good enough. If you call around your local suppliers just ask for either 4e cast iron rod or cast iron pipe, don't say centrifugal 'cause that only confuses people.

[oldcorollas]

Okay, firstly after some reading >

http://www.efunda.com/processes/meta...ri_casting.cfm

The properties between Centrifugal casting and normal cast round rods is insignificant.

the difference is in the grain structure and the grain orientation ie the size of the grains, and the orientation of the graphite flakes (for grey cast iron), or the size of the nodules in spheroidal graphite cast iron...
also, the centrifugally cast have more homgenous properties like expansion and strength, so when they heat up, they distort the bore less..

but for this case, maybe not so bad...

[abently]

Actually, your in luck > http://www.flocast.com.au/cent_iron.html

They are in Victoria and look like they've got 20mm ID and 50mm+ OD.

If the price difference is insignificant, then I think you have what you are looking for.

Grade 2P specs looks like what you need.

[abently]

the difference is in the grain structure and the grain orientation ie the size of the grains, and the orientation of the graphite flakes (for grey cast iron), or the size of the nodules in spheroidal graphite cast iron...
also, the centrifugally cast have more homgenous properties like expansion and strength, so when they heat up, they distort the bore less..

but for this case, maybe not so bad...

Yeah I agree there is a worthwhile difference but for this case I think, it shouldn't be that significant. Though if the price is right, you may as well do it right the first time considering the machining time.

[GT1978]

Is there any significant difference with 2 stroke and 4 stroke, other than the ports? I had a cylinder sleeved in one of my engines and it was only $100 for the one cylinder. Surely it would be easier to just take it to an engine machine shop and have them fit a sleeve for you. Admittantlt that price is now 5 or so years old but surely it could still be done for around $150?


Glen

[Sam_Q]

thanks heaps for the help absently and I would be going to buy that piece had it not be for the fact that I think I have found something to use. I will keep it for future referance anyway. I have had someone at my night school who works at a motorbike shop find a 80cc engine that has the right bore diameter. If I get it off him I will heat up the barrel, press it out and then machine it to suit.

GT1978: I was quoted around $300 just for a basic sleeve, stuff that for a joke


Well here is another problem for you guys, I would also like to make a con-rod but the needle bearings on a two stroke big and little end roll directly on the inside of the rod. Both ends have a 12mm pin and I was thinking of using tool steel to make something that had a 12mm inner, a 13mm outer, case harden it and then press it into a rod of my own construction. Any problems with this idea? I think I might post it on that engineering tips website

[abently]

Well here is another problem for you guys, I would also like to make a con-rod but the needle bearings on a two stroke big and little end roll directly on the inside of the rod. Both ends have a 12mm pin and I was thinking of using tool steel to make something that had a 12mm inner, a 13mm outer, case harden it and then press it into a rod of my own construction. Any problems with this idea? I think I might post it on that engineering tips website

Can you re-phrase that.... you want to make your own conrod and fit needle bearings into it right ?

You can buy needle bearings off the shelf and probably in the size you need if you search long and hard enough. I would recommend getting needle bearings in the size appropriate to the load it will have to displace rather then whatever fits best. There will be longevity issues... but yeah, post the idea on eng-tips.com. I'm sure someone there will be able to direct you to some r&d pages on similar trials and you might be able to intergrate their method into your own design.

[Sam_Q]

well the needle bearings directly roll on the inside of the con-rod big end, I want to make my own rod thats longer but i cant harden it when its part of a rod because its too risky. So I was thinking of making a con-rod out of high tensile steel and then pushing a case hardened shell into the big end of the rod to give it something hard to roll on. The catch is and the reason why I cany buy something off the shelf is I have shit all room between the rod and the crankcase. So I cant put a big shell in there and have enough room to have it fit in anymore. That is why I was thinking of just having a 0.5mm thick wall hardened section I push in and thats it. I also had the idea earlier on if I could possibly grab the thing i a lathe I could possibly chop my existing rod and machine a barrel shape out of each end and push that into my own rod. Yes I know I am doing a poor job explaining it