Compression Test Results

[Golf]

All cylinders between 145-150psi - except 7... Cyl #7 at 120psi.  10% would be no lower than 135. 

White smoke from driver (cyl 7 side) tail pipe at idle - low to nonexistent oil pressure at idle after warm up.

Where to start?

[VileZambonie]

#1 post the details on your truck, #2 what are you trying to determine by doing a compression test? #3 How are you checking your oil pressure, is there a noise issue? #4 Tell us what your concern is, what is it you are trying to determine or do?

[Golf]

84 c10 305... Saw smoke in exhaust wanted to see if rings and I was changing plugs anyway. Truck was free but didn't want to sink cash in motor if it's done for

[jetman]

Sounds like the numbers on my truck's 305.  In spite of the condition, I drive it almost every day making deliveries, will be driving it till it drops. 
Then organize a re-ring,  bearing and/or crank kit and back on the road with her.

[Golf]

Truck runs really well but aftermarket oil pressure gauge showing next to 0psi at idle which is why I did compression test. Has plenty when cold, instantly jumps when given throttle. Heard maybe try a different weight oil and some marvel mystery oil

[Jerr-conn]

Golf--- I have a similar oil pressure problem with a after market mechanical oil gauge. What brand name Gauge do you have? I'li have to check my gauge because right now I don't know what name
Brand mine is. Maybe the same.

[ChevyK20BBC]

Ive read before on some engines oil pressure can be as low as 5- 10 psi at idle, as long as it comes up with RPMs. Also Adding some Lucas oil stabilizer will bring the pressure up quite a bit. But that may be just masking the problem. Another thing to check could be a defective or clogged oil filter could give you a low pressure reading, or a worn oil pump,clogged pickup screen, bypass valve hanging open?