4ku Pistons

[Robbo!]

wen i bought my Ke70 in 2006 it came with a 4k block in the boot however the motor in the engine bay is a 4k-u with the dished pistons. ill be keeping one of the blocks and getting bored out etc. anyway my question is would it be possible to put the flat top pistons in the 4k-u block for better compression or would they hit the valves or cause any problems?

 

EDIT: i will be putting the original 4k head back on aswell

Edited July 16, 2008 by Robbo!

[Taz_Rx]

Swap the motors in the mean time!! :hmm: Few guy on here have had stock 4ku's and say they go a fair bit harder than an ADM 4kc.

 

I you want to use the original 4kc head, put it on the 4ku block with the 4kc solid lifters and rocker gear, and you have a low comp motor ready for some boosted fun!! :)

[Robbo!]

the guy i bought it off said the engine block in the boot (4k) he said the cylinders were stuffed but i don't know know what he means by that? thats y i was planning on getting it bored out first but getting the funds is a different story

[Taz_Rx]

Might have just meant it could do with a new set of rings. :)

[Robbo!]

yeh possibly but I'm still working on getting twin carbs for it and a cam and stuff so in the mean time ill want good compression so back to my original question, would the valves hit the pistons now that i put the 4k flat tops in or cause any problems?

[camerondownunder88]

run the 4K-u any day goes harder they have better exhaust ports over a 4K-c and better valves and are a nicer package. But all the dished piston 4K I have had are single row timing chain so look into swapping that to dual.

 

Cameron

[corolla_bitten]

hi, i tried what you want to do and now i have two sets of dished pistons, the valves left nice marks in the top of my flat top pistons, this is because the head is a lot more shaved to create the combustion lower in to the cylinder bore. even if you got a thicker head gasket, the compression ratio would be through the roof. stick with the standard 4ku until you get more money, i did what taz rx said by putting the 4kc head on the 4ku block, and it went good, but it was really boggy down low, needed forced induction or twin webbers. it also overheated very easily and i had a problem with the coolant leaky out the exhaust pipe onto the road behind me, hahaha. was fun but, very cool throaty noise even with standard carby.

 

 

 

ps, make sure you have got the correct spark plugs as they are longer than 4kc ones, helps with combustion remarkebly

[Taz_Rx]

It was boggy because it had low compression. Bet it was responsive as still though?

 

Did you get the 4kc head skimmed befor you put it on the 4ku? You probably had a blown head gasket!!

[corolla_bitten]

yeah the gasket ended up blowing, i think it was baggy beacause it had a standard exhaust, trying to push to much air volume through it.