4k-u Info Required

[7shades]

Just for some added trivia, its has those little extra square castings in the head underneath number 1 and 4 spark plug holes.

[lappy]

what are so good about the push rods?

[Felix]

Just for some added trivia, its has those little extra square castings in the head underneath number 1 and 4 spark plug holes.

Yep, they share the same head casting as a 5k. The inlet ports are sized between that of the smallport 3/4k heads, and bigport 3k's.

 

well if its really a monster as the claims are, i say reco it and keep it.

 

I wouldn't say they are a monster, but they definitely go harder than your normal flat top 4k in standard form.

 

Things going for the dished 4k's are:

 

More efficient combustion chamber.

Thinner compression rings for less bore friction.

Mid-sized inlet ports giving better allround performance.

Undercut exhaust valve stems for better exhaust port flow.

 

I say bump up the compression to around 10:1, tidy up the ports, fit a 270 degree cam, add extractors, and 1 7/8" system, a 28/36 DCD weber. Fit it to a ke1x and go have fun wasting v6 commodores, whilst getting 12km/L fuel economy. :y: Wait a minute, thats what I did with my old 4k. :)

[camerondownunder88]

Push rods Aint Push rods..LOL

 

Nah 4K-U push rods are shorter than normal K motor ones. Now since they run a solid lifter they have the cup up the top for an adjuster.

 

And for the 2 of us that I know of running 3F hilux lifters in a 5K you need these push rods so you can have it all bolt together. If not you have to mod stuff that just takes time and can risk breaking.

 

Cheers

Cameron

[Felix]

You could always run 3k pushrods which are 3.5mm shorter than normal 4k ones. :)

[7shades]

Mr. Felix's fun formula makes me think twice about giving the pushrods to teddy... and there is a ke20 around the corner I could possibly pry from the cold clammy hands of the old bugger who owns it...

 

Hmmm.

 

How hard is it to get reco bits for these... rings, bearings etc...

[camerondownunder88]

^^ NOPE..can't I tried early 3K and late 3K push rods adn no luck. You actually need dished piston push rods. I did it a while ago so Ill have to write up a how to and why FAQ article on it.

 

As dished piston push rods are like 5K hydro ones but tad longer and a cup on one end.

 

Cam

[camerondownunder88]

7shades,

As far as I know EASY to get parts. Crank is the same so bearings easy. Pistons would be only hard part and rings BUT I think it is the 4K-U that is still used in some small Toyota forklifts so just google and ask but I reckon it would be same as trying to source normal 4K parts.

 

Cameron

[Felix]

Ring part number for 4k dished pistons from ACL is C1843. Otherwise everything is pretty much the same as for a normal 4k, with the exception of the front and rear seals which are thinner and the same as a 5k.

 

Make sure you convert it to a double row timing chain.

[7shades]

Y'know those moments you have when there's a dude in a red suit holding a trident on one shoulder, and one in a nice white suit with a halo on the other....

 

And an unimpressed looking girlfriend standing behind you, reading your posts, saying things like "Isn't 12 bloody cars enough, how about you finish off a few projects before you get some more"

 

mmm.

 

Thanks for the info guys. Appreciate it.

Edited October 24, 2007 by 7shades

[Teddy]

I think i need to persuade you with More Vodka, More Vodka and More Vodka.

 

Did anyone say Vodka? Ive got a potato.

[tas_ae71]

More efficient combustion chamber.

Thinner compression rings for less bore friction.

Mid-sized inlet ports giving better allround performance.

Undercut exhaust valve stems for better exhaust port flow.

 

these small differences still don't seem to add upto the extra HP increase over a run of the mill 4k..?

 

so if the std compression is under 10:1, they don't have a wild cam or a huge carb/s how does it make 74hp!!??

[7shades]

f@$ks me, thats why I asked... but it hammers for a K :)

 

DOES need to revved to extract the goods though, although that may be the exhaust and weber influencing it.

[tas_ae71]

yes true, when i put the exhaust and weber on my 4ac it defiately made more power a little higher up but it would keep making power the more you revved it.

 

it got caught on my mates drive way can kinda crushed the pipe now its choking on its own gases... lol

[Felix]

these small differences still don't seem to add upto the extra HP increase over a run of the mill 4k..?

 

so if the std compression is under 10:1, they don't have a wild cam or a huge carb/s how does it make 74hp!!??

 

I think another variation is in the cam timing for different models of K motors (using the same basic cam).

 

Take half a dozen cam sprockets from different K motors and put them against each other and line them up by the cam locating dowel, and you will see quite a big difference in how the teeth line up. :) Using the one cam grind and varying the cam timing can make quite a change to the power curve.