Projects - Rebuilding Diesel Cylinder Head

Here's the first part of the complete engine rebuild that was done for the project Rabbit Pickup. I scored an NOS 1.5 Diesel cyclinder head so I had a good starting point. I ended up having the machine shop open up the head bolt holes to fit 12mm bolts. Everything else is from the 1.6 diesel cylinder head except the valves. Got those NOS as well...

Depending on how you're starting your project, you'll want to clean up the cylinder head as best you can. It may well be worth it to take it to a machine shop and have them clean it for you. Those high pressure parts washers that use heated water work great. I would not recommend using a solvent tank to clean an aluminum cylinder head unless you're using a specific chemical. Most of the solvents out there don't react well with aluminum.

At this point, I'm starting with a clean slate. Everything can be reversed to show how it can be removed instead of installed.

1. Sockets / Wrenches
2. Torque wrench
3. Valve spring compressor
4. Valve seal installer
5. Valve lapping tool
6. Feeler gauges
7. Valve bucket depressor
8. Valve shim pliers
9. Valve shim kit
10. Hammer (rubber mallet will do as well)
11. Metal file
12. Assembly lube
13. Nitrile / Latex gloves
14. Anti-Seize paste

I put the cylinder head upside down on the benchtop head stands. This allows easy access to both sides of the cylinder head when lapping the valves. Lapping the valves is a fairly straight forward process. Basically, you're making the two surfaces that will be seating against each other fit better (valve seat in cylinder head and valve surface). There can be small imperfections in the valve seats in the cylinder head or on the valves. This process smooths out those imperfections to make for a better seal.

The valve grinding compound is readily available at any auto parts store. The valve lapping tool is available online or at a specialty tool store. There are other ways to do the valve lapping. This way was the most straight forward so I went with it.

Put some engine oil on the valve stems. Test fit all the valves into place first. Sometimes the variances between valve stem size and valve guide bore can cause some issues. If a valve doesn't fit easily into place DO NOT FORCE IT. Try swapping the valves around until they all fit easily into place. Make sure the exhaust and intake valves are in the correct places.

Remove a valve. Make sure there's still enough engine oil on the valve stem. (you don't want to damage either the valve stem or the valve guide when doing this process) Apply a small amount of valve grinding compound to the back of the valve surface. Attach the valve to the lapping tool (it's a suction cup. just stick it to the valve).

Continue doing this for the rest of the valves. Make sure there's a little engine oil on the valve stems while doing the lapping process. Make sure all of the valve grinding compound is removed from the surfaces of the valve and the cylinder head when you're finished.

Now that all the valves are lapped and installed in their proper places, turn the cylinder head so the bottom of it is sitting on your work surface. To keep the valves from falling out, place a shop rag over the bottom of the cylinder head while turning it over.

Here's some more parts to install. There's the valve spring seats, valve stem seals, valve springs (inner / outer), valve spring retainers and the valve keepers. Notice also that the universal spring compressor has been installed on the cylinder head.


Start by installing the lower valve spring seats over the valve stems. Put one of the valve stem 'caps' over the valve stem. These caps keep the valve stem and seal protected while installing the valve stem seal. They should be included in a valve stem seal kit. If not, you can use a straw. All you're trying to do hear is keep the valve stem seal from catching on the top or grooves of the valve stem.


Time to install the valve stem seal now. Start by fitting the seal over the top of the valve stem by hand.


Place the valve seal installer over the top of the valve seal. Press the seal down as far as it will go


Finish seating the valve seal by driving it into place with a hammer. It doesn't take much so don't get too carried away. Just a few mild hits with the dead blow hammer did the trick.


Remove the valve seal installer and check that the seal is completely seated. You can see in this pic that the shouldered part of the valve guide is what the valve seal fits over.


Time for the more difficult parts. It's time to install the valve springs. This is just simply setting the springs down over the valve stems in making sure they are seated flat against the lower spring retainer.


Now place the upper spring retainer on the top of the springs. Give it a few jiggles to make sure it's seated in the springs correctly.


If you're using two different types of valves (3 groove keepers or 1 groove keepers) make sure you get the spring retainers on the correct valves. You can see from this pic that they are different. If you mix up the upper spring retainers the keepers won't fit properly. You can also see in the this pic that I've clamped the head down to the work bench (yellow bit in the lower left corner). This just makes it easier to use the spring compressor. Otherwise you're trying to hold the cylinder head down with one hand and pressing down on the spring compressor with the other...trust me, just clamp the head down. I just use a big bar quick clamp (about 3 feet long)


Let's get those valve keepers in place. Start by getting the rest of the valve spring compressor assembled and ready to use. I have the handle going away from me so I could try to get some better pics. Usually you're supposed to pull the handle towards you to get better leverage.

While pressing down on the spring retainer with the valve spring compressor, wedge one of the valve keepers into place. I found it a bit easier to push the spring compressor down a bit past the bottom groove of the valve and drop the keeper in with the smaller side of the wedge facing down. I used a pair of long needle nose pliers or tweezers to get the keeper in place. Sorry for the poor quality of the pic. Kind of difficult to take while doing this...

You can just make out the keeper around the back side of the valve stem.

Now we can install the cam. Now would also be a good time to put the cam seal into place. I had alread put mine on before starting this project. It can be seen at the right side of the camshaft next to the cam gear. The little brown donut looking thing.

Apply assembly lube to the cam bearing surfaces. Place the cam into position with the lobes over cylinder #1 (the cylinder to the far right in this pic) facing UP.

The process of measuring the valve clearance is well documented in the Bentley manual. I'm not going to go into detail on it here. If it's requested enough, I'll be sure and document it when I do my next valve adjustment at 1000 miles...which is fast approaching.

Now we can install the glow plugs and injectors. The glow plugs are very straight forward. I put a bit of anti-sieze on mine to make sure they would be easy to take out when they go bad. Make sure all dirt and debris is out of the injector holes on the cylinder head. Install a new heat shield into the injector holes on the cylinder head. I put some anti-sieze on the injectors to make sure they would be easy to remove as well. Thread the injectors in by hand as far as they will go.

I bought a socket specifically to be able to torque the injectors. It's a 1-1/16inch deep socket. I took an injector with me to make sure it would fit over the barbed fuel overflow nipples. After threading in all the injectors by hand, put the socket on a torque wrench and torque the injectors to 53 ft/lbs.

Now install the over flow hose. I got a Viton hose kit for when I start using bio.