125cc Sportsbikes Forum banner
1 - 20 of 31 Posts

·
Does not know Everything !
Joined
·
14,526 Posts
Are new engine components such as pistons and cylinders heat treated before sale ?

I'm thinking this would allow the materials to expand without danger of friction altering there shape, then letting them cool slowly (annealing ?!?) to take there final form.

Anybody know about this or tried it ?

I heat cycle new engine components but i am thinking of shoving them in an oven for a while first.

Do pistons require either annealing (making them softer and more ductile) or age hardening (making them harder and less ductile).

Is this even required ?
 

·
Registered
Joined
·
748 Posts
AFAIK, most are not heat treated, which is why people oval their pistons and bores so easily.

I'd say "suck it and see". BMW used to leave their racing engines outside the factory in the wind rain ice and snow to "cure". The temperature and humidity changes would gradually work the stresses out of the metal.

If i were you, i'd contact a metallurgist and have a chinwag, or maybe an engine expert such as Mr Stephens.

To be honest though, i don't think it's woth the hassle. Any gains aren't really going to be worth it, as the gains themselves (if any) will not be particularly great im

Jack
 

·
Does not know Everything !
Joined
·
14,526 Posts
Im thinking relaibilty and ease of run in to be honest, i'm not after making it faster.
 

·
Registered
Joined
·
385 Posts
it makes sence, but if you where to do it, id personally put they piston in the cylinder and bolt on the cylinder head too so that is they do "take their final form" all of the relevent parts would do it together and have the same "final form"

but make sure the piston is facing the correct way, or you might find it very dificalt to get the parts on the gear box


keep us posted, would be interesting to see it anything dose change
just take loads of measurments before and after

Have Fun
 

·
Registered
Joined
·
3,916 Posts
This is the whole point of heat cycling an engine before you actually ride it.

If you?re interested to see how much the parts need it, get two pistons of the same make and model. Measure them and put them in an oven at 200 degrees. Then measure them and compare the differences. Allow to cool and repeat a few times.

The new piston should reduce it?s expansion as it cycles a few times.

Not sure *how* much, but every bit counts to destroying a new engine on startup.

In short, fit new parts but heat cycle the engine before riding.
 

·
125cc Sportsbikes God
Joined
·
12,087 Posts
I'd say "suck it and see". BMW used to leave their racing engines outside the factory in the wind rain ice and snow to "cure". The temperature and humidity changes would gradually work the stresses out of the
iirc this was done with the crank casings for the 1400 turbo f1 car they had, casings where taken from old road cars that had done some serious millage iirc

think it was peter ham one of the lecturers at college that told me that, either way they made some serious power from the cc!
 

·
Does not know Everything !
Joined
·
14,526 Posts
Discussion Starter · #7 ·
I was thinking of oven cooking my next piston, would probably be a good idea with the rings as well.........
 

·
Does not know Everything !
Joined
·
14,526 Posts
Discussion Starter · #9 ·
Would you need to include the cylinder ?

I would have thought the nikosil coating process would require substantial heat ?
 

·
Does not know Everything !
Joined
·
14,526 Posts
Discussion Starter · #11 ·
Ah, i thought they might expand too much and wear unevenly in places making them less effective.
 

·
2 Strokes And I'm Happy
Joined
·
7,063 Posts
wouldnt bother doing it at all. just heat cycle it after you rebuild it, thats all thats needed.
 

·
Registered
Joined
·
656 Posts
Can't really see that by sticking your parts into an oven for a couple of hours at 250C would make much of a difference (though I'm not gonna say it deffo won't). Top of the piston is subjected to peak temps well in excess of 650C during combustion (if my memory serves me right), so it would take some serious improvements in performance to prove to me it makes that much of a difference.

Not saying it won't make a difference but it would require some effort to prove it does!

Knock yourself out, but just don't let the missus catch you baking a piston alongside the sunday roast!
 

·
Does not know Everything !
Joined
·
14,526 Posts
Discussion Starter · #14 ·
lol.

Apparently the process of heating and reheating a piece of metal stops it expanding unevenly, something i think would be very important during a break in period.

It alters the crystaline structure of the metal making it more uniform i think, form the smidge of reading i have done.

Anybody want another yorkshire piston ? lol
 

·
Registered
Joined
·
331 Posts
You need to run it in properly on the bike.

In the oven, the piston won't be moving. While the point of heat-treating is to slowly work out the inconsistencies in the metal, it's also to seat the rings properly to the cylinder walls.
 

·
Wheelies on peds with no gear = win
Joined
·
5,960 Posts
Interesting thread. Bacon boi you did you ever give it a try?
 

·
Wheelies on peds with no gear = win
Joined
·
5,960 Posts
he could do them at the same time as he oven bakes his bacon pizza
How long does the bacon pizza take to cook? Same time as a bacon poptart?
 
1 - 20 of 31 Posts
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top