dkrevs
01-05-2010, 01:17
Friend of mine has a problem. He has a valver with F7P block honed and stroked to F7R size. He brought it like that. Car was really fast. In fact it was as quick as a 182 Clio.
What he didn't know is that cam timing was out of order. Mechanic did a service on his car and he also replaced a timing belt. He normally aligned timing belt marks with those on camshaft sprocket and marks on valve cover(everything was done as it should be). When they started the motor inlet valves were hitting pistons slightly. That should be due very skimmed head(nobody knows exact figures), which means high CR. They made larger "holes" for inlet valves. But car didn't go as good as before. Now engine has altered inlet cam by one teeth. It goes a bit better than it went after service was done, but still not as it was before service.
I know that this is not a lot of information but can anyone tell how much do they alter cam timing if engine is tuned(I know this vary from setup to setup but anyway how much...)? This is for now the main reason for car not being fast as it should. Any other idea? How far can we alter cams(stock pulleys)?
PS: Lets say that cams are stock Williams or Valver, they may be uprated but very little chances of that. Engine is in very good condition.
What he didn't know is that cam timing was out of order. Mechanic did a service on his car and he also replaced a timing belt. He normally aligned timing belt marks with those on camshaft sprocket and marks on valve cover(everything was done as it should be). When they started the motor inlet valves were hitting pistons slightly. That should be due very skimmed head(nobody knows exact figures), which means high CR. They made larger "holes" for inlet valves. But car didn't go as good as before. Now engine has altered inlet cam by one teeth. It goes a bit better than it went after service was done, but still not as it was before service.
I know that this is not a lot of information but can anyone tell how much do they alter cam timing if engine is tuned(I know this vary from setup to setup but anyway how much...)? This is for now the main reason for car not being fast as it should. Any other idea? How far can we alter cams(stock pulleys)?
PS: Lets say that cams are stock Williams or Valver, they may be uprated but very little chances of that. Engine is in very good condition.