KA24DE head work

I got a quote of $220 to replace my valve seals and go over my head, and thought that was a little absurd. So, I decided to take the plunge and do it myself. There really isn’t much to it, after its all said and done. You just need the right tools that can be bought for under $50 from Harbor Freight, among other places.

The objective here is to completely rework a stock Ka head. This writeup covers:

– Removing the retainers/valves/springs
– Lapping the valves
– Replacing the valve seals
– Putting it all back together

To do this you will need the following:

-Valve spring compressor tool —> There are a few different types, and even one that’s specifically designed for our engine. I just used a generic valve tool and made an adapter to work with our head.

-Valve seals —> I paid $55 for aftermarket ones. OEM replacements were going to cost me $5 a piece (at wholesale!), so i just went with aftermarket. I would say OEM is best but, i was trying to do this cheaply.

-Valve lapper+valve lapping compound —> The valve lapper is a rod with a suction cup on the end to stick on the valve head. Lapping compound comes in two flavors, grease based or water based. I chose water, because that’s what I was recommended. However, I can see how grease would have some benefits. The water based doesnt stick as well to the metal, but it does a great job and is really easy to clean up. You can pick this stuff up at NAPA, and other places im sure.

-Magnet/Pick —> It really helps to have these to remove the valve retainers.

These are the tools I used to get the job done.

Sarted by taking the head apart. You have to be methodical about this job. Make SURE that you take a sharpee or something and label each lifter bucket when you take it out. I labeled them 1-16, intake 1-8 starting at the front of the motor, exhaust 9-16. You need to do the same thing with the valves, retainers, and springs. They ALL need to go back exactly the way you took them out.

This is the piece I made so I could use my valve spring compressor tool. The problem is that the valves are recessed into the top of the head, so the generic valve tool won’t work without something else. This is a custom job. So, if any of the regular Ka-T guys wants to do this, I can hook you up with this part and make your life really easy, or I can just make you one.

So, this is how you start. Adjust your tool to match the head. Then place the rod on the valve head like so.

Take the top part, and whatever tool you jerry rig to work, and place it on the valve spring retainer so you can still get access to the retainer.

Compress the spring and you will be able to remove the retainers. Sometimes the spring will try to move out of center, and it will make it a very difficult to remove the retainers. Just take a pick and center it back up. It’ll make your life a lot easier. Also, if you just go at it with whatever tool and try to pry the retainers out when they are stuck, there’s a good chance that they will fly across your shop and get lost. After you do a few you will get the idea and they are a snap.

Remove all the valves, springs, and retainers. This is how I kept everything together to avoid making mistakes that could ruin your job.

At this point, you can remove the valve seals. I just took a pair of needle nosed plyers and grabbed from the outside metal part of the seal. Theres a ‘rubber’ part that is pressed on to a metal thing that goes over the valve seat. Pull hard, they pop right off.

Now it’s time to lap the valves. Take your valve lapping tool, and mate it with the corresponding valve to whatever port your doing. Make SURE to keep everything in track. Do one at a time, and in sequence. I used some grease to make sure the suction cup would stick to the valve.

Stick the valve down into the seal with the head turned upside down. Make sure you put some cloth down over whatever you’re working on, so you don’t marr the sealing surfaces of your head. Apply a decent amount of valve lapping compound, and go at it. You want to spin the valve into the head with light pressure. Every few back and forth spins, pull the valve out and let the compound seep back into the sealing surface. You don’t need to do this long. As little as possible is ideal.

This is the motion you want to use when lapping the valves. Think caveman fire-starting..

Here’s what the job is doing. Your mating both surfaces together, making sure they are smooth so air can flow, and so they seal perfectly.

The valve, before and after:

The head itself:

After you do all 16 valves, then go onto installing the new valve seals. It’s pretty self explanatory. You just take the new seal and push it down onto the guide. I used a rod to push down on each one and tap it lightly with a hammer to make sure it was fully seated.

Then replace everything exactly the way you took it apart.

It’s also not a bad idea to replace the springs while your at it.

Written by: 480sx