Base Timing And Cas

[Botters]

This is my first attempt at adjusting the Base Timing on my R33Gtst. I got the timing light connected up and checked the timing. I can see the notches on the crank and the Marker on the caseing that you line it up with. THe maker seems to be pointing to the second notch from the left. So my understanding that this means the timing is currently at 5degrees BTDC.

The problem i have is that the CAS is pushed hard up to one side so i cannot advance the timing anymore. How do i advance the timing anymore if i cannt turn the CAS further,my understanding Base timing should be 15BTDC.

Does this mean the my CAS is on its way out and need replacing? Or does my Timing belt need to be replaced and everything need to be lined up?

[Botters]

Anyone?????

Someone must know. Im sure its a basic question. Im just a Noob

[blind_elk]

As the engine rotates, the first mark on the pulley to align with the marker on the timing case is 30BTDC, the last mark is TDC. The marks are 5 apart. So, yes, you seem to have 5BTDC.

What happens when you move the CAS the opposite direction?

[QWK32]

pushed up all the way in which direction? the cas turned all the way clockwise is full retard and all the way anti-clockwise is full advance. check this first, if its all the way anti-clockise or full advance then its possible the cas may be one or two teeth out.

[Botters]

If i move the CAS in the oppisite direction (Clockwise) the idle goes all over the place and cannot even read with the timing gun because it looks as if the timing is fluctuating from about 0- to somewhere before the marks even begin.

The CAS at the moment is rotated fully anti-clockwise so the bolts are hard up againts the right hand side of the CAS.

So when i look down at the Crank it lookes like

Marker ---> |

Crank --> | | | | | | |

0TDC 5BTDC 10BTDC 15BTDC 20BTDC 25BTDC 30BTDC

So i presume it reads as above?

[QWK32]

it is possible to put the cas on incorrectly and it be out one or two teeth. what timing light are you using? where are you getting the signal from? have you tried a different timing light?

if your confident your timing light is reading correctly you could try, unbolting the cas, pull it off, dont turn cas the shaft yet, have a look to see if the half moon shaped locating pin on the end of the cam shaft, is missing or not, if it is there the cas will only go on one way.

if its not the cas may have been put back on incorrectly so its out. then with the cas held so the shaft is facing you, turn the cas shaft anti-clockwise a little bit so when it goes back on it is one tooth advanced.

then put the timing light back on it again. you may have to move it more teeth to get it right.

[Botters]

This is the first time using this timing gun. Brand new, its only a cheapy $60 job. Im getting the signal from the first plug. Its an inductive type. So ive put the clip around the set of wires going to the coil pack.

Ive had the CAS off before, and looked at the teeth and half moon pin, they all look to be in good order. So i gather when i put it on last time there was only one way i could have put it on

[blind_elk]

it is possible to put the cas on incorrectly and it be out one or two teeth.

Only if the half-moon key is missing froom the end of the exhaust cam. If the key is missing, and you fit the CAS even 1 tooth out, the engine will not start (been there, done that).

The safest way to get the correct reading is to insert a plug lead between the coil and the plug, then connect the inductive pickup onto the plug leag.

[Botters]

So say if the CAS half moon key is there cus im 99.9% sure it is, last time i looked. What could the problem be??? Maybe the Timing belt being a tooth out? The cars getting close to the 100,000k mark. Im pretty sure that sticker one the cam cover says to change it every 100,000ks.

[QWK32]

i would get a better reading than just clamping the wiring loom. like blind_elk has said insert a plug lead between the coil and the plug. also make sure you are unplugging the aac valve before take a timing reading, so the engine sits at base idle.

[Godzilla32]

Sounds possible that the belt is out a tooth. Would explain it all.

[bnr#@]

Dont have an adgustable cam gear set to god know what back there do you?

[bubbabooga]

hey mate... awhile ago got nw water pump installed and ever since then had the same symptoms.. weird idle if you moved the timing anywhere away from full advance...

recentlly got new timing belt and all that..

turns out the guys that done my water pump put my timing belt on my exhaust cam one tooth off...

all fixed now.. runs like a dream

id say your exhaust cam is out by a tooth..

[Vija]

Almost certain it will be a half moon key as per the majority of Skylines and also Zeds using the Bitsashitty CAS. I'm told cheap timing guns can give double readings, mine definately does on my GTR as if I set it to the correct value visually it runs like crap and the CAS is adjusted right to one side. If I set it to double the value I want then the car runs beautifully and isn't pinging. I have no idea where the double readings come from but it's in several threads on this site.

Cheers,

Matt

So say if the CAS half moon key is there cus im 99.9% sure it is, last time i looked. What could the problem be??? Maybe the Timing belt being a tooth out? The cars getting close to the 100,000k mark. Im pretty sure that sticker one the cam cover says to change it every 100,000ks.

[Botters]

Hrm, not sure about it being a tooth out. I took off the timing belt cover. Looked at the notches and everything seemed to line up. I decided to move the exhaust cam advanced 1 tooth. Then put it all back together. I got the timing to 15degrees. The exhaust note seems a little different now. Car seems to perform a bit better.

Is there anyprob with moving the cam 1 tooth advanced from where the notches are?

[frozenwaffles]

sounds to me you need to go through the whole exercise of 'fitting a timimg belt' to make sure everything is correct. cound be on the crank that things are wrong and you wont see that unless you pull it all out...(being the timing covers, main pulley, etc etc etc)

[Botters]

Thats sounds like too big a job for me, maybe ill leave that to the mechanic. Unless anyone recomends it as being pretty easy? And a DIY job. Im sure theres a thread about it somewhere on here.