My 4K Engine Build

[84ke70]

Hey guys just chasing some input about my 4k motor build, its going to be street registered but will be used for motorkhana's, hill climbs etc etc, wondering if there is anything i need to look out for :hmm: ,

 

Full engine rebuild .020 oversize

blanced and lighten internals

The LAST adjustable romac timing kit in AUST :dance:

30/70 tighe 424 cam grind .440 lift

ported and polish head

port matched manifolds and extractors

31mm ex valve stock 28mm, 38mm inlet valves stock 36mm

h/d valve springs, collets and retainers

lightened flywheel about 1.5kg mainly on the outter casting rim

minium 10.5:1 compression

Will be running twin DHLA40 dellortos AKA webbers

extractors with a 2" sports exhaust system

5sp manual with a phamtom grip diff center :yes:

[snot35]

For the diff you might be able to source a T18 setup and a proper LSD rather than the phantom grip setup. It depends on your budget of course, but a decent proper LSD will probably be more reliable and will give you more tuning options (1.5 way, 2 way, more preload, less preload etc)

 

Otherwise, I look forward to seeing the build! I'm thinking of something similar with a 5k at the moment.

 

Hey guys just chasing some input about my 4k motor build, its going to be street registered but will be used for motorkhana's, hill climbs etc etc, wondering if there is anything i need to look out for :hmm: ,

 

Full engine rebuild .020 oversize

blanced and lighten internals

The LAST adjustable romac timing kit in AUST :dance:

30/70 tighe 424 cam grind .440 lift

ported and polish head

port matched manifolds and extractors

31mm ex valve stock 28mm, 38mm inlet valves stock 36mm

h/d valve springs, collets and retainers

lightened flywheel about 1.5kg mainly on the outter casting rim

minium 10.5:1 compression

Will be running twin DHLA40 dellortos AKA webbers

extractors with a 2" sports exhaust system

5sp manual with a phamtom grip diff center :yes:

[altezzaclub]

Yes- why not start with a 5K and do all that, you will get more bang for your buck.

 

No matter what you do to the 4K its still going to be an elderly 1300cc that looks just like a 1600cc without any grunt...

[84ke70]

Hey guys cheers for the info about the diff i've heard that the axles, crown and pinion gears in the stock diff are pretty strong just the spider gears are crap ?? anyways i'll have to keep an eye out for a t18 rear end or unless you guys know of one around??

 

Main reason for sticking with the 4K is Racing class limitations once you go above that 1500cc mark i've got no chance against 4age ca18et etc etc

[altezzaclub]

Ah, that makes sense.

 

Do you think opening the exhaust valves up is worth it? They play a minor role compared to the inlets..

 

Which gearbox?? The trouble of adapting a T series to get the better ratios?

 

...and a cold air intake, an electric fan, and an electronic dizzy setup, battery to the boot, or at least down on the chassis, baffled sump, and God dammit a crossflow head and two cams!! :laff:

[84ke70]

ha ha ha yea i wish twincam, cross flow etc etc :laff:

 

yea exhaust valves are quite restrictive when i'm running such a big cam and the dellortos :yes:

 

battery is in the boot

electric thermo fan done

modified and lightend bumpers

modified and lightend front chassis and k frame

 

At the end of the day it will be 850 KG max with roughly 110 RWHP :dance:

 

Engine spec are close to the Trd stage 3 build on a 3k that produce 165 hp

 

I'm running a k50 box but i have a another pulled down and i'm making custom high tensile gears, same steel as whats used in earth moving equipment, need to find a electric dissy, i was going to modify a steering rack to get really quick responsive steering but its pushing the limits of street rego :hmm:

 

should be fun :laff:

[Evan G]

110rwhp is a good goal but doesn't seam real plausible? but prove me wrong.

[SLO-030]

Go for the 5k. Still under the 1500cc cap at 1486cc ;)

[84ke70]

Yea the 110RWHP is getting up there but possible, engine hasn't cost much to build, i work in a gearcutting and engineering shop. The only thing i haven't done is get a old head an segment cut every 10-15mm to see how much room there is in the head, poor flow are whats holding these engines back.

 

To enter and compete in our local races there is a 1500cc limit, but when i go down and do big events governed by CAMS, limits come in to play so to do the noosa hill climb and targa events etc etc i come under the "A" class which is 0-1300cc so i'm only racing against mini's, austin healy sprite's etc etc.

 

i've been told with these engines when they getting upto high rpm's the block suffer from harmonics and crack, does anyone have any info or pic's??

[philbey]

110hp with the head work and valves should well be possible. cool. Sounds like you know your shit, I look forward to seeing plenty of engine build pics!

[towe001]

<snipe> limits come in to play so to do the noosa hill climb and <snipe>

Noosa hey.

I remember once upon time when that road was open to the traffic.

 

Power steering arms from the ae86 will help speed up the steering. But you'll have to upgrade the struts to something like corona or ae86 etc as well, the arms from the ae86 will not bolt to the ke70 struts.

http://www.club4ag.com/faq_and_tech_pages/Steering%20Box.htm

And i'm pretty sure if you have a hunt around on club4ag there was talk about "steering quickeners"

http://racebasics.com.au/afco-steering-quickner-1-5-1.html?osCsid=bf396425cdffd9bfa9416302f9361985

:)

[sepblaster]

Sounds like a lot of work, but I agree with the thought of staying in the 1300cc CAMS class... good way to keep the budget 'reasonable'.

 

You started a build thread for this yet? Get some pictures up... keen to have a look see...

Edited August 18, 2011 by sepblaster

[Mitch-12]

i made 102rwhp with stock motor and 8psi so with big cam big valves big revs big ports big exhaust you will make 110hp what holds mine back is the 1-1/4 primarys and it only does 5000rpm

EDIT: and the stock cam would be holding it back abit too and the small ports and the small valves

Edited August 18, 2011 by mitch-12