Which Is Better? 3k, 4k, 5k Or 7k?

[Jono.C]

okay,

 

So i have a 4k out of ke70 down the back that i was thinking of rebuilding for just a reliable daily motor that can reach the speed limit in under 20 minutes :P :D

 

but when i pulled it apart it was erhhh ahh knackered. :(

 

So i've been all the threads about 'K' motors on here about turbo this supercharged that but i couldnt find what i was after. :no:

 

What I'm asking is which of the 'K' motors would be bet suited for a daily? I.e fuel consumption, parts, reliabilty and with a bit of power when needed.. :(

 

I have the ability to get either of the motors but I'm unsure.. :hmm:

 

btw: mods would just be 5 speed box, extractors, lightened flywheel, skimmed head and such. ;)

 

 

Thanks in advance ;)

[Evan G]

5k for simplicity

[Jono.C]

are they any different to get parts for than say a 4k? i.e rings, bearings, gaskets?

[Evan G]

yea internals are different besides the crank, same as the 4k.

 

5k is 200mls bigger than 4k so a bit more torque and loves the revs.

 

as for inserting it into the engine bay same as the 4k.

[Jono.C]

Are the exhaust and inlet manifolds the same on the two? I read all bolt on accesorries from a 4k will fit a 7k including clutch.. does that mean they would fit a 5k?

[jono1986]

I was thinking the same thing, but someone on here told me the 5k would be the better option, i mean i would be coming from a 3k though. I was thinking the 7k but heard they were a bit pricey, everything bolts up except the sump on the 7k is deeper so i think you have to mod the front cross member to fit it in. Oh and i think the exhaust manifolds are slightly diffferent, not how they bolt up but the actuall design of the flow, but if you have extractors you don't have to worry about that stuff.

[Jono.C]

thanks for that :D i can get a 7k needing a rebuild for 100.. but i don't reakon i really need it..

[greenmac80]

jst mod the sump not the x member for the 7k.

look at 'gavclassic' he has a ke15 with a 7k. rather easy fit and with some minor mods he's making some good horsepower.

[white_sandshoe]

If the 7K is available, i'd take that instead of searching for a 5K... Though 4K is likely to be the easiest to find bits for, and can still be made into a fun little engine.

[Evan G]

7k don't like anything more than 5000rpm

[greenmac80]

bullshit

with a bit of porting work and extractors they'll rev to 7000rpm and be making power that high. in stock form they still go to 5600 ish.

 

oh and most stock 4k's won't even get to 5000rpm well i've had 3 now and none of em will comfortably go that high.

Edited May 22, 2010 by greenmac80

[Evan G]

yea because 4kc arent balanced from factory (from what ive read) thats why they feel like there gonna let go.

 

my 4k at 4 grand sounded like 8000rpm and a the engine screaming "youuurrrr killling mmeeeeee"

[Felix]

The biggest thing holding back a stock motor is the stock camshaft timing.

[white_sandshoe]

my 4k at 4 grand sounded like 8000rpm and a the engine screaming "youuurrrr killling mmeeeeee"

 

yeah, "youuurrrr killlling mmmeeeeee , but I looooooveee iiiiitttt!!!"

 

go the 4K, lumpy bump stick, 32/36 weber, 3KB head and extractors... then rev it to 8000...

[agius]

5k for simplicity

 

+1

 

short stroke = revs off its tits

 

plus making alright power when modded right