superbee_68
Well-Known Member
Working on a 66 block, 383, 906 heads. Block had the usual cam bearing and freeze plugs swapped along with getting cleaned. New pistons, new rings, new bearings, balanced rotating assembly, full head job. The heads were treated to new valve guides, hardened exhaust seats, a valve job, and a clean up of the surface for good sealing. All the stem heights and spring pressures were checked prior to assembly. Cam is a mild comp with new lifters. Standard push-rods and factory rockers. The machine shop assembled the long block. Unfortunately the motor was broken in with open headers. I didn't want to do this but I had no choice, long story. I primed the engine prior to the cam break in and used Joe Gibbs break in oil. I had one strange set back before starting the motor. The high volume oil pump would not build pressure at first. Once I finally got a prime on the pump, the pressure spiked the pressure gauge and maxed it out. Soon there after I heard a ping and the pressure dropped. I figured the relief valve was stuck and came unstuck with pressure. Oil pressure while priming thereafter was good. We started the motor and 30 seconds in to the cam break in, lost oil pressure. Assuming it was the pump, I swapped the oil pump and re-fired the motor. Oil pressure was back and was good. Finished the cam break in, 25 minutes of elevated rpm, varying slightly. I took the first pump apart and found the pressure relief valve seized in its bore. Brand new parts can be bad right out of the box, who knew. I got exhaust put on the car shortly there after.
Once I have exhaust on the car, I can hear a lifter/rocker noise coming from the right bank. Left bank is silent. I threw the car up on the trailer and drove it to my machine shop. They were afraid a cam lobe had been wiped during break in. We pulled the valve cover and checked lift across the whole bank. Exhaust all measured the same, as well as the intake for lift so no wiped cam lobe. We did notice the #2 exhaust seemed very loose. Since the rockers are not adjustable, we started to suspect incorrect push-rod length. After trying to rock all the rocker on the bank, we noticed the lifters on pretty much the whole bank were not pumped up.
So we found the problem, lifters are not pumping up. I still have the break in oil in the engine so the machine shop suggests changing the oil to 30 weight and letting the car idle for an extended period of time to get the lifter to pump up. I'm not so convinced this will fix the problem. I am also not convinced because the left bank seems silent. Granted, it only sounds like and appears to be one rocker making noise. Hughes performance thinks the oil holes in the lifters are clogged with trash and needs to be pulled and cleaned.
What do you guys think I should do? Can you pull a lifter to clean without pulling the intake, I have never tried but maybe with a magnet it could be done? Are the lifters bad? Did the huge spike in oil pressure from the initial prime damaged the lifters? I would love to hear ideas before I tear into it.
Thanks
Once I have exhaust on the car, I can hear a lifter/rocker noise coming from the right bank. Left bank is silent. I threw the car up on the trailer and drove it to my machine shop. They were afraid a cam lobe had been wiped during break in. We pulled the valve cover and checked lift across the whole bank. Exhaust all measured the same, as well as the intake for lift so no wiped cam lobe. We did notice the #2 exhaust seemed very loose. Since the rockers are not adjustable, we started to suspect incorrect push-rod length. After trying to rock all the rocker on the bank, we noticed the lifters on pretty much the whole bank were not pumped up.
So we found the problem, lifters are not pumping up. I still have the break in oil in the engine so the machine shop suggests changing the oil to 30 weight and letting the car idle for an extended period of time to get the lifter to pump up. I'm not so convinced this will fix the problem. I am also not convinced because the left bank seems silent. Granted, it only sounds like and appears to be one rocker making noise. Hughes performance thinks the oil holes in the lifters are clogged with trash and needs to be pulled and cleaned.
What do you guys think I should do? Can you pull a lifter to clean without pulling the intake, I have never tried but maybe with a magnet it could be done? Are the lifters bad? Did the huge spike in oil pressure from the initial prime damaged the lifters? I would love to hear ideas before I tear into it.
Thanks