Ive just broke a closed block and the pistons has hf on the back whats that stand for??? they any good or just standard

 

BUMP

 

Values of the pistons displacement are measured in HF

 

what?

 

Forged. Search reveals many similar Q & As.

 

I dont think it means forged, having a look up on google its a way of finding the displacement, would need to find something better but here is a quick search result.
Guestimation may show that there are different values of HF?

http://science.jrank.org/pages/3616/...integrals.html

Tony

 

Ive seen them in 2002 wrxs could be who every built it has used new age piston?? not a 100% am sure someone on here will no

 

As said before manufacturing
Piston stroke x internal diam x internal combustion x force x pressure
Engineers measure irregularity by means of hf with additions of mathematics

Hf is stamped if the piston is passed
Additional letters can also be added if thr are flaws

Any 1 ?

 

Found it.

 

Niceone guys there forged then as have no cross hatching just smooth.
next question then piston rings im guessing best to change even if there not to Sharpe?

 

so what does HB on a piston mean?

 

Click speedkings link it has the answers

 

thought it might be for 'Hard Boiled'.

Subaru must be very confident with their pistons if they actually cast or forge 'HF' on those pistons before they are thoroughly mathematically inspected.

I suppose an HB2 piston may be not quite hard boiled, eg. still a bit runny in the middle.

 

Yes you've got it Qwertyco
Finding the value of displacement is approximated by the area HF or other variants A A1 2H N B or H it corresponds to the number of rectangles in the math design

Boiled egg or not Subaru know the integrity math of piston design.. Thrs a 1000000 & 1 other factors wich come into play

 

Right hows about cosworth head gaskets how do you rate them??

 

Ha ha , u gotta luv this site

I dunno , maybe peel , creep , burst , vacuum ,leak,dye,head space,pressure ,or differential ..
Or you could wind your neck back in & pedal ur *** down to C engineering & ask them In person

Let us know the answer tho