Cylinder health opinion...
Ok...compression check yielded the following:
Cylinders 1-7: 155-160 psi
Cylinder 8: 125 psi
If my math was right, Cylinder 8 is around 20% down on compression.
The car leaks virtually no oil, except a drop or two when I run it hard or drive it for a long time...otherwise, none. It burns no oil whatsoever. It's only about 300 miles away from an oil change right now and it's STILL above the full line on the dipstick.
So my thinking was....does this sound like something with the valves? I'm thinking possibly I have a ground-down exhaust lobe on the cam for my #8 cylinder, which is causing the valve to act up. That's lifted from my Haynes manual...but I'm thinking, if the lobe is ground DOWN, shouldn't it make the valve open LESS, and not MORE, thereby not causing a loss of compression?
My idle rpms are steady at around 600-650, and even though the rpms don't fluctuate, the engine idles rough. Shakes quite a bit. It's got new plugs, decent wires, new Blaster TFI coil, new MSD cap and rotor, BRAND NEW 19 lb/hr Motorsport Injectors, various new sensors including coolant temp, TPS, and IAC.
So, opinions?? What could be wrong? I plan on building this motor so I'm hoping it's just the cam...I'd replace it anyways!
Thanks all.
__________________
'91 Mustang GT 5.0 AOD Daily Driver
Current stats: NEW 302 short block, E-303 cam (@.050, 220/220, .498/.498, 110 degrees), 1.6 roller rockers, Performer RPM heads (aluminum, 1.9/1.6, 60cc chambers), Cobra intake, Granatelli 75mm MAF, Billet AFPR, Equal-Length Shorty Headers, Off-Road X Pipe, Flowmasters, 4.10 POSI
13.73 at 103.8, ~2.2 60'
|