Cast or forged?
Turbo Mini Forums

I found the pictures for the zetec oil sqiurters on mini williams site.any one know the part number to save a lot of explaining up the ford garage!!,and which way is best to mount siamesed or singular ??

Metro turbo weekend driver,Mini turbo in the making again!

http://www.turbominis.co.uk/forums/index.php?p=vt&tid=1055

http://www.netsnapshot.com/pcw/b?KEY=1&ACCOUNT=4541
(my first instalation).

The round ones make it much easier to install...

Incidentally, Those links were found by using the following feature on the TM forum board

http://www.minispares.com/Product.aspx?pid=35484

Are these the pistons you use TurboDave? Do you increase the cc of the piston bowl from 6cc? if so what do you change it to?

here is the installtion of the jest in my engine, thanks again for dave for the engine build, food, beer, and looking at lots of women.

Team Racing

I machined the dish to 11cc. These sit a little further down the bore than the original 'turbo' piston, hence you don't machine it any further.
As it's a direct copy of the turbo piston, this is pretty safe (std turbo piston 12cc).

how about ceramic coating the tops of the cast pistons? any opinions on that?

Not for me thanks - I'm not building a WRC car.

only looiking to go up the strip in 13.7 sec , not re enter the earths atomsphere

Everyone knows that instructions only have to be read if the thing doesn't work....

Metro turbo weekend driver,Mini turbo in the making again!

Ceramic coating is pretty thin and is usually applied to the crown only. There is another coating that is applied to the skirt to minimize friction but that is another issue. It does not affect the piston size or shape.

There was an interesting article in Hot Rod or Popular Hot Rodding where they applied ceramic coating to a piston crown and the attacked the piston with a torch. It held something like 90 seconds before a hole appeared. Furthermore, the coating held the soft piston top intact even if the alloy was already molten. Just for reference, uncoated piston did not last that long... This is not a real life situation since in an engine you also have cylinder pressure to deal with (definitely wont last that long) but gives you an idea that these coatings so work and are infact used in production engines as well, e.g the new Hemi engine from Chrysler.

As for cast vs. forged, I have cast Omegas (73,5mm/11 cc), no spray jets and have so far been happy with them.

jukka

I'd go for the cast. The minispares items are basically the metro AE item.

A set of forged items may be a little lighter, but what major advantage is this going to be to you. As Dave said you aint going to be revving it that highly where the extra weight of the piston is going to be an issue.

I've gone the route of ceramic coating my crowns. It has other advantages in addition to lowering the undercrown temperature.

I'm still not to sure about the effectivness of the oil jets. I mean i can see them having a great effect in something like a dry sumped motor. But as our dear old A series has its gearbox in its bowls, surely this must fling loads of oil around ???? Anybody got any actual data on this or a block with a nice viewing window ??? lol

If you look at it that way it 'MIGHT' be ok for pistons 3&4, but 2 might not get a lot of spray, and i'm sure the speedo drive won't help #1 piston too much!

I'm not against ceramic coating, and if i was building what i'd consider to be a high spec engine, i'd probably get round to using it. I've got other things to be pursuing next however!

Seems like a fair point with regards to pistions however there are other areas in which ceramic coating could help 99% of turbo minis. I for one will be having the pistons and the exhaust coated. The 2nd mainly to keep the heat in the exhaust and away from the rest of the engine bay.

Just me 2p worth

Edited by BA_Lordflash on 16th Mar, 2005.