Posted By: Hemi ragtop
HEMI intake gasket leak update - 05/18/14 08:15 PM
Just to review, I built a 66 Coronet convertible and installed a 540 ci (4.5" stroke) HEMI with 727 and Dana w/3.54 gear. The car was built to drive and last summer I put it on several trips, through the mountains here in East TN and some freeway 100+ mile trips to cruise ins in nearby towns etc. Although the plugs always read an even light brown and the pipes would actually "chalk up" on these trips, the engine was using an alarming amount of oil, several quarts between 500 mile changes (I am a little anal about oil changes in a new engine). I checked everything, compression tests, leak downs etc. and all was fine. After posting on here and getting several replies to check the intake gaskets, I did. What I found shocked me. The gaskets (brand name paper composition) were glued to the ports with silicone and sealed tight as could be. However, the bottom of the gaskets were SATURATED with oil! You could squeeze them and oil would POUR out of the fiber material! This was causing the engine to consume over FOUR QUARTS of oil in 500 miles. Taking suggestions from this forum, I cleaned everything, checked for proper alignment (feeler gauges showed perfect fit) and installed Proformance gaskets, following the instructions with silicone ONLY on the end rails running slightly up the head. I finally have about 300 miles of driving and pulled the carbs today to check the ports (running a Stage V intake allows a clear view of the ports). They are clean and dry! I have been running Seafoam in the fuel to help clean the deposits that I know the oil left in the chambers and it has already removed most of the carbon built up on the intake valves and totally cleaned the ports. Just to be sure, I ran a clean rag all the way into each port with a set of surgery forcips. The rag was clean in each port, so my eyes were not fooling me. If I had it to do over, I would build the ENTIRE engine in PROFORMANCE gaskets! I am looking forward to putting a lot of fun miles on the car this summer with the top down and not worrying about how much oil is being sucked into the intake.
