Wossner Piston

http://www.forgedpistons.co.uk/Products/i/9011top.JPG

Some people have commented on how close the valve reliefs are to the edge of the piston. There is only a wafer thin piece of alloy metal left. Maybe the photo is not accurate? Any comments?

These seem to be a good deal, they are popular. Is that because they are cheap or just avaiable? Is there anything else avaiable for about the same price?

I would buy a set if I can get them ex VAT. Is there any way I can get them ex VAT but delivered to a UK address? A friend is traveling back to NZ soon so I could save on freight and GST at this end. If I have to pay VAT and or postage I will no doubt have to pay GST also at this end. It would not be worth it after that. Cheers!

a better photo of my pistons 85.6mm http://fos.prd.uth.gr/vas/coupe/internals/wossner_top.jpg

does look a bit thin, I guess it is OK, well mine surely is and it's done 11K already

Couldn't find anything similarly priced from a known company (I'm not talking noname odd things...)
Ask Paul, at a point I had given him prices for a set shipped to NZ and prices weren't bad.

cheers

V.

V

I had a look back to mt PM's from you but nothing there apart from a guy who is now doesn't do them.

Can you email me the link again and I will pass it on

Cheers

I have wossners 83mm got them from pec (performance engine products) or ebay?? £600.. pic

Paul,

you are right, guy stopped doing them. I do remember they were 600euro (for 4) with rings/pins/clips.
Just shop around

V.

Sorry mate, I should have said I was refering to 16VT pistons. However the valve cuts are very close to the edge on them too. The valve cuts on both 16V and 20V Wossners look a lot deeper than OE, why?

Does anyone know the dish volume?

To allow them to be fitted with high lift cams.

To allow them to be fitted with high lift cams.

Ah 16vt sorry,
So in order to fit high lift cams you have to change pistons? learn something new every day

It would depend on the profile because you can fit "high lift" cams with standard pistons.

Er no, if you fit higher lift cams with existing standard pistons you would deepen the valve cutouts.

If you were fitting forged pistons then you would presumably also be fitting a higher lift cam no? So the valve cut out is already deeper. For sure, it's not the correct way to do it, really you would start with a blank piston and flycut the cut-outs to suit, but the Wossner piston is an off-the-shelf item so one size fits all to keep it simple no doubt.

OE pistons are not avaiable anymore so aftermarket, usually forged is the only option.

It depends on how much 'higher lift' you go, how much has been skimmed from the head, how deep the valves are in the seats, how thick the head gasket is etc.
Every situation is different, I had to deepen them on mine otherwise I would have been left with a nice set of bent valves....

Ok, http://www.forgedpistons.co.uk will not export anymore.

Also Wossner list the dome volume at -38.5cc! Is that a mistake you think? Because if it isn't compression will be more like 7:1 not 8:1. Even with their 1mm gasket and a shaved block etc its nowhere near 8:1.

Is it worth changing the OE conrods for forged conrods? how much power can the OE conrods take?

Are this pistons reliable? They seem to be a bit cheap...

ohh, and another one, my engine is running perfectly, i'm thinking of fitting forged pistons only with the purpose of getting the engine running more realiably, what piston size is recomended? no need to bore the cilynders i guess...

waste of money

If your engine is running perfectly, then it must also be running reliably, so why spend money with the sole aim of making it do what its already doing?

As far as I can remember, there have been no instances of piston failure on unmodded cars that were running properly. Any failure has been down to external influence, such as oil issues (lack of oil, wrong grade, infrequent changes) or poor ignition / fuelling

By all means fit forged pistons to allow you to tune it more safely / reliably.

I honestly don't know, after selling them on I haven't got any standard pistons to check what they are either.

I don't think it's true that you can't get standard pistons anymore though, but then again, why would you when forged are now so cheap...

Nigel who said the car wasn't modded?? it as a GT28RS, FMIC with SIP, 3'' Downpipe and exaust, walbro, all the beginner modds... I just said it was running perfectly and i'm thinking on fitting forged internals before something bad happens...

84.0 are avaiable but oversize are NLA. If I could buy oversize I would. Forged are not easy to get in NZ.

Pretender - sorry, my mistake.

However, as long as your ignition and fuelling is OK and you're not running silly boost, there's still no reason to change to forged pistons. Ringland failure (melting of the edge of the piston) is probably the most common cause of piston failure and is usually cause by excessive boost, causing combustion below the piston crown. This is probably (closely) followed by detonation-induced failure, where the edge of the piston breaks away. Finally, there's simple melting of the piston, probably caused by way too much boost (high chargetemps, lean mixture or excessive EGT)

All of the above can be excluded if you say your car is running perfectly.

You should only be considering forged pistons if you intend to tune the car past the capabilities of the OE pistons. Generally, a well-intercooled and well-fuelled Coupe running a GT28RS at below 1.3 - 1.4 bar peak will be reliable on OE pistons. Save your money until you NEED the pistons to get higher performance.

And what can be considered going past the OE pistons capabilities? Pistons and conrods... what BHP can they take? Even if the car is well tuned...

We are talking about 16Vt's here so 5potters create your own wossner topic!!

Wössner pistons look like the real thing Scuderia, they won't melt

The limits have nothing to do with BHP

I've posted that in bold because I see the question you asked and wrongly answered every week on this and other forums.
It's down to RPM and like Nigel rightly said, if your motor is mapped properly and your intake charge is nice and cool then you can get good bhp on the standard set up.
I'm pushing over 360bhp on standard internals and it holds together, I'm not saying it is the correct way to do it and wouldn't really disagree with anyone who says that they need uprating, after all these bits in my car are over 16yrs old now, but have only covered about 60,000kms.

It all depends on what you want from the car, If you are going to keep it for some time and push it's limits then start from a good base with a set of forged rods, pistons and a new eight weight crank, stick on a gasflowed head and then the outer bits can be bolted on afterwards when ever you can afford or feel the need to take another step upwards on the power ladder.
Start as you mean to go on.

Edit: Sorry, just read your sig, I'm posting from my own point of view as a 16vt owner....