QuestionHi. I have a 1998 Suzuki Savage and am trying to adjust the valves but have to set TDC first. The TDC thing is a little messed up, pls help advise.
I know that when the piston at TDC, the intake and exhaust valves have a little bit of play. But mine at any point where the piston is at the top, the valves are all loose.
1. To find TDC: If we continue to turn past the TDC, clockwise, which valves will go down first, intake and exhaust? This is the only way I understand if I get the TDC right, because the valves seem to be all loose.
2. When the intake valves have a play (say probably at TDC), with my fingers I can raise the valve tips up a bit, but I feel a little bit of resistance at first and then a sudden click when they seem to become loose and go past a certain sticky (tight) point and come to a rest. When I push them down I feel the same reaction. The valves seem to rise or go lower than normal. Is this a sign of something broken?
What can I do to just set the TDC and the valves now just to get by?
Thanks
Lou
AnswerLou, a 4 stroke engine cycles between TDC Compression and TDC overlap, because it requires 2 revolutions to complete the necessary 4 strokes... intake, compression, firing, exhaust.
With the piston at TDC overlap, the exhaust valves are just closing, while the intakes are just opening.
At TDC compression, all valves are closed and should have the required clearances, specified by Suzuki.
If you have loose valves at BOTH TDC functions, then the valves were adjusted at the TDC overlap stroke, which will result in VERY LOOSE valves at TDC compression stroke.
At no time during any cycle of the engine, should the valve clearances be more than the specified clearances.
If you can move the valve stems up/down with finger pressure at TDC compression, they are probably bent from either inhaling something solid or if the engine was apart and camshaft timing was not done correctly on the reassembly and there was piston/valve interference damage when the engine was first kicked over. A compression test will tell you whether it is damaged or not. I would imagine that the compression values should be around 175 psi, normally.
I'm not familiar with that engine, but big singles often have a decompression function to aid in easier turnover for the starter motor. When activated, a valve will be held open to lower compression momentarily, until the engine begins to spin over in earnest, then the decompression function ceases to hold valves open and full compression is regained.
I just found this link for you....
http://suzukisavage.com/cgi-bin/YaBB.pl?board=tech;action=display;num=1169356966
Bill Silver
