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Most of us have heard of how engines with flat tappet camshafts have had increased failures in the past 15-20 years. There are a bunch of opinions on what is to blame but so far, I have seen no 100% smoking gun on the exact cause. The potential causes are numerous.
Reduced zinc in oil.
Camshafts and lifters made with softer metal than before.
Lower quality machining from Chinese factories.
Lifters that don't spin in the bores.
Valvesprings too stiff.
Improper break in.
Etc, etc....
While all of those things may be true AND if you have more than one of those situations together, the chances of a failure seem to grow exponentially.
I know that there are several threads on this site covering this topic, I was hoping to expand a bit on what has already been mentioned.
Being one with a curious mind, I wonder about a few things...
We have been told that with flat tappet systems, the lifters mate to the lobes. How? I've read that they establish a pattern to each other and that to swap in another lifter, it must be NEW and that the "break in" starts all over for that lifter.
Why? Has anyone ever published pictures and measurements of the actual wear patterns?
Who remembers Jim LaRoy/IQ52 ? he mentioned before that he has swapped lifters around and even reused them in dyno testing and had no failures. How is this possible?
I remember a buddy going out to the junkyard and pulling a couple lifters from an engine to swap into his engine. He had a couple sticky lifters in an old beater. I don't recall any future troubles that he had.
I did the same to a stock 318 years ago.
Reduced zinc in oil.
Camshafts and lifters made with softer metal than before.
Lower quality machining from Chinese factories.
Lifters that don't spin in the bores.
Valvesprings too stiff.
Improper break in.
Etc, etc....
While all of those things may be true AND if you have more than one of those situations together, the chances of a failure seem to grow exponentially.
I know that there are several threads on this site covering this topic, I was hoping to expand a bit on what has already been mentioned.
Being one with a curious mind, I wonder about a few things...
We have been told that with flat tappet systems, the lifters mate to the lobes. How? I've read that they establish a pattern to each other and that to swap in another lifter, it must be NEW and that the "break in" starts all over for that lifter.
Why? Has anyone ever published pictures and measurements of the actual wear patterns?
Who remembers Jim LaRoy/IQ52 ? he mentioned before that he has swapped lifters around and even reused them in dyno testing and had no failures. How is this possible?
I remember a buddy going out to the junkyard and pulling a couple lifters from an engine to swap into his engine. He had a couple sticky lifters in an old beater. I don't recall any future troubles that he had.
I did the same to a stock 318 years ago.
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