I have a 1969 chevy c-10 with a 400 small block in it, unknown miles. It ran fine, wouldn't really smoke the tires but ran fine, before a friend and I went through it and replaced some gaskets. It barely runs now, drives ok but won't hold an idle long and idles rough. I checked the compression and two pistons register very low compression. Someone told me the piston rings were probably bad. Recently someone said that if the lifters didn't get tightened right this could also cause the compression to be low. Anyone have any ideas? Does anyone know how tight the lifters are suppose to be tightened? Any suggestions would be greatly appreciated. Thanks.
Well, for the lifters if you have hydraulic lifters you can adjust them a couple of ways but I have had good luck with the EOIC method. That is exhaust opening and intake closing. Watch the rocker arms and when the exhaust valve just starts to open, -rocker just starting down- adjust the intake valve by spinning the pushrod until you feel it just begin to get resistance, then give it 1/2 -3/4 turn more and it should be set. You need to turn motor over -by hand preferably- until the rocker gets where you want them. To adjust the exhaust turn motor until the intake valve opens all the way and just starts to close- rocker all the way down and just starting to come up-
then you can adjust the exhaust valve. You can go through and do all intake then exhaust or you can work cylinder by cylinder. Be careful when you do this as it takes a light touch sometimes to feel when the rod gets resistance, try this part a few times till you get the feel of it. If you are unsure about this you can adjust with motor running but is very messy. With valve cover off let motor idle and back off rocker nut until it starts to tap and then tighten till tapping stops and give 1/2 - 3/4 turn more and you should be set. : Shock: