Hello Ben,
In the early stages worn valve guides may not effect compression. Some times old age hardened valve seals will pop off worn valve guides. If you remove the valve cover you can shine a flashlight in the valve springs to see if all the valve seals are in place. Next remove the spark plugs. Check to see if you have any crusty oil deposites on the spark plugs. If you have hard crusty deposites on any spark plugs then you have worn intake guides or a piston ring problem. If you find no crusty oil deposites. You probably have worn exhaust guides. Worn exhaust guides drip oil into the exhaust port and the oil burns off in the exhaust. Worn intake guides drips oil into the intake where it burns in the cylinders and leaves oil deposites on the plugs.
Eventually worn guides will also cause valves to wear and compression will fall off. Often during or before this time the old valve seals dislodge from their worn guides.
Some other things to consider:
A ruptured modulator diaphram in the transmission will cause transmission fluid consumption, white smoke and oily deposites on number six spark plug.
A leaky fuel starting solenoid valve on the intake can ge checked by temporarily pluging its fuel source.
Keep us up to date. Good luck!
Joe Alexander
Blacklick, Ohio
