Base Timing For Rb26

[williamsf1]

Ok having completed a few search's for the required info Im now here asking it in the open

I am having trouble setting the base timing on my GTR to 20 deg at idle... as the CAS is full advanced and only getting 16-17deg...

now I have only recently swapped CAS for this very problem, but having taken the CAS off to paint the timing belt cover and cam covers etc replacing it in the same place has left the car feeling a little flat...

and was confirmed today with a timing and AFR dyno run check....

any ideas?

http://www.skylinesaustralia.com/forums/in...showtopic=91660

also Im now in SA but it might get missed in little old Adelaide

cheers....

[Mik]

Ok having completed a few search's for the required info Im now here asking it in the open

I am having trouble setting the base timing on my GTR to 20 deg at idle... as the CAS is full advanced and only getting 16-17deg...

now I have only recently swapped CAS for this very problem, but having taken the CAS off to paint the timing belt cover and cam covers etc replacing it in the same place has left the car feeling a little flat...

and was confirmed today with a timing and AFR dyno run check....

any ideas?

http://www.skylinesaustralia.com/forums/in...showtopic=91660

also Im now in SA but it might get missed in little old Adelaide

cheers....

<{POST_SNAPBACK}>

Did you replace the CAS with a new one or second hand?

Sometimes the little half moon locating key way in either tha cam or CAS breaks, meaning that the CAS can be inserted in the wrong position.

[williamsf1]

it was a second hand one swapped off another GTR engine... I watched the timing max out at about 17 on the old one, then put this one on and was able to get the 20.... now however after taking it off and on it wont get 20

I checked the key way and it seems ok....

so just confirming base timing for the GTR is 20?

cheers....

[Mik]

it was a second hand one swapped off another GTR engine... I watched the timing max out at about 17 on the old one, then put this one on and was able to get the 20.... now however after taking it off and on it wont get 20

I checked the key way and it seems ok....

so just confirming base timing for the GTR is 20?

cheers....

<{POST_SNAPBACK}>

Yep...definately 20...and you should be able to get way more than that.

Are the keyways on the cam and CAS still good? Try remove the CAS and inserting it in a different orientation.

[williamsf1]

yep just took the CAS off and inspected the keyway on the CAS itself and the male end of it on the camshaft is also in perfect nick.... i.e. flat on one side with the half circle on the other....

so it is looking like I will need to find someone to back to back a CAS and timing check with another CAS.... hmmm

[Duncan]

That is really odd, are you sure the marks on the cam gears are lined up correctly? maybe it is 1 tooth out?

[williamsf1]

That is really odd, are you sure the marks on the cam gears are lined up correctly? maybe it is 1 tooth out?

<{POST_SNAPBACK}>

Errrrr Dunc's you have lost me there? as pauline would say... "please explain"

[ylwgtr2]

first thing make sure the cam timing is correct....then check to see what your true TDC is by fitting a positive stop in the spark plug hole and fit a degree wheel to the front of the balancer,then rotate the crank clockwise until the piston loads up on the stop and take a reading on the degree whel...then turn the crank the opposite way and take a reading again....then find the half way point between your two readings and thats you true TDC....stamp the balancer with a sharp chisel at the true TDC...i wouldnt be suprised to see it up to 5 degrees out...disconnect your aac/tps sensors then set it up

[williamsf1]

first thing make sure the cam timing is correct....then check to see what your true TDC is by fitting a positive stop in the spark plug hole and fit a degree wheel to the front of the balancer,then rotate the crank clockwise until the piston loads up on the stop and take a reading on the degree whel...then turn the crank the opposite way and take a reading again....then find the half way point between your two readings and thats you true TDC....stamp the balancer with a sharp chisel at the true TDC...i wouldnt be suprised to see it up to 5 degrees out...disconnect your aac/tps sensors then set it up

<{POST_SNAPBACK}>

Yep all that was done when the new cams were put in not that long ago....

the current problem stems from the tune being set to a base timing of 20, and this was achieved with the current CAS.... as the previous one had this problem also....

but on checking the base timing today its only 16-17 and car feels doughy above 6k....

they checked the timing by only using the black wire loop at the rear of the cam covers, and a timing light.... were as CRD used the first coil and a lead also with the rear wire....

hmmm..... I dare not ask what a new CAS is from nissan? this one was $200 second hand!