Outer Limits 4x4 Board

Hi there,


I just put a 1600 carby into my sierra and I have less power in it then my 1300.
I can just do 100km on the freeway and it’s not running at its potential.

Could this be because I haven’t yet had it tuned by a mechanic?

Dan!

Your question is a big vague. Did you give it a full service after the installation, new fluids, plugs, valve clearance adjustment. What condition is the carby in etc. A bit more detail and you will get a better response. You could just take it to a mechanic and say "fix it", but if you are okay with the tools you could probably sort it yourself, save some $$ and learn a bit too. If you did the conversion yourself, you should have no trouble getting it running right.

Layto....

Vacuum advance hooked up? Choke operational?

Steve.

choke was blocked on mine still does about the same as yours on freeway and my mechanic said thats the way it is

My choke doesn't work on mine, and the valve stem seals are shot and burns through oil but it can still cruise 110 with 32's. Fuel consumption on the other hand is about 14L/100km and thats why i've got a MPFI head ready to bolt on

Sounds like yours isn't running right, if u can afford it it might be worthwhile getting it tuned on a dyno.

What about timing? Could just be really retarded. Check the bible for timing settings but usually around 6-7 degrees BTDC. And while you are there, check the advances (mechanical and vacuum) are all working too.

What size tyres are you running, any gearing? Have you allowed for tyre size increase (if you have bugger tyres fitted?).

Layto....

the vit 1.6 carb's are Cr p to say the least.
save some money+wait+learn electronics = EFI

seriously though,

I have an efi bottom end + 1.3 carby head on it, I know its not efi (yet)
(when I have the time and money it will be and supercharged to boot! )

mine flies, I can do 140 (no wind and flat ground )

standard gears and 30"s,

I would check all your settings IE carby timing and dont forget your vacume lines! take em off and check there not blocked!!
after that if it dosent run any better, Check your compression
hope this helps
DAN

Make sure you do a build up Danzo , Cheers Paul.

zooker wrote:My choke doesn't work on mine, and the valve stem seals are shot and burns through oil but it can still cruise 110 with 32's. Fuel consumption on the other hand is about 14L/100km and thats why i've got a MPFI head ready to bolt on

Sounds like yours isn't running right, if u can afford it it might be worthwhile getting it tuned on a dyno.

have u got the right pistons aswell??

going on the timing issue, i have recently come across a couple of 1.6 engines (efi) with poor performance and the end result was the keyway on the crank was flogged out causing it to run lean. CHECK THE TENSION ON YOU CRANK BOLT. this is why they flog out because they are loose. you cant check without taking the timing gear off,
jason

mr green wrote:going on the timing issue, i have recently come across a couple of 1.6 engines (efi) with poor performance and the end result was the keyway on the crank was flogged out causing it to run lean. CHECK THE TENSION ON YOU CRANK BOLT. this is why they flog out because they are loose. you cant check without taking the timing gear off,
jason

It doesnt cause them to run lean , it causes them to have incorrect valve timing and thus low manifold vacuum , a good manifold vacuum is 18 -22 inches of mercury, if it is less than this its a good chance the keyway is flogged out. so if you have a vacuum gauge you can check for a flogged key without removing the timing covers. i use a vacuum gauge for all checks for poor engine performance , they can not only show a flogged key (incorrect valve timing), but a leaky valve , poor tuning , blocked catalytic converter , a lot of things (the needle reacts differently for different circumstances)

when i do a 1.6 carb i will often use the secondary jet out of the early swift carb , the sierra jets are an 099 primary and a 105 secondary , the early swift used a 141 secondary.

ive seen so many flogged keyways on 1.6 engines its not funny , and mostly it is caused by incorrect tightening of the crank sprocket when a front crank seal is installed ,or someone thinking the bolt has to be undone to remove the harmonic balancer.

danzo , if you have an efi bottom end your compression ratio would be lower , the pistons in the efi motor are dished and are generally used for decompressing swift engines for turbo applications , the 8 valve pistons are what you should be using in a n/a application , but its really a mute point if you are really going forced induction . the combustion chamber in the cylinder head of the 16 valve engine is also smaller than that of the stock 1.3 .

You could probably advance your timing more for greater power before you get pinging.

suzimad wrote:danzo , if you have an efi bottom end your compression ratio would be lower , the pistons in the efi motor are dished and are generally used for decompressing swift engines for turbo applications , the 8 valve pistons are what you should be using in a n/a application , but its really a mute point if you are really going forced induction . the combustion chamber in the cylinder head of the 16 valve engine is also smaller than that of the stock 1.3 .

You could probably advance your timing more for greater power before you get pinging.

wont using 8v pistons in a 16v motor make the valves hit pistons, as the cutouts are different???

suzimad wrote:danzo , if you have an efi bottom end your compression ratio would be lower , the pistons in the efi motor are dished and are generally used for decompressing swift engines for turbo applications , the 8 valve pistons are what you should be using in a n/a application , but its really a mute point if you are really going forced induction . the combustion chamber in the cylinder head of the 16 valve engine is also smaller than that of the stock 1.3 .

You could probably advance your timing more for greater power before you get pinging.

Chears for the info
sorry for the hijack
but?

am I better off keeping the 1.3 head and seeing if I can get larger exhaust valves put into it for the S/C "forced induction".. as to keep the larger crompression chamber
as I have been told the only real difference in them is the exhaust valve?

or
finding or recoing a 1.6 efi head for the "Supercharger" application?
either way Cant wait
as soon as I buy another D/D the zook will be getting stripped

11_evl wrote:

suzimad wrote:danzo , if you have an efi bottom end your compression ratio would be lower , the pistons in the efi motor are dished and are generally used for decompressing swift engines for turbo applications , the 8 valve pistons are what you should be using in a n/a application , but its really a mute point if you are really going forced induction . the combustion chamber in the cylinder head of the 16 valve engine is also smaller than that of the stock 1.3 .

You could probably advance your timing more for greater power before you get pinging.

wont using 8v pistons in a 16v motor make the valves hit pistons, as the cutouts are different???

danzo has an 8 valve head

11_evl wrote: wont using 8v pistons in a 16v motor make the valves hit pistons, as the cutouts are different???

Nope, the clearance is there (as long as you dont plan on hitting extreme revs and valve bouncing). However, if a timing belt snaps the pistons will hit the valves.

I'm currently in the process of putting a 16-valve injected head on my 8-valve carby vit engine. Should cure most of my engine issues.

Danzo wrote:

suzimad wrote:danzo , if you have an efi bottom end your compression ratio would be lower , the pistons in the efi motor are dished and are generally used for decompressing swift engines for turbo applications , the 8 valve pistons are what you should be using in a n/a application , but its really a mute point if you are really going forced induction . the combustion chamber in the cylinder head of the 16 valve engine is also smaller than that of the stock 1.3 .

You could probably advance your timing more for greater power before you get pinging.

Chears for the info
sorry for the hijack
but?

am I better off keeping the 1.3 head and seeing if I can get larger exhaust valves put into it for the S/C "forced induction".. as to keep the larger crompression chamber
as I have been told the only real difference in them is the exhaust valve?

or
finding or recoing a 1.6 efi head for the "Supercharger" application?
either way Cant wait
as soon as I buy another D/D the zook will be getting stripped

if you are going supercharged then you really should think about the entire efi setup. if you arent going efi no the efi head wont work because the intake ports are diff to a carby model , the 1.6 sohc head has larger valves but really with forced induction its all much of a muchness . also have you any plans on your setup ? are you going suckthrough or blowthrough , if you are going blowthrough , good luck to you , i suggest you go suckthrough with a 1 3/4 inch su carb off a old jag or something . with a blowthrough setup the carb cant see boost and wont adjust mixtures where as a suckthrough will , also with an su you can set them up better with diff needles for jetting and the mixture changes automatically.

yeah na I'm not going to worry about the whole carby deal.
Its going to be complete rebuild, probably use the whole efi set up,
- effi head
- wiring
- work to the motor to handle the S/C
(what ever is the best to suit the aplication, Yes further research is needed!)
- the works.

as far as I know once the efi is up and running it will be easier to get the draw through S/C
tuned and so forth.

my friends are trying to get me to put a commy v6 in the poor thing?

zooker wrote: (as long as you dont plan on hitting extreme revs and valve bouncing)

what are extreme high revs?
I dont go over 6grnd, no need its just reving with not much more push anyway
or do you mean simply valve bouncin?

yes i meant valve bouncing via over-revving

Yeah my Vitara is an absolute PITA to drive on the freeway, can't really do +100kmh and dies in the ass going up the slightest of hills. Im only running 235/75s but it was the same on stock tyres.
I was thinking an EFI motor or V6 commo conversion because I do at least one trip a year to QLD from Sydney.
Is there anything I can do to get 'decent' (ie able to drive on a freeway) performance out of this motor so i don't have to go through the pain of a engine conversion?

WTF are you guys with carb 1.6's doing ?
I could happily pull 32's on stock gears on a SPOA sierra at and well beyond the speed limit.

With 29's and a carbed 1.6 in the little red Zuk I had .. I ran out of nerve before I ran out of HP (a sierra running at 140 on the hume is kinda scary so I backed of to about 130 .. I actually wanted to make it to the hospital in the Zuk to see my son being born)

Dave Hazard wrote:Yeah my Vitara is an absolute PITA to drive on the freeway, can't really do +100kmh and dies in the ass going up the slightest of hills. Im only running 235/75s but it was the same on stock tyres.
I was thinking an EFI motor or V6 commo conversion because I do at least one trip a year to QLD from Sydney.
Is there anything I can do to get 'decent' (ie able to drive on a freeway) performance out of this motor so i don't have to go through the pain of a engine conversion?

I assume you have the vit carby engine. To avoid a full engine conversion i suggest you look into swapping a complete MPFI 16-valve head onto your current engine (along with wiring loom, fuel system etc.). Should cost less $$$ than a full engine conversion and give you more power and drivability on-road.

zooker wrote:

Dave Hazard wrote:Yeah my Vitara is an absolute PITA to drive on the freeway, can't really do +100kmh and dies in the ass going up the slightest of hills. Im only running 235/75s but it was the same on stock tyres.
I was thinking an EFI motor or V6 commo conversion because I do at least one trip a year to QLD from Sydney.
Is there anything I can do to get 'decent' (ie able to drive on a freeway) performance out of this motor so i don't have to go through the pain of a engine conversion?

I assume you have the vit carby engine. To avoid a full engine conversion i suggest you look into swapping a complete MPFI 16-valve head onto your current engine (along with wiring loom, fuel system etc.). Should cost less $$$ than a full engine conversion and give you more power and drivability on-road.

in my case which im thinking of doing the same i have an after market fuek tank what do i need to do to get this to work with efi??

also wiring how hard is this to do on your own??

cheers nick

Try_Me wrote:in my case which im thinking of doing the same i have an after market fuek tank what do i need to do to get this to work with efi??

also wiring how hard is this to do on your own??

cheers nick

What sort of aftermarket fuel tank do you have. A fuel tank from a efi vitara would be ideal as it has the correct fuel pump already and apparently fits up with a few small modifications.

In my conversion im going to use a low pressure facet fuel pump from the tank to a VL high pressure fuel pump. I'll see how this setup goes and may add a surge tank later on if its requires.