924Board.org

Kenodog · Joined: 25 Jun 2003 Posts: 2669 Location: Vancouver,B.C.

So I was down at Mikri's place today to have a look at the stroker engine I sold him.We removed a piston to compare it to a stock 924 piston/rod set.Standing both on end with the pistons "up" it appears the new ones are about .1"-.125" shorter at the wrist pin.Now assuming the crank is stock and this is the only change can someone with more math skills than I tell me the compression ratio if the piston is 88.46mm dia.I've talked Mikri into removing the crankshaft tomorrow so we can take it to a machine shop to have the distance between the rod journals measured.We can then compare this # to a stock crank to determine if it's truly an aftermarket or just a re-grind.Also the counter balancing lobes are .750" thick as compared to .620" for a stock 924 crank.You'd think an aftermarket crank of great value would be lighter and maybe knife edged,but thicker and heavier?Could this possible be from one of the AMC cars ?
_________________
1979 Euro 931, Olive
1981 931, Sabine
1991 Ford Ranger XLT 4x4, Ricky
1996 Ford E-350 ex-FedEx Van
2014 Mazda CX-5 (Kinderwagon)
2019 KTM 790 Adventure
2024 KLX300
2024 KLX140

My924gtc · Joined: 14 Aug 2004 Posts: 1362 Location: 248

It is not that easy to figure, check out this article and plug in the necessary numbers to the formula once you know themhttp://www.carcraft.com/techarticles/982/
_________________
MJ
'81 924 2.0L T
'82 924 2.3L SC/EFI <---online fall '06

Sponsor of the 944 Cup and Super Cup
Sponsor of the "2006 Battle in the Badlands"