RB25DET Rebuild Diary Day 6

First of all, i did not write this. I came across someone named Larry Chen on the net from the car team group-junkies who just recently did a "minor" maintenance on his datsun 240z(260, 280, not entirely sure)with the rb25det engine. All credits goes to him. I am backing up his maintenance diary here, just in case, like all the good tutorials out there goes down.Stuffs covered in this post:

• Intake manifold install

Day 6, Installation of GReddy Intake Manifold
Remember this? My piece of cardboard with a diagram for the bolts? Well guess what? It wont be needed unless you plan on installing the stock intake manifold, otherwise for the GReddy RB25DET Intake Plenum, it comes with a whole set of bolts.

Make sure the area you're working on is free of clutter. The metal intake gasket should be changed and no seal is needed. If you don't have a new intake manifold gasket, carefully inspect it, mine was still good so I opted in using my old one.

Here is the jumbled mess of bolts that come with the manifold.

You can see from the photo that there are four different size of bolts. The four bolts that are the second shortest (two sizes from the right) will be used for the throttle body if you don't have the original throttle body bolts. You will need to use the two longer bolts and the shortest bolt for the intake plenum.

NOTE: I did this part out of order, but should be done first! Off of your old intake manifold, remove the water tube that lays on the bottom with a 12mm socket. Six bolts in plain view.

It's these guys if you're still confused.

There is a 10mm bolt that acts like a bracket for the vacuum hose (for the air regulator) on the manifold. You can remove that or just remove the hose.

It would be easy to remove these 10mm bolts after you remove the whole assembly (with water tube) from the manifold.

On the top portion of the stock intake manifold, you can remove these three 12mm bolts that house the IAA unit.

Here it is removed from the stock manifold.

On the GReddy plenum you'll see the mounting location for the IAA valve (it's on the right silly).

Just one of those pictures for you blind people.

You should clean off the gasket that was on the IAA valve and make sure it looks something like this when you're done.

Then lather up that famous RTV gasket maker.

Remember the three 10mm bolts we used to take out the IAA valve, well these should be reused. I cleaned up the threads a little with a wire wheel, but do as you please here. A little blue thread locker wont hurt.

These three bolts should be torqued to 8.4-11 N-m or 0.86-1.1 km-m

Next is the beloved water tube.

Try to clean out as much of the old gasket and rust (if present) on this part. A good brake cleaner should work.

I dolled up the underside just a little too to make it look a little newer.

You can see how cluttered it is underneath the intake manifold when it's installed. This is why I highly recommend you installing the accessories on the manifold before you install the manifold!

More clutter...

It was soo tight in there that I decided to remove the water hoses and the oil cooler.

This allowed me to free up some room.

Use the original 6 12mm bolts that held in the water tube to re-secure the tube.

Use the same gasket maker and torque all 6 bolts to 16-21 N-m or 1.6-2.1 kg-m.

As you can see from this picture, I had no problem in torque for 5 bolts, but the one bolt that was closest to the camera on the far right (by the water pipe coming from the thermostat) I couldn't get my torque wrench in there for beans. So 5 out of 6 bolts were torqued and the 6th one I pray I get lucky.

Next comes all the washers and bolts for the intake manifold. There are washers and each washer has two sides. One side should be shiny and smooth while the other is rough. The order of the bolt should be, hex bolt, the compression washer, then washer (smooth side facing the hex bolt) and rough side down towards the intake plenum).

A word to the wise, before you install, place the correct size bolts through the manifold to get an idea of where each bolt needs to go.

Place thread locker on the bolts before if you want, but this stage is up to you, I highly recommend it.

Place the manifold on the head, and hand tighten the nuts that go on the stock stud at each end of the manifold.

And the other side...


Now the weird part, torque the 13mm hex bolts down in the correct order.The bolts should be torqued to 18-22 N-m or 1.8-2.2 kg-m.The nuts at the end should be torqued down to 11-13 N-m or 1.1-1.3 kg-m.