I currently have plastic oil line to my guage(soon to be copper) There are air bubbles in the line. will that effect the accuracy of the reading?
The air can be purged but it is messy. The worst that will happen with the bubbles in the line is that you get an average of the current pressure - a dampening of spikes that happen - but the gauge will respond to changes in oil pressure fast enough that you will see anything of importance. To rid the line of all air you simple start the engine and while it is idling you loosen the line at the gauge and let the oil and air escape until it is purged. Then you retighten the line and wipe up all the oil. (I did say it was messy)
Bob. It's easy to get them out. Just diconnect the hose from the back of the gauge and suck on it as hard as you can. When the last bubble comes out just stick it back on there fast.
I'm using 10-40 but i much prefer 5-30, it doesn't have the nutty after taste that the 10-40 has. I am not a fan of that. I prefer the fruitier mouth of the 5-30 so I guess i will just leave it til i replace the palstic line with copper