I am pretty baffled by my current situation with this motor. I have a new 383 that is using oil at the rate of about 1 qt every 100 miles. And it struggles to idle. It is pretty mild with a Lingenfelter 213/219 duration camshaft on a 214 centerline and brand new vortec heads with about 9 to 1 compression, so I am thinking it should idle almost like a stocker.
1. It only pulls about 15 lbs of vacum at idle. I thought perhaps it had an internal intake leak but if I pull the PVC and idle it there is no air being sucked into the valve cover filler. I used a strip of paper by the hole to test it. Yes I have checked everywhere for an external vacum leak and cannot find one.
2. You never see it smoking which is puzzling, you would think it would look like a mosquito fogger using that much oil.
3. After about 1000 miles The plugs were nasty oil fouled and in every cylinder not just one. in addition they were all fouled only on one side of the electrode, the other side looked pretty clean. I figured valve seals or valves loose in the guides so today I replaced the valve seals on one side of the motor but I honestly didnt see anything wrong with the ones I took off so I will be surprised if it makes a difference. The valves did not seem loose in the guides.
4. I have made sure the PVC is working properly, and I see no oil in the PVC hose or the manifold. I am running stock GM valve covers with baffles.
5. Leakdown test only shows about 6% leakdown in the two cylinders I tested, and they were two with the nastiest looking plugs.
6. It has 180lbs of compression dead on after 3 pumps in every cylinder.
Suggestions anyone?
Thanks
Roy