I've got a 7A head in the machine shop at the moment which is being rebuilt with new valve guides. The head is eventually going on my AAN and has already had the required mods carried out to fit (hall sensor bracket, water manifold machining etc).
The problem, (if indeed it is actually a problem) is that the new valve guides that I have are different from the original ones in the 7A head. Both guides are the same size in both diameter and overall height but if you look at the picture below you'll see that the new guide (on the left) has a collar which I believe should sit against the surface of the head once it's pushed in. The thing is that doing this will make the guide sit approximately 3mm further down into the cylinder than the original guides which have been removed. I've marked with an arrow on the picture the point where the original guide was seated in the head. For reference the old guides stick out approximately 11mm from the top of the head (cam end) where as the new ones would be 8mm if fitted down to the collar.
Are these guides the correct ones? Should they be fitted so that the collar touches the head? And is that 3mm going to cause any problems? Any help would be much appreciated!!
The problem, (if indeed it is actually a problem) is that the new valve guides that I have are different from the original ones in the 7A head. Both guides are the same size in both diameter and overall height but if you look at the picture below you'll see that the new guide (on the left) has a collar which I believe should sit against the surface of the head once it's pushed in. The thing is that doing this will make the guide sit approximately 3mm further down into the cylinder than the original guides which have been removed. I've marked with an arrow on the picture the point where the original guide was seated in the head. For reference the old guides stick out approximately 11mm from the top of the head (cam end) where as the new ones would be 8mm if fitted down to the collar.
Are these guides the correct ones? Should they be fitted so that the collar touches the head? And is that 3mm going to cause any problems? Any help would be much appreciated!!
Comment