|How to clean/recondition your Hydraulic Tappets|
By Yunus Patel from Club Calibra
you know when an engine reaches high mileage, components are not what they
were when they were fresh and young. Though the deciding factor is the
care that the owner takes to maintain youth reliability of components.
Regular servicing and oil changes are a must, also the use of good quality
oil, not the cheap reconditioned oil.
you imagine at start up a thicker oil would take some time to pressurise
the tappets, as the oil feed hole is very small, so a thinner oil would
flow into this more quickly. Another factor for rattles on tappets is the
oil feed hole may become blocked, with sludge, subsequently the inside
where the piston valve run would also suffer from this and possible
varnish build up.
with hydraulic tappets, it is generally best to use an oil that flows
well, not necessarily Mobil 0W40, but a range from about 0W – 10W should
be fine. I personally have found 5W40 a good compromise.
flush may help, but if they are really blocked, or infact the spring
inside the lifter is broken, there is no way you will know other than
taking them out and cleaning and testing each lifter.
I will go through the steps required to clean and test the Hydraulic
Lifters, in most cases they are just gummed up, and you can save around £160+
for a set of new lifters.
I have just taken out the lifters out of my car as I'm doing a top end rebuild, I initially though about replacing them before I learnt that they could be cleaned up and tested in their functionality.
picture below shows the piston inside the tappet.
Once the lifters have been taken out of the head (making sure you have numbered them to its original locations) give them a wipe, so to clean off any excess oil. Once this is done, find a wooden surface, not your kitchen table, as it will get quite messy, but an old MDF board or similar. Hold the lifter with the open end facing downwards and tap quite hard several times, and see if the piston has moved downwards? If it has the if will come off fairly easy with either further tapping or with assistance of a pair of mole grips.
|Again, full clean out the inside of the tappet, getting rid of any oil deposits, gum varnish etc , this is done by using a small brush/ cotton buds with some gunk poured into it.|
This picture shows the piston that is fitted inside the lifter, look to the centre, and you will see a ball bearing, this acts as a release valve to let oil in and out of the piston.
|Now that we have established this, you can get a pointed object, like a small punch or similar and depress the ball, what you will get is the oil will begin to come out, keep doing this
until all the oil has come out.
Having done this what you need to do now is to test to see if the spring inside is ok, or whether its collapsed or broken, this is done by compressing the piston. If all is ok, just clean up the piston, making sure the sides are totally clean with no varnish or gum.
|We will now go onto see how we can sort out the tappet itself, i.e. the bucket shaped part where the camshaft lobe pushes against. Normally after several thousand miles, you will no doubt have some wear. You will now need to linish the tops of each tappet, this can be done by using P240 wet/dry paper using WD40 as a lubricant, put the paper on a flat surface (a machined pieces of steel or a small sheet of glass) and then rub the base of the follower is a circular motion over the paper, make sure you turn the follower regularly as you linish, keep going until there are no scuff makers present.|
It should look something like this!
|If you have some wear on the sides of the tappet, then very
carefully and lightly smoothen up with some 1200 or 2000 grade wet and dry paper, but don't over do it as this need s to be a tight fit inside the cylinder head valve bores.
Finally once all the lifter have been cleaned assemble the lifters and put them in a bath of *hot* oil, the hot oil will cause any air inside to expand and be forced out, mind you don't burn your self.. put the lifters open side down. Then allow the oil to completely cool, the remaining air will contract and be replaced by oil.. that will get them nearly full, test each of the little ball valves before you put them back together.
|I must credit Dave Andrews for some of the information here, as he gave me a lot of
If you find the info useful, use it at your own risk, I will not be responsible for any problems/injury which may occur with you or your engine.