we need one, so i started one....discuss
if anyone wants to copy and paste the posts from the original ae86dc thread, please feel free...i cbf
*sticky*???
Last edited by slydar; 19th January 2009 at 09:51 AM.
this is a reply on my thread on toymods from some one asking what part of the rod usually fails, and under what conditions.
heres a thread i started last week. for all the guys who would like a basic DIY 7age .
comparisons.
rod length 4a 122 7a 132.5
little end 4a 18(late ge 20) 7a 20
7a deck height is an extra 15.4mm
"crank radius" 4a 38.5, 7a 42.75.
4A
-bore: 81.0 stroke: 77.0
7A-FE :
-bore: 81.0 stroke: 85.5
rod ratio
4a 1.58
7a 1.55
difference in rod length 10.5mm
difference in "crank radius" 4.25mm
total of 14.75mm. deck height difference as listed is 15.4mm.
so it should be noted, there is a difference is compression height of 0.65mm.
this is important to consider when calculating/selecting compression ratios. it can be accounted for by using thinner HG's. the reason for the discrepancy is most likely because the 7afe uses a metal hg standard, apparently .8mm, but certainly thinner than a 4a one.
also important to note, is the extra capacity of the 7a will give you a higher cr anyway, when using 4age pistons.
if i were building an NA motor, id still have the block deck machined 0.65mm anyway. as this is clearly possible/safe. no chance of piston/head interference, or rings popping out of the block.
soooo much love....
RIP Carly - a smile to light the world.
06/07/2011
for the 7a, yes. it is win. i will probably build one this year. theyre turning up more and more at the wreckers. missed on just the other week. would have cost me $120 or so.
bump. why not.
any idea on how much to pay at a wreckers for a 7afe bottom end ??
lol at white people in japan. just lol.
they wont ever sell you a bottom end. it will be a full motor.
the going rate used to be $600-$700, but they have started to come down at some places if you look around.