| I just finished a major top-end overhaul, porting, and upgrade. After reassembling the top end of my motor, I followed the JWT cam break in procedure. Lifter tick all but disappeared after 3 minutes. I then changed my oil and removed a good amount of metal particles. With fresh Royal Purple in my oil pan, I started my motor up again. Then, I began fiddling with Nistune to account for my new 370cc injectors (upgraded from 270cc's). Suddenly, my engine began loping horribly at idle. RPMs would vary between 400 and 1500. When this happened, my alternator voltage would fall dramatically and the car would almost stall. After 25 minutes, I realized that the tune wasn't a problem. My real problem was a barely-connected coil pack connector. The disconnected cylinder had a good amount of gasoline in it. Fixed that. For the 2nd time, I changed the oil (to remove any gasoline). This time, very few metal particles were left in the oil. Soon after starting the engine again, a horrible knocking noise developed at 1900 rpm. The knocking was coming from around the middle of the passenger side header. I pulled off the timing belt and valve covers only to discover the exhaust lifter (all are new ITM brand lifters) second from the rear on the passenger side was "squishy". It and 4 others on that side were filled with air. I know that all of the lifters were bled down before install. None were originally squishy. Some of the PS and DS intake lifters contained trapped air as well. I still need to check the DS exhaust. There is oil reaching the valve train, however I have no idea about oil pressure in that area. All I know is my oil pressure gauge reads 50+ psi at 2000 rpm. Pools of oil exist in the heads and all camshaft journals were filled with oil when the caps were removed. Here are my questions- What caused air to enter these lifters? Can our lifters purge themselves of air automatically? Is a substantial amount of oil pressure required in the heads to keep the lifters from filling with air? Severe lifter tick returned about 30 minutes after the initial start. Did a small bit of metal become lodged in a block oil restrictor? Would one blocked restrictor affect both heads? Are the ITM lifters just not designed well? I have the motor broken down (to the tops of the heads) at the moment and do not want to go through this process again. Should I install new OEM lifters, reassemble the engine, use my original 270cc injectors to be safe, and hope that the problem doesn't return? Should I pull my heads again and verify that the oil restrictors in the block aren't clogged? How common are clogged block oil restrictors? If there was only a temporary loss of oil pressure to the heads and air entered the lifters, will I be safe if I just install bled OEMs? What would you do? I don't want to repeat this repair work. I apologize for the long story and really appreciate any insight!
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