Rockers, Setting up valve adjustment.

12th August 2009

I decided that as there was a good possibility that the 1600 TP engine I was building would go turbo that I would be best to buy some bolt up camshafts . Luckily I found some bolt-up shafts with standard ratio's and elephant feet already fitted. Generally as you can see they were in very good condition and needed little work before fitting. I had hoped that the rockers were the needle valve version but unfortunately this turned out not to be the case. I fitted the rockers onto the heads and torqued up the bolts to 18 ft/lbs or 24 Nm. The engine was then left overnight to allow the rockers to come down to the temperature of the engine.

With certain high performance rockers it may be necessary to use shims under the rockers additionally be sure your rockers are shimmed properly on their shafts most rockers come with a selection of shim sizes, To check your rockers are shimmed correctly on their shaft and assuming you are running solid shafts, think of the rocker assembly as three distinct sections separated by the two rocker arms. Each of these sections should be shimmed to about .004" side clearance.

This is really easy to check with a set of feeler gauges. You can move the rockers side-to-side depending on where you put your shims. You should try to aim the rocker for the centre of the valve stem with ball type and elephant foot type adjusters on stock style rockers as well. For wiper and roller style rockers, try to get the pad/roller to be centered on the valve stem.

If you are still using stock adjusters, then aim for slightly to the left of centre on the valve stem; this will help the valve to spin slightly during operation. A very neat trick keeping the valve seat clean.

If you're using 1.4 or higher ratio rockers, you may need to start with a .060" shim under the rocker bases or you'll experience coil binding that you shouldn't be seeing. You will also certainly need to check the length of your push rods.

In my case because my rockers were using elephant foot adjusters this takes up a portion of the adjustment room that requires either shorter push rods or more shims to pack the rockers out. I managed to find enough room using two 0.60" shims that enabled enough adjustment at the rocker . The other option would have been to have ordered some cut to length push rod tubes these retail at about £50.00 and I did not want to go down this route just yet. It is also important to note that the elephant foot ball adjusters have a flat spot on them that has to be orientated onto the valve head before fitting so that the flat side rests up against the valve top.

It is very important when adjusting valves to ensure that the whole assembly is below 50 degrees Centigrade. The valve adjustment is the most important setting that can be adjusted in a V.W beetle engine because the valve adjustments are critical say for example if an exhaust valve is tight on #3 cylinder that sits behind the cooler then the oil gets hot as only three cylinders are working hard. When the oil gets hot it is inadequate to lubricate the connecting rods and they can eventually fail loosing a piston or just locking up your engine. Setting the valve adjustment is a simple task that can be completed by anyone with the correct tools at home and generally is better done at home as most garages use blowers to bring the temperature down, which is not nearly sufficient as an engine can give tighter settings if warmer than what you can achieve by leaving your car alone overnight.

One of the most important things about valve adjustment is finding the correct valve settings for your heads. Generally speaking I think it is most accepted now that 0.06" is the best setting for both inlet and outlet valve clearance. In my experience this is good for most modern heads Although this has been discussed vehemently in the past by checking for long or short rocker studs and can vary on the inlet and exhaust port to inlet 0.04" and exhaust 0.06" respectively. It has also been discussed that 40hp engines have long studs and should be set to 0.08" for the intake and 0.12" for the exhaust. Furthermore if you have an early 1500 engine and long studs, both should be set to 0.12" .Additionally if you have Chromoly push rods you should set both inlet and exhaust to .003".  Should you have steel Push rods then you will need to set both your inlet and exhaust to 0.02".

Once you have decided on the inlet and outlet adjustments that you want to use. You need to park your car up out of gear and chocked the night before where it can be accessed at the back from both sides of the car. Do not jack it up. You then need to also familiarize yourself with the parts of the engine. You need to know where each of the cylinders are, the rocker covers, pulley wheel and spark plugs. You also need to assemble a small tool kit. For this you need a 13mm spanner a good quality wide flat blade screwdriver, a large socket 30 mm and a wrench bar, Spark plug wrench and feeler gauges (metric or imperial). You also need to acquire new cork or rubber rocker cover gaskets.

The next day you are ready to start. Your car has cooled sufficiently to allow you to start setting the valve adjustments. The first thing you need to do is to find Top-Dead-Centre. This is usually where people go wrong as their instincts tell them to go and look at the distributer and look for #1 cylinder lead. This is not always a good accurate method of finding TDC as your engine could have just been rebuilt or the distribute could have been removed for another reason. Ensure the ignition is off and the car is out of gear.

To determine TDC (Top-Dead-Centre) you must find the point were the engine revolves and compresses the gas on the #1 cylinder . Remove the distributor cap and check to see if there is a mark on the distributor body. Place the 30mm socket on the pulley and rotate the engine clockwise until the rotor arm points to this mark. Check to see if your mark on the pulley is in line with this or 7.5-15 degrees away. Move your pulley wheel to TDC. With your engine set theoretically you should have no #1 firing position but we want to check this. Start by locating #1 cylinder examine it carefully and remove the spark plug wire from the end of it and remove it with a spark plug wrench. With the spark plug removed you can use a thin piece of wood to measure how far the piston is down the cylinder . Ensure your piece of wood is solid and is thick enough not to brake. A paint brush handle from an artist brush is a good choice. Place the 30mm wrench on to the pulley and start turning the engine over by hand in a clockwise direction and then anti clockwise. Your ignition must be turned off as you rotate the engine. Test how far the piece of wood goes into #1 you should see it rise and fall as you rotate the engine left and right you can narrow this down to find the highest point the piece of wood sticks out. This is actual TDC and should have placed your notch on your pulley at 12' o 'clock.

With the location of TDC acquired you need to remove the rocker covers place an old rag below the rocker cover to catch any oil. There are two types of rocker cover fixings a bolt on type with 13mm bolts or a spring system. If you have the lever spring system use a screwdriver to lever off the the spring clip.

Sit on the floor next to #1 cylinder and look at the area you have uncovered . You will see four rockers that are sitting on a horizontal shaft. At one end of each rocker there is a cup that locates the push rod, and at the other a screw adjustment that sits on top of the valve spring assembly for each cylinder. The two rockers that are nearest the front of the car on the drivers side control no#1 cylinder. The two further back control cylinder #2. On the opposite side of the car the two nearest the front of the car control cylinder #3 and the remaining two are for cylinder #4. The rockers that are furthest out from the middle and are at opposing ends of the shaft are the exhaust port rockers. The two inner rockers control the inlet valves.

With #1 cylinders inlet and outlet rockers located find your feeler gauge and select the blades to make up the size of the adjustment you are going to use in my case 0.06". Push the tail end of the exhaust rocker arm down so that it swivels down towards the push rod. Try the blades you selected of the feeler gauge in the gap between the adjuster screw and the top of the valve head. It should just fit and you should feel it drag as it pulls through the gap between the rocker and valve top. If it does not feel like this or it feels stiff or will not fit you need to adjust this valve. The rocker adjustment is a machine screw with a locking nut. You need to use the 13mm spanner to undo the locking nut. With the locking nut removed you can undo the screw with a screwdriver to create more gap anti clockwise or clockwise to reduce the gap. There are two ways of setting the gap one is by trial and error the other which I favour is the entrapment method.This consist of trapping the blade between the screw of the adjuster and the valve head. Once you have the blade trapped the screw can be held with a screwdriver whilst the locking nut is done up. This can take several attempts to get it right. When you have made the adjustment and are satisfied with the setting ensure the locking nut is tightened adequately before repeating the same procedure with the inlet valve. With both valves set for #1 cylinder you need to move the engine counter-clockwise 180 degrees 1/2 the circle of the pulley or the BDC (Bottom Dead Centre)mark. Once you have rotated the engine you can adjust the valves for #2 cylinder as described above remembering that the valves are a mirror image of #1's cylinder with the inlet towards the front of the car and the exhaust valve at the rear. Once complete the engine is rotated 180 degrees 1/2 a circle of the pulley wheel TDC so that the adjustments can be made on cylinder #3. Remember this is similar to #1 cylinder and the exhaust port is the one nearest the front of the car. Once completed finally the engine can be rotated for the last time 180 degrees or 1/2 a circle of the pulley and BDC and #4 cylinder valves can be adjusted. The exhaust port is again the one nearest the back of the car.

When you have adjusted all four cylinders sit back and admire your handywork. You can replace the valve covers ensuring to renew the cork/rubber gasket.