Join Date: Oct 2007
428 oil pressure problems
I recently rebuilt a 1969 428 CJ for a customer of mine. The reason for the rebuild was when he had the heads done at onther shop, the spring pressures and stem hights wer all over the place, also the lifters were not set correctly (factory hyd. adjustable), resulting in bent pushrods. Also the engine was rebuilt previously, but the block was not honed right, crappy pistons and rings, and the rings never sealed up. So he brought it to us. We completely rebuilt the cylinder heads, new valves, springs, seals, seats, guides. We also re-honed the block, (already .030), reconned the rods with new bolts, cranks was fine. Installed new cam bearings and frost plugs. Oiling mods were already done to the block. We did not put the restrictors in the heads though. Also a larger 427 oil filter adapter was installed, matching up to the already opened up holes in the block.
So anyways, we put the motor back together. Everything was spotless! Hot tanked and scrubbed. Drill primed the engine on the stand(m57hv pump), had good oil pressure like 68 lbs.
I went to the guys place to break the cam in for him. After about ten minutes of run time, I noticed a decrease in oil pressure. (New autometer mechanical gauge). Eventually at idle it had only 10 psi. The next day, I brought my gauge out, and verified that his gauge was reading correctly. I pulled the pan, put another new oil pump in it, started it back up. It had about 25 lbs at this point. Got late had to get some sleep.
Next morning he called back, and stated that the engine had a knock. He hadnt driven the car, he just started it to check his oil pressure. I went out, pulled the pan and there was aluminum/copper shaving in pan. Pulled all the main caps, all the main bearings looked good. We decided the customer should pull the motor.
A few days later, he borugh the motor beck in to my shop. I disassembled it to see what the heck was going on. Copper was coming for a rod bearing, aluminum was coming from the trashed cam bearings. The bearings were smeared, could hardly get cam out of the block. Sent the cam bearings back to durabond for evaluation. As figured, they gave me the runaround.
So the entire motor was once again disassembled, heads disassemble, everything cleaned once again. I had to have the crank turned at this point. Also we put new H beam rods in it, the customer wanted these. Rebalanced the whole works. All new bearings, but this time I used Clevite HP cam bearings. Put new cam and lifters in (hyd. comp about 530 lift) as well. Once again everything went together well, all clearances verified. Drill primed the engine again, about 68 psi on yet another new oil pump.
Went to customers agin the do initial fire on engine and cam break in. Everthing went well this time...or so I thought. Went out next dar, he said there was noisy lifter. Re adjusted all valves, still noisy. Got it narrowed down to which one it was, and noticed the adjusting screw on the rocker was down further than the rest. Had a lobe fail on break in I guess. Also once again the oil pressure was dangerously low!
I don't know what I am missing. We have built alot of engines, have never seen anything like this. At this point, I am out of ideas!
To answer some questions you may ask...
Yes, cam bearing are installed properly.
Yes, drainback shields in heads are installed
Yes, I made sure the blockoff plugs in the lifter valley are romoved blow the others for hydraulic cam
Stock pan with windage tray
New heavy duty oil pump shaft
The only things that have really changed as far as parts changes (besides the obvious hard parts) form before he brough it in to me (previously, before I touched it, it had good oil pressure, the reason he brough it in it had bent pushrods, wiped cam, etc) were:
427 oil filter adapter
The only thing I noticed with the cams I put in it were the journals (not lobes) have a groove machined in them, the one I pulled out the first time was a speed pro and did not have these grooves.
Any help would be so appreciated guys!