Adj Camshaft Pulley & New Cam Belt

[wolverine]

People have played around with adustable cam gears on neo's.

Bass Junky has a long thread on what he did in forced induction from a few years ago.

There is some adjustment on the factory exhaust cam gear (on the back side).

Bass Junky didn't find much advantage in cam gear changes but others like joeyjoejoe...etc believes it was worthwhile.

You can move the curves around with them to where it suits you most but allow that you will need to spend time and money on the dyno getting it spot on so perhaps a set of TypeB 260deg poncams are better value when all is said and done (but you will need to check valve clearances and may need to re-shim which is more time and money). The 260 deg poncams make more power everywhere in my experience.

Generally it will prove to be cheaper to buy the best turbo combo money can buy for your goal and spend on good tuning.

[KiwiRS4T]

Don't know about neos but a while back i got an adjustable ex cam gear and set it to 4 deg retard as per SK's post. Months later I got someone to adjust it on the dyno for best midrange power and he came up with 3.5 deg retard ...so the 4deg should be good enough.

But as Wolverine says if you want more power more boost and a good tune is the essential ingredient so after a bigger exhaust, adequate fuel supply and some means of tuning (nistune, emanage, aftermarket ecu) you need a bigger (or highflowed) turbo next.

[burnoutnut]

can i use the balancer puller to put the the balancer back on?

[QWK32]

Just gently knock the balancer on far enough until you can use the balancers bolt to pull it up the rest of the way.

[burnoutnut]

hahahah everything ive read said not to....

[n/a_neo_r33]

i just did mine. the important word is Gently tap it in till you can use the bolt. why would you hahahaha at someone trying to give you advice.

[pvdm]

I know this is an old thread but I used it to change my timing belt and have a couple of things to add that might help others. My car is a c34 Rs4S (i.e. manual, series 2 w/ RB25det neo).

I used a genuine belt and seals and NSK idler and tensioner. Firstly, even though it is a manual, I could not lock it in gear with the parking brake on and remove the crank pulley bolt. With the force required to remove it, it will easily drive forward (even uphill) and you will not have enough throw to get it undone. With the radiator out, you can undo the mounts for the aircon condenser and the small bracket that is right in front of the pulley and just get a rattle gun in there. Once the rattle gun in in place it will undo easily just against compression. For tightening, I could do it up to the specified torque by simply locking it in gear with the hand brake on though. Secondly, you do not need to remove spark plugs to turn the engine over when aligning the marks and for after the installation. If you turn it over slowly, you will have no troubles.

The most important thing is the tension to apply to the belt before you finish the job. The translated manual is not very clear with this as its a bad translation. The job of the tensioner spring (that you should replace when doing this job) is to set the specified tension, by itself. So, once everything is installed and aligned correctly (but with the tensioner mounting bolt loose), turn the motor over 2 or 3 full rotations (TDC - TDC) to help settle the tensioner and belt. At this point, the tensioner will have applied the correct, factory determined tension on the belt. Now all you have to do is hold the tensioner in place with the allen key hole and tighten its bolt to the specified torque. Job done. If you try and set the tension by either the twist method or the +/- 5mm at longest throw method, you might get it wrong and have an over tightened belt that whines and makes a terrible noise when the engine heats up.

Last thing that I noticed was that, like many people have found, the timing loops (blue and white) at the back of the motor near the fire wall give strange readings. I tried many things and always got too much advance when using the loops. Even with the CAS all the way against the stops, there was still not enough adjustment to get a correct reading. I still don't really know what is going on, but apparently, some timing lights pick up on an earlier signal when using the timing loops and you get roughly double the reading. On one of my loops, there was two signals coming through and I could just make out two different timing marks. One was way out and moving all over the place and the other was about what I would expect and when set correctly to 20deg the CAS was almost in its original position.

Hope this helps others. Cheers!

[Gameboy]

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.

I apologize for bumping an old thread, but can this guide be used on an rb30det?

[KiwiRS4T]

If you have an RB25 head it should be pretty much the same. The main thing is not to turn anything with the belt off! And as per the previous post probably better to insert a lead between the no1 coil and plug and time off that.

[Gameboy]

If you have an RB25 head it should be pretty much the same. The main thing is not to turn anything with the belt off! And as per the previous post probably better to insert a lead between the no1 coil and plug and time off that.

I haven't put the head on it yet. If I turn the engine over and get the piston to tdc, and then turn the cams over and align the the dots then install the head, would that be ok?

would the timing be good enough to then be able to start and fine tune it with a light?

Sorry for the heaps of questions, first time im putting an engine together.

[KiwiRS4T]

I haven't put the head on it yet. If I turn the engine over and get the piston to tdc, and then turn the cams over and align the the dots then install the head, would that be ok?

would the timing be good enough to then be able to start and fine tune it with a light?

Sorry for the heaps of questions, first time im putting an engine together.

Yep should be ok - you can double check before you put the cam covers on that everything is opening and closing at the right time. A tip - assuming you are keeping VCT get an adjustable gear for the exhaust cam in order to get full value from your RB30.

[Gameboy]

Yep should be ok - you can double check before you put the cam covers on that everything is opening and closing at the right time. A tip - assuming you are keeping VCT get an adjustable gear for the exhaust cam in order to get full value from your RB30.

Thanks, yeah keeping VCT and my bro is giving me his adjustabe cam gear from his old engine

[Ben C34]

I haven't put the head on it yet. If I turn the engine over and get the piston to tdc, and then turn the cams over and align the the dots then install the head, would that be ok?

would the timing be good enough to then be able to start and fine tune it with a light?

Sorry for the heaps of questions, first time im putting an engine together.

You can't fine tune cam timing using a timing light.

[KiwiRS4T]

You can't fine tune cam timing using a timing light.

Presumably he means setting the ignition timing by rotating the CAS

[Ben C34]

Presumably he means setting the ignition timing by rotating the CAS

You never know