4k Mods

[rollake70]

hey I'm going to get

 

-extractors

-cam

-and a bigger carby

-also 2 or 2.5" system

this is all for my 4k engine because i want to have fun while I'm on my p's so what I'm asking is

 

exactly what carby i should get and cam, I'm asking from people who have upgraded their engine to doing this already or have done it before??

 

I'm going to order the exhaust stuff and extractors but i need people to tell me what cam and carby fits straight on any help would be great thanks

 

I'm not going to bore out any heads this is as far as I'm going with the 4k

[ke70dave]

nah you don't want to go any higher than about 1.75", 2" max on the exhaust.

 

2.25" is prolly a bit big on my 4age still, and its 1.6L and flows a bit more air than a 4k.

 

i can't help with the rest as ive not done it, but check this link out:

 

http://www.rollaclub.com/faq/index.php?tit...a_tough_K_motor

 

bit of a write up on K motor mods.

[rollake70]

yeh thanks 4 that

yeh ive been through that but I'm looking for exact like u know 4 some 1 to say yeh i using this carby with ...this cam u know so i can just order 1 in or buy 1 either way i need a bigger carby and a cam

[ca18ae71]

hi mate carbs is tricky but i went with twin side drought webers 42mm with a massive grind cam and a 1.75" exhaust

[altezzaclub]

I've got twin 1&1/4" SU carbs, just fine for a 1300cc that is not used on the racetrack. Rob has 1&1/2 SUs on his, used regularly for motorsport.

 

Exhaust is 4into1 extractors into a 2" pipe through a 2" resonator and then back into the stock system. I'll fit an 1&3/4" pipe and free-flow rear muffler later. 2" full system is way bigger than a 4K will ever need.

 

Cam is Crow 606, good low down & strong mid-range with a grumpy idle. That sounds a bit odd because the exhaust is so quiet, but it keeps up with the traffic...

 

Getting the Lynx manifold for the SU carbs is the hard part, so most guys use the Weber down-draught carb. Best would be twin side-draughts, but you would have a 1300cc motor using fuel like a 3litre...

[RainWarriorDregs]

hey mate, good to hear you're sprucing up your 4k.

 

with webers you'll find it depends on the person you talk to. personally i'm going to run 32/36 DGEV Weber, but i've been told over and over its too big, but i got it for free so you know can't complain. i've heard that 28/32 DCD is the best i think. I THINK. but really if you're putting a cam and all that stuff in basically any carby off a stock 1.5 or so litre engine should do fine, once again i'm no mechanic but from hours and hours of trawling rollaclub and other sites this is what i've come across. or you can go down the twins road and run twin webers or twin 40s but thats a fair bit of work and money and i don't know much about that. Except for the noise that dellortos (twin 40s) puts out makes me happy in the pants.

 

um, most carbies will fit with an adaptor plate from redline, my 32/36 one cost me about 40 bucks

 

with the cam, i've only had experience with Tighe Cams, but you can also have a geez around Crow Cams and Camtech (not sure on sites for these guys)

 

but with tighe, i've been told from tighe and others that the Tighe 113 grind is the best suited to a 4k with limited mods (no need for modified valve springs). i'm getting the tighe 104 which is a bit more aggressive as i've done some head work on the ol girl.

 

other than that go for gold, i can tell you tho, the build will snowball haha i went from just putting a VRS kit through my 4k to a full rebuild new bearings, new rings, some headwork, new evrything (water pump, fuel pump etc etc) haha, i got bitten by the "might as well do it while the engine is out" bug ahha.

 

good luck

[altezzaclub]

i got bitten by the "might as well do it while the engine is out" bug

 

haha! Yeah that is the killer on all projects! I did bearings & oil pump mod and a head job that I never planned initially... It needed some porting and then I raised the compression and had the valves and seats done too.

 

Here's a few cam options. You can lift 0.4" without changing valve springs.

 

The reason I got the Crow 606 is that it opens quicker. So although the advertised (total) duration is 270, the same as the Tighe 113 & 104, when you look at the 50thou duration you can see it is open longer. So on the usual tappet gap the Crow will open the valve faster to the same amount (0.4") and close it later (and faster I assume) to the same duration.

 

Cost was $170 odd, which included machining the cam follwers also.

Edited May 24, 2010 by altezzaclub

[RainWarriorDregs]

did you do that oil pump mod putting the washer in to shim it? how exactly do you do that and what does it do? becuase i got my oil filter out and wouldn't mind doing this to it to increase oil pressure.

 

i've been told by tighe that i can run the 104 which has .423 of lift without changing the valve springs. i dunno whether to believe them of not tho.

 

PLUS i wouldn't know where to get better valve springs from either? anyone know?

 

 

*EDIT: i may have answered my own question about the oil pump mod, haha, help would be appreciated tho

Edited May 24, 2010 by RainWarriorDregs

[Evan G]

did you do that oil pump mod putting the washer in to shim it? how exactly do you do that and what does it do? becuase i got my oil filter out and wouldn't mind doing this to it to increase oil pressure.

 

i've been told by tighe that i can run the 104 which has .423 of lift without changing the valve springs. i dunno whether to believe them of not tho.

 

PLUS i wouldn't know where to get better valve springs from either? anyone know?

 

 

*EDIT: i may have answered my own question about the oil pump mod, haha, help would be appreciated tho

 

sump must be off/dissy removed.

 

remove oil pump securing bolt (1 10mm bolt)

 

remove the split pin SLOWLY

 

spring will pop out with like a washer.

 

all 3mm of spacers (washers smaller than 14mm wide if i remember correctly)

 

push the spring in with the tip of long nose pliers

 

insert the NEW split pin and wrap it around the oil pump

 

 

HEY PRESTO

[altezzaclub]

Engine out & sump off for the oil pump mod. It just increases the max pressure before the return valve lets go in the pump.

 

The replacement valve springs are from the Holden 202 blue motor. A tenant of mine works for a Holden dealer and said $6 each spring.

[Evan G]

tooooo slow mr altezzaclub ;)

[altezzaclub]

lol Evan!

[RainWarriorDregs]

oh sweet, so all i need to do is get some 3mm thick washers. the engine is out and all dissassembled so it seems like the best time to do the mod. haha

 

The replacement valve springs are from the Holden 202 blue motor. A tenant of mine works for a Holden dealer and said $6 each spring.

 

would you be able to acquire me some of these valve springs? ;) my heads just been redone but he hasn't put the valves in or it back together because i have to send him the valve stem seals.

[philbey]

I would argue against the need for 202 springs. I'm yet to fit my set into my 5K but Crow Cams 4220's fit up well in a STOCK unmachined head. And they're double springs, don't need head machining and will most likely run a lower nose pressure than a single.

Edited May 25, 2010 by philbey

[RainWarriorDregs]

would that be the case in a 4k head? so the crow cam springs are double?

 

i'm contemplating just leaving stock springs in it for the moment, is that a bad idea