the stroked 7m...again. possibly some new info?

[87hilux7mge]

so, ill be getting some parts through a trade, one of said parts is a 97.5 mm stroker crank.

after doing some math (albeit some pretty crappy math, mine sucks) i deduced that if you use the stroker crank, and a stock compression height piston, you would need a 5.85" connecting rods.

so i searched, and found these. forged eagle "I" beam 5.85" rods. so heres the difference in measurements.

stock rods:.......................................... SBC rods:
length: 5.984"/151.986mm................... length: 5.853"/148.659mm
rod journal: 2.047"/51.991mm.............. rod journal: 2.100"/53.337mm
housing bore: 2.167"/55.039mm........... housing bore: 2.250"/57.147mm
pin size: .866"/21.995mm.................... pin size: .927"/23.545mm
big end width: .977"/24.815mm............ big end width: .940"/23.875mm
pin end width: .977"/24.815mm............ pin end width: 1.060"/26.923mm
weight: 615 grams............................... weight: 580 grams

differences:
length: -.134"
rod journal: +.053"
housing bore: +.083"
pin size: +.061"
big end width: -.037"
pin end width: +.083"
weight: -35 grams

so its got larger bore for the pin and journal, but i might be able to find a bearing to soak up the extra, as well as a pin bushing. being as they differences are excessive, i should be able to find the appropriate pieces.

stock:.................................................. .. stroked:
bore: 3.307"/84mm ................................ bore: same
stroke: 3.583"/91mm............................... stroke: 3.839"/97.5mm
displacement: 184.559cid/3.024L.............. displacement: 197.746cid/3.240L
rod/stroke: 1.670:1................................. rod/stroke: 1.527:1
avg. piston speed: 3565.68 fpm................ avg. piston speed: 3814.68 fpm

so we end up with an increase of .216 liters, as well as a lower rod/stroke ratio and a slightly higher piston speed, and about 150 grams weight savings over stock (less if you go for a H beam style rod).

the benefits are, less dwell for the piston at TDC, increasing cylinder fill velocity in the lower rpm's, which should help out the large ported, long runner 7m engine in the low rpm.

the gains are smaller, but i think it could be done, and i intend to build this at a later date. if anyone has any other opinions on this subject, id be happy to hear them, as im thoroughly open to others input and calculations.

go!