Pistons and rods

[z3i]

Whipped my sump of the other day to change the gasket and sort a leak (turned out to be PCV breather anyway)
Whilst i was there i had a peak at my Pistons and noticed the bottom was machined flat and they had 1245 xx77 stamped on them, as well as some writing but i couldnt see it as the gudgeon pin was in the way
Standard g40 size and bore is 1272 and a 75mm bore, would this have any effect on the compression ratio? and cause pinking?

On the base of the rods was stamped 66 with and underscore beneath it. are these standard?

the guy who sold me the car must have not know much as his words were "nearly standard" since then ive found its got a GT manifold, PSD full blend PSD camshaft, paddle clutch, forged pistions and potentially rods, ported throttle.
havnt had the head of to check for any work there
who would go through all that work and fit a standard exhaust/downpipe and standard injectors?
Many thanks Taylor

[metz]

Could they be these?
http://www.docstoc.com/docs/document-preview.aspx?doc_id=37622578

[z3i]

Possibly, got any pics of the underside? mine is machined flat where the gudgeon pin goes through. whereas most ive seen have cast marks

the compression ratio has been increased according to those grids
thanks for putting that up, might get into contact with them

[z3i]

Could they be these?
http://www.docstoc.com/docs/document-preview.aspx?doc_id=37622578

just realised that number on the left is the part number! so these definitely are the pistons i have!
thanks bud!
well this may explain my pinking then, accralite compression ratio is 9:0:1 and standard is 8:0:1
any other benefits of having these?

[dub-disaster]

yea, they wont melt!

[Andy]

If you've got a chip designed for 8:1 CR then it'll be pinking like a good un.

[z3i]

If you've got a chip designed for 8:1 CR then it'll be pinking like a good un.

Quite possibly!! i was reading about yours, you have high compression and massive boost, but dont get any pinking, said its all down to mapping
It has had a "chip" of sort. this could be mCain oven chip for all i know. it revs up to over 7k so could just be the rev limit moved opposed to a chip

any chance of sending you a list of my modifications with high compression and getting a chip close enough to them? No potatoes please

Did a compression test today, not really sure what the readings mean so if anyone could make sense of them

Cylinder 1: 192.5
Cylinder 2: 192.5
Cylinder 3: 188
Cylinder 4: 195

all seem pretty close to each other which is good luckily i got the last reading on cylinder 4 just before the gauge exploded!!
Many thanks Taylor

[z3i]

yea, they wont melt!

Lol

[Jezza-7]

yea, they wont melt!

Shouldn't melt.

I remember seeing some wossner pistons that had melted.

[Andy]

Email: chips@poloperformanceparts.co.uk with your spec and I can quote for a suitable chip if you want.

[z3i]

Email: chips@poloperformanceparts.co.uk with your spec and I can quote for a suitable chip if you want.

Sent