No, the Piltdown man is not evidence for evolution. But it is not evidence against it either.
There have been all sorts of frauds committed for Christianity. The number of holy relics alone in Europe is truly incredible. It was Mark Twain that first made me aware of this:
"The main point of interest about the cathedral is the little Chapel of St. John the Baptist. They only allow women to enter it on one day in the year, on account of the animosity they still cherish against the sex because of the murder of the Saint to gratify a caprice of Herodias. In this Chapel is a marble chest, in which, they told us, were the ashes of St. John; and around it was wound a chain, which, they said, had confined him when he was in prison. We did not desire to disbelieve these statements, and yet we could not feel certain that they were correct-- partly because we could have broken that chain, and so could St. John, and partly because we had seen St. John's ashes before, in another church. We could not bring ourselves to think St. John had two sets of ashes.
They also showed us a portrait of the Madonna which was painted by St. Luke, and it did not look half as old and smoky as some of the pictures by Rubens. We could not help admiring the Apostle's modesty in never once mentioning in his writings that he could paint.
But isn't this relic matter a little overdone? We find a piece of the true cross in every old church we go into, and some of the nails that held it together. I would not like to be positive, but I think we have seen as much as a keg of these nails. Then there is the crown of thorns; they have part of one in Sainte Chapelle, in Paris, and part of one also in Notre Dame. And as for bones of St. Denis, I feel certain we have seen enough of them to duplicate him if necessary."
The Innocents Abroad by Mark Twain: Chapter 17 (continued) - The Literature Page
The sheer number of relics guarantee that at least some of them are fakes. Does that disprove the Jesus story? You are not thinking rationally. If fakes disprove an idea then Christianity is disproven. Piltdown man was never well accepted. The British liked him just because he was found there, but scientists in other countries were not so quick to drink the Kool-Aid.
Meanwhile I am waiting to hear more about Java man.