Installed a create 454 and after driving a couple thousand miles, I hear what seems to be lifter noise when driving at speeds over 65MPH (3400 RPM). When I come to a stop, the noise quits after 15-20 seconds. Also, the oil pressure guage flucuates about 8PSI when slowing or speeding up. Oil pressure is 65 at startup the drops to around 55 after warmup. Any suggestions?
I believe you mean "crate"motor. I see no problems with the oil pressure fluctuation. Go to your source of the crate motor let them listen and report back. Perhaps they will tell you you did not follow correct cam break-in procedures.
Thanks for the response. Did not re-check my spelling and left the extra character.
3400 rpm at 65 mph?
Wow.
Tell us a bit more about your configuration with regards to the block vintage and the valve train. For example, does this crate motor have a hydraulic flat tappet, mechanical or roller lifters???
What oil are you using?
How did you break the motor in?
What’s your block/coolant temp when the engine is warm?
Is this a steady cruise to stop or are you blasting forward then coming to a stop? This is a question ralated to pump starvation. Do you know if you have a windage tray in the pan?
Just some off the head questions. You will need to provide a lot more info for anyone to diagnose from a distance…
Block vintage is 1970-90. COMP cam components with flat tappet lifters.
Oil is Castrol 20w-50.
Don’t remember all the details about the break-in but drove very slow and easy. Did not abuse the engine.
Block temp: On cold days it stays at 180. On warm days it can get to 205 at a stop light. Driving on warm days it stays about 190-195.
I can hear the lifters while driving at 65 or over and I always do a slow stop. Noise will stop after 15 seconds or so.
No windage tray.
Since install of engine, I have 2-3 thousand miles. Noise did not start for about 2K miles.
Might is be as simple of adjusting the lifters?
Thanks for the reply.
OK, sounds like a Mark IV block then. Lifter noise at speed is usually a sign of excessive clearance and they’re floating. Noise at idle after running at speed is more like oil starvation although your pressure numbers are right up there.
The big question now is, are they hydraulic or mechanical (solid) lifters. If they are hydraulic, I fear you may have some cam lobe wear. If they are mechanical lifters, it may just be a matter of adjustment. Super easy to check on your motor. Pop the plugs to make turning the engine by hand easier and then pop off the valve covers.
IMO, not the best break-in method for those kind of lifters and cam. They like to see something more like 2000-2500 rpm sustained for at least 20 minutes during run-in. You never want them to sit at idle for any time during this initial break-in since the break-in lube will wear off fast and this can lead to premature lobe/lifter wear. What did the break-in directions from the engine builder state?
They are hydralic. With the 373 rear end, driving slow (30-40mph) would have acheived 2000-2500 RPM. Book states: Start engine and run at 1500 RPM for 30 minutes then drive at 30mph and periodically accelerate to 50 mph and repeat. This is very close to what I remember we did. Think I should try and adjust the lifters as a first try?
Hmmm, I’m not big on their method. It’s driveline dependant as you well know. Although, the second part is mainly to seat the rings and all you need to do is load them up appropriately. In your case, they got loaded a bit more than most 
I’m curious about one more thing; why did you choose to run 20W-50? I wouldn’t run anything thicker than 10W30 in my big blocks, especially when they’re fresh rebuilds. I typically run straight 30W in the summer. Also, is that what you ran during the break-in?
It can’t hurt to check lifter clearance. Are you comfortable with the process?
I ran 10w-30 for breakin. My brother-in-law told me to run the 20w-50 some time back. Maybe I will switch back. I can work thru the lifter process. I appreciate your comments. Thanks.
Yeah, I would switch back. That’s some thick oil to be running on a brand new motor where the clearances are nice and tight. Most of the time, people run that kind of viscosity on a tired motor to make up for excessive clearances or if they are running in really extreme temperatures for extended periods.
It’s also a 30pt spread- those viscosity improvers are not oil and so do nothing to lubricate the motor. I want as much lubrication as possible. You’re starting out with a thick oil and it’s not thinning much at temp either. That could be a significant contributor to your problem.
Good luck!