kakluote

anyone has idea of this will be appreciated

my new os 12tz spec2 even needle value is closed a lot, smoke from car start to high speed is so heavy.......


what may cause this?


i use cosmo 20% fuel

thanks

Pattojnr

iTrader: (19)

you have posted this question 3 times.
i thikn i read you have only 2lts of fuel through it.
OS engines are very tight, it may take 3 or 4 tls for it to loosen up properly.
due to how tight they are, replace the conrod pretty soon.

the smoke trail is saying its rich still. how is the power ? if boggy or doesnt revv out. then it probably is still quite rich. but i would leave it for another Lt of fuel if the power is ok.

kakluote

the power is not good

but i cant close the needle value anymore because

it will increase the idle speed...dont know why

afm

First of all lets clear up terms. You are using the terms that appear in the OS Engine manual, which are confusing.

Metering Needle (OS Term) is actually your Low Speed Needle (LSN).
Needle Valve (OS Term) is actually your Main or High Speed Needle (HSN).
Mixture Control Valve (OS Term) is actually the main jet of the carburator, commonly called Mid Range Needle. (MRN)
Throttle Stop Screw (OS Term) is actually your Idle Speed Needle (ISN)

OK so now that we have terms cleared up, you have to start regulating your OS TZ spec II engine starting here:

High Speed Needle (HSN) 2 turns out from closed.

Low Speed Needle (LSN) close it fully (with carb open, so as not to damage the main jet), teh open it util it is flush with the slide body.

Main Jet Needle or Valve (MRN) has to be flush with carburator body, and leave it there and never touch it again.

Idle Speed Needle (ISN), close it until slide valve is open about 1mm, and then when engine has started and warmed enough readjust to a slow steady idle.

When you have tried this como back and let me know how it went

AFM

kakluote

thanks for your suggestion!

now,
HSN is about one and half turns out

question about LSN

i can not close lsn anymore but the smoke is also heavy

why i say i can not close lsn anymore:

when i give full throttle open and close it, the engine keep remaining higher rpm than idle speed,do now come down to the idle speed smoothly

GREGORY!

iTrader: (1)

close the low needle and readjust the idle.

afm

Some racers make the mistake of setting the idle speed opening to wide (high idle) and set the bottom end too rich. This will give a false normal idle speed, even though the speed is set to high, because it “loads up” the engine with excess fuel causing the idle to be lower than set. The end result is a very unstable idling engine that surges and may cut out as full throttle is applied because the over rich bottom end can disguise a too lean top end setting!

It is possible too set the idle screw adjustment in to far, but yet the idle speed is not high!, even though the air regulation (carb barrel or slide) may be set to a position that would normally equal a vary fast idle, the idle is low because the low speed mixture adjustment is set so rich that the engine loads up with excess fuel, and the engine goes into what’s commonly called a four cycle idle.

One tell-tale sign of this is if after revving up the completely warmed up engine, it tends to idle fast for a few seconds, then drops to a lower idle speed. In other words, it’s something like da.da.da.da.da.da.da.da then it drops to da….da….da….da.
So you must start leaning the bottom end a little at a time (then repeat the revving up and idle test), and if it takes longer before the idle drops, you’re going in the right direction. Eventually as you keep leaning the bottom, the idle will stay high, and not drop. Now it is time to lower the idle to where it belongs by re-adjusting the idle screw.

Now that you have the idle set correctly, the top end may be too lean! so readjust accordingly

AFM

Renault_Tech

iTrader: (7)

.

kakluote

Thanks much for your support!!

i am a little confusz here.........
"So you must start leaning the bottom end a little at a time (then repeat the revving up and idle test), and if it takes longer before the idle drops, you’re going in the right direction. "

you mention that if it takes longer before the idle drops,i am in the right direction?

does leaning the bottom here mean close/clockwise turn the value?

I can not understand at this point,,,if it takes longer after i lean the HSN,it should be a clue that the LSN or HSN is too lean ,right?

Can u give a advise here, and can u give a simple instruction that how to configure engine to the best performane

Thanks alot!!!!!

afm

Yes, leaning either the LSN or the HSN means closing the needle (turn clockwise)

From what you described as your problem, I understand that if you accelerate your engine full throttle several times, and then you let it idle, the engine stays idling high, and then after a couple of secs. the idle drops down, right??

Well as i explained , it means you have to much fuel in LSN, so you must clse the LSN needle a little at a time (1/8th of a turn), until the idle settles up into an even speed, which normally is high, so then you must open your idle screw to lower the idle speed to the lowest speed possible, without the engine shuting down.

Once you have adjusted your LSN mixture and idle speed, you must readjust your HSN, probably open it , it should finish close to 1 3/4 turns opened from closed position.

AFM

kakluote

Hi Thanks!

Excatly

but, i heard that there is a different understanding of the high idle speed

say if the rpm do not want to go down smoothly.......like


when the rpm come down from very high to mid or low speed, the rpm remain some time then come down or even do not come down anymore,

it means needle is set too lean ,need open a little

this theoretics is totally different ...........


i am confused again


btw:until the idle settles up into an even speed,

does here mean the idle will come up and remain stable?


Thanks!!!!

afm

You start your engine, it has a normal idle and then after several full accelerations you let go so the engine goes back to idle, and it stays with a high speed idle and doesn't drop at all to normal, that means your LSN is to lean and you must richen it by opening the LSN needle, but if you start your engine and it has a high idle from start, then first you must lower the idle speed with the idle screw, and then dio the testing.

Keep in mind that all of these adjustments must be done with a very well warmed up engine, put in on the track several laps and then go to boxes and start adjusting the needles.

Once you set well LSN and Idle, yes, you run the engine hard, and as soon as you let go, engine should go to normal idle inmediately.

AFM

Kodak Hodak

iTrader: (10)

you will love the OS once tuned right - it keep sup and can out perform the top standard NOVA engines!

I been rather successful with my OS and still after 8+ litres through my engine its got plenty of pinch (compression)

Great engine - for competitive racing!

kakluote

Yes, i am looking forward to it

need to work out how to make my engine in perfect value points......

it is a little bit difficulity