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Tuning turbo time!

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Tuning turbo time!

Did a little work on my engine today.
Fitted the pistons but during fitment decided I never liked one so machined another piston.

thought it would be interesting to see how strong the piston crown is heated the piston up quite a bit then hit the middle with a punch... first hit displaced a bit of alloy but no deformation on the underside. left a pit about half a mm deep.
hit it in the same place again and popped a small hole in it.

defiantly look strong enough to me.


torqued up the con rods/crank, refitted seal plate and oil pump
 
If det can crack them in a NA engine, they're probably not -- this is silly -- if they're strong enough why did the factory replace them? This is FIAT we're talking about -- the guys who replace fabricated tubular wishbones with forged ones to save a couple of lira, who replaced a chain driven cam (and steering pump) with a belt driven one 'cos it was cheaper (and maybe quieter) and the perfectly good pulley operated handbrake on the Cinq with the stupid peice of bent metal on the Sei.........

You really can't tell much about the molecular level of an alloy by bashing it wiv an ammer! I'd not expect to break the cheapest cast piston by repeatedly crashing a hammer down on the crown......... Det is something else -- a truly massive force.
 
craigb244 said:
thought it would be interesting to see how strong the piston crown is heated the piston up quite a bit then hit the middle with a punch... first hit displaced a bit of alloy but no deformation on the underside. left a pit about half a mm deep.
hit it in the same place again and popped a small hole in it.

defiantly look strong enough to me.
Click to expand...

That is the least scientific test for piston strength I have ever read.

OK, truth is I havent read many, but it still sounds like a waste of time :p

I agree with fingers, it doesnt sound very strong to me either.
 
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lol it was a waste of time but the piston was scrap. I was just going to drill a hole to get a very accurate thickness measurement so thought I might as well smack it with a fine punch to see how "hard" it is. never ment for it to sound like a true test. :)

fingers. .. thanks for your concern... I'm just doing this to try it. I have nothing to loose just my time. I've not seen any cracked pistons but I very much dobut the crown cracks as its very thick. my guess is they crack from the ring lands to squish band which I've not removed metal from.

you must be slighty intrested in my attempt ;-)
 
Todger182 said:
Want me to take some photo's of these demolished pistons I have? :devil:

Thanks

X
Click to expand...

go for it... I found some photos from a person with nos and they had broke from the ring land.

munkel you edited your post when i replied. dont get me wrong they are strong. I hit the thinnest part of the piston with a very fine and sharp punch very hard with a lump hammer. the first hit never did much and the second harder hit caused the alloy to crack a hole out the bottom making a cone shape in the back.

the thinnest part of the crown (where i punched the hole) is 5mm thick... more then enough.

I did a lot of research before doing them anyway and found it done on other cars (500bhp + beemers) with much thinner crowns and much much larger pistons where the forces would be much higher on the given area.

from what ive seen I have quite a lot of faith in them but only time will tell (y)

Craig
 
fingers99 said:
%mm is thick enough given decent material. That'd be my doubt.
Click to expand...

guess we will have to wait and see... altho today my dad went to a local place to pick some parts up for hes gaffers rally car.
they make con rods on a cnc from blocks of billet. £70 each and to your spec. :cool:
Going to see how much they will make pistons for if needed.


anyway...
fitted all the valves painted block and alloy sump extension.

finished mounting the fuel rail... looks perfect. the rail is fitted upside down so the pipes come from the other side and gives me the clearance i needed for the throttle body
the plastic manifold rests just on the fuel pressure regulator :eek:
 

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Looking good. If you could spec the material, machined rods could be almost as good as forged H beam ones.

One thing I've toyed with mentally is having the TB on the opposite side allowing (shift the positions of the rad and intercooler) a better path for the inlet, through the driver side inner wing and back in again. At the top there's probably enough space (room on the passenger side for the charcoal cannister on Seis).
 
fingers99 said:
Looking good. If you could spec the material, machined rods could be almost as good as forged H beam ones.

One thing I've toyed with mentally is having the TB on the opposite side allowing (shift the positions of the rad and intercooler) a better path for the inlet, through the driver side inner wing and back in again. At the top there's probably enough space (room on the passenger side for the charcoal cannister on Seis).
Click to expand...

Im not interested in the rods but am in pistons if they are cheap enough. my dad said they are family run and make stuff for F1 car engines (cranks) so defiantly know what they are doing.


it wouldnt be to hard to move the TB to the other side on the 16valve.

when i fit the 16valve i do want to change the layout a lot. Im thinking of moving the rad to the other side as its away from the hot exhaust and less restriction behind it

not sure about intercooler. best bet would be a charge cooler above the gearbox with a small radiator where the old one was
 
I don't understand something, are you removing the turbo and putting a 16v engine (1.2?) or will turbo it too ? :confused:
 
Very good :D

So, you was running the stock 16v pistons like lower compression solution, and now you're machinig them or you're getting other pistons?

I was thinking also about making my 1.2 turbo, low boost like emma for example, 0,3 bar 95-100 hp isn't bad, and it should be reliable without opening the engine, right? What's your opinion about the low boost solutions for daily driving (sometimes fast , and sometimes slow, with long total wide open runs too).
 
I have the 8v ;) Punto 75, 1995 337 000 km :D (engine change and rebuild at 280 000).

So it should be good for a low boost configuration.

For the high boost I don't know which way is better for reduce compression, machining the head, if possibile (not become to thin), machining pistons seems no good (too thin), 16v pistons or decomp plate.
 
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went to a engine builders yesterday to pick up my mates head from been skimmed.
He knows hes fiats it seems so asked about pistons and lower compression.

he reckons my machined pistons will be spot on (hes machined pistons the same way on loads of turbo conversion engines over the years)

Bit of a confidence boost.

need to crack on with my manifold...
 
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