Regular readers of this Forum will recognize that I have frequently posted about problems with this valve sticking on my Apine. Here are two previous threads where I have posted lots of thoughts on the subject:
http://www.sunbeamalpine.org/forum/showthread.php?t=20023
http://www.sunbeamalpine.org/forum/showthread.php?t=16416
The thread 20023 even includes a photo of the stuck valve. I have long been puzzled as to why I seem to have more problems with this valve than most Alpine owners. Part of it may be due to the fact that I probably drive my Alpine more miles than most. On my 7000 mile 2011 trip I had to remove and unstick the valve approximately every 800-1000 miles.
But on my recent 7500 mile trip it only stuck once! I think I now understand. Each time the valve has stuck, when I removed it and checked its operation it was "sticky". A couple pushes on the end of the piston and a little wiping and it was good to go. Each time I thought the stickiness felt like there was grit in the bore. It was not like the piston got hung up on one worn edge.
I have now come to believe the actual cause was GRIT or Dirt in the oil. Now, several oil changes and filter changes later, the problem is almost gone. When I rebuilt the motor in 2008, after receiving the block back from the machine shop I DID thoroughly clean it, inside and out- with solvent and then with soap and water as suggested by the machine shop. I was careful to fully clean the water passages as well. But during discussions with my buddy, Bob, while on my recent trip I came to realize I probably did not blow out the oil gallery! I now suspect that all, or most, of my OPV problems were due to a small amount of dirt in the oil passages. The oil in my engine rarely looked dirty, but I now suspect that a few grains of dirt would get into the bore of the OPV and cause the sticking. I hope a few more oil and filter changes will eliminate the problem totally.
If anyone else has a similar problem, I suggest you remove the valve and see if it seems to be sticking with a "gritty" feel to its motion when first removed. If so change your oil and filter.
Tom
http://www.sunbeamalpine.org/forum/showthread.php?t=20023
http://www.sunbeamalpine.org/forum/showthread.php?t=16416
The thread 20023 even includes a photo of the stuck valve. I have long been puzzled as to why I seem to have more problems with this valve than most Alpine owners. Part of it may be due to the fact that I probably drive my Alpine more miles than most. On my 7000 mile 2011 trip I had to remove and unstick the valve approximately every 800-1000 miles.
But on my recent 7500 mile trip it only stuck once! I think I now understand. Each time the valve has stuck, when I removed it and checked its operation it was "sticky". A couple pushes on the end of the piston and a little wiping and it was good to go. Each time I thought the stickiness felt like there was grit in the bore. It was not like the piston got hung up on one worn edge.
I have now come to believe the actual cause was GRIT or Dirt in the oil. Now, several oil changes and filter changes later, the problem is almost gone. When I rebuilt the motor in 2008, after receiving the block back from the machine shop I DID thoroughly clean it, inside and out- with solvent and then with soap and water as suggested by the machine shop. I was careful to fully clean the water passages as well. But during discussions with my buddy, Bob, while on my recent trip I came to realize I probably did not blow out the oil gallery! I now suspect that all, or most, of my OPV problems were due to a small amount of dirt in the oil passages. The oil in my engine rarely looked dirty, but I now suspect that a few grains of dirt would get into the bore of the OPV and cause the sticking. I hope a few more oil and filter changes will eliminate the problem totally.
If anyone else has a similar problem, I suggest you remove the valve and see if it seems to be sticking with a "gritty" feel to its motion when first removed. If so change your oil and filter.
Tom