Basics - Adjusting tappets

[Les Henson]

Engine shown is a 2.5 N/A, but the method of adjusting the tappets is the same on most engines that don't have hydraulic tappets. The gap between rocker arm pad and the top of the valve stem is important for several reasons - to allow for expansion of the metal, to ensure that the valve is fully closed when needed, and to ensure the smooth running/timing of the engine.

The rocker cover gasket or oil filler cap leak eventually over a period of time, and the top of the engine gets in a right mess, like the one shown here.

On series and 2.5 N/A or TD engines - remove the filler (series have a 7/16" bolt in the side of the cover to retain the filler)

The heater hoses are held by one of the three acorn nuts that hold the rocker cover on. Remove the centre nut, then slacken the 10mm pinch bolt enough for the pipe support to be removed.

Remove the other two acorn nuts and alloy washers, then the rocker cover will lift away.

The rocker assembly:-

Each tappet should have a locknut and slotted thread - you will need a 13mm ring spanner and blade screwdriver.

Starting at the front of the engine - turn the crankshaft by way of the crank bolt until No2 valve is open. The camshaft lobe for No1 is now out of the way and the tappet for it can be adjusted. Undo the locknut a couple of turns - if the threaded part turns as well, then keep it still with a screwdriver.

Insert the right thickness blade in the gap between the rocker pad and top of the valve stem and turn the tappet thread until the blade is slightly pinched. Keep the screwdriver dead still and tighten the locknut.

You may find that the tappet gap will close too much when you tighten the locknut. If that happens, then re-set the gap, allowing for this. Work through all 8-tappets, making sure that you set the correct gap for the valve - inlet or exhaust. Once done - clean around the top of the head, the gasket faces, and the rocker cover inside and out.

Sticky gaskets are very handy.

Refit the cover, use new alloy washers on the three studs, and re-attach the heater hose clamp.

Les.

[GBMUD]

I have always used the "Rule of 9" to adjust tappets. When number one is rocking you can adjust number eight as they add up to 9. When number 6 is rocking, adjust number 3 and so on.. You get 2 rockers rocking at any one time - this only works for a 4-pot BTW.

Chris

[BogMonster]

I have always used the "Rule of 9" to adjust tappets. When number one is rocking you can adjust number eight as they add up to 9. When number 6 is rocking, adjust number 3 and so on.. You get 2 rockers rocking at any one time - this only works for a 4-pot BTW.

Chris

That's an easy way to remember it, but I guess the "Rule of 9" also only works if the firing order is the same? - I suppose (though I am not sure) that it probably is in all LR engines but I don't know about other 4cyl, do any others have a different firing order?

[bill van snorkle]

I have always used the "Rule of 9" to adjust tappets. When number one is rocking you can adjust number eight as they add up to 9. When number 6 is rocking, adjust number 3 and so on.. You get 2 rockers rocking at any one time - this only works for a 4-pot BTW.

Chris

I agree with the rule of 9 method Chris,but I think you mean it the other way round. When number 8 is fully open you adjust number 1 and so on. Rule of 13 on 6 cyl Landeys if there are any that still survive.

Bill.

[02GF74]

That's an easy way to remember it, but I guess the "Rule of 9" also only works if the firing order is the same? - I suppose (though I am not sure) that it probably is in all LR engines but I don't know about other 4cyl, do any others have a different firing order?

yeah; I was thnking of rule of 9 and without thinking too hard, it has gotta be related to firining order; LR and a lot of British 4 cylinder engines (A, B series) are 1-3-4-2 but Ford crossflow is 1-2-4-3.

[bill van snorkle]

To turn the engine over when doing tappets I find it easier to jack the passenger side front wheel off the ground, put the gearbox in 4th or 5th gear with park brake on and wheels chocked. Turning the wheel by hand turns the engine quite easily. Of course this doesn't work on auto trans.

If it hasn't been mentioned already, on 300TDI and some 200's There are caps on top of the valve stems. Make sure these haven't worn through, and replace with new ones as necessary.

Bill.

[simonb]

Another excellent thread Les, tell you what, if you keep on going on like this, workshop manuals will soon be redundant!

For those of you who have some basic mechanical knowledge and tools but haven't yet plucked up the courage to do your own work, then take the plunge! You will save a fortune in garage costs and will have the satisfaction of knowing you have done the job correctely yourself. Its all fairly simple and if you get stuck, post a question on the forum. Someone will be along with the answer within hours.

Les' articles are far more use to the beginners than some Land Rover magazines articles on servicing and upgrades. I note one of them is doing brake discs and shocks and springs for the nth time over the last year......

[steve_a]

what a stonking idea bill. I want to do the tappets on my 195K mile disco, but I was so used to the starter dog on the old series I kept on putting it off as I couldn't think of an easy way to get the valves moving.

As another comment, a mate gave me a special tappet tool which clicks for each thousand of an inch or something. You tighten it down and then back off the right number of clicks (5 for a series and probably a TDi) then lock it off. On older motors you have have slight bell worn on the faces of the push rod/rocker contact which mean you aren't setting the gap as close as it should. Although noting Les uses the gap between spring, don't know if that would suffer the same problem.

[simonb]

Aah Mr Adams a bit of lateral thinking is required. I do the tappets on the series with the starting handle to turn the engine over, but on the 90, its the wheel in the air and in 5th gear method, even easier if you take out the glow plugs...