4K Bores

[altezzaclub]

Ah- so completely new moulds.

 

Well, has anyone got a tame engine builder with a sonic probe that has checked a few 4K and 5K blocks??

 

Oh look- there's a flying pig!

[altezzaclub]

Too expensive Evan, and too likely to fail... I wouldn't want to do anything to it really, apart from bore it, so we have a straight-forward cheap power increase for everyday use.

 

Ok, so we have to get a 5K block... then we run into other problems fitting our 4K head I'm sure, and end up fitting a different motor rather than just re-boring a worn 4K.

[Evan G]

my engine builder said its around $100 each bore to resleeve

[SLO-030]

So $400 later... Can pick up a 5K for less than that.

[Mitch-12]

4k bored to 5k pistons would maybe be ok for na with lowish comp and not a big cam keep cyl press down

[Mitch-12]

thicker bores is always better

[altezzaclub]

Well, the local specialised engine builder has a sonic tester and he said $125 to measure bore wall thickness.

 

So if you're doing a rebuild that price is cheap compared to the overall job, but if it fails you're out $125 for nothing except education!

 

This guy has done it and said it was no problem-

 

Engine specs:

Twin solex carbs

double valve springs

ported head

extractors

Bored out to fit 5k pistons

Deburred block

knife edged crank

electronic ignition

http://www.ae86drivi...rens-KE70-wagon

 

""na didnt have any block problems at all, just had to use a 5k headgasket with it. Thats all a 5k is, a bored out 4k really....

 

No problems and u really notice the extra torque. compared to a stock 4k it putts along quite nicely and my mate referred to mine as " it goes like a 4age ""

Edited July 28, 2011 by altezzaclub

[WET.K30]

i wana build a 1500 4k! haha but i want some one on here to do it first so i can see if it f@$ks up :)

[Mitch-12]

wouldnt work with boost

[WET.K30]

all i wana do is the bore, twin 40 side draughts, extractors, cam and few other bits n peices.

will it work?

[Mitch-12]

it will work but the bores will flex and will have blowbye

[altezzaclub]

I PMd Darren at that link, he's in WA, and asked him about doing it.

 

He never gave bore wall thickness a thought, and said the motor has worked fine!

 

I've saved a few more links to people who have done it here-

 

http://www.rollaclub.com/board/topic/42407-the-girls-ke70/page__st__60

 

 

 

 

 

mitch, I reckon you're getting hysterical. Do you have any engineering data to backup what you're saying?

[Mitch-12]

weve done it it doesnt work even if you go 60thou over let alone 200thou over they flex in a performance case making good cylinder pressure or boosted, when we are building engines using road car blocks we search to get a block that is stock bore size and get custom pistons to suit just a clean up thicker is better but really anyone can do what they want.. if thin walls didnt matter toyota would of just made 4k with bigger bores to be a 5k but no the made a new cast and toyota know there shit

[WET.K30]

iv decided to be a test dummy in this one, as soon as i have all the parts togeather I'm not going to bother with any testing id rather find out the hard way.

 

few questions tho.

 

any cam recomendations?

 

what is a cam grind, do they grind your cam to what ever spec you give them or something like that?

(sorry bout that question probs stupid but yeh I'm 17 and and its my first build and i tryed looking it up on google and couldent find any stright forward answers.............or any i could understand.

 

thanks for your help evrione

 

ALSO IF ANYONE HAS A DONER 4K IN NSW..SYDNEY LET ME KNOWW :y:

[Mitch-12]

i thought it was a good idea till i actually thought about what a 5k really is, you end up with around 3mm bore wall thickness not much metal to hold in compression but i guess it would be okay in a road car situation and yes it seems to work in low horsepower instances, i noticed in altezzaclubs post that someone said you need a industrial 4k with siamese bores and thicker walls