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My daily driver's B20 always was a bit noisy. The last 1000 miles however, it got progressively worse. Especially on (cold) startup, there was a very clear nocking sound. It sounded exactly (imo) like an eaten big end bearing.
To prevent letting the engine ruin itself beyond repair, I decided to lift the engine out and have a look in side. The big end and main bearings looked ok, but the fiber timing gear had lost some of its teeth.
This has probably been causing the nocking sound, although I still dont see how it could sound so much like the low pitch sound of a big end bearing. Any way, nothing serious so far realy. Things got more serious when I took out the lifters and (K)cam, which I had put in about 10k miles ago. On the last valve clearance check, I noticed #1 exhaust had 3 mm less lift compared to the other 7 valve, so I already knew something was wrong there. Opening up the engine confirmed this: the #1 exhaust lobe was rounded of quite a bit... The cause of this is (imo) the according lifter: the bottom surface is full of 'craters'.
When I put in the cam 10k miles ago, I used new lifters. The above pic shows the #1 lifter, but all the other lifters also had some pitting on the surface. Some bearely visible, some very clear (but not to the extend of the #1 lifter).
Now, my question ofcourse is what the cuase of this is. The broken teeth on the fiber gear is a relative common failure, but the surface of the lifter is an other story. How can this happen in 10k miles of normal driving? Could it be that the lifters have just been crap? (and therefor also ruined my new cam shaft) I'm asking since I have a brand new set of lifters on the shelf (of the same supplier) of which I'm not sure I should use them.
cheers, ben
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P131, '65, B20B+M47+DGV. P131, '69, B20E+AW71L+LSD. (www.tinustechniek.tk)
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