Timing Mark Line Up

[Sydneykid]

"Why are you checking the cam timing? Are you looking for a problem or just trying to create one?"

Yes i actually do have a problem!

This is an engine i got from an importer and installed in a C35 laurel chassis.

The engine at idle is a little lumpy even though i cleaned aac / throttle bodies etc, plus when given a quick rev it gives a "noisy tappets kinda sound as it falls back to idle and then is normal again at idle.

The other noise that had me concerned and made me start investigating is an "over tightened timing belt" kinda groan coming from the exhaust rocker cover in line with the no. 2 piston.

This noise is very audible and can be pinpointed to this one spot using the ole screw driver method, and only happens when the car is up to temp.

So i guess this may be the reason my idle is lumpy?!?

And can some one pls tell me what this groaning noise might be ???? it really has me bummy!

Cam bearings?

Cheers

Gary

[Don Dada]

excuse my ignorance but....

Do u mean the cam brackets???

[Swiper the Fox]

excuse my ignorance but....

Do u mean the cam brackets???

yes...cam caps.

[TriniGT]

Hmmm overtightened cam caps??? Check and also make sure that the CAS is not overtightened as well. Remove the balancer and line up the gears and the crank properly replace and tighten the tensioner to factory specs. I think SK has a detailed sticky on how to set the timing for the RB25DET, the FSM as well. Use a long screwdriver as well when getting TDC on number one and at the same time ensure that all others are in sync as well.

[Don Dada]

I know these have specific markings on the to tell their location, but can i swap it with another one to hear if the noise "moves" to the one that i swap it with?

Or maybe use one from a 25det as i have a spare head? Not sure if they are the same tho.

Just trying to figure out how to diagnose the problem.

Thanks.

[TriniGT]

Cam caps are specific and need to be line bored to work, using from a next head can cause the cam to snap upon torqueing. Slacken them per FSM order and retorque if you think it may be a problem. I suggest try getting the timing fixed before looking at a next problem.

[Don Dada]

Hmmm overtightened cam caps??? Check and also make sure that the CAS is not overtightened as well. Remove the balancer and line up the gears and the crank properly replace and tighten the tensioner to factory specs. I think SK has a detailed sticky on how to set the timing for the RB25DET, the FSM as well. Use a long screwdriver as well when getting TDC on number one and at the same time ensure that all others are in sync as well.

Cas is not overtightened, even changed it to make sure that wasnt the problem.

Going by wall on Saturday to get the timing sorted out

[Don Dada]

update

Well i took out the balancer today to check the timing, and what do ya know, it was spot on, all three marks lined up.

The good part is now i know the "overtightened timing belt" sound i was distinctly hearing from the ex cover around piston 2 was actually because the timing belt was overtightened!!

What can i say....It's funny how sound travels in engines i guess . I have slackened the belt which has eased it up some, but there is still a faint sound, but i guess i'll have to live with that till i go back in there to put on my adj. gears.

So now a new question!

Like i said before, when the cams line up the balancer reads about 5*. So when i set my timing (20*) using a light ,does it mean i now have to set it to the 6th mark oh the balancer which originally would have been 25* but in my case would be 20* ?!?

I have it set to the 5th mark right now, which in my case should be 15* and the car gives me a slight ign rattle when pulling off with the ac on.

Should i advance it to the next mark to get the 20* or leave it as is? Our best fuel here is 95. I run stock ecu, 12psi when the weather is 'hot' and 14 psi when 'cool'

Thanks again

[r33_racer]

The bearing is stuffed and will need replacing at somestage. That growling wont go away.

Leave it lower, especially if the fuel is not that great.

[Sydneykid]

when the cams line up the balancer reads about 5*. So when i set my timing (20*) using a light ,does it mean i now have to set it to the 6th mark oh the balancer which originally would have been 25* but in my case would be 20* ?!?

I have it set to the 5th mark right now, which in my case should be 15* and the car gives me a slight ign rattle when pulling off with the ac on.

Should i advance it to the next mark to get the 20* or leave it as is? Our best fuel here is 95. I run stock ecu, 12psi when the weather is 'hot' and 14 psi when 'cool'

Thanks again

It's not physicaly possible for the crank sprocket to line up with the TDC mark while the damper lines up with the 5 degrees BTC mark, unless the outer damper ring has rotated on the inner hub and/or the keyway is worn and/or in the wrong place. Either way you need to find out why the timing marks don't align before you go any further. A detached damper or bad keyway are small problems that will get quite huge if not fixed.

Cheers

Gary

[Don Dada]

Yeh.... the mechanic was just as confused as me because the keyway had no wear or deformities and the damper looked ok as well, just had some small cracks in a few places but looked well intact still

[The Dan]

Correct me if I'm wrong, and it has been a while since I actually took notice of this, but the R32's run the orange mark at -5deg.

I know you have a 33 but is it possible you have a 32 balancer or something silly like that?

Therefore the second mark from the left is actually 0.

Like I said, it's been a while but I'm fairly sure this is the case and from memory I read it in the 32 manual also.

[Don Dada]

Any thing is possible with those Japs.....

Can some one with a R32 manual confirm this.

[Don Dada]

Correct me if I'm wrong, and it has been a while since I actually took notice of this, but the R32's run the orange mark at -5deg.

I know you have a 33 but is it possible you have a 32 balancer or something silly like that?

Therefore the second mark from the left is actually 0.

Like I said, it's been a while but I'm fairly sure this is the case and from memory I read it in the 32 manual also.

Well i dug up the R32 GTR manual and the first mark on the balancer is 0* also, so no luck there either!

As i said the keyway is normal, but i noticed in the manual it states "Crankshaft key must be facing up"

Does this mean directly up as in 12 o'clock?

Cause mine faces probably about 11 o'clock with everything lined up.

Anyway, i am baffled as to why it is not lining up to the 0* mark, but not too concerned as i know the crank and cams are lined up to spec.

So what do i do, take the second mark (5*) as 0* and adjust my timing from there???

[r33_racer]

If your keyway isnt dead at 12 o'clock, chances are no1 piston is NOT at TDC. Check it with a dial indicator to make sure it is, otherwise your timing will be off.

Also as I stated on the other page and as Daniel stated, im pretty sure on r33's the second dash is 0, first line is -5. Im pretty sure that explains why the second line on my balancer is orange and the others are white.

[The Dan]

And also the fact that this guy has not posted one single picture of the balancer mark or the cam gear area. How are we supposed to know he is actually reading the marks correctly?

Post up pics.

[Don Dada]

If your keyway isnt dead at 12 o'clock, chances are no1 piston is NOT at TDC. Check it with a dial indicator to make sure it is, otherwise your timing will be off.

Also as I stated on the other page and as Daniel stated, im pretty sure on r33's the second dash is 0, first line is -5. Im pretty sure that explains why the second line on my balancer is orange and the others are white.

Just checked, the first line on my balancer is orange.

And both the R32 & R33 GTR manual has the first mark as 0*

[r33_racer]

That must be the difference between a gtr and gtst then.

Eitherway I would check that the piston is at TDC when the cams are aligned with the markings on the back camshaft timing cover. Even if you just do it the old fashion way with a screw driver down the sparkplug hole...

[Guilt-Toy]

I had this issue on my car. after alot of f**king around I worked out that my marks on the harmonic balancer is...

-5 0 5 10 15 20

It is a RB25 balancer. from which RB25 i am not sure because i got it from wrecker. Maybe the RB25 balancers are different to the R33 R34's in the markings.

As long as the thing is timed correctly on the pulleys then you will be fine, just set the timing with the balancer on 0 in your case.

[zebra]

does anyone have a pic of said marks on the oil pump and crank...gonna double check mine tomorrow

Thanks

Andrew