[Rusho]

Hi All,

As stated, how hard is it to do 1.3 sierra?? Any suggestions, or should i just let the pro's do it??

Cheers

[gypsy]

its not hard but let the pro's do it they fully clean it and set it up like new. But rebuild kits are only $40 so have a go if u cant do it then get it done

[Lokidog]

gypsy wrote:

its not hard but let the pro's do it they fully clean it and set it up like new. But rebuild kits are only $40 so have a go if u cant do it then get it done

Apart from gaskets and new jets, what else is in the kit?

I've got a spare 1.3 aisin carby in the shed and I was thinking of having a bash at this myself??

Also tempted to go the Weber or Holley path, but apart from the 'angle' issue, I've heard these can be a PITA?

[Lokidog]

If you have the time and confidence to give it a go by yourself, put up some pics and a bit of info how you did it.

I'm keen to give this a shot myself. I won't have a chance until later this year as we're hopefully moving house over the next few months.

[steak_knife]

Give it a go!!
gotta learn some how, that way if its shits in da bush you know whats goin on inside it!!

[gypsy]

u get every thing u need, i do mine and do them al the time at work

[31zook]

The rebuild kits are about $80 from repco, make sure you get all the springs and one ball bearing so you don't lose them... So it's easy to say the least... just take your time...

[Rusho]

I cracked the shits this arvo..I have a spare one so I started tampering and carefully disassemble...Patience not there right now. Took 1 in pieces and off the shit heap annoying fuck of a car, just have to bolt on in a couple of days. I am going to have a go at the other one though, don't do, don't ever know!!

[gypsy]

if u need a hand pm me

[Rusho]

Thanks Gypsy

[Lokidog]

Thought I'd dig this thread up and post here…

Took my original (spare) carby from my 95 sierra to a specialist last Friday. I've asked him to rebuild it and put in some slightly bigger jets.

I was keen to give this a go myself, but time, know how and confidence elude me. The carby I have on my zook now was rebuilt by him ages ago. It's all good other than a possible solenoid issue. This issue causes the idle to sit on 1200rpm after a long run on the freeway, I turn the fan on and the idle drops to 500 - 600rpm and then corrects itself to 850rpm and settles on that.
This carby was from an earlier model sierra (which the owner now runs a Holley 180) and If I recall has an extra vaccuum diaphram. (It's been a few years since I put it on the Zook).
My thinking is that everything will be done correctly on the rebuild as well as the final tuning. I've been looking on here, and searching in the shadows of outers, finding out info about rebuilding the carby. From everything I can see and understand, rebuilding a carb is not that difficult, its the actual tuning that's the hard part. Plus I also don't have one of those thingymajigs to measure the exhaust gases to fine tune the fuel air mixture. My main concern is tuning it too lean and farking up the engine. The carby should be ready to be installed this thursday .

If this works and there is a noticable difference, I'll post up info regarding what jet sizes he used. I've got a fairly fresh motor (rebuilt a couple of years ago), Lukey extractors, 2" system, K&N filter and custom gear stick knobs… I'm expecting big things with this combination

[Lokidog]

Got the Zook back yesterday after the carby overhaul.

Pat from AJM Carburettors increased the jet size to 105/148. I think the original sizes were 99/141. I haven't yet had it on the freeway to see if there is any improvement at highway speeds. I have noticed an improvement in acceleration though. Other noticeable differences in the Zook are… the engine seemingly runs smoother, the choke is working on cold starts (not that it was cold today) and there is no fuel smell coming through the back.

Since my engine rebuild, I have noticed the fuel consumption had gradually increased from 10L/100km to 11L/100km. When I look at my spare carby (the one recently removed) it looks like it could do with a good clean and kit put through it. This may explain the decrease in economy. I'll be watching the fuel consumption over the next few weeks to see if there is any improvement.

One thing to mention… Since I've had the extractors and 2" system, I have not ever had the carby 'tuned' to suit the new exhaust system and K&N Filter I recently put in. The importance of tuning a carby to suit/match any performance mod has been mentioned here in another thread. I'm happy as a pig in shit that this has now finally been done and wished I'd done it earlier.

[Santos]

Lokidog wrote:

Got the Zook back yesterday after the carby overhaul.

Pat from AJM Carburettors increased the jet size to 105/148. I think the original sizes were 99/141. I haven't yet had it on the freeway to see if there is any improvement at highway speeds. :

WT sierra 99/105, sa413 swift 99/141.

i have been looting jets from varius mikuni/aisian/nikki carbs
99 is actually a bigg-ish jet for 1.3l cause every carb car with a 1.3l was in the 91-102 range/
the 105 is the smallest secondary jet in any 1.3l, the larget is like 153. Generally the smaller the primary the larger the secondary.

I am interesed how the 105 jet goes on light loads and cruising when the primaries are going solo. Bigger jets in theory are less likely be able to respond to changes in throttle. I have a rebuilt carb and manifold that is waiting 'that afternoon' to be put in... its going with the 99/141 jets... cause if its ok for a swift i must be ok for a sierra

[Lokidog]

Took the Sierra for a blast up the freeway yesterday to check out the carb's rebuild and tune up.

1. The random idle issue after a freeway run is gone
2. Improved acceleration at the top end (60-100kph)
3. Comfortably sits on the max speed 100kph (which it did before, but I feel there's a slight improvement)

I'm going the reconfirm the exact jet sizes next week. I'm positive Pat said the 99 was increased to 105, but when he mentioned the 148 he said something about 141. Not sure whether he'd corrected himself or mentioned something about drilling out a 141. He seems to know his stuff when it comes to carburettor set ups. One thing he and the dude that worked with him mentioned was to only use 98 ron fuel.

[SuziBlu]

98 is the only fuel to burn, advance timing 2-3° to allow for the slower burning fuel and to maximize effect.

[Lokidog]

Ok, fuel consumption results in… back to 10L/100km. This is me driving it a bit harder than usual because I'm enjoying the responsiveness in the acceleration.

I spoke to Pat and have confirmed the jet setup…

1. Primary up to 100.
2. Secondary left as is 105 (I'm assuming that the secondary is that as the carby is a 95 sierra).
3. Idle Jet (or progression jet) up to 50.

This is a bit different to the original information I got from Pat, so I'm still unsure as to exactly what he did, without actually pulling down the carby (which I won't be doing as it's running perfectly). Perhaps this may make more sense to you Santos.

I firmly believe that I'd easily use somewhere between 9 - 10L per every 100km if I drove it a bit more conservatively.

Oh, and my tyre size is 235's (10% out on the speedo/odometer) so I'd actually be averaging 440km on a full tank.

[31zook]

how much did it cost to get the carby rebuilt?

[Lokidog]

I was quoted $375 for the rebuild and $50 to fit and tune.

When I picked it up he said he'd changed the fuel filter as well.

Total cost $448 inc GST

I was happy to pay this as there is a noticeable difference in power and economy.

FWIW - Three years ago I was quoted around the $350 mark, but I ended up buying a reconditioned one off ebay instead.

It would have been cheaper for me to try doing it myself. BUT… I don't think I would have achieved the same results as what I did having Pat do it.

[Lokidog]

Just did a quick and rough calculation and I should save around $170 in fuel costs in the next 12 months.

This is based on…
1. Fuel price of $1.30 L for 98 ron
2. Achieving 10L/100km on average rather than 11L/100km
3. 250km average per week

[Rusho]

It will probably need another tune up inside 12 months...did you factor that cost in ??? Not to sound like a prick....but I got my carb rebuilt and tuned for $250. In saying that I took the carb off and put it back on though. The difference is really great, best money I have spent on my zook so far

[Lokidog]

Cost wasn't really an issue.

Considering I've owned the car for almost 15 years (from new) and it was only evident that the carby required a rebuild at around 11 years after owning the zook, it's not too bad. I'm sure it will go for quite a few years before it needs another rebuild, and if it does require a tune up I'm sure it will be done for a lot less than the total rebuild, fitting and tuning which was just done.

I'm actually contemplating on getting the rebuild kit and having a go myself on my spare carby, now that my Zook is running well. My 'now' spare carb wasn't in too bad a nick either, other than a dicky idle solenoid and needing a good clean. The only thing stopping me from having a go at tuning it myself is a) I've never done it before, b) I don't have the gauge/meter to check the exhaust gases to get the right air/fuel mixture.
I know there are guys who say back it right off and then give it half a turn or whatever.
I'm no mechanic, but I like to learn stuff and give it a go myself if I can. I'll have to lurk in the interweb's shadows and search for information of how to do it like the professionals. I know people who wouldn't know how to change their oil and spark plugs, but can map the computer on a R34 Skyline GT.

I know that fuel injection is the way to go… But why I still have a carburetted vehicle it, will be nice to know more about it and have a bit of experience playing with it.

[ZOOKCREW]

Just got mine rebuilt . IPSWICH CARBURETTOR SERVICES. $420 for a full rebuild and tune.. best thing i ever got done.

[RobJ]

Could one of you Carby Gurus point me in the direction of a guide for tuning the stock carbs?

[Marko_SJ]

RobJ wrote:

Could one of you Carby Gurus point me in the direction of a guide for tuning the stock carbs?

Not a guru. Is it the idle that you are interested in? Remove the tamperproof on the idle mixture screw and then set it in a similar fashion as a motorcycle pilot circuit adjustment.

[RobJ]

The story is that I bodged a timing belt swap and got exhaust gunk into the carb. I gave the car to a mechanic to clean the carb and it ran fine until winter, then would become a bastard to start in the morning (needed a tonne of throttle to kick over which you has to hold until the engine warmed).

Since then I've given the car to my dad to have a stab at fixing the mixes, but thinks he changed the wrong screw and now we can't get it to start.

I'm basically looking for how to tune a carb from scratch

[Marko_SJ]

RobJ wrote:

The story is that I bodged a timing belt swap and got exhaust gunk into the carb. I gave the car to a mechanic to clean the carb and it ran fine until winter, then would become a bastard to start in the morning (needed a tonne of throttle to kick over which you has to hold until the engine warmed).

Since then I've given the car to my dad to have a stab at fixing the mixes, but thinks he changed the wrong screw and now we can't get it to start.

I'm basically looking for how to tune a carb from scratch

Screw the mixture all the way in, turn it 2.5 turns from bottomed out. Adjust mixture screw to tune for highest idle (adjust throttle stop as necessary) and make sure it doesn't bog when given throttle.

There are two things you can play with. Idle mixture screw and throttle stop. Make sure all circuits are clean before you even bother.

[fordem]

RobJ wrote:

The story is that I bodged a timing belt swap and got exhaust gunk into the carb. I gave the car to a mechanic to clean the carb and it ran fine until winter, then would become a bastard to start in the morning (needed a tonne of throttle to kick over which you has to hold until the engine warmed).

This does not sound like a "tuning" issue - there may be a problem with the choke assembly - remove the top of the air filter with the engine cold and look at the choke plate, is it open or closed?

Typically those carbs require you to completely depress the throttle before starting to set the choke and a bi-metallic strip pulls it off as the engine warms, if the bi-metallic thing is incorrectly mounted the choke will not set, there should also be a cold idle speed adjustment that holds the idle speed higher until the choke comes off.

[Marko_SJ]

fordem wrote:

RobJ wrote:

The story is that I bodged a timing belt swap and got exhaust gunk into the carb. I gave the car to a mechanic to clean the carb and it ran fine until winter, then would become a bastard to start in the morning (needed a tonne of throttle to kick over which you has to hold until the engine warmed).

This does not sound like a "tuning" issue - there may be a problem with the choke assembly - remove the top of the air filter with the engine cold and look at the choke plate, is it open or closed?

Typically those carbs require you to completely depress the throttle before starting to set the choke and a bi-metallic strip pulls it off as the engine warms, if the bi-metallic thing is incorrectly mounted the choke will not set, there should also be a cold idle speed adjustment that holds the idle speed higher until the choke comes off.

I agree, however they have played with how it was set from factory.

[RobJ]

Would correcting the choke assembly be a big job (assuming that was in fact that underlying problem?)

I will have a look in the carby to confirm in a few weeks, when I'm next in Newcastle.

The mechanic charged me $450 to clean it the first time around, and if I'm looking at similar money it might be worth just replacing the unit.

[RobJ]

You guys were spot on.

My dad took it to a mechanic and it was indeed a choke issue. $160 later it's all sorted.