5K head on a flat top 4K

[Gavatron]

Looking at you OC

What sort of compression ratio would I be getting if I put a 5K head on a flat top piston 4K out of a KE70?

[SeptemberSquall]

depends on any chamber work or porting
decking of block and head
gasket thickness etc

[Gavatron]

Stock chamers, stock block and head; no shaving/decking. Standard ACL gasket. I'm putting it on regardless, just wanted to know what I'll end up with. Chambers on the 5K head are visibly shallower than the 4K one.

[oldcorollas]

from vague memory, 5K chamber is 16-17cc

the usual 4K chamber is maybe 36cc? (you can calculate it easily)

basically, you have half the combustion chamber = not good.

[Gavatron]

Yeah, I did just work that out and may not be doing it regardless

I believe my sums ended up somewhere in diesel territory @ 21:1

[takai]

I got 17-18:1, still stupidly high.

[Gavatron]

North U-Pull-It was way more successful than Southern. KE55 5 Speed extension housing, and a decent 4K head. Took 1 3K and 2 other 4K head removals before I found one with little corrosion.

[cambelt]

Ive been curious on this for years , I was allways going to try a a late head on a early bottem end that i ran on LPG in a suzuki stockman but never did it . There easy to work on and at worst you just have to pull it off and stick the 4 k one on.
Dave

[oldcorollas]

as you go from K to 3K to 4K, the head volumes get progressivle larger by abotu 3-4cc.. ie, 30-33-36 or something liek that.

but the 4K and 5K dish piston heads are 16-17cc... which is just sooo wrong

the valves are closer to piston, so there is not much room to dig out the chamber either.
you can remove a few mm from the K heads, but might need to weld some of the galleries up to retain strength...


then again..... 4k block, 1G pistons and rods, 5K head..... the 3mm down the bore of the pistons gives you 13.6cc...
still high comp, low squish.. (are the 1G pistons dished? this might just work )

[Gavatron]

All assembled now. 3K inlet and exhaust manifolds to get rid of EGR etc., stripped down KE70 carby that will hopefully still work.

That extension housing swapped over no problems too OC

[Matt-AE86]

1GGTE or 1GGE ?

[oldcorollas]

dunno yet probably 1GGTE...
what are the differenecs?

[cambelt]

Its also why as the motors chambers increased so did there fuel consumption.
The best for sure was the KE 10 3K and K motors.
5 and 7 K have shit economy and to make it worse i heard that the carby 7K has a higher comp than the EFI 7 K .
Toyota allways have a habbit of de tuning there efi motors . i think 2TG and 18 RG were like this also.
Dave

[oldcorollas]

but the bigger motors are in bigger cars...., heck the 7K is in a big van..
the KE10's only weigh 720ish, so they have less mass to move around..

[dfunkt]

of the 3 engine's i've had in my ke20, the original tired 3k, a BHG 5k and a warm 4k, they all gave me less than 10L per 100km. the 3k was about ~9L and the 4k and 5k were ~9.5L.