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Tappets and wear

Posted: 19 Aug 2016, 20:24
by 123-jn
I have just borrowed 4 tappets from my old 1.9 engine to try to iron out an issue with the ones in my new 2.1 engine and was shocked to see the condition of these tappets which were new less than 30,000 miles ago with a new cam at the same time. Two of the four have pits in the faces albeit small ones and are slightly dished in the centre where the cam acts. The other two are ok face wise but quite badly dished in the centre. These were from The engine shop. One of the others on the other bank that came from JK had such bad pits on the surface that I have binned it already!!! I dread to think what they would have been like after a 100,000 mile life!!!
Trying to decide which cylinder the noisy poorly functioning new tappet is on in my 2.1 I have just run a compression test. The results are as follows.
cyl 1 150psi (a bit low)
cyl 2 170psi (nice)
cyl 3 145psi (worse)
cyl 4 170psi (nice)

next job to swap out the tappets on 3 and see what happens!!! Then on cyl1 on which I have already swapped out one which would not pump up on the inlet.

If I ever build another one it's solid tappets for me!!!

Re: Tappets and wear

Posted: 20 Aug 2016, 17:55
by silverbullet
Cam followers are (mechanically) very hard indeed, far harder than the cam which acts on them. I have only seen a degree of dishing on the contact face. On my first DG I taped over the oil holes and put them on our surface grinder to flash a few thou off them, to run on a new cam without risk of spoiling the lobes.
Unfortunately all the new followera dont aeem to be as good quality or as consistent as the OEM supplied ones.
If you do change to solid ones, be aware that the cam is not the same profile as a hydraulic so there may be problems down the line.