After the last situation of a vacuum leak and poor MPG I decided to install a vacuum guage. Here is what I have found: 62/ impala 327/300 idles at a steady 18 drops on hard accel to near 0 recovers to a cruise of 20 on decel it will raise to 24 I thought that the decel should read higher, and if memory is correct that means damaged rings or valves, but i thought the idle number would be lower. I have no visual signs of burnt oil or smoke when running other than a slight puff from one side of the dual exhaust when first strating up after sitting. However the #1 spark plug will be oil fouled after a few 1000 miles. The compression is equal accross all cylinders, but only the one plug fouls. Should i be concerend about the lower vacuum, is it most likely a valve seal or could it be rings?
Go with the chart Special Ed found and posted. Your engine is basically sound, just a bit tired. It could be a combination of things, but you may cure the plug-fouling with a quick valve seal job. Bob
I have never seen an engine drop to zero when accelerating at a "normal" pace with traffic. That tells me you are heavy footed, or the engine is ready for freshening. I think when the heads come off, you will find bad guides in that number one hole, and poor guides in the rest. If it runs OK, drive it. If you want it right, do it right, do it once.
Vacuum diagnosis will only get you so far...then you might need to do some checks with other diagnostic equipment. You could try putting new O rings on the valve stems, don't cost much to do it, but like they said if you want it perfect you probably need to rebuild the engine with a lot of new parts.
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