Urgent Help Needed, Info On Cam Timing

[isijappanisi]

Hi.

I just checked my cam timing (RB25DET), the markings on the timing belt pulley on the crank, and the markings on the cam pulleys are all lined up. But when i checked the ignition markings on the crank pulley, it shows 15 degrees when the cams are ligned up with their markings. According to the manual, the ignition markings should be at TDC O degrees when the cams are aligned.

Has anyone ever checked their ignition markings against the cam markings?

How can it be possible to get 15 degrees offset on the ignition markings when all the timing belt marks are aligned?

[Duncan]

OK the cam and ignition timing are not directly related.

You set the cam timing by lining up the marks ont he cam gears with the marks on the backing plate (correct as your pic shows) and the crank gear (under the harmonic balancer) with the mark on the oil pump. I can't see that in your pic.

The ignition timing is controlled by the CAS and is checked using a timing light when the motor is running. that is when you need to be looking for 15o (or 20o GTR)

Have you or someone else taken the timing belt off? Or are you just checking it? You can't confirm the cam timing is correct without taking off the harmonic balancer

[isijappanisi]

Hi,

I've built the engine myself, so i know the position of the markings behind the harmonic balancer. I think though that there might be 1 tooth offset on the crank, I removed spark plug 1. and used a pin do check the position of piston 1. against the timing marks. the piston was not at top before I had turned the crank so that it alligned with the timing TDC. Also the manual says that the timing markings and cam markings should be spot on. I will move the timing belt one tooth tomorrow and see how the engine reacts then.

Thanks for your reply

[Guilt-Toy]

Hey dude

I know this is going to suck but It looks like your timing is out. ( *edit* your confusing the cam timing to the ignition timing, your cam timing seems to be out)

When the top 2 are set on the marks the harmonic balancer should be on the first or second line. I cant remember for sure but i am pretty sure yours is out unless something is up with the balancer or something. I remember mine being on the first line which is 5deg on your manual you posted.

What your going to need to do is pull the harmonic balancer off and look at the COG...

I stole this from GTAAHH's post of his bottom cog. (and edited it for you)

You need to make sure the dot is on the mark on the oil pump. Look at pic here (open it)

Edit 2 (made pic more visable)

I have the front of my engine pulled appart at the moment because of a massive F OFF oil leak from what i think is the front seal. going to put it back together this weekend.

If you cannot see the . on the cog, then you have it on the wrong way (the dot is facing the oil pump not harmonic balancer as it should be.

It sucks cos you gotta pull out the radiator and the bottom cover and you MUST use a proper harmonic balancer puller, IF you use the one with the arms that grab on the outside of the balancer where the belts run THEN YOU WILL DESTROY your balancer. You must use the type that uses the M6 (or 5 cant remember now) bolts that screw into the balancer and you pull from there.

You have been warned... I will pm you my phone number if you have any questions when doin this mission.

Good luck

Edited May 7, 2008 by Guilt-Toy

[isijappanisi]

Problem solved! The cam timing was 1 tooth offset.

[Guilt-Toy]

aha!!! problem solved =)

looked out to me.... anyway post up the power run with fixed timing