I am bringing this over here as a general FYI:
engine measurements

I've compiled some info from my spare engine and since questions arise, thought I would put them in one place: (maybe this should be a sticky?)

Block:
bore: 77mm (3.03"), piston area: 46.5 sq cm,
stroke: 85.8mm (3.380") (from the Mullet link to Tridec; not personally measured)
displacement per cylinder: 399 cc (1600cc total)
bore-to-bore centerline: 85.34mm (3.36"), web between bores: .330"
rod length: 130mm (5.11") (eye-center to eye-center)
Rod/Stroke ratio: 1.53
deck height: -3.6mm (-.145") piston is below deck surface;
head gasket: .025"( compressed)
piston: flat with .020 depression to 1/2" of perimeter


(comment: a 1mm ovebore gives 1640cc, about 40cc increase and recuces the web to about .290".)

Head:
intake ports: 1.675" x .85"
exhaust ports: 1.348" x .8"
intake valve: 30.2mm (1.189"), throat below seat: 25.9mm (1.02")
exhaust valve: 23.3mm (.918"), throat below seat: 18.8mm (.74")
rocker ratio: intake 1.65:1; exhaust 1.43:1

cam: base circle 1.185" dia
lobe lift: intake .202", exhaust: .217"
valve lift: intake .333" exhaust: .310"

(PROMINI cam: base circle 1.145" dia intake, 1.132 dia exhaust)
lobe lift: intake .228", exhaust: .240"
valve lift: intake .378" exhaust: .343")

valve adjusters are hydraulic piston, located in the rocker, dia .47"
cam followers are rollers

header ports: 1.366" x .975" (Supersprint is 1.60" x 1.05")
header primaries: 1.36" (Supersprint is 1.63")
header secondaries, Supersprint is 1-3/4"
header collector: 2.3" (Supersprint is 2.5"")

intake runners:
-valve back to flange: 3.5"/4.6" (bottom of port/top of port);
-intake flange to manifold interior plenum: 4.0"/4.5"
total, plenum to valve: 7.5" along port bottom, 9.1" along port roof.

exhaust runners:
-valve back to flange: 2.6"/3.45"

 

Good stuff. How do you measure the port roof/floor lengths?

 

lay a string along the runner from the port to the valve seat or use a flexible rule

 

here is the link to the original posthttp://www.mini2.com/forum/showthrea...ghlight=rocker

 

Very Nice Compilation of data. The numbers are pretty much 100% what I got off of my spare motor that we (Pilo and DPR) are using to design our pistons.

 

guess not much changed over the last year since i took those measurements

 

So, what would be the stock height be from the spring base area to the exhaust valve stem, using a valve height micrometer on a mini R50 head?