Piston dome height

Okay, okay, so for once I'm the one being ambiguous I meant "...so you'd be taking 0.3mm off the diameter of the top of the dome, rather than across the entire diameter of the piston, which WOULD have the same effect as skimming the heads or using a thinner head gasket, cam timing and DCR notwithstanding"

Clear?

NO!

I think I know what I think your getting at, but ignore the 'height', you just need to remove the equivalent 'volume' in CC from the piston according to the volume lost by skimming the head/thinner gasket...

pr2 x 0.03cm
The r is 4.505 cm and about 3.5 on the dome from memory .I've had to much wine to get the decimal point in the right place .1.9cc?

I think it's about 0.50mm I need to shift to compensate

Yes I KNOW!!!!! I was saying that removing 0.3mm off the dome DOES NOT have the same effect BECAUSE you're not removing 0.3mm across the whole diameter.

And relax...

(took too long buggering about with smileys there.... that was a reply to Dave, Sorry!

Yeh .....when's Stephen gonna sort that out ,copy paste
Skyline owners http://www.skyline-owners-club.com/foru ... ngHead.gif

pr2 x 0.03cm
The r is 4.505 cm and about 3.5 on the dome from memory .I've had to much wine to get the decimal point in the right place .1.9cc?

I think it's about 0.50mm I need to shift to compensate

Sorry, yes thats about right, I was caluclating 1mm above for some reason, forgot it was 0.3

It will need to be a bit more than 0.50mm though, as if it wasnt a tapering dome and just a 70mm x 3.6mm cylinder on the top of the piston, the total volume of it would be 13845mm'2, meaning a 1mm slice of it would be 3846mm2

91mm x 0.3mm area would be 1950mm2, so that would equate to 0.5mm needed (as you said) to be removed from the 'tube', but as in reality the dome is smaller at the top than at the bottom, you would need slighly more taken off as the volume removed increases the lower you cut into the dome...

Anyway, how are you going to do it, angle grinder or hammer and chisel?

Yes I KNOW!!!!! I was saying that removing 0.3mm off the dome DOES NOT have the same effect BECAUSE you're not removing 0.3mm across the whole diameter.

And relax...

You only had to write that...

[Alpineandy]

You could take some out of the combustion chamber instead

Skyline owners http://www.skyline-owners-club.com/foru ... ngHead.gif

Yeah, they have the best collection of smileys

Where's my belt sander
http://www.poeton.co.uk/coatings-motorsport.htm

Anyway, how are you going to do it, angle grinder or hammer and chisel?

Take 'em down to Tesco and ask them to be put through the bacon slicer - set to its thinnest slice. Take yer Archimedes can and measure the volume of water displaced by each slice, until you get 1.95cc - then your laughing

After all that I'm prob not going to machine them The crown thickness is 8mm at its thinest so probably Ok to take a good mil+ off ?
The dome is a lot smaller diameter than I remembered ,47 out to 69 over a 3.6 drop .I will draw them up and do a proper calc on how much material needs removing .

If you think of it like a pile of 36 0.1mm discs, your first 0.1mm will give you 0.17cc and the last one would give you 0.37cc. Not strictly a linear relationship for the ones in between but I guess you wouldnt be that far off if you added .01cc for every second "disc"

Bling on the inside Waiting for rings now then can build the bottom end up ..............



I miss my GTA I'm sure it would have caught up a lot quicker than the ratter Mondeo Mmmmmmmmm GT3

V nice - did you take owt off them in the end?