Adj Camshaft Pulley & New Cam Belt

[Sydneykid]

Well the adjustable exhaust camshaft pulley arrived today, I ordered an Apexi one form Nengun originally, but they don't make them anymore. I had to settle for one of the new duralium HKS pulleys.......

I weighed it (just out of interest) at 350 grams, from memory a standard pulley weighs around 550 grams.

I already have the cambelt which is due for replacement.........

So it's time to fit it up, more pictures and a how to do it guide will follow over the next few days. So watch this space

cheers

Edited June 15, 2006 by Sydneykid

[Jay95R33]

Great stuff SK. Will be watching this thread.

Cheers

J

[Sydneykid]

First job is to read the workshop manual, for those that don't have one I have attached the relevant drawings from the RB20/25/26 manual. They are all pretty much the same, I have just chosen the best diagram from each manual.

This is a picture of the crankshaft pulley, you need to make sure it is at TDC (Top Dead Centre on #1 or Zero Degrees), when you start, and when you finish.

This is a picture of the camshaft orientation, you need to make sure they are both at TDC, when you start, when you finish and at all times in between.

If you don't want (need) to remove the cam covers, you can check the camshaft orientation by the location

of the knock pins, as per the following diagram;

The best way to check this is the camshaft pulleys, they have a dot on each pulley that should (has to) line up with the dots on the backing plate. Like this;

Take a look at the picture of the HKS exhaust camshaft pulley (in the previous post) and you can see the dot on the tooth just above the "EX" mark.

There is also an alignment dot on the cambelt pulley on the crankshaft, you need to make sure it is at TDC (Top Dead Centre on #1 or Zero Degrees), when you start, when you finish and at all times in between;

Nissan knows how important it is top make sure you have the crankshaft and camshaft timing aligned. That's why there are all of these dots and markers to make sure you align them when you put it back together. Use them, they will save you a lot of heartache if you get it wrong.

Most of these parts I will have to remove to change the timing belt and replace the camshaft pulley;

Note the torque wrench settings for each nut and bolt, it is important not to overtighten them or leave them loose.

The next post will contain some digital pictures of the RB25DET in the Stagea and the parts that need to be removed to get at the front of the engine. So that I can remove the crank pulley and the cambelt covers. Taking pictures as I go will take longer than I could do it without stopping, but I will have a nice record of what to do. As I get a lot of questions from guys who have done or would like to do their own cambelt service or fit an adjustable camshaft pulley/s.

More to come over the weekend.

Edited June 15, 2006 by Sydneykid

[PHaT MR30]

u going to replace the water pump while your doing the timing belt?

[Sydneykid]

u going to replace the water pump while your doing the timing belt?

Why? It is not noisy, or has any play in the shaft, or leaks. They have service life well over 200,000k's

[Sydneykid]

Next step, mark the CAS so I can put it back in the standard position;

I always mark 2 of the 3 bolt positions, just in case 1 gets rubbed off.

Now check the standard ignition timing with the timing light. Connect the timing light sensor around the black with yellow stripe wire (nice loop Nissan);

Confirm that the ignition timing is set at the usual (factory) 15 degrees;

Trick photography huh?

Next post we will start removing the parts that are in the way

cheers

Edited June 15, 2006 by Sydneykid

[emanuelt]

What advantages will you get from installing the adj Camshaft?

[GTRgeoff]

Just rude of you SK to hide this in the Stag section

Champion effort and great trick photography

I'll be sure to just direct the team here instead of having to explain the procedure for cam belt/pully changes another time.

[Driver]

Im doin the exact thing (using same cam gear too) to my rb26 engine - just cant get my main pully bolt loose

[PHATR32]

also, do you have advise on how tight we should make the belt? i think i over tightened my belt and it made a whiing noise when i started it up.

Ill replace the pulleys to make sure, but i just wanted to see if there was a way of checking to see hwo tight it is. i know theres a tool that can check for you.

steve

[Sydneykid]

also, do you have advise on how tight we should make the belt? i think i over tightened my belt and it made a whiing noise when i started it up.

Ill replace the pulleys to make sure, but i just wanted to see if there was a way of checking to see hwo tight it is. i know theres a tool that can check for you.

steve

Personally I set the belt tension so that I can move it 5mm in and out (ie; 10 mm total movement) using one finger. You should not able to play it like a violin because it is so tight. Measurement is done between the inlet pulley and the tensioner. You should have the same amount of movement from the exhaust camshaft pulley to the idler pulley.

When I check the Stagea belt tension I will post up the pictures.

[Sydneykid]

I will be adding some more words over the next couple of days, so watch this space....

When you take the top cover off, this is what you should see when the crankshaft pulley is at TDC. Note the alignment of the dots. I have added the red dots in PhotoStudio so they stand out in the pictures.

This is the exhaust camshaft pulley, note how the dot on the pulley lines up with the dot on the rear cover plate;

This is the cheap harmonic balance puller I used, ~$25 from SupaCheap;

The genuine Nissan cambelt has these markings on it, note the arrows indicating front and the dotted and solid lines that align with the dots on the camshaft pulleys and the dots on the rear cover. This makes it very easy to get the camshaft timing correct, which is very important, obviously.

This is after the harmonic balancer was removed, showing how the puller is located;

The HKS Pulley is on and its dot aligned wth the dot on the rear cover;

Note the position of the CAS spigot in the camshaft, with the flat facing up. This makes it easy to align the CAS when refitting it. I set the exhaust camshaft timing at zero, I will adjust it on the dyno the week after next.

Note the dots on the crankshaft cambelt pulley aligned with the one on the oil pump cover. This indicates TDC, which is usefull when you have the harmonic balancer off;

I have added the yelllow dots in PhotoStudio, so they stand out in the pictures.

The finished product,

Note how the CAS is slightly rotated clockwise from its original position. I adjusted it using the timing light to ensure that the ignition timing was back at its original 15 degrees advanced. This change in orientation occurs because the new cambelt is shorter than the old one, it had obviously stretched a little over its 105,000 k life.

Don't forget to fill in the cambelt changed sticker and whack it on the top cover so you know when it needs changing next.

The tools used in the this job were;

5mm allen key socket

10/11/12/14/27mm sockets

10/12/14/17/19mm rachet ring spanners

3/8" socket drive with short & long extensions

1/4" socket drive with short & long extensions

1/2" tension wrench

1/2" rattle gun (essential for removing the harmonic balancer in an auto, maybe you could get away with using the 1/2" tension wrench in an manual)

Several flat and Philips screw drivers

Harmonic balancer puller (essential, don't even think about trying it without one)

Timing light (essential, don't even think about trying it without one)

oil catch tray

rags

Things to remember;

Buy some coolant, as you will loose most of it when you remove the radiator

Buy some auto trans fluid, as you will loose some when you disconnect the cooler hoses from the radiator

Check the condition of the waterpump, make sure it spins freely and has no sign of leaks from the front seal. At the same time check the tensioner and idler pulleys, they should spin freely with no tight spots or noise.

Bleed the air out of the engine, while filling up the radiator, this is the fitting on the inlet manifold to enable that;

Hope that helps someone else do there own adjustable camshaft pulley upgrade or cambelt service.

cheers

Edited June 15, 2006 by Sydneykid

[BigMicky]

A good tip....

When using the balancer puller, you need to find 2 bolts that will screw in to the threads provided. After realising all the ones in the kit you got dont fit and that you dont have the right bolts anywhere, look in the pile of bolts you've undone so far.

The top 2 bolts that held the timing cover on are perfect. Just find 2 washers and your set to go.

If I'm not mistaken, these are the bolts that SK has used as shown in the above picture.

[Sydneykid]

A good tip....

When using the balancer puller, you need to find 2 bolts that will screw in to the threads provided. After realising all the ones in the kit you got dont fit and that you dont have the right bolts anywhere, look in the pile of bolts you've undone so far.

The top 2 bolts that held the timing cover on are perfect. Just find 2 washers and your set to go.

If I'm not mistaken, these are the bolts that SK has used as shown in the above picture.

You are not mistaken:cheers:

[lwells]

SydneyKid, once again, you've outdone yourself. Excellent, excellent, excellent.

Lucien.

[Sydneykid]

SydneyKid, once again, you've outdone yourself.  Excellent, excellent, excellent.

Lucien.

Thanks Lucien, I have just about finished and updated the tools used etc, I think :confused:

To all, please let me know if I haven't covered something that you might need to know:cheers:

[Blk33]

Hi SK,

Very interesting and useful guide!

Are you planning to adjust the exhaust cam timing and run some dyno tests?

When I fitted my WOLF ECU, I had to wire in some mods to activate the intake cam solenoid. I left it standard until about 2000rpm, activated it (advanced the cam), then dropped it out at about 6000rpm. I did dyno runs and an advanced intake cam helps power at mid rpm, but I was unable to detect any improvement above 6000rpm advanced or standard. This was with the standard turbo. I have since high flowed the turbo but not re checked the intake cam vs power.

Any thoughts?

Rob

[Techo]

Hi SK,

Whats the total cost for this mod all up?

[Sydneykid]

Hi SK,

Very interesting and useful guide!

Are you planning to adjust the exhaust cam timing and run some dyno tests?

When I fitted my WOLF ECU, I had to wire in some mods to activate the intake cam solenoid. I left it standard until about 2000rpm, activated it (advanced the cam), then dropped it out at about 6000rpm. I did dyno runs and an advanced intake cam helps power at mid rpm, but I was unable to detect any improvement above 6000rpm advanced or standard. This was with the standard turbo. I have since high flowed the turbo but not re checked the intake cam vs power.

Any thoughts?

Rob

Hi Rob, the way we do it is to do 2 power runs on the dyno, one with the VVT on and one with the VVT off. We then overlay the 2 graphs, that tells us exactly where the change over points should be. Even on fairly modified RB25DET's (305 rwkw) with Tomei Poncams, the standard change over points are pretty much spot on.

[Sydneykid]

Hi SK,

Whats the total cost for this mod all up?

Genuine cam belt = ~$90

HKS Pulley from Nengun = ~$185

Castrol Radiator concentrate fill = ~$9

Castrol Auto Trans fluid top up = ~$10

One day of my time = priceless

On the same day I did an engine oil change, filter change, radiator flush and a full cooling system refill. Plus I bought a new harmonic balancer puller for ~$25, but I can use that again obviously.