4k corolla carby

[built4thrashing]

After having a weber on the zook i decided to play about with a different carby. So i went to the wreckers and bought a 4K corolla carby.

The corolla carby is a straight bolt on and only requires minor mods to the accel cable to get started. Now i havent figured out all the vac hoses but on the first drive it was rather impressive. It seems to pull harder than the weber at low revs but runs out of legs up high. It still allows it to rev to 6000rpm but not as willing as the weber.

The only thing i can pick wrong is it tends to try to rev on for a bit when you back off. is this a vac problem or an over fueling problem.

What have other with this carby done with the vac hoses. What have you connected and what have you blocked off.

[Bad JuJu]

One vac line to Dizzy, one to charcoal canister, taped the manifold for brake booster... but mine was from a KE-30 rolla 1300cc. So it didnt have many lines to worry about.

And the thing that causes it to not drop revs instantly is like that for emissions, basically it is an air bleed valve that stops an overfueling condition when the throttle is closed and there is a fair ammount of fuel going in. Its sounds like it is correct. You can just plug this line.

[want33s]

I've played with these carbs in Corollas before. The 'rev on when you back off' is a damper on the linkage assembly (looks like vac sec pot) Easily adjusted out if you like. If you fit a free flowing air intake and ream the main jet a tiny bit you will get a marked increase in power and revability. Float level can be set a couple of thou lower than standard(helps on steep inclines). Usual tricks can be applied like extending bowl breather horns etc.
As for connecting hoses you will need vac advance, this is a small port just ABOVE the main butterfly and brake booster vacuum,the rest can be blocked off & it will run great (may not meet pollution regs anymore).

[shakes]

i decided to play about with a different carby.

what happened to the EFI idea dude? much better option

[Dooley]

Just recently put the same in mine. Haven't had a weber so I can't compare and well never had a near new carby in anyway but it goes faster off the line than it ever has with me. Maybe it's just me but it also seems a little quiter, although maybe the original was just never running right.

I'm still pondering about the air box and doing a few things.

I've got some photocopies of the carby and EGR sections of a corolla manual that helped me out, might be able to scan them for you.

Maybe the throttle positioner is your problem ?

According to the manual it leaves the throttle on for a 4-12 seconds or something like that to reduce emissions. Wouldn't have a clue what it acts like with it on as mine was removed when I got it, runs fine with out it so I don't care less.

IIRC, vacuum tubes, don't recall exactly. Got on from the dizzy and charcoal canister going on the engine side, another one on that side blocked up, I know one goes to the air box as well, although don't know if that's another one of those 4 or the choke breaker.

I also found it pretty easy as it is very similar. Needed a few bits from the Sierra carby, but basically it all bolted straight on.

The hook bit that holds the fuel inlet barb was drilled out the original mounting hole to fit on the 4k carby then just attached with an existing bolt. The 1/4 circle bit the accelerator cable goes onto was taken off and the sierra one put on. Then a bracket was made with a rectangle piece of metal welded to the head of a bolt for the accelerator cable. So no modification of accelerator cable required.

Now I'm just putting in a manual choke cable, trying to find that 3 conductor connector and work out how to get the airbox to fit.


edit:

Well getting that connector might only be possible from the wreckers and even then doubt they'd want to give it a snip.

I wanted to make just a short little adaptor cable between the two so that if I ever wanted to for some reason sell or put the 4k one back on corolla that can happen and I could also put the original back in no probs, but really I like it how it is right now and I don't see myself going back, unless it's really bad offroad, which I need to test once I get the air box sorted. Don't want it sucking dirt/sand in as it isn't sealing properly right now.

Toyota are shit for parts btw. Wanted to get a price on the rubber ring to seal the top of the carby. Don't do it anymore, can't get it. Massive servicing centre, comfy chairs and tvs inside, looks like a friggin hotel. Yet you can't get me a part !

Not like it's off some rare prototype model or something, it's a bloody carolla, Suzuki atleast always have what I want even if it is a rip off.

So might go the nic way with that, clark rubber, as I found with the old sierra carby one it had loosened up over time and didn't fit all that well, so not sure a wreckers one will fit.

[built4thrashing]

Had a bit of a ply with it this morning and ive turned that pita vac device into an idle up when the lights or heater is on. (dont ask as i used old escort vac bits to do it, will do a write up on it later) It works ok but needs perfecting. The corolla carb is better than the weber at low revs but no comparison up high. Might look at putting a bigger main jet in the secondarys. Will use the primary main from the suzuki carby and see how it goes. Might even see what it is like with mechanical secondaries.

As for connecting up to the air box i tried 2 options.
First i used the original carby hat from the suzuki carby as they both have the same size top. but with a 2in BL the airbox doesnt align up properly so i customized . using some of the original airbox rubber elbows i fitted it over the top of the carby and held it on with the barb poked through a hole in the elbow and a big hose clamp around the carby throat. this is then conected to the original rubber intake hose on the air box with some PVC pipe i had lying about. It works and look s smick

will keep updating with any changes

B4T

[zookimal]

I've got a 3k carb at home, I'm going to swap it on I think. The Weber is running well but not well enough on angles.

Interested is those manuals if anyone has anything relevant.

Will keep posted.

[built4thrashing]

i fixed the weber. It was a leak on the primary throatle shaft and it only needed a different seal to fix.

The rolla carb seems better suited for low end power which is what you want for out in the bush but for on the road the weber is heaps better. it pulls harder with the weber out on the hwy and so far the weber was better on fuel than the rolla carb on the hwy but i am still playing with the rolla carb so most driving is heavy footed.

i want to find an accelerator cable that is 6inches longerso i can mount the rolla carby backwards so it will only flood on downhills.

Any ideas?

[zookimal]

Tested back to back does it appear the toy carb would be better than the weber on angles?

I think I'm going to extend the breather tubes and mount the 3k carb (I think it's a 3k? not sure).

Guess we'll have to wait and see.

I'm not bothered with top end as it rarely sees anything over 3500rpm. So hopefully this is a step forward rather than backwards.

[zookimal]

Well it's on. Took about 10 minutes work.

Straight onto standard studs with a standard gasket.

I'll start by throwing in a disclaimer that mine is currently not a road car and I doubt that the Toy carb would meet emissions standards.

My zook previously had a Weber on it so I'm not sure exactly which parts were stock and which were previously modified by whoever fitted the Weber in the past.

For example, I don't think my throttle cable is standard suzuki. Mine still needs some slight adjustment. It is long enough overall but the exposed length is around 30mm too short so it is currently booty fabbed. Soon to be fixed.

Fitted up the vacuum lines as has been previously mentioned here.

Still need to fit a manual choke cable which I have lying around here somewhere. Bought one from SuperCheap for about $12-14 a while back that I had planned on fitting to the Weber.

Biggest hassle was getting a fitting that I could use with the fuel line. I had the hose which was just clamped onto the Weber on a barb fitting but the toy carb had a female thread on it for a factory line. (Which I didn't have). Couldn't get anything to fit it from any of the trade supply joints, and still haven't identified what the thread actually is, and after driving all over town eventually grabbed a 90 degree 1/4 from pirtek and tapped it out to suit.

Cranked it into life and it started straight away without any choke (after it pumped enough fuel to fill my filter and the float bowl) and idled perfectly smooth at about 400rpm. Slight mixture and idle speed adjustment and hey presto, perfect running.

On the tracks I've had it on it runs great. Definately not the top end or the acceleration of the weber, and while it's been a while since I drove a standard carbed 1.3 I think it's probably pretty close when measured from the drivers seat. It's amazingly smooth from idle through to 4000rpm which is something I was never able to get the Weber to be. That's not me having a go at the Weber, but just my inability to tune it to suit all my needs. I didn't have much luck with it. Haven't had a chance to try the toy carb at angles, or to measure fuel economy yet for those interested in those things.

Just need to get either a standard filter housing (which i think will fit) or an aftermarket air filter to suit.

Will keep this updated.

[nicbeer]

mod it to suit, i've been running one for about a year on my old zook.

fuel inlet was the easist thing. take the bit off the zook carb and bolt it onto the toy carb. (they are both aisin carbs.

finally people have been giving the zook carb the flick.

Nic

[zookimal]

mod it to suit, i've been running one for about a year on my old zook.

fuel inlet was the easist thing. take the bit off the zook carb and bolt it onto the toy carb. (they are both aisin carbs.

finally people have been giving the zook carb the flick.

Nic

I should have added Nic that I didn't have a zook carb to pinch any bits off either. Otherwise I think the fuel fitting would have been much easier.

Interested in your success or failure with the carb. If it fails on me I'll go and find a standard carb or fit injection to it. The toy carb cost me roughly $20 in running around and a mate who works at a wreckers had 5 or 6 sitting on the shelf (in varying condition and model) as well.

[NIK]

B4T I used a universal type throttle cable on mine. You get the inner cable and a end to screw on. I used parts from the original cable, the sheath of a bonnet cable and the universal cable. Can make it any length. I used this to be able to put my weber on with the bowl facing forward ( linkage on the engine side ) but I didnt like it so I put it backwards again.
Nik

[Ole Grizzly]

Have any of you guys tried a Holly Carb or heard how they perform on a Sierra ?
I have one in the shed..a 180 I think.

[roc box]

also can anyone post a couple of pics of how they extended their breather tubes please

[Bad JuJu]

RocBox,
Go to a model shop and you can buy alloy and brass tubes like drinking straws in various diameters from about 8mm down to maybe 3.5mm. Buy one that will slip over the tube just and cut it to length and shape the top the same as the std one.

smear some rtv sealent on the bottom 3/4 or so of the std tube then slip your extended one over the top.

rated 1.5 bananas for complexity.

[Dooley]

Have any of you guys tried a Holly Carb or heard how they perform on a Sierra ?
I have one in the shed..a 180 I think.

What I've been told and seems to be the case is that the Holley 180 is identical to the Weber 32/36.

So pretty much look up how webers go and theres your answer.


It is quite a bit easier with the original carby to pinch bits from. Don't need all that many parts but makes it so much easier.

Didn't need to mod the fuel inlet or the accelerator cable as I swapped parts between them.

[Aerenandmel]

also can anyone post a couple of pics of how they extended their breather tubes please

Just push a 2" piece of fuel hose onto the two breathers,

[roc box]

thats what i did thanks was wondering what would happen if you looped the 2 together

[built4thrashing]

both breathers are from the one float bowl so if you conected them together it would not be venting properly.

What i did was loop them together but put a tee with another bit of hose leading further up into the intake with a small filter on the end.

[zookimal]

Only issue so far appears to be that after longish periods at 3000rpm the engine will fall in a heap, stutter and carry on and be powerless under load, won't idle but will rev freely with the clutch in. Has happened twice. General driving at lower revs is fine.

If I stop the car, put my hand over the barrel and give it a rev it will spit out fuel, stall and then run fine after restarting.

Thought it might be flooding at revs as the corolla normally runs on 4 psi of fuel pressure whereas the zook is about 7psi and I don't currently have a regulator on it. Takes that length of time at revs to build up enough pressure to force it's way into the carb, but doesn't happen in normal driving?

Vacuum lines are all hooked up correctly, no apparent blockages in carb and ignition system is ok I think.

Any ideas? This isn't really my forte.

[Dooley]

Dunno, mine has no problems so far. I'll try it at 3000 and see how it goes but I doubt there'll be issues as I haven't experienced anything so far.

Said it doesn't idle, I'm not all the knowledgeable on carbies but maybe the idle stop solenoid is kicking in then not coming back on ?

Probably not right but that's all I can think of as apparently that's mean to turn of idle at higher rpm, so may explain it, it's kicking in then not coming back on when needed.

So yeah, probably wrong but that's all I can think of.

Mine has no regulator btw, just an inline fuel filter after the pump.